Antifungal drugs

 

Introduction

According to basic difference fungi are classified as: Phycomycetes; Ascomycetes ; Basidiomycetes ; Dueteromycetes.

§   Human and fungi parasitic relationship result in fungal infection.

§   Fungal infections are common, not only as primary disease, but also secondary to therapy with oral antibiotics.

§   Individuals suffering from malignancy, diabetes mellitus and AIDS are more prone to develop fungal infection.

§   The mycotic infection are classified on the tissue level colonized:

(A)     Superficial mycosis                                       (B)Cutaneous mycosis

(C)      Subcutaneous mycosis                        (D)Systemic  mycosis

(E) Opportunistic mycosis

Fungi and Disease

Humans have a high level of innate immunity to fungi and most of the infections they cause are mild and self-limiting.

This resistance is due to:

• 1. The fatty acid content of the skin,
• 2. The pH of the skin, mucosal surfaces and body fluids,
• 3. Epithelial cell turnover,
• 4. Normal flora,
• 5. Transferrin,
• 6. Cilia of the respiratory tract.

When fungi do pass the resistance barriers of the human body and establish infections, the infections are classified according to the tissue levels initially colonized.

A. Superficial mycosis- infections limited to the outermost layers of the skin and hair.

Disease	Etiological Agent	Symptoms	Identification of Organism
Pityriasis versicolor	Malassezia furfur	hypopigmented macules	"Spaghetti and meatballs" appearance of organims in skin scrapings.
Tinea nigra	Exophiala werneckii	black macules	Black, 2-celled oval yeast in skin scrapings
Black piedra	Piedraia hortai	black nodule on hair shaft	black nodule on hair shaft composed of spore sacs and spores
White piedra	Trichosporom beigelii	creme-colored nodules on hair shaft	white nodule on hair shaft composed of mycelia that fragment into arthrospores

B. Cutaneous mycosis- infections that extend deeper into the epidermis, as well as invasive hair and nail diseases.

These diseases are restricted to the keritinized layers of the skin, hair, and nails. Unlike the superficial mycosis, host immun       - 2 -e responses may be evoked, resulting in pathologic changes expressed in the deeper layers of the skin. The organisms that cause these diseases are called dermatophytes. These diseases are often called ringworm or tinea. All the following diseases are causes by Microsporum (other images), Trichophyton, and Epidermophyton, which comprise 41 species.

Disease	Symptoms	Identification of organism
Tinea capitis	ringworm of scalp	presence/absence and shape of micro- and macroconidia in scrapings of lesion, KOH mount
Tinea corporis	ringworm of trunk, arms, legs	as similar above
Tinea manus	ringworm of hand	as similar above
Tinea cruris	ringworm of groin "jock itch"	as similar above
Tinea pedis	ringworm of foot "athlete's foot	as similar above
Tinea unguium	infection of nails	as similar above
Ectothrix	infection of hair shaft surface	mycelium and spores on hair shaft
Endothrix	infection of hair shaft interior	mycelium and spores in hair shaft

C. Subcutaneous mycosis- infections involve the dermis, subcutaneous tissues, muscle, and fascia. These infections are chronic and are initiated by trauma to the skin. These infections are difficult to treat and may require surgical intervention.
 

Disease	Etiological agent	Symptoms	ID of organism
Sporotrichosis	Sporothrix schenckii 1.     yeast 2.     mold	Nodules and ulcers along lymphatics and at site of inoculation	Yeast in tissue; mold at rm temp with "rosette pattern"
Chromoblastomycosis	Fonsecaea pedrosoi or compacta, Wangiella dermatitidis	warty nodules that progress to "cauliflower-like" appearance a inoculation site.	copper-colored spherical yeasts called "Medlar bodies" in tissue
Mycetoma	Pseudallescheria boydii, Madurella grisea or mycetomatis	draining sinus tracts at site of inoculation	white, brown, yellow or black granules in exudate that are fungal colonies

D. Systemic mycosis- infections that originate primarily in the lungs and may spread to many organ systems. These organisms are inherently virulent. All but Cryptococcus are dimorphic fungi.

Histoplasma capsulatum- Ohio and Mississippi river valleys, Yeast cells in tissue, Tuberculate macroconidia in mycelial phase.

Blastomyces dermatitidis- Ohio and Mississippi river valleys, Broad Base Budding yeast in tissue, Mycelia= microconidia

Coccidioides immitis- Southwestern US. Spherule in tissue, barrel-shaped Arthroconidia in mycelia phase.

Cryptococcus neoformans- Only yeast phase but unusual in that the cells are encapsulated as demonstrated by an India Ink stain (another image).

E. Opportunistic mycosis- infections of patients with immune deficiencies who would otherwise not be infected. Ex. AIDS, altered normal flora, diabetes mellitus, immunosuppressive therapy, malignancy.

Antifungal Agents :-

These are drugs used for superficial and deep (systemic ) fungal infections.

A disquietening trend after 1950s has been the emergence of more siniter type of fungal infections which are , to a large extent, iatrogenic. These are associated with the use of broad spectrum antibiotics, corticosteroides, cytotoxic drugs, ind welling catheters and implants and emergence of AIDS .As a result of breakdown of host defence mechanisms , saprophytic fungi easily invade living tissue.

Many topical antifungals have been available since the antiseptic era. Two important antibiotics amphotericin B-to deal with systemic mycosis and griseofulvin to supplement attack on dermatophytes were introduced around 1950. Antifungal property of flucytosine was noted in 1970, but it could serve only as a companion drug to amphotericin. The development of imidazoles in the mild  1970s and triazoles in 1980 has been an advancement. Introduction of ketoconazole into medical practice in the early 1970s initiated a new era of antifungal therapy. The availability of an orally absorbed drug with low toxicity permitted outpatient therapy of deep mycosis , long term prophylaxis of immunocompromised patients and treatment of low-morbidity conditions. Some new compounds like terbinafine have been added recently .

CLASSFICATION OF ANTIFUNGAL AGENTS

1.     Antibiotics:

A.   Polyenes : Amphotericin B (AMB), Nystatin, Hamycin, Natamycin

Amphotericin B

Mechanism of action: binds to sterols present in the plasma membrane

more selective for ergosterol = major fungal sterol forms cytotoxic pore

broadest spectrum of any antifungal

Absorption: very poor

given slowly IV as liposome suspension, or used topically

given orally for GI fungi, but as such is really acting ‘topically’

Uses:

Initial drug of choice for life-threatening systemic infections

Invasive Aspergillus (30% survival); used with itraconazole

Cryptococcal meningitis; used with flucytosine  (alternative:      fluconazole)

Rapidly developing Histoplasmosis

some limited use for cutaneous (dermatophytic) infections

or mucocutaneous infections

Adverse effects: fairly toxic [some binding to mammalian membranes; effects reduced via use of liposome delivery]

- fever and chills; vomiting; muscle spasms; modest hypotension (nearly 100% but treatable; small test dose usually given to assess reactions)

- renal impairment (near 80%)

- hypokalemia (=  reduced serum K)

Nystatin :

Mechanism of action: same as for Amphotericin B

Absorption: extremely poor

Uses: much too toxic for systemic (parental) use  

® used only topically

local (dermal), oropharyngeal, GI and vaginal candidiasis only

[other than its nasty, bitter taste, adverse effects are uncommon]

B.   Heterocyclic benzofuran : Griseofulvin.

Griseofulvin :

Mechanism of action: proposed to inhibit microtubules

blocks fungal mitosis, therefore is fungistatic

also binds keratin

Absorption: poor - very insoluble

orally administered in a microcrystalline form

(improved when taken with fatty foods)

Uses:

Systemic uses for dermatophytosis (eg. skin and, esp. nail infections, though

for the latter terbinafine is preferred), requiring extended treatments [after

or sometimes with treatment with triazoles][also highly effective against

Athlete’s foot and ringworm]

              

Adverse effects: (low incidence)

- allergic syndrome (like serum sickness: fatigue.. - rare)

- hepatitis

- drug interaction with warfarin or Phenobarbital

2.     Antimetabolite: Flucytosine ( 5-FC)

Flucytosine :

Mechanism of action: selectively converted by fungi to active metabolites

inhibits fungal RNA and DNA synthesis

Absorption: well absorbed; used orally (only)

Uses: only in combination with

® amphotericin B for cryptococcal meningitis

® itraconazole for blastomycosis

[high incidence of resistance as well as toxicity reduced via use in drug combinations]

Adverse effects: (narrow therapeutic window)

® results from fluorouracil = major metabolite

- inflamed bowel (enterocolitis)

- bone marrow toxicity

- possible liver toxicity

3.              Azoles:

A.            Imidazoles-

(I)            Topical: clotrimazol, econazole, miconazol

(II)         systemic: ketoconazole

(Imidazoles)

              Mechanism of action: inhibit fungal ergosterol biosynthesis selectively inhibit fungal cytochrome P₄₅₀ enzymes

Ketoconazole :

(original oral ‘azole’, not as selective as newer azoles, ie. significant inhibition of  mammalian P450 enzymes)

Absorption: low - improved with food and low gastric pH

used orally, but has very slow onset; poor CSF and urinary tract                       penetration

Uses:

mucocutaneous candidiasis

coccidioidomycosis (non-meningeal)

in shampoos for seborrheic dermatitis

(largely supplanted by more expensive itraconazole or fluconazole)

Adverse effects: (narrow therapeutic window) highly dose-dependent

- nausea and vomiting

- endocrine: interferes with adrenal and gonadal steroid synthesis*

- hepatotoxicity (rare but can prove fatal)

- drug interactions

®*action on human cytochrome P₄₅₀ (eg. ­ warfarin; ­ cyclosporine; and vice versa)

® decreased absorption of ketoconazole when administered with rifampin, H₂ antagonists or antacids

 Miconazole and Clotrimazole

Absorption: extremely poor - both used topically: creams and, in the case

of clotrimazole, oral troches (=lozenges)

Uses: wide-spread, over-the-counter use as topical antifungals

vulvovaginal candidiasis

dermatophytic infections (eg. tineas corporis)

oropharyngeal thrush (candidiasis; alternatives to nystatin)

B.               Triazoles-

Systemic: Fluconazole, itraconazole.

Mechanism of action: inhibit fungal ergosterol biosynthesis

Itraconazole ***

Absorption: OK, low bioavailability (no CSF penetration)

- improved with food and low gastric pH

Uses:     most potent of the azoles for systemic infections

drug of choice for persistent dermatophytic infections

effective against all types of Aspergillus infection

preferred agent for endemic mycosis (eg. Histoplasma)

Adverse effects:

- drug interactions (esp. non-sedating antihistamines)

(no effect on steroid biosynthesis; variable effect on mammalian P₄₅₀        system, less than with ketoconazole but still of potential concern)

Fluconazole

Absorption: good; used orally and IV (excellent CSF penetration)

Uses:

agent of choice for cryptococcal meningitis (unless life         reatening: usAmpB)

mucocutaneous candidiasis prophylactically for bone marrow transplants and AIDS patients.

Adverse effects:  (widest therapeutic window)  few and mild concern for all azoles: newly observed emergence of resistant strains in AIDS [resistance to azoles is otherwise fairly rare]

Voriconazole (most recently approved (2002) azole, derived from fluconazole)

Absorption: good; used orally and IV (good CSF penetration, however*)

Uses: agent of choice for invasive Aspergillus active against Candida      (even those resistant to fluconazole), Cryptococcus and endemic mycosis, but ineffective against mucormycosis (soil saprophytes)

Adverse effects:  sporadic visual disturbances* (~30%);          hepatotoxicity (2-3%)

4.                 Allylamine: Terbinafine, Naftifine.

Naftifine and Terbinafine

Mechanism of action: inhibits fungal squalene metabolism increased levels of squalene are toxic to fungi; also reduces ergosterol

Uses: effective for most cutaneous mycosis either topically (eg.       tinea corporis and tinea cruris) or, in the case of terbinafine, orally for     nail infections (90% cure rate, without side effects) [not                             effective against Candida]

5.                 Natural products:

Pyrrolnitrin, variotin

siccanin,  Eulivin

ambruticin.

6.                 Other organic compounds:

Salicylanilide, salicylic Acid, Aminacrine, acrisorcin, Halopragin, salicylamide, p-chloro-metaxylenol, iodochlorhydroxyquin, m-cresyl acetate, Dimethazole, Chlordantoin,Gention violet, pecilocin, di-iodohydroxy- quinoline, iodine, Thymol, phenylmercuric Nitrate, zinc pyrithione.

7.                 Miscellaneous Topical Agnets:-

·                    Tolnaftate,

·                    Undecylenic Acid,

·                    Benzoic Acid,

·                    Quiniodochlor Ciclopirox  olamine, sod. Thiosulphate.

8.                 Investingertional Drugs:

A.               Azol :

1.                 Variconazole (VRC)

2.                 Ravuconazole

3.                 Posaconazole

B.                                                   Echinocandins :

1.                 Micafungin

2.                 Anidulafungin (LY30336)

3.                 FK 436

4.                 Capsofungin (MK-0991).

Caspofungin (most recently approved antifungal – Jan 2001)

Mechanism of action: inhibits beta (1,3)-D-glucan synthesis, blocking cellwall synthesis

Absorption:  poor; highly protein; administered IV

Uses:  active against a number of fungi, but particularly effective against invasive candidiasis and aspergillosis (promising new alternative to amphotericin) via once daily IV administration; no activity against cryptococcus Adverse effects:  fever, nausea,      vomiting, flushing; some irritation at inj site; small elevation of        liver enzymes.

KETOCONAZOLE

1. Physicochemical properties of Ketoconazole

Chemistry :          Ketoconazole is an imidazole antifungal agent. As with other imidazoles, it has five membred ring structures , containing two nitrogen atoms.

                         

  C ₂₆H₂₈CI₂N₄O₄                                                                                                           Mol. Wt. 531.44

                             Ketoconazole is cis-1-acetyl-4-[2-(2,4-dichlorophenyl-2-(1-imidazolylmethyl)-1,3-dioxolan-4-ylmethoxylphenyl-piperazine. Ketoconazole is a white to off-white, crystalline odourless powder.

Standards :          ketoconazole contains not less than 98.0 percent and not more than 102.0 percent of C₂₆H₂₈CI₂N₄O₄ calculated with reference to the dried substance.

Identification :     A. The infra-red absorption spectrum, is concordant with reference spectrum of ketoconazole or with the spectrum obtained from ketoconazole RS.

                             B. Melts between 148⁰ and 152⁰                                           Specific optical rotation : Between-1⁰ and +1⁰ , determined on a 4% w/v selection on methanol.

Heavy metals :     Not more than 20 ppm

Sulphated ash :   Not more than 0.1%

Loss on drying :  Not more than 0.5%, determined on 1 g by drying at a pressure not exceeding 2.7 kpa at 80⁰ for 4 hours.

Solubility :           Freely soluble in dichloromethane, soluble in chloroform and in methanol; sparingly soluble in ethanol (95%); practically insoluble in water and in ether. ketoconazole is a highly lipophilic compound.

pKa value :          ketoconazole is a dibasic compound (pKa(1) = 6.51; pKa (2) = 2.94) and almost insoluble in water except at a pH lower than 3.

Flash point:                   Considered to be not inflammable

Stability:              Stable under ordinary conditions.

2. Mode of action/Mechanism of action :-

As with all azole antifungal agents, ketoconazole works principally by inhibition of cytochrome P450 specially CYP3A4. This enzyme is in the sterol biosynthesis pathway that leads from lanosterol to ergosterol. Ergosterol is a vital component of fungal cell membrane.  So ketoconazole interfering with erogosterol synthesis. It is believed that ketoconazole increases cellular membrane permeability and causes secondary metabolic effects and growth inhibition. The affinity of ketoconazole for fungal cell membranes is less compared to that of fluconazole and itraconazole. Ketoconazole has thus more potential to effect mammalian cell membranes and induce toxicity.       

                      (Mechanism of action of Ketoconazole)

3. Pharmacological action :

·        At usual doses and serum concentrations, ketoconazole is fungistatic against susceptible fungi . At higher concentrations for prolonged periods of time or against very susceptible organisms, ketoconazole may be fungicidal. The fungicidal action of ketoconazole may be due to a direct effect on cell membranes.

·        It is believed that ketoconazole increases cellular membrane permeability and causes secondary metabolic effects and growth inhibition . The exact mechanism for these effects have not been determined , but may be due to ketoconazole interfering with ergosterol synthesis.

·        Ketoconazole also has endocrine effects as steroid synthesis is directly inhibited by blocking several cytochrome P-450 enzyme systems.

·        Measurable reductions in testosterone or cortisol synthesis can occur at dosages used for antifungal therapy, but higher dosages are generally required to reduce levels of testosterone or cortisol to be clinically useful in the treatment of prostatic carcinoma or hyperadrenocorticism effects on mineralocorticoids are negligible.

·        Ketoconazole causes suppression of estradiol synthesis.

·        Ketoconazole causes decrease in serum hydrocortisone.

·        Ketoconazole produces mild and asymptomatic elevation of serum transaminases.

4. Antifungal spectrum :-

     Ketoconazole is a broad-spectrum synthetic antifungal agent which is fungistatic at concentrations achieved clinically. ketoconazole has a wide spectrum of antimicrobial activity in vitro including activity against candida spp., Blastomyces dermatitidis coccidioides immitis, cryptococcus neoformans, Epidermophyton floccosum, Histoplasma capsulatum, paracoccidioides brasiliensis, malassezia furfur, Microsporum canis, Trichophyton mentagrophytes, and T. rubrum. The MIC for many of these organisms ranges from 0.1 to 2 g per mL. Higher MICs  have been reported for some candida spp. Some strains of Aspergillus spp. And Sporothrix schenckii are sensitive. Ketoconazole has activity against some Gram-positive bacteria.

5. Pharmacokinetics:

     Oral absorption of ketoconazole varies among individuals . Since an acidic environment is required for the dissolution of ketoconazole. The absorption of ketoconazole from the gastro-intestinal tract increases with decreasing stomach pH. After oral doses of 200, 400 and 800 mg plasma concentrations of ketoconazole are approximately 4,8 and 20 m /ml.

     In blood , 84% of ketoconazole is bound to plasma proteins, largely albumin; 15% is bound to erythrocytes, and 1% is free.

It is widely distributed but penetration into the cerebrospinal fluid is poor; not effective in fungal meningitis. However, therapeutic concentrations are attained in the skin and vagina fluid.

Table Selected pharmacologic properties of Ketoconazole

                   Dose                                                           Ketoconazole,

                                                                                      200 mg po

                   Oral bioavailability, %                               75

                   Peak plasma concentration, mg/ml              1.5-3.1

                   Time to peak plasma concentration.           1-4

                   Protein binding %                                       99

                   CSF penetration, %                                    <10

                   Terminal elimination half-life                     >10

                   Active drug in urine %                                2-4

    

Ketoconazole is metabolized extensively by the liver into several inactive metabolites. Ketoconazole is metabolized by oxidation, O-dealkylation and aromatic hydroxylation.

     The drug elimination of Ketoconazole is reported to be biphasic, with an initial half-life of 2 hours and a terminal half-life of about 8 hours. The half life of the drug increases with dose, and it may be as long as  7 to 8 hours when the dose is 800 mg. Ketoconazole is excreted as metabolites and unchanged drug chiefly in the faeces: some is excreted in the urine.

     Metabolism of the drug is unchanged by azotemia, hemodialysis, or peritoneal dialysis. Moderate hepatic dysfunction has no effect of the concentration of Ketoconazole.

6. Formulations:

     Basically ketoconazole has oral tablet, cream and dandruff shampoo formulations. Other formulations of ketoconazole such as ointment, solution, lotion, ketoconazole foam, microemulsion and gel are also available.

Tablet : - Ketoconazole is a synthetic broad-spectrum antifungal agent available in  scored white tablets, each containing ketoconazole base for oral administration. Inactive ingredients are colloidal silicon dioxide, corn starch, lactose, magnesium stearate, microcrystalline cellulose and povidone.

Shampoo: Ketoconazole 2% Shampoo is a red-orange liquid for topical application, containing the broad spectrum synthetic antifungal agent ketoconazole in an aqueous suspension. It also contains coconut fatty acid diethanolamide, disodium monolauryl ether sulfosuccinate, FD&C Red No. 40, hydrochloric acid, imidurea laurdimonium hydrolyzed animal collagen, macrogol 120 methyl glucose dioleate, perfume bouquet, sodium chloride,sodium hydroxide ,sodium lauryl ether sulphate , and purified water.

Cream; Ketoconazole cream contains the broad-spectrum synthetic agent ketoconazole formulated in an aqueous cream vehicle consisting of propylene glycol,stearyl and cetyl alcohols,sorbitan monostearate, polysorbate 60, isopropyl myristate, sodium sulfite anhydrous, polysorbate 80 and purified water.

Preparation of micro emulsion

     A water- in – oil micro emulsion  of ketoconazole was prepared by mixing about 1.1 g of Ketoconazole with the proportion of olive oil , water , and labrafil M 1994 CS and plurol oleique (1:1) in the microemulsion region to obtain 100 ml Then , 11.1 ml dehydrated alcohol was added to help make Ketoconazole soluble in the system .

Preparation of gel :

     A gel formulation of Ketoconazole was prepared by dissolving about 1 g of Ketoconazole in 90 ml of dehydrated alcohol . Then 30% w/w carbopol 974p solution in water was used to make up 100 g of gel formulation .

7. Adverse Effects:

     The most common side effects of Ketoconazole are dose-dependent nausea, anorexia and vomiting, which occur in about 20% of patients receiving 400 mg daily. Administration of drug with food, at bedtime or in divided doses may improve tolerance. Diarrhoea, constipation and abdominal pain have been reported in about 1% of patients. An  allergic rash occur in about 4% of Ketoconazole treated patients and pruritus without rash in about 2%. Hair loss has also been reported.

     Hepatic toxicity consisting of cholangiohepatitis and increased liver enzymes has been reported with Ketoconazole and may be either idiosyncratic in nature or a dose related phenomenon. Thrombocytopenia has also been reported with Ketoconazole therapy, but is rarely encounterd.

     Ketoconazole inhibits steroid biosynthesis in patients, as it does in fungi, by inhibition of cytochrome P450-dependent enzyme systems. Several endocrin ologic abnormalties thus may be evident. Approximately 10% of females report menstrual irregularities probably due to suppression of estradiol synthesis. A variable number of males experience gynaecomastia and decreased  libido and potency. At high doses, azoospermia has been reported , but sterility has not been permanent. Doses of Ketoconazole as low as 400 mg can cause a transient drop in the plasma concentrations of free testosterone and estradiol C-17b. Similar doses can  also  cause a transient decrease in the ACTH-stimulated plasma catrisol response and can suppress androgen production in women with polycystic ovary syndrome. Hypertension and fluid retention have been reported and are associated with elevated concentrations of deoxycorticosterone, corticosterone and 11-deoxycortisol.

     Mild and asymptomatic elevation of serum transaminases occurs in ~5% patients, but serious hepatoxicity is rare. Other adverse effects include hypersensivity reactions. (difficulty breathing; closing of the throat, swelling of the lips, tongue, or face), pruritus rash, headache, dizziness and somnolence.

     The effects of Ketoconazole on functions of the thyroid gland have also been investigated . There have been a number of reports suggesting that Ketoconazole may have antithyroid function via impairment of thyroglobin iodination and iodothyrosine coupling .

     After topical administration of Ketoconazole , irritation, dermatitis, or a burning sensation has occurred.

Drug	Common Adverse effects
Ketoconazole	Nausea Anorexia Vomiting Hepatotoxicity.

8. Drug Interactions :

Background : Drug interaction can arise with virtually any antifungal therapy and occur primarily to in the gastro intestinal tract, liver and kidneys by several distinct mechanisms . the majority of drug interactions are pharmacokinetic nature, resulting in changes on the absorption or elimination of the interacting drugs as well as the antifungal agent. In the GI tract, changes in pH, complexation, with ions, or interference with transport and enzymatic processes in the intestinal lumen can interfere with drug absorbance . Indication or inhibition of metabolism in the liver can inhibit or accelerate , respectively, drug clearance from the body. Therefore any patient receiving Ketoconazole therapy should be carefully monitored for potentially severe drug interactions.

Interactions of drug absorption :-

Ketoconazole is weak base , virtually insoluble in water, and is ionized only at low pH consequently dissolution and absorption of Ketoconazole is heavily dependent on acidic gastric condition in the stomach . Drugs that increase gastric pH (e.g. H₂ antagonists, proton pump inhibitors) slow the dissolution of the solid dosage forms and decrease drug available for adsorption in the intestinal lumen.

     Antacids, metal ion containing drugs (e.g. sucralfate), and vitamin supplements can also slow dissolution and absorption of Ketoconazole through binding or chelation interactions that impair transport of the drug across intestinal epithelium.

Absorption from sustained release oral dosage forms of theophylline may be reduced by Ketoconazole. 

Interactions of drugs Metabolism :  

The principal site for drug metabolism is the liver where lipophilic compounds are transformed into ionized metabolites.  For renal elimination. This transformation or metabolism generally occurs via two different types of reactions.

1.           Phase I (Non synthetic) reactions , which include oxidation, reduction and hydrolysis and

2.           Phase II (synthetic ) reactions resulting from conjugation with other molecules (e.g. glucoronidation, sulfation) to improve aqueous solubility.

Phase I oxidative reactions are an important mechanism for biotransformation of  azole antifungals. Most oxidative reactions are catalyzed by a super family of mixed function monooxygenases called the cytochrome P450 system. Rifampin and phenytoin induce Ketoconazole metabolism and reduce its efficacy Ketoconazole inhibits the metabolism of terfenadine thus increasing the risk of cardiotoxicity ; a similar effects occurs with astemizole . Mitotane and ketoconazole are not recommended to be used together to treat hyperadrenocorticism as  the adrenolytic effects for mitotane may be inhibited by ketoconazole’s inhibition of cytochrome P450 enzymes.

Other Interactions :-

Ketoconazole has been reported to increase plasma concentrations of chlordiazepoxide, cyclosporin, methylprednisolone and quinidine. The effect of roal anticoagulants such as warfarin may be increased by ketoconazole.

Elevated concentrations of cisapride with resultant ventricular arrhythmias may result if coadminstered with ketoconazole.

Ethanol may interact with ketoconazole and produce a disulfiram like reaction (vomiting,).Ketocanazole may exhibit synergism with acyclovir against herpes  simplex viruses. Cyclosporin blood level may be increased by ketoconazole.

Overview of Common Drug Interactions with Ketoconazole Therapy

Effect	Mechanism	Drug involved	Suggested Clinical management
1. Decreased serum concentration of ketoconazole Antacids H2 receptor antagonists sucralfate Omeprazole 2. Increased metabolism of ketoconazole Isoniazid Rifampin Phenytoin Phenobarbital Ritonavir 3. Increased Plasma concentration of co-administered drug or metabolite cyclosporine Phenytoin Sulfonylureas Loratadine Warfarin Chlordiazepoxide Triazolam , Alprazolam, Midazolam Indinavir Ritonavir	Decreased dissolution/absorption of solid dosage form Induction of mammalian cytochrome P450 mediated metabolism of ketoconazole. Inhibition of cytochrome P450 ,P-glycoprotein,  or both	Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole Ketoconazole	Use solution formulation of ketoconazole if indicated . Avoid taking antacids within 2 hours of oral ketoconazole therapy. Avoid concomitant use of these agents with ketoconazole may require switch to amphotericin B formulations. Avoid concomitant use if possible.

Dose & administration :-

     The usual dose for treatment and prophylaxis of fungal infections is 200mg once daily taken with food. This may be increased to 400 mg  daily                                                                                                                                           if an adequate response is not obtained.In some infections even higher doses have been used. Children may be given approximately 3 mg per kg body-weight daily, or 50 mg for those aged 1 to 4 years and 100 mg for children aged 5 to 12 years. Treatment should usually be continued for at least one weak after symptoms have cleared and cultures have become negative.

Dosing in ketoconazole sensitive diseases :-

1. Aspergillosis :

Administration of ketoconazole 400 mg daily for one year is necessary for symptomatic relief.

2. Blastomycosis :-for treatment of non-life threatening non-meningeal blastomycosis is to start treatment with ketoconazole 40 mg daily; the dose can be increased to 600 to 800 mg daily of clinical  response dose not occur with the lower dose. Genitourinary tract infection should be treated with ketoconazole 600 to 800 mg daily.

3. Candidiasis :- Mucocutaneous candidiasis ketoconazole 200 mg daily is used by oral route.

Oesophageal candidiasis :- It occurs frequently in immunosuppressed patients and is often presenting feature in HIV infection. Ketoconazole 200 mg to 400 mg daily  by mouth is effective.  A dose of 400 mg once daily for 5 days is used for the treatment of chronic vaginal candidiasis. 

4. Coccidioidomycosis :

Ketoconazole in doses of 200 to 400 mg daily by mouth is used successfully in coccidioidomycosis and it may be considered the drug of choice in some patients.

5. Malignant neoplasm of the prostate :-

Ketoconazole 200 to 400 mg by mouth every 8 hours is used for patients with progressive prostatic cancer who have not responded to hormonal treatment.

6.Histoplasmosis :

Ketoconazole in doses of 400 or 800 mg daily by mouth for a minimum of 6 months is used in the treatment of localised, disseminated or chronic cavitary histoplasmosis without CNS involvement.       

7. Leishmaniasis :-

Ketoconazole 200 to 400 mg daily by mouth for 4 to 6 weeks is used for treatment.

8. Paracoccidioidomycosis :-

ketoconazole 200 mg daily by mouth, increased to 400 mg daily in severe disseminated disease or in the event of an inadequate response, for 6 to 12 month is used for treatment.

9. Seborrhoeic dermatitis :-

Ketoconazole 2% cream or shampoo may be effective in seborrhoeic dermatitis where the yeast pityrosporum is involved .

10. Pityriasis versicolar :-

A single dose of 400 mg/day is effective in treatment. .

Contraindication  & Precautions

·        Ketoconazole is contraindicated in pregnant and nursing women, because of secretion of the drug into breast milk.

·        Since ketoconazole has been reported to cause hepatotoxicity it should not be administered to patients with pre-existing liver disease. Liver function tests should be performed before commencement of long-term treatment with ketoconazole and then at least monthly throughout treatment.

·        Use caution when driving or performing other hazardous activities ketoconazole may cause dizziness. If you experience dizziness avoid these activities.

·        Alcohol should be used with moderation while taking ketoconazole. Alcohol and ketoconazole can both affect the liver.

·        Ketoconazole (Tablets, shampoo and cream) is contraindicated in patients who have shown hypersensitivity to the drug or excipients of the formulations.

·        Ketoconazole 2% cream is not for ophthalmic use.

·        It should be used with caution in patients with hepatic disease or thrombocytopenia.

·        Drug should keep out of the reach of children in a container that small children cannot open.

·        Store at room temperature between 15 and 30 degrees C. Keep container tightly closed. Throw away any unused medicine after the expiration date.

·        Store in a cool, dry place, away from direct heat and light.

Uses of Ketoconazole :-

·        Ketoconazole is used in a variety of fungal infections and more important of these are .

(i) Candidiasis :-

                   Mucocutaneous candidiasis.

                   Oesophageal candidiasis

                   Candida vulvovaginitis

(ii)  Blastomycosis

(iii) Coccidioidomycosis

(iii) Histoplasmosis

(iv) Leishmaniasis

(vi) Para coccidioidomycosis

(vii)Aspergillosis

(viiii) Pseudallescheriasis

(ix) Cryptococcosis

(x) Sporotrichosis

(xi) Ringworm

(xii) Tinea versicolor

(xiii) Chromomycosis

·        Ketoconazole suppresses hormone synthesis and has been used in rare instances to treat conditions associated with excessive production of the hormone cortisone from the adrenal gland (cushing’s Disease)

·        Ketoconazole is also used in rare cases in treatment of prostatic carcinoma.

·        It has been given for the prophylaxis of fungal infections in immunocompromised patients.

·        Ketoconazole is also used in rare cases in treatment of precocious puberty.

·        Ketoconazole is applied topically as a 2% cream in the treatment of candidal or tinea infections of the skin, or the treatment of pityriasis versicolor.

·        Ketoconazole 2% shampoo is indicated for the reduction of scaling due to dandruff.

·        Ketoconazole 2% shampoo is also used in treatment  of seborrhoeic dermatitis or in pityriasis versicolor.

·        Ketoconazole has also been tried in kala azar.

ANALYSIS OF KETOCONAZOLE

Quantitative determination of Ketoconazole :-  

1. Ketoconazole Assay (IP 1996)

Non-Aqueous Titration :- Weigh accurately about 0.2 g, dissolve in 40 ml of anhydrous glacial acetic acid, warming and cooling if necessary, or prepare a solution and determine the equivalence point potentiometrically using 0.1 M perchloric acid as titrant. Potentiometric titration may be carried out using a glass electrode and a standard reference electrode, e.g. calomel reference electrode containing saturated solution of potassium chloride in water. Potentio metric titrations may also be carried out by using a glass electrode and saturated calomel reference electrode in which the saturated solution of potassium chloride in water has been replaced by a saturated solution of potassium chloride in  methanol . It must be ensured that no leakage of salt-bridge solution occurs. Alternatively, a combined electrode may be used. The junction between the calomel electrode and the titration liquid should have a reasonably low electrical resistance and there should be a minimum of transfer of liquid from one side to the other. The connections between the potentiometer and the electrode system must be made according the manufacturer’s instructions to avoid problems of instability . Perform a blank determination and make  any necessary  correction when the temperature (t₂) of the titrant at the time of the assay is different from the temperature (t₁) of the titrant when it was standardised, multiply the volume of the titrant required by [(1+ 0.001 (t₁-t₂)] and calculate the result of the assay from the corrected volume

     Each ml of 0.1M perchloric acid is equivalent to 0.02657 g of C₂₆H₂₈Cl₂N₄O_4.

KETOCONAZOLE TABLETS          

Assay : (IP 1996) For Ketoconazole tablet high performance liquid chromatography (HPLC) is used for assay.

High performance liquid chromatography (HPLC) , is esseantially a form of column  chromatography in which the stationary phase consists of small particle (3-50um ) packings contained in a  column with a small  bore (2-5mm ) , One end of which is attached to a source of pressurized liquid eluant (mobile phase) . The three  forms of high performance liquid chromatography most often used are ion- exchange , partition and adsorption .

Apparatus   

The apparatus consists of a high –pressure solvent pumping system , a sample injection device attached to one end of a column containing the stationary phase, detector, amplifier and recorder .The pumping system delivers the mobile phase solvent from one or several reservoirs to the column at a constant rate through high –pressure tubing and fittings .

The two ways of introducing the sample solution onto the column are injection into a flowing stream  and a ‘stop-flow’ injection. In the injection technique, the sample solution is injected with a syringe through a septum or through an injection valve or a fixed –volume loop injector , In the ‘stop –flow ‘ technique , the column flow is stopped  and the sample solution is injected into the column when the pressure falls to zero ; the port is then closed and the flow is resumed.

The column is usually made of stainless steel (the inside may be glass –lined)  and is capable of withstanding high pressure .

The following solutions are used.

 For solution  (1) Weigh and powder 20 tablets. Weigh accurately a quantity of the powder equivalent to 200 mg of Ketoconazole, shake with 50.0 ml of a mixture of   equal volumes of methanol and dichloromethane  and centrifuge . To 5.0 ml of   this solution add 5.0 ml of a 0.5% w/v solution of terconazole RS (internal  standard )in the methanol –dichloromethane  solvent mixture and dilute to 50.0 ml with the same solvent mixture . For solution .

(2) Dissolve 20 mg of ketoconazole RS in 20 ml o the methanol –dichloromethane  solvent mixture , add 5.0 ml of the internal standard solution and dilute  to 50.0 ml with the same solvent  mixture .

The chromatographic procedure may be carried be out using  (a) A stainless steel  column (30cm x 39mm) packed  with stationary phase Octadecylsilane chemically bonded to porous silica or ceramic microparticles, 5 to 10 um in diameter (LC1).

(b) A mixture of  7  volumes of 0.2% w/v of  di-isopropylamine in methanol and 3 volumes  of a 0.5% w/v solution of ammonium acetate as the mobile phase with a flow rate of 3ml per minute and .

(c) A detection wavelength of about 225 nm .

The relative retention times are about 0.6 for ketoconazole and 1.0 for terconazole . Calculate the content of C₂₆H₂₈CI₂N₄O₄ in the tablet from the declared content of C₂₆H₂₈CI₂N₄O₄ in ketoconazole RS .

(3) Spectrophotometric method for the determination of ketoconazole  based on the oxidation reactions .

A new spectrophotometric method is proposed for the determiniation of Ketoconazole in pharmaceutical preparations . The method is based on the coupled redox –complexation , which proceed in the Ketoconazole –iron (III) and 1,10-phenanthroline system . A linear calibration  graph was obtained between 1.6 -16.0 ppm of Ketoconazole  . The resulting colored  complex between fe (II) and 1,10,-phenanthroline was determined at 512 nm .

  The propoded method is simple , rapid an sensitive . The procedure was successfully applied for the determination of Ketoconazole in tablet ,

cream and shampoo samples .

Apparatus

A LKB model 4054 uv-vis recording spectrophotometer equipped with 10 mm matched silica cells was used for all spectral measurements . The pH  values were determined with a WTW moltilab 540 lonalyzer  (Germany ) pH /mV meter using a combined electrode .

Reagents 

All the chemicals used in this study were of highest purity available and used without further purification . Triply distilled water was used throughout .  A working standard solution of 0.001 M of Ketoconazole was prepared  by dissolving 0.0267 g of pure drug in 50 ml   of water containing a few drop of  hydrochloric acid (about 0.04 M )followed by further diluting of 5ml  of this solution to 50 ml .

General procedure 

An accurate ml volume of standard or sample solution  containing an appropriate amount of Ketoconazole was pipetted into a 50 ml volumetric flask and 5ml of fe (III) 0.01 M was added . The resulting  solution was mixed well , and allowed to stand for 10 min. Then ,25 ml of 1,10-phenanthroline 0.2% and 5ml of acetate buffer solution 1 M  was added and diluted to the mark with distilled water (pH=5.0 ) . The absorbance of the solution was measured against a reagent blank at 512 nm after 10 min .

Tablet and cream sample solutions  

An accurately weighed amount of ketoconazole  cream or finely powdered ketoconazole tablet was dissolved in water containing a few drops of HCI 1 M . The excipients were  separated by filtration and the filter paper was washed  three times with  water . The filtrate and washing solutions o the tablet or cream samples were  transferred quantitatively into 100 –ml calibrated flask and diluted  to the marc with water, and the spectrophotometric procedure was  followed .

Shampoo sample solution

An accurately weighed portion of the Ketoconazole shampoo equivalent to 10 mg of the drug was dissolved in water containing 1ml of HCI  1M  and 0.5ml of CTAB 0.01M , and  the volume was made to 100 ml in  a volumetric flask . An   accurate ml volume of the resulting solution was pipetted into 100ml  volumetric flask and the recommended procedure for the determination of ketoconazole was followed . The method of standard addition was used for the accurate determination of the ketoconazole content .

Beer ‘s law study

A calibration graph for ketoconazole was obtained under the optimum conditions (fig 4 ) .

Beer ‘s law was obeyed  over the concentration range of 1.6-16.0  ppm at 512 nm with molar absorption coefficients (absorbtivity ) of 4.2 x 10⁴ 1mol ^-1 cm^{-1 .}

Calibration graph for the determination of Ketoconazole under the

optimum conditions

Determination of ketoconazole in tablets and creams. (Titrametric method)

Assay of Ketoconazole in its powdered tablets and creams  using the proposed method  and the official potentiometric method was carried out and result are summarized in table -1 . The data given in table 1 clearly  indicate a good agreement  between the Ketoconazole contents determined by the proposed and  

Official methods as the declared amounts of the drug in the preparation used . This is indicative of non-interference of  the other ingredients and the excipients, which are in the  formulations .

Potentiometric titration of a Ketoconazole tablet sample (equivalent to 108 mg of the drug) dissolved in 30 ml glacial acetic acid with 0.101 M perchloric acid.

Determination of  Ketoconazole in shampoo . 

We have evaluated the accuracy of the proposed method by performing experiments on the samples prepared from dosage form and pure drugs . A mean recovery of 99.5 % was obtained from  shampoo samples .

Table Results of determination of Ketoconazole in its formulations

Sample       Labeled                                   Found* (X ± SD)

                                                Proposed method                   Official method

Tablet         200mg                  210.6±1.98mg                208±2.0mg

Cream         2%                        2.05±0.20%                             2.10±0.15%

Shampoo              2%                        1.70±0.15%                                     --

(4) Analysis of ketoconarole  by spectrophotometric and spectrofluorimetric methods in different pharmaceutical dosage forms .

spectrophotometric one depends on the  interaction between imidazole antifungal drugs as  n –electron donor with  the pi acceptor 2,3 dichloro -5 , 6  dicyano -1 , 4 –benzoquinone (DDQ) in methanol or with p-chloranilic acid (P-CA ) in acetonitrile . The produced chromogens obey beer ‘s law at lambda (MAX)  460 and 520 nm in the concentration range 22.5 -200 and 7.9-280 microg ml (-1) for DDQ , and P-CA respectively . Spectrofluorimetric  method is based on the measurement of the native fluorescence of ketoconazole at 375 nm with excitation at 288 nm . Fluorescence intensity versus concentration is linear for ketoconazole at 49.7-800 ng ml (-1) . The proposed methods are applied successfully for the determination of ketoconazole in their pharmaceutical formulations .

(5).HPLC analysis of gel formulation and microemulsion of ketoconazole

HPLC Analysis of Ketoconazole

HPLC apparatus was set at the wavelength of 254  nm . The analyasis was performed using a 3.9 x 300 mm stainless steel  column packed with 10-micron particles. A composition of 60% v/v acetonitrile , 40% v/v deionized water containing 0.2% v/v diethylamine was used as a mobile phase to elute Ketoconazole . A 25-ul volume each of standard and sample solutions was injected , and ketoconazole was eluted is isocratically using a flow rate of 1.0ml /min at room temperature .

Standard preparations

USP standard stock solution was prepared by weighting approximately 10 mg Ketoconazole into a 10- ml volumetric flask containing 8 ml of methanol. The volume was then adjusted to 10ml with methanol, and this solution was used as the standard stock solution. Standard solutions with Ketoconazole concentrations of 10, 50, 100, 150, and 200 ug / ml were prepared accordingly by diluting the standard stock solution with methanol . Each standard solution was filtered through a 0.45 um membrance filter before injection onto the HPLC column .

Sample preparations

About 0.1 ml of the microemulsion was transferred into a 10 – ml volumetric flask and adjusted to volume with methanol . For the gel formulation , 0.1 g gel was weighed into a 10 –ml volumetric flask and adjusted to volume with methanol . Each sample solution was filtered through a 0.45  um membrane filter before injection onto the HPLC column .

Table Comparison of Ketoconazole release from Microemulsion and gel formulation

                                         Ketoconazole released %

Time (hr)             Microemulsion                                 Gel

                             (Mean±SD, n=6)                      (Mean±SD,n=6)

1                           8.2±2.70                                  11.16±2.59

2.                          15.15±3.13                              19.16±2.89

3.5-4                     25.02±3.01(3.5hr)                             31.57±3.10(4hr)

5                           33.66±3.01                              34.50±2.95

7                           44.04±4.24                              40.55±2.09

8                           47.01±5.51                              42.64±1.98

22                         73.59±2.28                              64.77±2.87.

24                         73.74±1.91                              65.29±4.81

 

6.Ion-selective membrane electrode method for Ketoconazole Determination .

  The inherent advantages of ion – selective electrodes (ISEs) are simplicity , short measurement time , low cost adequate precision and accuracy , adequate detection  limits , wide analytical range , and particularly the ability to measure the activity of various drugs selectively , and  in most cases , without prior  separation of the drug of interest from  the formulation matrix in colored or cloudy samples . These make ISE potentiometry very attractive for pharmaceutical analysis .. The membrane used in this electrode was made from liquid – plasticized PVC and was based on a water –insoluble Ketoconazole –tetraphenylborate ion pair as an ion-exchanger.

Electrode preparation

The general procedure to prepare the PVC membrane was to throughly mix 33 mg of powdered  PVC , 65 mg of plasticizer nitrophenyl octyl ether  (NPOE)  and 2 mg of Ketoconazole –tetraphenylborate ion pair in 2 cm³ of tetrahydrofuran (THF) . The resulting mixture was transferred into a glass dish  of 2 cm diameter . The solvent was slowly evaporated until an oily concentrated  mixture was obtained. A pyrex tube (3-5mm i.d.) was dipped into the mixture for about 10 s so that a membrane of about 0.3 mm thickness was formed . The tube was then  pulled out from mixture and kept at room temperature for about I hour . The tube was then filled with an internal filling solution (1.0 x 10^-2 mol dm^-3  ketoconazole ) .The electrode was finally conditioned for 24 hour soaking in a 1.0x 10^-3 mol dm^-3  solution of Ketoconazole . A silver / silver chloride – coated wire was used as an internal – reference  electrode .

EMF MEASUREMENTS

All emf measurements were carried out with the following assembly : Ag –Ag Cl , 3 mol dm ^-3 KCI / internal solution (1.0 x10^-2 mol dm ^-3 ketoconazole)/PVC membrane /test solution /Ag – AgCl , 3mol dm^-3 KCI .

A model 692 metrohm ion analyzer pH/mV meter is used for potential mesasurements at 25.0 ± 0.1⁰C   .

Potentiometric assay of pharmaceutical preparations.(Electrode method). 

Tablets. A homogenized  powder was prepared from three accurately weighed tablets . An approporiate amount of this powder was transferred into a 50 cm³ calibrated flask containing 8.0 cm³ of 1.0 mol dm^-3 HCI . Dissoultion of the drug was assisted by means of a mechanical shaker . The solution  was then made up to the mark with water . A 2.0 cm³  portion of this  solution was transferred into a 25 cm³ calibrated flask and diluted to the mark  with 0.1 mol dm^-3 acetate  buffer (pH=4.5). The ketoconazole content is then determined by both the calibration  method ²³ and titration with 0.0107 mol dm^-3 sodium tetraphenylborate .

Creams  . The cream sample (10 g ) was transferred into a 50 cm³ Erlenmeyer flask containing 8.0 cm³  of 1.0 mol dm^-3  HCI and vigorously stirred to quantitatively  extract the drug into acidic solution  . The solution was then filtered and washed with water  into a 25 cm3 calibrated flask and made up with water to the  mark . Hereafter  the operation was the same as in the case of tablets .

Table Results of determination of Ketoconazole in pharmaceutical formulations

Sample       Labeled                                   Found*

                                                Titration    Calibration          Official method

Tablet         200mg                  216             197                       206

Cream         2%                        2.07            1.90                      1.99

             (w% drug)

 

HERBAL ANTIFUNGAL DRUGS

There are so many plants or plants parts (roots, leaves, seeds, flowers or their extracts) used for the treatment of fungal infection. Some of them are described below: -

Passion flower

Passion flower, a medicinal plant, is naturally grown herb which is approved in the treatment of insomnia and nervousness…

Rose Water

Rose water is very much preferred as an important ingredient in many cosmetics till date. Neem Oil: Facts and Products

The Neem oil has numerous remarkable proven medicinal properties which have been used since olden days.

Herbs for Menopause

Herbs that are used to treat the symptoms associated with menopause.

Spice…the Variety of Life

Seasoning with herbs and spices keeps food interesting and pleasing to the palate, as long as you don't overdo it, and as long as the seasonings are fresh.

Guggulu - Herbs From The Land of India

Guggulu is considered to be one of the most and natural cleansing herbs. It helps in treating various skin related diseases and is effective in many more conditions.
Shilajit - Herbs From The Land of India

Shilajit is considered to be one of the most useful herbs, which can be used in treatment of almost any disease/ailment...

Shatavari - Herbs From The Land of India

Information about the herb Shatavari which is helpful to both men and women and because of its qualities which is called 'Women's Best Friend'.

Amla - Herbal Gift From India

Today we will discuss one more herb from the soil of India, which is called AMLA, also better known as Indian Gooseberry, or as Emblic Myrobalan in other countries. In our quest of finding the right herb that not only boosts our immune system and helps in fighting various diseases but also helps us in building our personality by enhancing our physical looks and rejuvenate ourselves, Amla is surely one herb that never can be denied its important role in the array of Indian herbs.

Shankhapushpi - Brain Tonic From India

As we take care of our physical health, it is also very important to take care of our mental health. If our brain is strong and functioning at its best, then our entire body system works to give the peak performance. To keep ourselves mentally fit and fine, we need to use ingredients, which are natural and are without side effects such as shankhapushpi, jatamanasi, brahmi etc.

CURRENT MARKETED PRODCUTS

CURRENT MARKETED COMBINATION PRODUCTS OF KETOCONAZOLE

Drug (Trade Name)	Type of Dosage form	Strength	Manufacture Name
1. Ketaconazole 2%w/v +Zinc Pyrithione 1% w/v (CANFREE-ZPTO) 2. Ketoconazole 2% w/v + ZPTO 1% w/v (DENZY) 3.KETOCONAZOLE 2% w/v +ZPTO 1% w/v (ENDAN) 4. Ketoconazole 2% w/v +Beclomethasone Dipropionate 0.025 % w/v (KEN B TOPICAL) 5.Ketoconazole 2 % w/v + Zinc Pyrithione 1% w/v (KTC Medicated Shampoo) 6. Ktoconazole 2% w/v + Zinc Pyithione 1% w/v (NUFORCE Shampoo)	Shampoo Lotion Shampoo Solution Shampoo Shampoo	66 ml 50 ml 50 ml 25 ml 50 ml 50 ml	Chem + Pled Pharma Zee lab Gnine Marketing Digmedi (P) Ltd Yash Pharma Mankind

SUMMARY & CONCLUSION

The incidence of fungal infections has markedly increased in recent years. Several factors have contributed to this increase. These include greater use of immunosuppressive drugs ; prolonged use of broad spectrum antibiotics ; wide spread use of indwelling catheters ; and the acquired immunodeficiency syndrome. Syndrome (AIDS).

Major fungal infection :-

     Cutaneous = skin, hair and nails                                        Most common

              eg.          ‘Athlete’s foot’, Ringworm, and Tinea cruris

     Mucocutaneous = moist skin and mucous membranes                Common

     Such as GI, Perianal and vulvovaginal areas

                             Eg. candida albicans

     Pulmonary/Systemic                                                        Less

                             Frequent

                   Eg. Invasive Aspergillus, cryptococcal meningitis,

                   pulmonary histoplasmosis; also, systemic candidiasis.

For treatment various antifungal agents are used such as Antibiotics, Azoles, Allylamine, Antimetabolites etc. This project is basically related with  an imidazole known as Ketoconazole., a new orally active antifungal agent is an imidazole derivative structurally related to micronaozle and clotrimazole. It impairs the synthesis of erogosterol (the main sterol in fungal cell membranes) in susceptible organisms, including yeast, fungi, and dermatophytes. Ketoconazole is absorbed from the gastrointestinal tract; it is better absorbed from acidic aqueous solutions, so drugs  that alter the pH of the stomach affect ketoconazole absorption. Therapeutic plasma concentrations are maintained for several hours following ketoconazole administration. Ketoconazole distributes readily into blood, urine, saliva, joint fluid, sebum and cerumen; recent data indicate it may penetrate into cerebrospinal fluid as well. Elimination is biphasic, with a half-life of two hours during the first 10 hours following a dose, and half-life of eight hours thereafter. Ketoconazole is metabolized by the hepatic microsomal oxidation system; metabolites are excreted renally.

Nausea and vomiting are the most common adverse effect encountered with ketoconazole. Transient elevations in serum liver enzymes have been noted occasionally. Initial daily ketoconazole dosage is 200 mg taken with a meal ; 400 daily has been used for some conditions. .

Ketoconazole is effective in treatment of several local and systemic fungal infections. It is approved by FDA for treating candidiasis, chronic mucocutaneous candidiasis oral thrush, candiduria, coccidioidomycosis, histoplasmosis, chromomycosis, and paracoccidioidomycosis.

Conclusion

Ketoconazole is a promising new drug, especially when one considers other available antifungal agents.Although an effective compound ketoconazole has become a second-line drug due to the ready availability of the somewhat safer agents, itraconazole and fluconazole.

REFERENCE

1.     Satish gupte M.D., “Short Textbook of medical microbiology”, 7^th edition JAYPEE Brothers , Medical publishers (P) LTD. P- 497-518.

2.     Martindale “The extra Pharmacopoeia” 30^th edition Edited by James E.F. Reynolds, 315-332.

3.     “Indian Pharmacopoeia” V^th Edition-1996. Ist volume. Appendix. 3.44 ;

4.     K.D. TRIPATHI “Essentials of Medical Pharmacology” Jaypee Brothers Medical Publishers (P) LTD. Fifth-edition 2002, P-770-780.

5.     F.S.K. BARAR “Essentials of Pharmacotherapeutics” S. Chand & Company LTd. Third edition-2000.P-501-507.

6.     “The Merck index”, Twelfth edition.

7.     “Drug Today” Edition-October-December 2004,P- 347,584.

8.     Kohan, S.L., C.E. Guillen, E.M. Pardes, M. Junco, and R.J. Soto, 1992. Effects of Ketoconazole on the iodide uptake by FRTL-5 Cells 127:449-453.

9.     Como JA, Dismukes W.E., Oral azole drugs as systemic antifungal therapy N. Engl J med 1994;330:263-265.

10.                        Drugs for the treatment of systemic fungal infection Med Lett Drugs Ther. 1984;26:36-38.

11.                        Kauffman CA. role of aroles in antifungal therapy Clin infect Dis 1996 ; 22(Suppl) :5148-5151.

12.                        Piscitelli SC. Goss T.F. Wilton JH et al. Effects of Ranitidine and Sucralfate on Ketoconazole bioavailability. Antimicrob agents Chemother 1991;35(9):1765-71.

13.                        Fabris A, Pellanda MV, Gardin C et al. Pharmacokinetics of antifungal agents. Peritoneal Dialysis International 1993;13(suppl; 2):S380-2.

14.                        Sud IJ and Feingold DS. Mechanism of action of the antimycotic imidazoles . The Journal of Investigative Dermatology 1981;76:438-41.

15.                        Baciewicz, A.M. , and F.A. Baciewicz. 1993. Ketoconazole and fluconazole drug interactions. Arch Intern. Med . 153:1970-1976.

16.                        Gubbins, P.O. A., McConnel, and S.R. Penazak. 2001. Antifungal Agents In S.C. Piscitelli and K.A. Rodvold (ed.), Drug Interactions in Infectious Diseases. Humana Press, Totowa, N.J.

17.                        F.C. Odds, L.J. R. Milne, J.C. Gentles, and E.H. Ball., J. Antimicrob, Chemother., 1980, 6,97.

18.                        V.V. Cosofret, “Membrane Electrodes in Drug Substnaces Analysis”, 1982 Pergamon Press, Oxford.

19.                        J. Koryta and K. Stulik, “Ion-Selective Electrodes”, 2^nd ed., 1983, Cambridge University Press, Cambridge, 100                                                                  .J.N. Delado and W.A. Remers, Wilson and Gisvold’s Textbook of Organic Medical and Pharmaceutical Cehmistry, New York 1991.

20.                        C.M. Riley and M.O. James. J. Chromatogr. 1986, 37, 287.

21.                        M. Shamsipur and kh. Fahadi, Electroanalysis, 2000,12,429.

22.                        Z.Marezenko,” Separation and Spectrophotometric Determination of Elements”, John Wily & Sons 1986, P.531.

23.                        United States Pharmacopeias, 1985, 16^th Ed., Esaston, Pa. 572p.580.

24.                        Attwood D : Microemulsions, in Kreuter H (ed) : Colloidal Drug Delivery System, New York, Marcel Decker, 1994, p 312.

25.                        Ogino K, Abe M: Microemulsiojn formation with some typical surfactants in Matijevic E (ed): Surface and Colloid Science, New York, Plenum Press, 1993, p 31.

26.                        Paul BK, Moulik SP : Microemulsions : An overview,. J. Disp Sci 18(4):301, 1997.

27.                        Tenjarla S.N. : Microemulsions : An overview and pharmaceutical applications. Critical reviews^TM in Therapeutic Drug Carrier Systems 16:461-521,1999.