Griseofulvin

Fast-dissolving microparticles fail to show improved oral bioavailability

Oral dosage forms are the preferred means of delivering drugs for systemic absorption. However, development problems occur for drugs with poor water solubility and/or gastrointestinal permeability. It is generally believed that the in-vivo bioavailability of poorly water-soluble drugs from Class II of the Biopharmaceutics Classification System can be improved by increasing the dissolution rate. We have attempted to increase the in-vivo oral bioavailability of a model Class II drug (griseofulvin) by preparing rapidly-dissolving particles. The solvent-diffusion method was used to prepare particles with hydrophilic surfactants (Brij 76/Tween 80 surfactant blend) and in-vivo studies were conducted in rats. The griseofulvin particles produced were bipyramidal in habit with a particle size of 2.18 ± 0.12 mm; they contained crystalline drug and a relatively large proportion (12% w/w) of hydrophilic surfactant. The latter and the small particle size ensured rapid particle dispersion and dissolution in-vitro. Thus, within 30 min of the in-vitro dissolution test, the bipyramidal particles had released ∼70% of drug compared with ∼10% from the starting material (particle size 12.61 ± 1.11 μm). However, the rapid and increased drug dissolution in-vitro was not translated to rapid and enhanced absorption in-vivo, and the oral bioavailability of the model drug was found to be the same from the control and from the bipyramidal particles. The poor in-vivo performance of the bipyramidal particles showed that although the dissolution rate of a Class II drug is thought to be a good indicator of its in-vivo bioavailability, this is not always the case.

Electrospray ionization LC-MS/MS validated method to quantify griseofulvin in human plasma and its application to bioequivalence study

A simple, sensitive and rapid liquid chromatography/tandem mass spectrometry (LC-MS/MS) method has been developed and validated to quantify griseofulvin in human plasma using propranolol hydrochloride as internal standard (IS). Samples were prepared using solid phase extraction and analysed without drying and reconstitution. The analytes were chromatographed on Hypersil, hypurity C18 reverse phase column under isocratic conditions using 0.05% formic acid in water:acetonitrile (30:70, v/v) as the mobile phase. Total chromatographic run time was 3.0 min. Quantitation was done on a triple quadrupole mass analyzer API-3000, equipped with turbo ion spray interface and operating in multiple reaction monitoring (MRM) mode to detect parent-->product ion transition for analyte and IS. The method was validated for sensitivity, matrix effect, accuracy and precision, linearity, recovery and stability studies. Linearity in plasma was observed over the concentration range 20-3000 ng/mL for griseofulvin. Lower limit of quantification (LLOQ) achieved was 20 ng/mL with precision (CV) less than 10% using 5 microL injection volume. The absolute recovery of analyte (87.36%) and IS (98.91%) from spiked plasma samples was consistent and reproducible. Inter-batch and intra-batch coefficients of variation across four validation runs (LLOQ, LQC, MQC and HQC) was less than 7.5%. The accuracy determined at these levels was within +/-4.2% in terms of relative error. The method was applied to a pilot bioequivalence study of 500 mg griseofulvin tablet in six healthy human subjects under fed condition.

Treatment of tinea capitis

OBJECTIVE

To review the epidemiology, pathogenesis, mycology, clinical presentation, and pharmacotherapy of tinea capitis, and describe the role of newer antimycotic agents.

DATA SOURCES

A MEDLINE search restricted to English-language articles published from 1966 through 1996 and journal references were used in preparing this review.

DATA EXTRACTION

The data on mycology, pharmacokinetics, adverse effects, and drug interactions were obtained from controlled studies and case reports appearing in the literature. Both open-label and comparative studies were evaluated to assess the efficacy of antimycotics in the treatment of this infection.

DATA SYNTHESIS

Griseofulvin is the drug of choice in the treatment of tinea capitis. Newer agents with greater efficacy or shorter treatment durations continue to be explored. Ketoconazole, the first azole studied for efficacy in tinea capitis, has not demonstrated any clinical advantage over griseofulvin in several controlled clinical trials. Itraconazole is effective, but the available data are limited to case reports and a single uncontrolled study. Terbinafine similarly has shown promise in the treatment of tinea capitis, but the oral formulation was only recently approved in the US. Existing studies reflect the results in infection with pathogens not seen in the US. Both itraconazole and terbinafine achieve high concentrations in the hair and stratum corneum that persist for several weeks following drug administration. This may enable shorter courses of therapy; however, comparative studies need to be conducted in the US.

CONCLUSIONS

Tinea capitis remains the most common dermatophyte infection in young urban children. Oral antifungal therapy is required for effective treatment, often for several months. The combination of griseofulvin with a selenium sulfide shampoo continues to be the mainstay of therapy until more experience is gained with the newer antimycotics.

Short-duration treatment of fingernail dermatophytosis: a randomized, double-blind study with terbinafine and griseofulvin. LAGOS III Study Group

BACKGROUND

Dermatophytic infections of the fingernail can be effectively treated with oral antifungal agents; however, a long duration of treatment, generally several months, is required for cure.

OBJECTIVE

Our purpose was to compare the efficacies of short-duration treatment with terbinafine and griseofulvin in the management of fingernail dermatophytosis.

METHODS

In this randomized, double-blind study 180 patients with fingernail dermatophytosis were treated with daily doses of either terbinafine, 250 mg/day, or microsized griseofulvin, 500 mg/day, for 12 weeks. Patients subsequently received placebo for 12 weeks and were observed for an additional 24 weeks. Drug efficacy was assessed by mycologic examination and measurement of the growth of unaffected nail.

RESULTS

At the end of the study 76% of the group who received terbinafine and 39% of those who received griseofulvin were found to be completely cured (p = 0.001). Drug tolerability was equally good in both treatment groups, without any clinically relevant changes in laboratory biochemical values.

CONCLUSION

Short-duration treatment (3 months) for fingernail dermatophytosis with terbinafine and griseofulvin is well tolerated. However, terbinafine was associated with a higher cure rate.

In vitro evaluation of griseofulvin, ketoconazole, and itraconazole against various dermatophytes in Singapore

BACKGROUND

Superficial cutaneous fungal infection, principally dermatophytosis, is an extremely common skin disease. Various in vitro test systems have been developed in recent years to determine the antifungal activity of various drugs. The minimum inhibitory concentration (MIC) obtained may give an indication of the in vivo potency of the drugs.

METHODS

One hundred patients (69 men and 31 women) with a clinical diagnosis of dermatophytosis were entered into the study. Direct microscopy and culture were done on all patients. The MICS were determined using the broth dilution method.

RESULTS

The age range was 1-76 years. The most common diagnosis was tinea corporis (36%), followed by tinea cruris (22%), and tinea pedis (19%). The most common fungus isolated was T. rubrum (58%), followed by E. floccosum (14%), and T. mentagrophytes (10%). The majority of the isolates was sensitive to the three drugs tested (griseofulvin, ketoconazole, and itraconazole). Of the isolates, 82% were sensitive to griseofulvin, 78% to ketoconazole, and 81% to itraconazole, all at a concentration of < 0.25 micrograms/mL. For T. rubrum, there were four isolates that had an MIC of > or = 64 micrograms/mL to griseofulvin, seven isolates and nine isolates with an MIC > or = 64 micrograms/mL to ketoconazole and itraconazole, respectively. T. interdigitale was relatively resistant to the three drugs in vitro with four of seven isolates having an MIC > or = 4 micrograms/mL with griseofulvin, one of seven isolate with an MIC > or = 64 micrograms/mL with ketoconazole, and three of seven isolates with an MIC > or = 32 micrograms/mL with itraconazole.

CONCLUSIONS

The in vitro antifungal activity of griseofulvin, ketoconazole, and itraconazole are similar against dermatophytes in Singapore. Griseofulvin may be given as the first-line drug for treating such infections in Singapore.

Griseofulvin: a new look at an old drug

Griseofulvin is the oral antifungal agent of choice for the treatment of dermatophytoses. This article reviews the history, pharmacokinetics, adverse reactions, and traditional therapeutic applications of griseofulvin. In addition, reports since 1960 of the use of the drug in the treatment of Raynaud's phenomenon, progressive systemic sclerosis, lichen planus, mycosis fungoides, herpes zoster, eosinophilic fasciitis, and molluscum contagiosum are discussed, noting the varying degree of therapeutic success.

A comparative double-blind study of terbinafine (Lamisil) and griseofulvin in tinea corporis and tinea cruris

In a double-blind randomized study, 92 patients with culturally proven tinea corporis and/or tinea cruris were treated orally with either terbinafine (Lamisil) (125 mg b.i.d.) or griseofulvin (500 mg b.i.d.) for up to 6 weeks. The two groups of patients and distribution of the target lesions were similar, but the analysis of the clinical scores showed that the terbinafine group had slightly higher mean scores at baseline (P = 0.186). At the end of therapy the proportion of patients with negative microscopy and culture was 78% in the terbinafine group and 83% in the griseofulvin-treated group. At the assessment 8 weeks after the end of therapy the percentages of terbinafine- and griseofulvin-treated patients with negative mycology were 93 and 95%, respectively. There were three relapses after mycological cure in the griseofulvin group (8%) and two in the terbinafine group (4%). Griseofulvin-treated patients were treated for shorter periods than terbinafine-treated patients (i.e. 58% compared to 26% received only 2-4 weeks of therapy). In terms of overall effectiveness, there were no significant differences between the two treatments. Thirty-seven terbinafine patients (77%) compared to 36 griseofulvin patients (82%) had overall effective therapy. Eight terbinafine patients (16%) compared to 10 griseofulvin patients (20%) experienced at least one adverse event. Five patients in the terbinafine group and six in the griseofulvin group had to stop the treatment due to headaches or gastrointestinal disorders. One terbinafine patient had an elevation of liver function tests after 6 weeks of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Erythema multiforme due to griseofulvin

Three patients are reported who developed erythema multiforme during treatment with griseofulvin. To our knowledge there have been no previously documented reports of this drug causing erythema multiforme in either the English or American literature.