Evoclin (Clindamycin Phosphate Topical) - Description and Clinical Pharmacology

DESCRIPTION

Evoclin Foam contains clindamycin phosphate, USP, a topical antibiotic for topical dermatologic use.

Clindamycin phosphate is a water-soluble ester of the semi-synthetic antibiotic produced by a 7 (S)-chloro-substitution of the 7 (R)-hydroxyl group of the parent antibiotic, lincomycin.

The chemical name for clindamycin phosphate is methyl 7-chloro-6,7,8-trideoxy-6-(1-methyl-trans-4-propyl-L-2-pyrrolidinecarboxamido)-1-thio-L-threo-a-Dgalacto-octopyranoside 2-(dihydrogen phosphate), with the empirical formula C₁₈H₃₄CIN₂O₈PS, a molecular weight of 504.97. The following is the chemical structure:

Evoclin® (clindamycin phosphate) Foam, 1%, contains clindamycin phosphate,USP, at a concentration equivalent to 10 mg clindamycin per gram in a thermolabile hydroethanolic foam vehicle consisting of cetyl alcohol, ethanol (58%), polysorbate 60, potassium hydroxide, propylene glycol, purified water, and stearyl alcohol pressurized with a hydrocarbon (propane/butane) propellant.

CLINICAL PHARMACOLOGY

Pharmacokinetics:

In an open label, parallel group study in 24 patients with acne vulgaris, 12 patients (3 male and 9 female) applied 4 grams of Evoclin Foam once-daily for five days, and 12 patients (7 male and 5 female) applied 4 grams of Clindagel^® (clindamycin phosphate) Topical Gel, 1%, once daily for five days. On Day 5, the mean C_max and AUC(0-12) were 23% and 9% lower, respectively, for Evoclin Foam than for Clindagel^®.

Following multiple applications of Evoclin Foam less than 0.024% of the total dose was excreted unchanged in the urine over 12 hours on Day 5.

Microbiology:

The clindamycin component has been shown to have in vitro activity against Propionibacterium acnes, an organism which is associated with acne vulgaris; however, the clinical significance of this activity against P. acnes was not examined in clinical trials with this product. Cross-resistance between clindamycin and erythromycin has been demonstrated.

CLINICAL STUDIES

In one multicenter, randomized, double-blind, vehicle-controlled clinical trial patients with mild to moderate acne vulgaris used Evoclin (clindamycin phosphate) Foam, 1% or the vehicle foam once daily for twelve weeks. Treatment response, defined as the proportion of patients clear or almost clear, based on the Investigator Static Global Assessment (ISGA), and the mean percent reductions in lesion counts at the end of treatment in this study are shown in the following table:

	Evoclin Foam	Vehicle Foam
Efficacy Parameters	n=386	N=127
Treatment response (ISGA)	31%	18%P< 0.05
Percent reduction in lesion counts
Inflammatory Lesions	49%	35%
Noninflammatory Lesions	38%	27%
Total Lesions	43%	31%