Absorption kinetics of topical clindamycin preparations

Area of Science:

• Dermatology
• Pharmacokinetics
• Clinical Pharmacology

Background:

• Topical clindamycin is widely used for acne treatment.
• Understanding systemic absorption is crucial for safety and efficacy assessments.

Purpose of the Study:

• To compare the systemic absorption of clindamycin from two topical formulations: Cleocin-T and clindamycin HCl in Vehicle-N (Neutrogena).
• To determine the absolute bioavailability and pharmacokinetic profiles of these topical formulations.

Main Methods:

• A crossover study involving 12 healthy male Caucasians.
• Topical application of 1 ml of Cleocin-T and 1% clindamycin HCl in Vehicle-N to the face every 12 hours for 4 days.
• Intravenous (IV) infusion of 300 mg clindamycin phosphate for absolute bioavailability calculation.
• Measurement of cumulative urinary excretion and serum AUCs to assess systemic absorption.

Main Results:

• Systemic absorption was significantly higher for clindamycin in Vehicle-N (7.5% bioavailability) compared to Cleocin-T (1.7% bioavailability).
• Peak serum concentrations were higher for Vehicle-N (4-20 ng/ml) than for Cleocin-T (<0.5-6 ng/ml).
• Zero-order absorption kinetics were observed with Cleocin-T, and no significant systemic accumulation occurred with repeated topical applications.

Conclusions:

• Clindamycin in Vehicle-N demonstrates greater systemic absorption than Cleocin-T following topical facial application.
• Despite differences in absorption, systemic exposure to clindamycin from both topical formulations is minimal.
• These findings contribute to the understanding of topical clindamycin pharmacokinetics in non-acne subjects.