Absorption of clindamycin after intravaginal application of clindamycin phosphate 2% cream

In recent clinical studies, clindamycin phosphate cream administered intravaginally has been shown to be efficacious in the treatment of bacterial vaginosis (BV). In support of the safety profile for this dosage form, a study assessing the systemic absorption of clindamycin was undertaken in five BV patients and six healthy volunteers who were dosed with 5 mL (100 mg) clindamycin phosphate 2% cream intravaginally once daily in the evening for 7 days. Two weeks later, a single 100 mg dose of clindamycin phosphate sterile solution was administered as a 4 min iv infusion. Serial blood samples were collected on days 1, 4, and 7 after dosing with the cream and over a 16 h period after the iv treatment. Clindamycin concentrations in serum samples were assayed by capillary gas chromatography. After treatment with the cream, steady-state serum clindamycin concentrations were reached by 24 h in all but one subject in each group. Mean absolute bioavailability was 2.7%-4.3% in the BV group and 2.7%-4.7% in the healthy group. These results indicate that systemic exposure to clindamycin from intravaginal administration of clindamycin phosphate cream is minimal.