Solid state NMR and bioequivalence comparison of the pharmacokinetic parameters of two formulations of clindamycin.

The purpose of this study was to compare the pharmacokinetic parameters and determine the bioequivalence of a generic formulation of clindamycin that is sold in the local markets in the Middle East (Clindox® 150 mg capsule; test) with a reference formulation (Dalacin C® 150 mg capsule) in healthy adult male volunteers. A single-dose, open-label, 2-period crossover study was conducted. Healthy male volunteers were randomly assigned to oral administration of a single treatment of the reference and test formulations. The same groups were given the alternate formulation. After dosing, serial blood samples were withdrawn for a period of 24 h. Serum harvested from the blood samples was analyzed for clindamycin by high performance liquid chromatography (HPLC) with ultraviolet detection. Pharmacokinetic parameters, including AUC(0-∞), AUC(0-t), C(max), K(e), tmax and t(1/2) were determined from the serum concentrations for both formulations (test and reference). The products were tested for bioequivalence after log-transformation of the data. 24 healthy adult male volunteers from Jordan (mean [SD] age, 28.8 (7.7) years (range 19 - 45 years); height, 175.8 (10.6) cm (range 159.0 - 192.0 cm); weight, 75.6 (11.0) kg (range 58 - 101 kg); and body mass index, 24.4 (1.8) kg/m² (range 21.3 - 28 kg/m²) were enrolled in and completed the study. The 13C NMR spectra for both Dalacin C® and Clindox® showed 18 distinct lines associated with the 18 different carbon atoms. The statistical comparison suggested that Clindox® capsules are bioequivalent to Dalacin C® capsules. The 13C CPMAS results confirmed that the two drugs exhibit typical clindamycin spectra.