Context: Celecoxib (CXB, 0.2 g)-loaded anionic and cationic nanosized emulsions were prepared by a well-established combined emulsification method.
Objectives: To investigate the effect of non-phospholipid-based cationic and phospholipid-based anionic emulsions on skin retention and anti-inflammatory activity of CXB.
Methods: Using Keshary-Chien diffusion cells with cellulose acetate membrane or excised rat skin, in vitro release and skin retention of CXB from solution and emulsions were studied. The anti-inflammatory activity was evaluated by the carrageenan-induced hind paw edema method in Wistar rats.
Results: The amount of drug released through artificial membrane has decreased from 122.00 ± 0.70 μg/cm(2) for the CXB solution to 55.80 ± 0.70 μg/cm(2) for anionic emulsion, and then further decreased to 24.79 ± 0.90 μg/cm(2) for cationic emulsion. The JSS value obtained with solution, anionic, and cationic emulsions were 6825.79 ± 920.86, 2513.15 ± 382.71, and 1925.67 ± 147.42, respectively. Cationic emulsion showed a significantly higher level (P ≤ 0.05) of drug accumulation in full-thickness rat skin than anionic emulsion, and a substantially lesser percentage inhibition of edema values compared with both solution and anionic emulsion.
Discussion and conclusion: Sustained drug release together with increased skin accumulation and simultaneously decreased skin permeation as observed with cationic emulsion should substantiate its suitability as a topical delivery vehicle for CXB.