Preparation and pharmacokinetic evaluation of carbamazepine controlled release solid dispersion granules

Solvent evaporation technique was applied to prepare granules of carbamazepine coprecipitates using Eudragit RLPM, Eudragit RS 100, Cellulose acetate phthalate and Ethyl cellulose in 1: 1 and 1:2 drug: polymer w/w. In vitro release of carbamazepine from its coprecipitates with the previously mentioned polymers as well as the commercially available tablets [Tegretol CR200 tablets, Ciba] was carried out in gradient pH media [1.2, 2.5, 4.5, 7, 7.4] for 7 hours. The data were kinetically treated. Pharmacokinetic studies of the selected formula made with ethyl cellulose [1:1] and Tegretol CR 200 mg tablets [Ciba], as a reference standard, as well as carbamazepine powder were done using albino rabbits. Carbamazepine plasma level was determined using HPLC. The in vitro and in vivo data revealed that the suggested formula and the innovator's product exhibit% dissolution, tmax, Cpmax, AUC and /delta[1/2] as follows, 58.4%, 8 hr, 24.15 +/- 5.5/-microg/ml, 277.24hr microg/ml, 5.6hr and 64.22%, 8hr, 28.93 +/- 315.14 microg/ml, 313.6 hr, microg/ml, 5.2 hr respectively. It is worthy to note that the suggested formula showed a more prolonged duration of action