Formulation and Evaluation of Microemulsion Based Topical Gel of Carbamazepine

Abstract

Carbamazepine(CBZ) is a synthetic compound of the benzodiazepine class, used as an anticonvulsant and analgesic drug. Carbamazepine is relatively slowly but well absorbed after oral administration. Its plasma half-life is about 30 hours when it is given as single dose, but it is a strong inducer of hepatic enzymes and the plasma half-life shortens to about 15 hours when it is given repeatedly. Psoriasis is autoimmune disease in which genetic and environmental factors have a significant role. Carbamazepine was accidently discovered to have antipsoriatic properties. Carbamazepine was obtained as a gift sample from Lupin. Characterization of carbamazepine was carried out by melting point and IR. Carbamazepine has limited aqueous solubility so in literature Self microemulsifying drug delivery system (SMEDDS) have been reported. In the present study, a topical microemulsion based gel of Carbamazepine was prepared. The pseudo ternary phase diagram was prepared to find the microemulsion region. Various microemulsion gel formulations were prepared using carbopol-974 and poloxamer-407 in varied concentrations. Prepared formulations (FG1 to FG10) were evaluated for various parameters like color, appearance, consistency, pH, spreadability and IR. The microemulsion based gels were found to have good spreadability and pH within the range of skin pH and thus suitable to use on skin.