Studies on effect of variables by response surface methodology for losartan microspheres.

ABSTRACT

Microspheres of Losartan potassium were formulated using combination of Ethyl cellulose and Acycoat L30D polymer by solvent evaporation method. A 32 factorial design was used to elucidate the effect of variables viz. the amount of drug and the amount of polymer. Discrete spherical microspheres in the range of 40-50 μm were produced with the encapsulation efficiency of more than 80 %. Polynomial equations and response surface plots were generated for all dependent variables. It was observed that both the factors had significant influence on all dependent variables studied. It was observed that as the amount of polymer increases, the rate of release decreases. So t50 increases and the amount of drug released in 2 h (X120) decreases. Drug polymer interaction study was absent as evidenced by HPLC and FT-IR studies.