Formulation and evaluation of sustained release microbeads of mefenamic acid

Abstract

Sustained release microbeads of mefenamic acid were successfully prepared by ionotropic gelation technique. The prepared all formulations were evaluated for Percentage yield, %Entrapment efficiency, Bulk and Tapped density, Hausner ratio, SEM analysis, Swelling index(%), In vitro drug release studies and stability studies. Results from Hausner ratio of prepared formulations F4 showed good to excellent flow property. It is found to be (1.154). The percentage yield of formulation F4 was found to be 97%. Bulk density of formulation F4 was found to be 0.652 gm/ml, and Tapped density of formulation F4 was found to be 0.772 gm/ml. Drug entrapment efficiency (%) of Mefenamic acid alginate microbeads increased with increase in concentration of sodium alginate in formulation F4. The entrapment efficiency was found to be (97.01%). Swelling of the dry beads is mainly attributed to the hydration of the hydrophilic groups of alginate, HPMC E3. Formulations F4 exhibited significant swelling rates when exposed to the alkaline medium (pH 7.4). The swelling index was found to be (89.31%). The in- vitro dissolution studies using two different dissolution media pH 1.2 and pH 7.4 performed for 12 h. Formulation F4 was showed exellent in - vitro drug release. It is found to be (98.33±0.12%). The formulation F4 showed more sustained release. This indicates that the release rate was retarded due to increase in percentage of Polymers (sodium alginate & pectin) and cross linking agents because of strong bonds between sodium alginate and divalent ions. Also the results revealed that the increase in the sodium alginate concentration, diminished the drug release profile. According to stability study it was found that there was no variation in percentage yield, Entrapment efficiency,and In-vitro drug release profile of optimized formulation F4 for 1 month periods. From the overall studies it can be concluded that the formulation F4 considered as the best formulation amoung Five formulation by comparing all the evaluated parameters. Therefore mucoadhesive microbeads could be a feasible approach to achieve sustained release profile of mefenamic acid by reducing its serious side effects, and to improve the bioavailability and patient compliance.