TOPICAL EMULSIONS STABILIZED BY SILICA NANOPARTICLES: IN VITRO RELEASE AND ANTIINFLAMMATORY STUDIES OF FLURBIPROFEN AND DICLOFENAC SODIUM

Abstract

Simple and multiple emulsions have a wide range ofpharmaceutical applications. Therefore, the stabilization of suchemulsions is a challenge to ensure a stable formulation along theperiod of storage, usage and at the same time to conserve theefficacy of the incorporated medicament. Simple o/w and multiplew/o/w emulsions were prepared using castor and paraffin oils asoil phases and stabilized solely by silica nanoparticles of wellcontrolledsurface properties. Two non-steroidal ant-inflammatorydrugs, namely flurbiprofen and diclofenac sodium wereincorporated in the stabilized simple and multiple emulsions,respectively. The stability of emulsions and the in vitro release ofthe drugs from the prepared emulsions were studied. In addition,the anti-inflammatory activity of the drugs from these liquidformulations was assessed using carageenan-induced hindpawedema in rats. The results indicated that the prepared liquidemulsions, which stabilized with silica nanoparticles, were highlystable. The in vitro release of flurbiprofen and diclofenac sodiumfrom these simple and multiple emulsions showed higher ratescompared with those preapred from paraffin oil due to their lowerviscosities. The results revealed also that the percentage of oil hasa pronounced effect on the in vitro release rates of the drugs fromthe emulsions. Furthermore, topical flurbiprofen and diclofenacsodium emulsions exhibited a potent local anti-inflammatoryactivity compared with the orally adminstered drugs in thesuspension form and this activity reached its peak (57-84%) 3 hrsafter carrageenan injection and persisted for 5 hrs, the period ofstudy.