Kinetics of Alkaline Hydrolysis of Indomethacin in the Presence of Surfactants and Cosolvents

Abstract

The effect of nonionic and ionic surfactants as well as water-miscible cosolvents on the alkaline hydrolysis of indomethacin was investigated. Degradation in the presence and absence of surfactants was found to follow pseudo first-order kinetics. The nonionic surfactant, polysorbate 80, produced a 7-fold increase in the stability of indomethacin. The ionic surfactants, cetrimonium bromide, benzalkonium chloride and sodium lauryl sulphate, also resulted in an increase in the stability of indomethacin but to a lesser extent than polysorbate 80. The order of surfactants in increasing the stability of indomethacin was: polysorbate 80 > sodium lauryl sulphate > benzalkonium chloride > cetrimonium bromide. Polyethylene glycol 400 was found more effective than glycerin and propylene