Enhancement of dissolution and in vivo evaluation of lornoxicam ternary system with Gelucire 50/13 and polysorbate 80

Abstract

Background: Lornoxicam is an important non-steroidal anti-inflammatory agent. It is practically insoluble in water leading to difficulty in formulation and adversely affecting its pharmacokinetic and pharmacodynamic properties. For drugs like lornoxicam, the rate of absorption is often controlled by the rate of dissolution. Thus the enhancement of the dissolution rate and in turn solubility of poorly soluble drugs is important. Aims: The purpose of this present study was to prepare binary and ternary systems with lornoxicam, carrier and surfactant. Materials and Methods: Binary solid dispersions of lornoxicam with Gelucire 50/13were prepared at different drug to carrier ratios(1:1), (1:3), and (1:5). Polysorbate 80, a nonionic surfactant, was incorporated as a third component to obtain the ternary solid dispersion system. The solubilizing and absorption enhancer properties of this ternary solid dispersion system was then investigated. Solid systems were prepared by mixing or co precipitation and were characterized by different scanning calorimetery, X- ray diffractometery followed by tests for dissolution behavior. Results: The results thus obtained showed a remarkably improved dissolution of drug from the ternary solid dispersion systems when compared with the binary solid dispersion systems. In order to verify the improved dissolution therapeutically, a paw edema test for the formulation was carried in rats where in the ternary system exhibited a potent local anti-inflammatory activity against carrageenan induced paw edema when compared to pure drug. Thus vindicating the solubilizing and dissolution enhancing effect due to the addition of third additive to the binary system of lornoxicam. ¬¬¬¬¬¬¬¬¬Conclusions: The drug loaded lornoxicam binary solid dispersion with GL50/13 exhibited faster dissolution rate than drug alone. The significant high drug-dissolution rate was obtained in a ternary solid dispersion system using tween 80 as a third component. The fastest drug dissolution obtained was in the ratio of 1:5:1 w/w/w (LOR /GL50/13/ tween 80). The in vivo experimental results corroborated the in vitro outcomes of lornoxicam.