Abstract

The objective of this study is to formulate niosomes of pentoxifylline, characterize niosomes in terms of entrapment efficiency, particle size distribution, in vitro release and stability and investigate the bronchodilatory activity of plain and niosomal pentoxifylline in vivo in guinea pigs. Pentoxifylline was entrapped in niosomes by lipid layer hydration method using Span 60, cholesterol and dicetyl phosphate. The entrapment efficiency of niosomes of pentoxifylline was determined by separating the entrapped drug from the free drug by centrifugation. The in vitro release profile of the drug from niosomes was carried out in phosphate buffer saline (pH 7.4). The stability of niosomes was assessed by storage at 4 plus minus 1 degree, 25 plus minus 1 degree, 37 plus minus 1 degree and 45 plus minus 1 degree for one month. The plain (20, 40 and 80mg/kg) and niosomal pentoxifylline (5, 10, 20 and 40 mg/kg) was injected intraperitoneally to guinea pigs for evaluating bronchodilatory activity. The entrapment efficiency of niosomes of pentoxifylline was found to be 9.26 plus minus 1.93 percent giving a sustained release of drug over a period of 24h and better stability over the period of storage. The plain and niosomal pentoxifylline produced significant bronchodilatory effect in guinea pigs on histamine-induced bronchoconstriction. The study indicates that pentoxifylline may be an effective bronchodilator.