The Potential Use of Natural Rubber in Pharmaceutical Closures

Abstract

Current manufacturing techniques could produce natural rubber closures that meet all criteria standardized by pharmacopeias except the ultraviolet absorbance limit in the range of 220–360 nm for the closures’ leachate. The type and the dosage of the rubber compounds’ ingredients affected the ultraviolet absorbance of the leachate, while rinsing the closures in water with ultrasonic waves and ozone did not. Intensive washing of the rubber coagulum and deproteinization of the rubber latex using bromelain reduced ultraviolet absorbance of the leachate significantly. Further purification of natural rubber latex is necessary to enable the use of natural rubber in pharmaceutical closures.