Comparative Impact of Stirring and Shearing in Drug Dissolution Testing with USP Paddle and Crescent-Shaped Spindles

Introduction Drug dissolution testing is an integral part of drug product development and quality assessment. Often drug dissolution testing is a regulatory requirement to establish the quality of a drug product [1-3]. In reality,drug dissolution testing is a solubility determination technique. It utilizes specialized equipment for that purpose,commonly known as basket and paddle apparatuses. These apparatuses have official recognition throughout the world,generally through pharmacopoeias, such as USP,where these apparatuses are also referred to as Apparatuses 1 and 2,respectively [1]. It has been well documented that results obtained from dissolution testing using these apparatuses may be highly variable and unpredictable [4-9] and often lack relevance to the in vivo drug release characteristics (bioavailability) of the products [10-11]. In recently reported studies [12-15], it has also been demonstrated that,because of the lack of an adequate stirring and mixing environment in the dissolution vessels, inaccurate comparative drug dissolution/release of the test products may also be observed. To address these flaws and artefacts of the currently used apparatuses,we have proposed a new spindle for providing improved stirring and mixing and thus improved productmedium interaction [12-15]. This report provides further evidence in support of the superiority of the crescentshaped spindle over the currently used spindles.