A HPLC assay for coating integrity of topiramate sprinkle formulation

A HPLC method has been developed for the determination of coating integrity of topiramate sprinkle formulation. This method determines the completeness of the sprinkle coating and, indirectly, the completeness of taste masking of the product. This method utilizes a sample preparation where the sprinkles are placed in a specially designed stainless steel basket equipped with a screen, 25-mesh size, at the bottom. Water is used to solubilize any incompletely coated drug. The aqueous solution is analyzed for topiramate using a phenyl column in the reversed-phase mode, isocratic elution, and refractive index detection. This analytical method, for recovered topiramate, provides an indirect measure of drug taste-masking in the sprinkle formulation. It was also used in formulation selection by screening sprinkles beads that contained different amounts of coating to see which formula can best mask the taste with an acceptable level of exposed topiramate drug substance. This method has been validated to meet FDA validation guidelines.