Development of a liquid enzyme-based ceruminolytic product

Various compositions for removal of human cerumen are marketed but they are not very effective. Therefore, a proteolytic enzyme‐based ceruminolytic product was developed containing the enzyme, methyl trypsin, and sodium bicarbonate. Efficacy was optimized based on in vitro testing using both human and artificial cerumen preparations. Both qualitative (visual observation) and quantitative (spectrophotometric) assessments of ceruminolytic efficacy were employed. Optimal enzyme stability was observed for the aqueous formulation at pH 4, while greater ceruminolytic efficacy was observed at pH 8. The optimal concentration range of enzyme was 150-300 absorbance U/mL based on efficacy and stability considerations. An aqueous formulation containing both methyl trypsin and sodium bicarbonate was shown to be more effective than two commercial products, Murine® Ear Wax Removal Drops and Cerumenex® Ear Drops. A two‐part packaging system was employed to provide adequate shelf‐life. Long‐term stability studies confirmed that the formulation maintained >75% enzyme stability for 24 months at 5 and 25°C and after reconstitution at room temperature for up to 1 day. © 2008 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:4970-4982, 2008