Stability improvement of a liquid enzyme product.

The shelf-life of a previously developed two-part liquid-liquid enzyme ceruminolytic product was improved maintaining the same final reconstituted composition and re-formulating the liquid enzyme portion as a drug granulate by a double wet granulation process. The critical steps for the preparation of the granulate were studied (mixing/granulating times and drying) determining the proteolytic activity, the residual ethanol, and the moisture content of the granulates. The original liquid-liquid formulation had been proven effective as a ceruminolytic agent, but only had stability of greater than 75% enzyme activity for up to 18 months and up to 1 day at room temperature after combining the two parts. The resulting improved product was proven to be stable for up to 24 months at 30 degrees C, and up to 3 days at room temperature after combining the two parts. Therefore, maintaining the enzyme in a granulated form until reconstitution afforded an improvement in stability compared with the original two-part liquid-liquid formulation.