A novel cryogenic particle engineering technology to micronize water-insoluble drugs and enhance their dissolution properties : spray-freezing into liquid

Poorly water-soluble and insoluble chemical agents are routinely investigated in the pharmaceutical industry for pharmacological activity, but many of these are never commercialized due to inadequate dissolution and subsequent low oral bioavailability following oral administration. The bioavailability of many hydrophobic active pharmaceutical ingredients (APIs) can be increased by enhancing their aqueous dissolution. Spray-Freezing into Liquid (SFL) is a novel particle engineering technology that has been demonstrated in the following studies to significantly enhance the dissolution of insoluble APIs. The ultimate goal throughout the studies was to produce micronized SFL powders where the inherently insoluble API would be completely dissolved in aqueous dissolution media within a minimal amount of time (less than ca. 10 minutes). The SFL particle engineering technology is a novel process that was developed, investigated and optimized in order to broaden its applications in pharmaceutical drug delivery systems. Micronized SFL powders were compared head-to-head with powders produced from milling, co-grinding with excipients and slow freezing of liquids containing dissolved API and excipients followed by lyophilization. To strengthen the applicability of the SFL particle engineering technology, studies were conducted where micronized SFL powders were exposed to various stability storage conditions, and characterized to determine the influences of the exposure conditions and time on the physicochemical properties of the powder containing the API. The utility of the SFL process was further enhanced by developing an atmospheric freeze-drying (ATMFD) technique to obtain dry micronized SFL powders. Micronized SFL powders dried by ATMFD were compared to micronized SFL powders dried by vacuum-freeze drying to determine any changes in physicochemical properties or dissolution profiles as a function of the drying technique utilized. The usefulness of the SFL particle engineering technology was broadened when it was found that highly concentrated emulsions could be processed by SFL to produce micronized powders that rapidly wetted and dissolved in dissolution media. Micronized SFL powders produced from emulsion were investigated and compared to slowly frozen agglomerates from emulsion and a micronized SFL powder from solution. As a result of the following studies, the enabling examples using the SFL platform were designed to illustrate applications of the SFL technology as a tool to enhance the aqueous dissolution of poorly water-soluble and insoluble APIs. Therefore, it was demonstrated that this novel particle engineering technology is a feasible method that may be used in the pharmaceutical industry to solve the ever-present solubility and dissolution problems associated with poorly water-soluble or insoluble APIs, or chemical agents being investigated for pharmacological activity as future APIs