Despite being very commonly used in the food and chemical industries for decades, spray drying has, until quite recently, only been a niche technology in pharmaceutical manufacturing. In fact, until the 1980s, drug companies tended to favour easy-to-process molecules — so called BCS 1 substances — that inherently demonstrated good solubility and permeability properties.
When the medical community’s focus shifted to diseases such as AIDS, however, poorly soluble molecules could no longer be ignored. Providing the ability to form solid dispersions, spray drying appeared to offer a solution. Yet, even though industry was now able to enhance the solubility and, consequently, the bioavailability of BCS 2 drugs, some remained unconvinced.
Concerns centred on the notion that the high temperatures applied during spray drying would denature delicate pharmaceutical substances, notwithstanding the fact that many proteins — and even enzymes — are successfully spray dried in the food industry!