Spray drying of pharmaceuticals and biopharmaceuticals: experimental optimization of process and formulation

peer-reviewed
Oral consumption is the most commonly used method of small molecule drug delivery due to its simple administration, flexible formulation design, cost-effectiveness and established production technology. The typical pathway for an orally ingested drug involves dissolution in the gastrointestinal fluid, followed by permeation across the gut membrane and systemic circulation until it reaches the point of action. The rate of dissolution is therefore of critical importance to ensure high drug adsorption and maximum efficacy. The Biopharmaceutical Classification System (BCS) classified active pharmaceutical ingredients (APIs) into 4 categories based on their solubility and permeability among which BCS class II APIs are defined as being poorly soluble but highly permeable. The share of BCS class II APIs of newly developed drugs has increased from 30% to 60% in recent years. Therefore, it is critical for the industry to incorporate effective formulation approaches for improving solubility and dissolution rates of these APIs. In this regard, a number of approaches have been investigated. Amorphous solid dispersion (ASD) is a successful approach for transforming and stabilizing crystalline drugs to amorphous form with higher solubility/dissolution rates. Spray drying (SD) is a solvent-based drying method that has been used for formulating ASDs with improved solubility and stability. Biopharmaceuticals are pharmaceuticals that are inherently biological in nature and manufactured using biotechnology. This broad definition includes any type of blood product, vaccines, antibodies, proteins and nucleic acids. Protein-based pharmaceuticals are among the fastest growing categories of therapeutic agents. Therefore, the development of stable protein based formulations with controlled physicochemical properties is of high interest. Reversible and irreversible aggregation in liquid protein formulations specifically at high concentrations is a challenging problem for biopharmaceutical pr