Issue link: https://www.e-digitaleditions.com/i/1138630
ery of multiple APIs and mid-clinical-phase dose adjust- ments but are costly and time-intensive to develop and manufacture. The following guidance can help formula- tors make informed decisions. Types of OCR formulations OCR product types vary widely and can be character- ized by functionality or composition. Examples of possi- ble OCR dosage forms are: • Matrix: The API is dispersed within a polymer matrix. • Reservoir: The API in solution resides in a per- meable polymer shell as a monolith or multipar- ticulate. Note that premature coating failure in monolithic reservoirs can cause APIs to be released all at once, possibly leading to toxic blood levels and short durations of effect. • Diffusion: The API diffuses across a polymer membrane, such as in a reservoir system or through a gelled matrix. • Erosion: Only dissolution of the matrix or coat- ing releases the API. • Monolith: The product is a single entity. • Multiparticulate: Small beads containing the API and excipients are placed in a capsule, preparing the beads by various methods, including spray coating or powder layering the API onto a core, such as a sugar sphere. API-loaded beads can also be coated with polymers to modify the API release rate, and multiple populations of beads can be included to create combination products or different drug-release profiles. • Ion exchange: A drug-resin complex releases the API in the presence of a specific pH. • Osmotic: A semipermeable polymer coats a core containing the API and an osmotic agent. As water penetrates the polymer, the API dissolves and exits through the coating via osmotic pressure. • Hybrids and new developments: Combination formats, novel materials and processes, and inno- v a t i v e a d d - o n t e c h n o l o g i e s a r e c o n s t a n t l y expanding the possibilities. Tablets & Capsules July 2019 15 Photo 1: Manufacturing monolithic-matrix tablets uses simple equipment and is relatively quick and inexpensive. Delayed release can be achieved by applying a coating that prevents the tablets from immediately dissolving in the stomach.