Challenges for Powders for injection (PIs)
Powders for injection (PIs) are a popular parenteral dosage form for drugs ( active molecules). Because of their instability in the aqueous environment, PIs cannot be marketed as ready-to-use injectables. Instead, they are marketed as dry powders to be reconstituted with a suitable vehicle just before administration. The final form after reconstitution may be either a solution or a suspension. Typical molecules in this category include ß-lactam antibiotics, cephalosporins, and acyclovir. A few ready-to-use infusion products are marketed as frozen solutions in plastic bags for these molecules. However, the low temperature required for their shipment and storage makes these products an unviable option, especially in countries in which a cold chain from manufacturing to the point of consumption is difficult to establish. PIs are relatively simple with respect to formulation and process development. However, their performance and stability are critically affected by a number of parameters....