Sterile powders are prepared by removing moisture from a solution or suspension to produce a dry product that can be reconstituted before use.
Steps in Formulation of Sterile Powders:
Preparation of the Solution:
The drug and excipients are dissolved or suspended in a suitable vehicle.
Common excipients include stabilizers, bulking agents (e.g., mannitol), and buffers.
Sterilization:
The solution is sterilized by filtration or heat to ensure microbial absence.
Freeze-Drying (Lyophilization):
The sterilized solution is frozen, and water is removed by sublimation under reduced pressure.
Lyophilization maintains drug stability, especially for heat-sensitive biologics or peptides.
Packaging:
The powder is filled into sterile vials under aseptic conditions and sealed with rubber stoppers and aluminum caps.
Advantages of Sterile Powders:
Enhanced stability for drugs sensitive to hydrolysis.
Extended shelf life.
Convenient storage and transportation.
Examples:
Antibiotics like ceftriaxone, vaccines, and certain biologics.