Lyophilization – freeze drying – is a crucial enabling process technology for many important parenteral drugs. Approx. 60% of biopharmaceuticals, including enzymes, proteins, hormones & monoclonal antibodies, must be lyophilized as these therapeutic agents are insufficiently stable for ready-to-use solution dosage forms.
In solution, many drug substances are susceptible to even modest changes in temperature & chemical environment. These complex molecules undergo hydrolytic, oxidative & aggregation reactions, compromising both potency & safety. Consequently, parenterals must often be distributed “cold-chained” – refrigerated or maintained frozen from manufacturing line to patient. Even then, freezing & thawing may cause some proteins to aggregate.
When the bulk drug ingredients are not stable in liquid or frozen state, lyophilization becomes necessary.