Unexpected changes in the physical-chemical properties of an API or excipient are often the culprit behind drug shortages. However, the changes are difficult to resolve.
"Sometimes the cause may be understood in advance, but processing controls are insufficient to avoid the problem," writes an unnamed (to nonsubscribers) GLG Research expert contributor. The expert's opinion comes in the form of an analysis of a recent WSJ story on the shortage of attention deficit disorder drugs.
According to the WSJ, the Shire drugs' API is derived from amphetamine, a substance controlled through a quota by the Drug Enforcement Agency. The DEA says it stands ready to approve a quota increase, meaning more of the substance would become available to all users, including Shire. The drugmaker says the agency takes too long.
The GLG expert pooh-poohs the finger-pointing and stands by the API cause. "I base this claim on observations and 20 years' experience with big pharma," he or she writes. The API differences are enough to affect the processing or the quality properties of the drug. "Usually the cause is unexpected, unanticipated."