In-use stability studies: guidelines and challenges.

Pharmaceutical products delivered in multidose containers require in-use stability studies. Moreover, those pharmaceutical products requiring dilution or reconstitution prior to use also require in-use stability studies. In-use stability can be described as how well a pharmaceutical product remains stable during in-use within a particular closure system. During the in-use period, the pharmaceutical product remains within its physical, chemical, and microbiological specifications and retains its safety, efficacy, and performance. Even though the different guidelines are available, specific information for in-use stability studies that can smoothly guide applicant for regulatory submission is not at par. In-use stability studies should be performed in accordance to the various guidelines published by the regulatory agencies or by appropriate, justifiable ways that satisfy the regulators. This review explores current in-use stability guidelines, numerous examples of performed in-use stability studies, challenges to in-use stability and other relevant aspects.