The primary duty of the regulatory bodies across the world is to prevent harm from unsafe drugs. In the United States, the law ensures that there shall be a written stability testing programme to assess the stability characteristics of drug products. Stability is the critical quality attribute of a drug product. Further it ensures the capacity of a drug substance, said Kim Huynh-Ba, Technical director of Pharmalytik, Newark in USA.

She was addressing a gathering attended in the workshop organized as part of the IPA Convention 2010 on Stability Testing for global submission, in Chennai on March 12.

Kim said the purpose of stability testing is to provide evidence on how the quality of a drug substance or drug product varies with time under the influence of a variety of environmental factors, such as temperature, humidity, and light. It permits the establishment of a recommended storage condition, retest periods and shelf-lives. Another aim of the stability study is to understand one of the basic properties of the API, she said.

According to her, if there is a program conducted on global stability testing, it will help in many ways like improvement in efficiency and good use of testing. Further it will avoid repeat testing due to the regional difference. Other important advantage of global stability testing is that there is facility for all the tests to be conducted simultaneously at the same lab. Here, the quality can be ‘measured’ instead of ‘designed’, she said.

According to Prabu Nambiar, vice president of Vertex Pharmaceuticals, Cambridge, for compliance of GMP and regulatory requirements, stability testing is necessary. He said if there is no stability, there is no drug at all.

Later while speaking to Pharmabiz, he said there are different norms for stability testing compared to geographical and climatical phenomena. “There are global regulatory challenges. Products for US may not be stable for Chennai. They depend on the temperature. So the storage conditions vary from place to place. Some drugs require long term storage condition. The stability needs of ASEAN countries are far different from western countries,” he said.

According to him, stability testing should be conducted as early as practicable. Though it depends on the nature of the product, preferably the testing can be done within 20-30 days of the formulation. He said generally the stability tests are done for commercial purposes.