Aging of drug molecules is generally studied following regulatory procedures, i.e. under forced conditions
and for relatively limited storage time; therefore naturally aged samples are rare and provide scientific
reference data beyond regulatory considerations. Tienoxolol was studied after 25 years of storage in
the dark under ambient conditions. About 86% of the samples still consisted of tienoxolol and the main
impurity (13%) was caused by the hydrolysis of the ester moiety. Protection from hu...
Mahé, N. [et al.]. Crystal structure and solid-state studies of aged samples of tienoxolol, an API designed against hypertension. "International journal of pharmaceutics", 2012, vol. 422, núm. 1-2, p. 47-51.