Hypothyroidism is a condition where insufficient thyroid hormone, thyroxine, is produced in the body to meet the body’s daily requirements, potentially leading to serious complications which directly or indirectly involve the thyroid gland. Levothyroxine is currently available as low dose tablets containing 25 µg, 50 µg, and 100 µg per tablet. Levothyroxine products upon storage have been reported to be susceptible to chemical instability, which alters drug stability and affects therapeutic and physicochemical properties such as bioavailability and content uniformity, respectively. Environmental factors, mainly temperature, play an important role in the production of levothyroxine breakdown products and the drug has been on the Medicines and Healthcare Product Regulatory Agency (MHRA) yellow card since 2009 due to its apparent poor formulation stability. Since 2011, the scheme has recorded a high loss in efficacy for levothyroxine tablets, with 87 negative reports on levothyroxine chemical stability. However, the precise mechanism by which the compound is subject to chemical instability remains unclear.
Development, characterisation and assessment of chemical stability of fast dissolving oral levothyroxine films
Shaban, K. (Author). 2018
Student thesis: Doctoral Thesis