Methimazole

As a common endocrine and metabolic disease, hyperthyroidism has a domestic prevalence rate of approximately 1.2%, among which about 70% of patients require long-term treatment with antithyroid drugs. Methimazole is currently the first-choice thiourea antithyroid drug in clinical practice. Its mechanism of action is to inhibit the activity of thyroid peroxidase, block the oxidation of iodide and the coupling of tyrosine, reduce the synthesis of triiodothyronine (T3) and thyroxine (T4), and does not affect the release of synthesized hormones. It is applicable to all types of hyperthyroidism patients, especially suitable for people with mild to moderate goiter, adolescents and elderly patients, and can also be used as an adjuvant drug for preoperative preparation of hyperthyroidism and radioactive iodine therapy.

The domestic market size of methimazole preparations has been steadily above 1.5 billion yuan for many years. In recent years, with the improvement of the popularization rate of hyperthyroidism screening, the annual market growth rate has been maintained at 4%~6%. The competitive landscape is characterized by the coexistence of original research drugs and generics. In public medical institution channels, original research products account for about 42%, and domestic generics account for about 58%. At present, more than 12 domestic enterprises have passed the consistency evaluation for their oral immediate-release dosage forms. The maximum price drop of the selected products in multiple provincial centralized procurements is more than 80% compared with the original research products, which greatly reduces the economic burden of patients for long-term medication.

The original research enterprise of methimazole is Merck KGaA, Germany, with the original research trade name of Thiamazole. The core compound patent expired globally in 1996. At present, the original research dosage form approved in China is tablet, with specifications of 5mg and 10mg. It has been included in the China Listed Drug Catalogue as a reference listed drug, and is also included in the FDA Reference Listed Drug Catalogue. On the API level, nearly 30 domestic enterprises have obtained CDE registration numbers for methimazole APIs, among which more than 20 are in status A, which can support the marketing declaration of corresponding preparations. A number of preparation varieties such as methimazole tablets and enteric-coated tablets have been approved for marketing in China. (Data as of June 2025, please refer to the official website of CDE for the latest information)

CATO can provide a full set of impurity reference standards for methimazole API. Most products are in stock. For in-stock products, orders placed before 16:00 will be shipped on the same day. The products meet the requirements of multiple regulations including Chinese Pharmacopoeia and FDA at the same time, and can provide stable reference material support for pharmaceutical enterprises in API research and development, quality control and consistency evaluation work.