How to Prevent Carbimazole Conversion to Methimazole

Methimazole, or thiamazole, inhibits the thyroid gland from using iodine to produce thyroid hormone, and it is used as the primary antithyroid pharmaceutical around the world. In the United States, the drug is branded as Tapazole, according to Daily Med. However, in Europe, carbimazole, or neomercazole, is the preferred drug. Because carbimazole is converted naturally and rapidly to methimazole in the body after administration, it cannot be detected, so measures must be taken to prevent its conversion. Methimazole is used to treat Grave's disease and experimental thyroiditis in small animals, according to Endocrinology Journals.

Things You'll Need

• Blood sample
• Polyethylene catheter
• Test tube
• Centrifuge equipment
• Cooling apparatus
• Carbimazole
• Saline
• pH indicator

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Instructions

• 1

  Stop the conversion of carbimazole to methimazole before any methimazole is created. The reaction is very fast once it has begun. Methimazole has a plasma half-life of between six and 15 hours. It is distributed throughout the body, as explained by Alkam Tripod.

• 2

  Take a 10ml blood sample from a healthy patient, using a polyethylene catheter. Transfer the blood to a test tube.

• 3

  Centrifuge the blood for 10 minutes to obtain the plasma serum component. Plasma is the medium of the reaction you are going to be testing for and preventing. Cool to 4 degrees Celsius during centrifugation using a standard laboratory cooling apparatus.

• 4

  Dissolve a small quantity of carbimazole in saline. A sufficient amount should be 5g, but you can use less. Carbimazole can be obtained from specialist laboratories, according to Springerlink.

• 5

  Maintain a constant pH of 6.0. Achieving "acidosis" is the most important measure you can take, because changes to the pH promote the reaction from carbimazole to methimazole, which is the process you are aiming to prevent. Measure the pH of the solution every minute using a pH indicator paper such as Litmus paper, a pH probe and meter if your sample is quite large, or a pH indicator reagent. A high-quality, narrow-range dye or paper indicator is best for small-scale laboratory measurements that need precision.

• 6

  Add the saline-dissolved carbimazole to the plasma. Measure the solution for the presence of methimazole using high-pressure liquid chromatography, as described by the Journal of Clinical Pharmacology.