Carbidopa Capsules for Insulinoma Diagnostic: Compounding and Stability Study

Abstract Background Carbidopa is a drug mainly used to treat Parkinson’s disease. Associations with levodopa or with levodopa/entacapone are commercialized, but there is no oral formulation of carbidopa alone available in Europe. As carbidopa can also be used as premedication of adult patients for insulinoma diagnosis, it must be compounded as single dose mg capsules. The single dose administration of a magistral preparation implies the compounding of only one capsule, or the loss of consequent quantities of active pharmaceutical ingredient. As an alternative solution, carbidopa capsules could be compounded as batches of hospital preparation. Method With this objective, a stability-indicating dosing method for 200 mg carbidopa capsules was developed. Then, the compounding process was assessed according to the European Pharmacopeia requirements. Finally, the stability of carbidopa capsules stored protected from light at room temperature was studied for one year. Results 200 mg carbidopa capsules compounding process was validated on three independent batches. The beyond use date was fixed at one year. Conclusion Our work confirms that carbidopa 200 mg capsules can be realized in hospital pharmacy and its stability allows the compounding of large batches.