Report: Preparation of levodopa/carbidopa compound drug resins.

The main objective of this study was to prepare the levodopa/carbidopa compound drug resins and investigate affecting factors such as drug concentration, temperature, particle size. The drug resins were made by bath method and the effects of above factors during the process of preparation was studied. Studies on the stabilities of drugs and drug resins were carried out by HPLC. The Results showed that the preparation of drug resins was influenced by drug concentration, resin particle size, reaction temperature and solvent concentration. In certain conditions the degradation peaks were found in the chromatograms of levodopa and carbidopa while the drug-resins remained undegraded. The study indicates that the drug resin technology is an effective way of improving stability of the drug and possesses certain sustained-release effects.