Studies On Nefopan Hydrochloride-resion Complexes

Drug-resin is a kind of high polymer, that is insoluble in water and consists of ion exchange resin and drug. Besides control-released pharmaceutics, drug-resin is also used for increasing stability, increasing solubility and taste masking. There are two methods used for preparing drug-resin, they are bath method and column method, In the preparing process, temperature, preparing time, drug concentration and resin particle size all influence preparing.In this paper, the sustained-release drug-resin was made of nefopam with gel-type strong acidic cationic exchange resin as carrier. The research work was composed of preparation and releasing and coating.In the preformulation study, Ultraviolet spectra and stability in different solvent of nefopam hydrochloride were investigated. Nefopam hydrochloride's assaying method in vitro was established, the method was validated by methodology and was proved to be reliable.In order to get the higher availability and higher drug-loading of nefopam, the bath method was optimized based on the orthogonal design. The result showed that preparing temperature should be as high as possible; though high drug concentration brought high drug-loading, the availability would be decreased; Oscillation frequency and preparing time influenced insignificantly.It was proved by IR, TGA and DSC test that there was no physical absorption or crystallization on resin particle surface. Drug and resin were connected by chemical bond.In the investigation of drug-resin's in vitro releasing, we found that diffusion was main rate-limiting step, the factors promoting drug's diffusion will be profit to drug's releasing.Sustained-release drug-resin pellets were prepared by coating Eurdrugit RL 30D, 6g; TEC, 0.3g; talc powder, 1g; SDS, 0.01 g; water,25 g, per 40g drug-resin.