Preparation And Pharmacokinetics Study Of PH-dependent Subing Sustained-release Pellets

To effectively prevent the usual incidence of angina pectoris at early morning hours, this paper prepared pH-dependent Subing Sustained-release Pellets by taking reference the prescription of Subing Dropping Pill. Being a semi-flowable and sticky liquid, styrax is both of volatility and inconvenient for use. Borneol sublimes easily. The β-cyclodextrin (β-CD) inclusion complexes of styrax and borneol were prepared by co-precipitation method under the room temperature.The ratios of drug and excipient are as follows, styrax:β-CD=1:12, borneol:β-CD=1:8. DSC thermal analysis method confirmed the formation of inclusion complexes.Drug-containing pellets were prepared by an extrusion-spheronization method, using domestic MCC as the forming excipient and 10% ethanol as the wetting agent. Optimized processing conditions were obtained after the study of formulation factors and processing factors. The pellets produced were of good sphericity, proper hardness and good reproducibility. The average recovery of pellets within mesh20~24 was 86%.The uncoated pellets were covered with sustained release film using a bottom-spray fluidized bed coater. Pellets were covered with gastro-soluble RT(?) coating material for drug release in stomach where the film dissolves. Pellets covered with Eudragit(?) L30D-55 are expected to release drug at duodenum when the coating film dissolves at pH≥5.5. The 1:4 mixture of Eudragit(?)L100 and Eudragit S100 was also used for coating to release drug at the middle and lower part of small intestine where the film dissolves at pH>6.8. Continuously changing dissolution medium simulating gastro-intestinal pH values was used for cumulative release testing. The optimal coating levels were thus determined at 5%, 20% and 15% respectively for the above three kinds of pellets.The above three kinds of pellets were filled into capsules at 2 ratios, forming tested...