Preparation of controlled porosity osmotic pump tablets for salvianolic acid and optimization of the formulation using an artificial neural network method

In this paper controlled porosity osmotic pump tablets(CPOPT)for salvianolic acid(SA)were prepared and optimized with experimental design methods including an artificial neutral network(ANN)method.Three causal factors,i.e.,drug,osmotic pressure promoting agent rate,PEG400 content in coating solution and coating weight,were evaluated based on their effects on drug release rate.The linear correlation coefficient of the accumulative amount of drug release and the time of 12 h,r(Y_(1)),and the sum of the absolute value between measured and projected values,Y_(2),were used as outputs to optimize the formulation.The weight expression Y=(1-Y_(1))^(2)+Y_(2)^(2) was used in the calculation.Furthermore,the ANN and uniform design gave similar optimization results,but ANN projected the outputs better than the uniform design.This paper showed that the release rate of salvianolic acid B and that of the total salvianolic acid was consistent in the optimized formulation.

Redefinition to bilayer osmotic pump tablets as subterranean river system within mini-earth via three-dimensional structure mechanism

Defining and visualizing the three-dimensional(3 D) structures of pharmaceuticals provides a new and important tool to elucidate the phenomenal behavior and underlying mechanisms of drug delivery systems. The mechanism of drug release from complex structured dosage forms, such as bilayer osmotic pump tablets, has not been investigated widely for most solid 3 D structures. In this study, bilayer osmotic pump tablets undergoing dissolution, as well as after dissolution in a desiccated solid state were examined, and visualized by synchrotron radiation micro-computed tomography(SR-μCT). In situ formed 3 D structures at different in vitro drug release states were characterized comprehensively. A distinct movement pattern of NaCl crystals from the push layer to the drug layer was observed, beneath the semi-permeable coating in the desiccated tablet samples. The 3 D structures at different dissolution time revealed that the pushing upsurge in the bilayer osmotic pump tablet was directed via peripheral“roadways”. Typically, different regions of the osmotic front, infiltration region, and dormant region were classified in the push layer during the dissolution of drug from tablet samples. According to the observed3 D microstructures, a “subterranean river model” for the drug release mechanism has been defined to explain the drug release mechanism.