The effect of core and coating composition on drug release: from directly compressed time-controlled release tablets

The authors prepared and tested press-coated tablets with various weight ratios of ethylcellulose to hydroxypropylcellulose (HPC) and various ratios of two different batches of HPC as an outer coating shell and fillers in core tablets. The tablets were examined for changes in time lag and release patterns of salbutamol sulfate. Various drug-release mechanisms were observed by incorporating different polymers into the outer shell and different core compositions. By deepening the knowledge of polymeric materials' behavior in dosage forms and, in particular, their application in the press-coating of different core compositions, a safe and more accurate targeting of the drug from dosage forms can be achieved.