A novel concept for simultaneous monitoring of dissolution and permeation rates of active tablet ingredients was designed to replace the traditional HPLC-based procedure.
Monitoring of propanolol HCl tablets was automated to exploit the native fluorescence of propranolol HCl in Krebs–Ringer buffer. The streams from dissolution and permeation modules were sampled with high frequency at three different locations, using a conventional SI apparatus as the central hub that provided the connection to detector, auxiliary reagents and autosampler.
The dissolution module was equipped with the flow throughcell, and the permeation module was subdivided into two compartments: the open apical and the closed, circulating basolateral compartment, which held a stirred reservoir. Samples taken at sampling port D, yield the dissolution response.
Concentrations sampled at A, located at the permeation module, provide readout for the apical side of the Caco-2 monolayer. Solution sampled at B allows the calculation of the amount of analyte that permeated through the Caco-2 monolayer.
The method demonstrates that replacing the conventional HPLC procedure with an SI automated system saves labor, reagents and time.