Molecular state of chlorpheniramine in resinates

Chlorpheniramine (CPM) maleate was prepared as a series of resinates by the batch method. The several resinates were investigated by differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD) and infrared (IR) spectrometry. The results from DSC and XRPD showed that the molecular state of the entrapped drug changed from the crystalline to amorphous state. IR spectra indicated that only CPM species was entrapped in the resinates. Moreover, it also showed that the positively charged amine group of the drug interacted with the sulfonate groups of the resin by ionic association. The dissolution of the drug and resinates was also studied where it was found that the dissolution of the resinates was retarded by their crosslinked structure and markedly affected by the quantity of resin.