In vitro and in vivo evaluation of novel immediate release carbamazepine tablets: complexation with hydroxypropyl-β-cyclodextrin in the presence of HPMC.

Carbamazepine (CBZ)-hydroxypropyl-β-cyclodextrin (HP-β-CD) complex in the presence of HPMC was prepared and characterized by differential scanning calorimetry (DSC) and X-ray diffractometer intended for improving the dissolution rate of CBZ. The phase-solubility method was used to investigate the effect of HP-β-CD and HPMC on the solubility of CBZ. Tablets of the resulting complex were prepared using direct compression method and the bioavailability was evaluated in beagle dogs using a UPLC/MS/MS method. The results showed solubility of CBZ was increased up to 95 times by complexation with HP-β-CD in the presence of 0.1% HPMC. The results of DSC and X-ray diffraction proved a formation of complex between CBZ and HP-β-CD. Dissolution rate of CBZ was notably improved from complex tablets with more than 97.39% released within 10 min; whereas for the commercial tablets, around 60% was released within 30 min. Using commercial tablets as the reference formulation, the bioavailability of complex tablets was considerably increased by 1.5-fold (P<0.05) and T(max) was reduced to 0.88 h compared with 1.25 h for commercial tablets. Furthermore, a lower inter-subject variability (49.9%) was observed compared with that of the commercial tablets (39.7%). It is evident from the results herein that complexation with HP-β-CD in the presence of HPMC is a feasible way to prepare a rapidly acting and better absorbed CBZ oral product.