Effect of hydroxypropylmethylcellulose (HPMC) on the release profiles and bioavailability of a poorly water-soluble drug from tablets prepared using macrogol and HPMC

The aim of the present study was to investigate the effect of hydroxypropylmethylcellulose (HPMC-2208), used as an excipient for controlled release of drug, on the release profiles and bioavailability of the poorly water-soluble nifedipine (NP) from a tablet prepared using macrogol 6000 (PEG) and HPMC. The crushing tolerance of the NP tablet prepared using PEG and HPMC (NP-PEG-HPMC tablet) was markedly increased with increasing compression force used during the preparation from 20 to 200 MPa. The values reached their maximal levels (approximately 13 kg for the NP-PEG-HPMC tablet and 8 kg for the PEG tablet) at the compression force of 100 MPa. Although NP is a poorly water-soluble drug, it was rapidly dissolved from the NP-PEG tablet (without HPMC) due to the improvement of its dissolution rate in the presence of PEG. NP dissolution was complete at the latest within 1 h. On the other hand, dissolution of NP from the NP-PEG-HPMC tablet was significantly delayed with an increase in the concentration of HPMC in the tablet. The dissolution of NP from the NP-PEG-HPMC tablet containing 50% HPMC-2208 was markedly delayed as the viscosity of HPMC also increased. Interestingly, the same peak plasma NP concentration (Cmax) and the area under the plasma NP concentration–time curve (AUC0–10) were observed for both the NP-PEG tablet and NP-PEG-HPMC tablets, however, the time to Cmax (tmax) for the NP-PEG-HPMC tablet was significantly higher when the NP-PEG-HPMC tablet was orally administered to rabbits. We describe here a preparation method of a new sustained-release NP-PEG-HPMC tablet using a mixture of NP-PEG granules (prepared with PEG) and HPMC.