抄録
We previously examined methylcellulose and methylcellulose/alginate oral liquid sustained-release formulations that are gelled in situ and are suitable for elderly and dysphagic patients. The present study aimed to determine how the addition of drugs (acetaminophen, mexiletine, metoprolol, ambroxol, loxoprofen, theophylline, ketotifen and salbutamol) affects the rheological and in vitro drug release characteristics of a 2% methylcellulose formulation and of a 2% methylcellulose/0.5% alginate formulation. With such addition, the viscosity at the lower shear rate of the methylcellulose formulation containing salbutamol rose slightly. The gelation temperature of both formulations significantly increased with the addition of mexiletine and ambroxol, but it was still less than 37°C. In the stress-strain curve of the methylcellulose/alginate gels prepared by heating at 37°C, the gel strength was decreased for some basic drugs. Although the addition of various drugs to methylcellulose and methylcellulose/alginate formulations causes some changes to their rheological properties, the in vitro release of all drugs from the methylcellulose formulation and the methylcellulose/alginate formulation was sustainably restrained at the pHs of 1.2 and 6.8. This study suggests that formulations of methylcellulose and of methylcellulose/alginate may have potential applications as in situ gelling vehicles for the delivery of various drugs.
