PURPOSE: To evaluate the usefulness of a miniaturized rotating disk equipment for the determination of factors influencing the in vitro dissolution rate, G, of a model basic drug substance (terfenadine) in different aqueous media, using experimental design and multivariate data analysis. The apparent solubility, S, was included in the chemometric study. METHODS: The dissolution rate was determined with a miniaturized rotating disk apparatus and the solubility by shake-flask methodology. Media were based on acetate, phosphate or maleate buffers-the latter used in fasted state simulated intestinal fluid (FaSSIF-V2). The chemometric analyses included fractional factorial design, principal component analysis (PCA) and orthogonal partial least squares (OPLS). Quantifications were made with a RP-HPLC-DAD system. RESULTS: The most influential factor for both G and S of terfenadine in the different media was pH. Apart from the ionic strength and sodium chloride concentration in the acetate medium, the effects of the other variables were insignificant, implying no wetting effect of the surfactants. CONCLUSIONS: The miniaturized rotating disk equipment was suitable to use, in conjunction with the chemometric analyses, in the evaluation of the factors affecting the in vitro dissolution rate. The apparent solubility was found to be influenced by the same factors as G.
PURPOSE: To evaluate the usefulness of a miniaturized rotating disk equipment for the determination of factors influencing the in vitro dissolution rate, G, of a model basic drug substance (terfenadine) in different aqueous media, using experimental design and multivariate data analysis. The apparent solubility, S, was included in the chemometric study. METHODS: The dissolution rate was determined with a miniaturized rotating disk apparatus and the solubility by shake-flask methodology. Media were based on acetate, phosphate or maleate buffers-the latter used in fasted state simulated intestinal fluid (FaSSIF-V2). The chemometric analyses included fractional factorial design, principal component analysis (PCA) and orthogonal partial least squares (OPLS). Quantifications were made with a RP-HPLC-DAD system. RESULTS: The most influential factor for both G and S of terfenadine in the different media was pH. Apart from the ionic strength and sodium chloride concentration in the acetate medium, the effects of the other variables were insignificant, implying no wetting effect of the surfactants. CONCLUSIONS: The miniaturized rotating disk equipment was suitable to use, in conjunction with the chemometric analyses, in the evaluation of the factors affecting the in vitro dissolution rate. The apparent solubility was found to be influenced by the same factors as G.