Abstract
Colloidal particles, produced upon the dispersion into water of a solid dispersion system composed of (R)-1-[2, 3-dihydro-1-(2'-methylphenacyl)-2-oxo-5-phenyl-1H-1, 4-benzodiazepin-3-yl]-3-(3-methylphenyl)urea (YM022), hydroxypropylmethylcellulose 2910 (TC-5E) and polyoxyethylene hydrogenated castor oil 60 (HCO-60) at a weight ratio of 1 : 3.5 : 0.5, were characterized with respect to their physicohemical properties. From the IR absorption spectroscopic analysis, it was found that the colloidal particles, composed of YM022, TC-5E and HCO-60, have a combined weight ratio of 1 : 0.2 : 0.3. Although colloidal particles were prepared form solid dispersion systems with various weright ratios of YM022/TC-5E/HCO-60, they showed a similarity in combined ratio, suggesting the presence of specific interactions among the components. Particle diameter seemed to be affected by the composition of colloidal particles. Smaller particles contained less TC-5E which was related to the large portion of YM022 in colloidal particles. The amount of HCO-60 incorporated into colloidal particles was not affected by the particle diameter and correlated with the amount of YM022 at a fixed ratio (1.0 : 0.3). This suggested that TC-5E might function as a 3-dimensional framework for solid dispersion, while HCO-60 might interact with YM022 resulting in a fixed weight ratio between YM022/HCO-60 in colloidal particles.
