Abstract
In order to improve the dissolution characteristics of hydrophobic drug from capsule dosage forms, a hydrophilic and non-ionic surfactant was allowed to adsorb onto crystal surfaces ; the solid-state polyoxyethylene cetyl ether and phenylbutazone, dissolved into methylene chloride, were cospray-dried in a mini-spray drier. The concentrations of surfactant added varied in the range of 0-1%. From the results of scanning electron photomicrographic observations of spray-dried samples, it was estimated that a thin film of the surfactant was developed over the crystal surfaces. The surface characteristics of the samples were evaluated by a contact angle measured by the droplet method. The contact angle decreased significantly in the range of more than 0.2% addition of surfactant, and, thus, the effective hydrophilization could be achieved. As for hydrophobic or hydrophilic formulation systems containing a small amount of surfactant-treated phenylbutazone, the hydrophilization effect was plainly reflected in the contact angle and a dissolution rate from an encapsulated formulation in the former system, whereas it was not apparently reflected in the latter.
