In this study, using the melt-adsorption method, we developed sustained-release microparticles containing the potent drug, tamsulosin HCl, for use as orally disintegrating tablets. A high-speed kneading granulator was used, enabling temperature modulation and uniform material distribution. A lipid and ethylcellulose suspension (Surelease®) was applied to retard drug release, and magnesium aluminometasilicate (Neusilin®) was used as adsorbent. Among various lipid candidates for melt-adsorption, beeswax and glyceryl behenate were selected due to their high mechanical strength. Hot stage microscopy and powder X-ray diffraction analysis results showed compatibility between tamsulosin HCl and both lipids. Characteristic adsorption behavior was observed depending on the physicochemical properties of each composition. Especially, the specific surface area of Neusilin® decreased with increasing amounts of Surelease®, attributed to the pore-covering effect of Surelease®, which significantly increased the size of the microparticles after the lipid adsorption. For a Surelease®-to-beeswax ratio 1:50, both the desired particle size distribution and low burst release were achieved. Furthermore, the orally disintegrating tablet containing optimized microparticles had acceptable tablet hardness and rapid disintegration. Herein, the feasibility of melt-adsorption for the preparation of sustained-release microparticles was well demonstrated. With its convenience and efficiency, the proposed method is a promising alternative to conventional methods, which are relatively difficult and time consuming.
Keywords: Lipid; Melt-adsorption; Neusilin®; Orally disintegrating tablet; Surelease®; Sustained-release microparticles.