DESIGN AND EVALUATION OF A DRY SOLIDIFICATION TECHNIQUE FOR PREPARINGPHARMACEUTICAL BEADS

A dry solidification technique was adopted in this study to replace th e traditional method of using organic solvents as solidification media (which can be referred to as the wet solidification technique) in the preparation of agar and gelatin bends. This new technique was based o n dropping warm aqueous solution of either polymer over a stationary, rotating or vibrating magnesium stearate powder (chosen as a hydrophob ic medium) in which the followed drops could be solidified Dust-free b ends could be obtained after sieving the solidified drops and blowing them with a stream of cold air. It was found that stationary method pr oduced the most spherical bends while that of vibrating method produce d lens-shaped ones. In the case of rotating method, mixtures of spheri cal, elongated and oval bends were obtained. The nature and shape of t he formed bends were dependent on the concentration of the polymer sol ution, the height from which the samples were dropped and the rotation or the vibration speed used. The in vitro release of sulphamethizole (urinary tract antiseptic) from agar bends prepared by stationary meth od was found to be slightly higher than those prepared by solidificati on in cold ethyl acetate. However, the drug bioavailability in terms o f cummulative amount excreted in urine (mg), T-max and AUC(0-12h) fron t the former bends was 8 to 16% higher than that excreted from the lat er traditional ones.