PROLONGED RELEASE OF TEGAFUR FROM S O/W MULTIPLE EMULSION/

To develop a prolonged and sustained release preparation, we prepared an albumin microsphere-in-oil-in-water emulsion (S/O/W) and examined s ustained release from it in comparison with other control preparations such as water-in-oil (W/O) emulsions and microspheres in vitro and in vivo, respectively. Tegafur was used as a model drug. A microsphere-i n-oil emulsion was prepared by adding albumin microspheres to soybean oil containing 20% Span 80. To prepare an S/O/W emulsion, the microsph ere-in-oil emulsion was added into an aqueous solution of hydroxypropy l methylcellulose containing Pluronic F68. The mean particle size of t he albumin microspheres was 3 mu m, and the ratio of entrapment of teg afur into albumin microspheres was about 25%. In an in vitro release t est, the t(75) of the S/O/W emulsion was fourfold greater and in an in vivo release test the mean residence time of tegafur from the S/O/W e mulsion was more than twofold that from a W/O emulsion or microsphere system. The mean residence time of 5-fluorouracil (5-FU) from an S/O/W emulsion was also greater than with other dosage forms. These results suggest the possible usefulness of art S/O/W emulsion for the sustain ed and prolonged release of tegafur.