DEVELOPMENT AND CHARACTERIZATION OF AN ORAL CONTROLLED-RELEASE DELIVERY SYSTEM FOR MELATONIN

Sugar spheres loaded with melatonin (MT) were coated with Aquacoat(R) to control the release rate of MT. Dissolution of MT was evaluated usi ng the USP basket method. With 18-20 mesh beads, T-50% (time to releas e 50% of drug) for 5%, 10%, and 20% coatings was 10 min, 35 min, and 6 0 min, respectively. A desired release pattern over 8 hours was obtain ed with 20% coating on 8-10 mesh beads. T-50% for 5%, 10%, and 20% coa tings was about 1, 2, and 4 hours, respectively. MT in 20% coated bead s was quite stable during storage at room temperature with less than 5 % MT degraded during 6 months of storage. Dissolution profiles from 8- 10 mesh beads with a 20% coating were unchanged after 6 months of stor age at room temperature. Administration of the dosage form to human su bjects maintained MT plasma concentrations over 100 pg/ml for approxim ately 8 hours.