ABSTRACT
β-Carotene is one of the most abundant natural pigments in foods; however, usage of β-carotene is limited because of its instability. Microencapsulation techniques are usually applied to protect microencapsulated β-carotene from oxidization. In this study, β-carotene was microencapsulated using different drying processes: spray-drying, spray freeze-drying, coating, and spray granulation. The properties of morphology, particle size, water content, thermal characteristic, and chemical stability have been explored and compared. Scanning electron microscopy measure¬ments showed that the coated powder had a dense surface surrounded by starch and suggested that the coating process gave a microencapsulated powder with the smallest bulk density and the best compressibility among the prepared powders. The chemical stabilities of microcapsules were evaluated during six months of storage at different temperatures. The coated powder had the highest mass fraction of β-carotene, which indicated that the coating pro¬cess was superior to the three other drying processes.
ABSTRACT
OBJECTIVE: To prepare tanshinone II A solid dispersion using spray freeze drying (SFD) method. METHODS: Dissolution profiles of tanshinone II A from different solid dispersions prepared with various excipients were plotted. Based on the dissolution rate, F68 was selected as the excipient. The optimized formula was characterized in terms of morphology, surface area and crystallinity. RESULTS: Compared to raw material, the specific surface of tanshinone II A solid dispersion prepared by SFD method with drug-F68 ratio of 1:9 (w/w) increased by 3 folds. The majority of the tanshinone II A in the solid dispersion transformed from crystalline form to amorphous state. As a result, the dissolution rate of Tanshinone II A significantly enhanced, and 70% of tanshinone II A in the solid dispersion were dissolved in 10 min. CONCLUSION: SFD method has been successfully utilized to prepare solid dispersion of tanshinone II A with enhanced dissolution rate than that of the raw material, which is a prerequisite for increasing its oral bioavailability in vivo. Copyright 2012 by the Chinese Pharmaceutical Association.