title: Effect of process variables on the microencapsulation of vitamin A palmitate by gelatin-acacia coacervation.
abstract: Microcapsules of vitamin A palmitate were prepared by gelatin-acacia complex coacervation. The effects of colloid mixing ratio, core-to-wall ratio, hardening agent, concentration of core solution, and drying method on the coacervation process and the properties of the microcapsules were investigated. The microcapsules of vitamin A palmitate were prepared using different weight ratios of gelatin and acacia, that is, 2:3, 1:1, and 3:2 under controlled conditions. The other factors studied were 1:1, 1:2, and 1:3 core-to-wall ratios; 30, 60, and 120 min of hardening time; 2, 5, and 10 ml of formaldehyde per 280 g of coacervation system as a hardening agent; and 30%, 40%, and 50% w/w vitamin A palmitate in corn oil as a core material. The drying methods used were air drying, hot air at 40 degrees C, and freeze-drying. The results showed that spherical microcapsules were obtainedfor all conditions except for 30 min of hardening time, which did not result in microcapsules. The optimum conditions for free-flowing microcapsules with a high percentage of entrapped drug were 1:1 gelatin-to-acacia ratio and 1:2 core-to-wall ratio when hardening with 2 ml formaldehyde for 60 min and using 40% w/w vitamin A palmitate in corn oil as the core concentration. In addition, drying the microcapsules by freeze-drying provided microcapsules with excellent appearance.
authors.affiliation: Department of Pharmacy, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand. pyvbp@mahidol.ac.th
authors.forename: V B
authors.initials: VB
authors.lastname: Junyaprasert
authors.forename: A
authors.initials: A
authors.lastname: Mitrevej
authors.forename: N
authors.initials: N
authors.lastname: Sinchaipanid
authors.forename: P
authors.initials: P
authors.lastname: Boonme
authors.forename: D E
authors.initials: DE
authors.lastname: Wurster
mesh_terms: D000045:Acacia; D000975:Antioxidants / Q000008:administration & dosage / Q000032:analysis / Q000737:chemistry*; D002214:Capsules; D003890:Desiccation; D004224:Diterpenes; D004339:Drug Compounding; D005079:Excipients; D005557:Formaldehyde; D005780:Gelatin; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D000084562:Retinyl Esters; D013056:Spectrophotometry, Ultraviolet; D014801:Vitamin A / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D002214:Capsules; D004224:Diterpenes; D005079:Excipients; D000084562:Retinyl Esters; D014801:Vitamin A; C014794:retinol palmitate; D005557:Formaldehyde; D005780:Gelatin