Abstract
Microspheres loaded with carnosic acid (CA) as an active ingredient which was extracted from various species of Salvia L., were prepared by a spray drying technology. The matrix of the microspheres consisted of 85% deacetylated chitosan (average MW 55000 kDa), poloxamer P407 and carnosic acid. Briefly, chitosan and poloxamer P407 were dissolved in 1% v/v acetic acid followed by dispersion of carnosic acid under vigorous stirring. The dispersion was then fed into a spray dryer (190 Mini, Büchi, Flawil, Switzerland) and processed under the following operative conditions: T inlet 180°C, T outlet 120°C, air aspiration 70% and peristaltic pump 15% (feeding rate 4 mL/min). This process yielded microspheres with 5-8 μm in diameter containing 17% active ingredients corresponding to an encapsulation efficiency of 45% and a practical yield of 34%.