Gavini E, Alamanni M C, Cossu M, Giunchedi P
Dipartimento di Scineze del Farmaco, University of Sassari, Italy.
J Microencapsul. 2005 Aug;22(5):487-99. doi: 10.1080/02652040500099919.
Controlled release dosage forms based on tabletted microspheres containing fresh artichoke Cynara scolymus extract were performed for the oral administration of a nutritional supplement. Microspheres were prepared using a spray-drying technique; lactose or hypromellose have been chosen as excipients. Microspheres were characterized in terms of encapsulated extract content, size and morphology. Qualitative and quantitative composition of the extract before and after the spray process was determined. Compressed matrices (tablets) were prepared by direct compression of the spray-dried microspheres. In vitro release tests of microparticles and tablets prepared were carried out in both acidic and neutral media. Spray-drying is a good method to prepare microspheres containing the artichoke extract. The microspheres encapsulate an amount of extract close to the theoretical value. Particle size analyses indicate that the microparticles have dvs of approximately 6-7 microm. Electronic microscopy observations reveal that particles based on lactose have spherical shape and particles containing hypromellose are almost collapsed. The hydroalcoholic extract is stable to the microsphere production process: its polyphenolic composition (qualitative and quantitative) did not change after spraying. In vitro release studies show that microparticles characterized by a quick polyphenolic release both in acidic and neutral media due to the high water solubility of the carrier lactose. On the contrary, microspheres based hypromellose release only 20% of the loaded extract at pH 1.2 in 2 h and the total amount of polyphenols is released only after about further 6 h at pH 6.8. Matrices prepared tabletting lactose microspheres and hypromellose microparticles in the weight ratio 1:1 show a slow release rate, that lasts approximately 24 h. This one-a-day sustained release formulation containing Cynara scolymus extract could be proposed as a nutraceutical controlled release dosage form for oral administration.
基于含有新鲜洋蓟（Cynara scolymus）提取物的压制微球的控释剂型被用于营养补充剂的口服给药。微球采用喷雾干燥技术制备；乳糖或羟丙甲纤维素被选作辅料。对微球进行了包封提取物含量、大小和形态方面的表征。测定了喷雾过程前后提取物的定性和定量组成。通过直接压制喷雾干燥的微球制备了压缩基质（片剂）。对制备的微粒和片剂在酸性和中性介质中进行了体外释放试验。喷雾干燥是制备含有洋蓟提取物微球的良好方法。微球包封的提取物量接近理论值。粒度分析表明微粒的体积平均直径约为6 - 7微米。电子显微镜观察显示，基于乳糖的颗粒呈球形，而含有羟丙甲纤维素的颗粒几乎塌陷。水醇提取物对微球生产过程稳定：喷雾后其多酚组成（定性和定量）未发生变化。体外释放研究表明，由于载体乳糖的高水溶性，以在酸性和中性介质中多酚快速释放为特征的微粒。相反，基于羟丙甲纤维素的微球在pH 1.2时2小时内仅释放20%的负载提取物，多酚总量在pH 6.8时约6小时后才完全释放。以1:1重量比压片乳糖微球和羟丙甲纤维素微粒制备的基质显示出缓慢的释放速率，持续约24小时。这种含有洋蓟提取物的一日一次缓释制剂可作为口服给药的营养保健品控释剂型。
