Yüksel N, Dinç E, Onur F, Baykara T
Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Ankara, Turkey.
Pharm Dev Technol. 1998 Feb;3(1):115-21. doi: 10.3109/10837459809028485.
The purpose of this study was to prepare and evaluate an enteric coated dosage form of nicardipine hydrochloride (NCH)-loaded microspheres for delivery over a 12-hr period. Microspheres containing Eudragit RS and L with different ratios were prepared by solvent evaporation method and the effect of swelling on the release rate and characteristics was investigated. The change in the diameters of microspheres with time in simulated intestinal fluid (pH 7.5) at 37 degrees C has been studied. Drug release was determined using the flow-through cell method, and related to the degree of swelling (Q) of the microspheres. Q values in turn depended on the ratio of Eudragit RS-L used. Release of NCH from microspheres increased with Eudragit L amount, but no controlled-release pattern was observed. Q values > or = 18.88 caused a slow initial release followed by an accelerated release. Microspheres with an Eudragit RS-L ratio of 1:5.7, Q value of 38.71, and drug release rate of 0.155% min-1 exhibited a remarkable delayed time for erosion to begin (120 min). Thus, microspheres prepared from this formulation may provide an effective enteric dosage form, releasing NCH at a predetermined rate.
本研究的目的是制备并评估一种用于12小时给药的盐酸尼卡地平（NCH）肠溶包衣微球剂型。采用溶剂蒸发法制备了含有不同比例的Eudragit RS和L的微球，并研究了溶胀对释放速率和特性的影响。研究了微球在37℃模拟肠液（pH 7.5）中直径随时间的变化。采用流通池法测定药物释放，并与微球的溶胀程度（Q）相关。Q值又取决于所用Eudragit RS-L的比例。NCH从微球中的释放随Eudragit L用量的增加而增加，但未观察到控释模式。Q值≥18.88导致初始释放缓慢，随后加速释放。Eudragit RS-L比例为1:5.7、Q值为38.71且药物释放速率为0.155% min-1的微球表现出显著的延迟侵蚀开始时间（120分钟）。因此，由该制剂制备的微球可提供一种有效的肠溶剂型，以预定速率释放NCH。
