Vilivalam V D, Adeyeye C M
Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282.
J Microencapsul. 1994 Jul-Aug;11(4):455-70. doi: 10.3109/02652049409034263.
Diclofenac wax microspheres were prepared using the congealable dispersephase encapsulation method. Emulsifiers, glyceryl monostearate (GMS) and stearic acid, were added to improve the efficiency of emulsification. Microspheres containing either of the emulsifiers or both showed a high drug content (80-90%) and the particle size distribution was log-normal compared with microspheres without the emulsifiers. Increase in GMS concentration decreased the drug release and, in contrast, stearic acid appeared to channel the drug from the wax matrix. The addition of both emulsifiers at different concentrations modified drug release. Increase in dispersant (PVP) concentration, and decrease in microsphere size accelerated the rate of drug release. Higuchi/Baker Londsdale spherical matrix dissolution kinetics was followed. Disintegrating tableted microspheres were prepared with Avicel and Explotab. With the increase in compression pressure the crushing force and disintegrating time increased, but the thickness decreased, and the dissolution profile did not appear to be affected. Slightly faster release was noticed with tableted microspheres compared with that of uncompressed microspheres. Tablets containing 40 and 60% microsphere loadings had disintegration times of 5.12 +/- 0.63 and 57.73 +/- 3.53 min, respectively. In contrast, tablet formulation containing 80% microsphere load had a significant increase in disintegration time (130.83 +/- 4.26 min). The dissolution from this formulation also showed a lag time of 30 min in contrast with the other two formulations, which showed no lag time. Increased microsphere size from 215 to 630 microns had no effect on tableting properties (such as hardness and thickness); and only very little effect on dissolution. The microspheres appeared deformed but intact irrespective of compression pressures on scanning electron micrographs.
采用可凝结分散相包封法制备双氯芬酸蜡微球。加入乳化剂单硬脂酸甘油酯（GMS）和硬脂酸以提高乳化效率。含有任一种乳化剂或两者的微球显示出高药物含量（80 - 90%），与不含乳化剂的微球相比，粒径分布呈对数正态分布。GMS浓度的增加降低了药物释放，相反，硬脂酸似乎使药物从蜡基质中通道化。不同浓度的两种乳化剂的添加改变了药物释放。分散剂（PVP）浓度的增加和微球尺寸的减小加速了药物释放速率。遵循Higuchi/Baker Londsdale球形基质溶解动力学。用微晶纤维素和交联羧甲基纤维素钠制备崩解性微球片剂。随着压缩压力的增加，压碎力和崩解时间增加，但厚度减小，并且溶出曲线似乎未受影响。与未压缩的微球相比，微球片剂的释放稍快。含有40%和60%微球负载量的片剂的崩解时间分别为5.12±0.63和57.73±3.53分钟。相比之下，含有80%微球负载量的片剂配方的崩解时间显著增加（130.83±4.26分钟）。与其他两种无滞后时间的配方相比，该配方的溶出也显示出30分钟的滞后时间。微球尺寸从215微米增加到630微米对压片性能（如硬度和厚度）没有影响；对溶出仅有很小的影响。在扫描电子显微镜照片上，无论压缩压力如何，微球似乎都有变形但完整。
