Abd-Allah F I, Dawaba H M, Ahmed A Ms
Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Al-Azhar University, Nasr City, Cairo, Egypt.
Drug Discov Ther. 2010 Aug;4(4):267-75.
The main purpose of this work was to determine the in vitro release of piroxicam in microemulsion formulations from different pharmaceutical topical preparations including different gel bases, such as, methyl cellulose (MC), carboxy methyl cellulose (CMC), hydroxypropyl methyl cellulose (HPMC), Carbopol 934, Carbopol 940, and Pluronic F-127 bases. The effect of the employed gel bases on the in vitro release profiles of piroxicam was examined to choose the base which gave the highest in vitro release. The kinetic treatments and parameters derived from in vitro release of piroxicam formulations were calculated according to different kinetic orders or systems. These gel formulations were selected for rheological and stability studies. Stability studies were conducted to investigate the change in drug content, viscosity, and pH of the semisolid formulations. The results showed that, the incorporation of piroxicam in microemulsion formulas could lead to enhancement of piroxicam release profiles by allowing constant and regular in vitro release. Three percent MC gel base showed the highest release of piroxicam-microemulsion after 180 min (97.70%) followed by 3% HPMC (94.0%) when compared to bases containing piroxicam alone. All the medicated gel bases containing piroxicam exhibit pseudoplastic flow with thixotropic behavior. The degradation of piroxicam from its topical formulations was found to be a zero-order reaction based on the mean value of correlation coefficients. All formulations were quite stable. The shelf life of the gel containing HPMC base was about 2.85 years. Considering the in vitro release, rheological properties and shelf life, HPMC gel base containing 0.5% piroxicam in a microemulsion formula was the best among the studied formulations.
这项工作的主要目的是测定吡罗昔康在微乳剂配方中的体外释放情况，这些微乳剂配方来自不同的药物外用制剂，包括不同的凝胶基质，如甲基纤维素（MC）、羧甲基纤维素（CMC）、羟丙基甲基纤维素（HPMC）、卡波姆934、卡波姆940和泊洛沙姆F - 127基质。研究了所用凝胶基质对吡罗昔康体外释放曲线的影响，以选择能实现最高体外释放率的基质。根据不同的动力学级数或体系计算了吡罗昔康制剂体外释放的动力学处理方法和参数。选择这些凝胶制剂进行流变学和稳定性研究。进行稳定性研究以考察半固体制剂的药物含量、粘度和pH值的变化。结果表明，将吡罗昔康加入微乳剂配方中可通过实现恒定且规律的体外释放来提高吡罗昔康的释放曲线。与仅含吡罗昔康的基质相比，3%的MC凝胶基质在180分钟后显示出吡罗昔康 - 微乳剂的最高释放率（97.70%），其次是3%的HPMC（94.0%）。所有含吡罗昔康的药用凝胶基质均表现出具有触变性的假塑性流动。基于相关系数的平均值，发现吡罗昔康从其外用制剂中的降解为零级反应。所有制剂都相当稳定。含HPMC基质的凝胶的保质期约为2.85年。考虑到体外释放、流变学性质和保质期，在微乳剂配方中含0.5%吡罗昔康的HPMC凝胶基质是所研究制剂中最佳的。
