Nagpal Manju, Singh Shailendra Kumar, Mishra Dinanath
Department of Pharmaceutics, Chitkara College of Pharmacy, Chitkara University, Patiala, Punjab.
Int J Pharm Investig. 2013 Apr;3(2):88-94. doi: 10.4103/2230-973X.114906.
Current research was aimed at the development of the drug delivery systems based on the superporous hydrogels (SPH) with the desired swelling and the mechanical properties.
Superporous hydrogel composites (SPHCs) and superporous hybrid hydrogels (SPHHs) based on the chitosan and the polyacrylamide were synthesized using the gas blowing technique. The prepared hydrogels were evaluated for swelling studies, mechanical strength and scanning electron microscopy. The selected hydrogels were loaded with the drug (verapamil hydrochloride) by aqueous loading method. Drug integrity with in polymeric network was evaluated via fourier transform infrared spectroscopy (FTIR), X-ray diffraction (X-RD), differential scanning calorimetry (DSC), proton nuclear magnetic resonance ((1)HNMR) studies. In vitro drug release studies were carried out using the united state pharmacopoeial (USP) dissolution apparatus (type II).
The mechanical strength was observed to be higher in SPH hybrids in comparison to that in SPHCs while no significant difference was observed in swelling behavior. In situ crosslinking of chitosan with glutaraldehyde (GA) may be responsible for high mechanical strength. The equilibrium swelling time was slight higher in SPHH than in SPHCs. The integrity of pores was maintained in ethanol treated hydrogels as observed in scanning electron micrographs. Whereas, freeze dried SPH samples showed non-uniform pores. No drug polymer interaction was observed as indicated by DSC, FTIR, X-RD and NMR studies. However, the crosslinking of chitosan with GA was clearly indicated by these studies. The in vitro drug release studies from SPH hybrids indicated initial fast release (65%) with in first 2 h and then sustained release at the end of 24 h (95%). The addition of hydroxypropyl methyl cellulose with drug; however, leads to a significant decrease in drug release (56% at the end of 24 h).
Superporous hybrid hydrogels can be promising devices for the sustained delivery of drug candidates to the gastrointestinal region.
当前研究旨在开发具有所需溶胀和机械性能的基于超多孔水凝胶（SPH）的药物递送系统。
采用气体发泡技术合成了基于壳聚糖和聚丙烯酰胺的超多孔水凝胶复合材料（SPHCs）和超多孔杂化水凝胶（SPHHs）。对制备的水凝胶进行溶胀研究、机械强度和扫描电子显微镜评估。通过水相负载法将药物（盐酸维拉帕米）负载到选定的水凝胶中。通过傅里叶变换红外光谱（FTIR）、X射线衍射（X-RD）、差示扫描量热法（DSC）、质子核磁共振（¹HNMR）研究评估聚合物网络中药物的完整性。使用美国药典（USP）溶出装置（II型）进行体外药物释放研究。
观察到SPH杂化物的机械强度高于SPHCs，而溶胀行为无显著差异。壳聚糖与戊二醛（GA）的原位交联可能是导致高机械强度的原因。SPHH的平衡溶胀时间略高于SPHCs。如扫描电子显微镜照片所示，乙醇处理的水凝胶中孔隙的完整性得以保持。而冷冻干燥的SPH样品显示孔隙不均匀。DSC、FTIR、X-RD和NMR研究表明未观察到药物与聚合物的相互作用。然而，这些研究清楚地表明了壳聚糖与GA的交联。来自SPH杂化物的体外药物释放研究表明，最初2小时内快速释放（65%），然后在24小时结束时持续释放（95%）。然而，药物中加入羟丙基甲基纤维素会导致药物释放显著降低（24小时结束时为56%）。
超多孔杂化水凝胶有望成为将候选药物持续递送至胃肠道区域的装置。
