Ferreira L, Vidal M M, Gil M H
Departamento de Engenharia Química, Universidade de Coimbra, Pinhal de Marrocos, 3030, Coimbra, Portugal.
Int J Pharm. 2000 Jan 25;194(2):169-80. doi: 10.1016/s0378-5173(99)00375-0.
Studies of dynamic and equilibrium swelling, structural characterisation and solute transport in swollen poly(2-hydroxyethyl methacrylate) gels (pHEMA) cross-linked with tripropyleneglycol diacrylate (TPGDA) were done for a wide range of TPGDA concentrations. The influence of the pH on these pHEMA properties was evaluated. In swelling studies it was found that in changing the pH from 6.5 to 12.0, a large increase in swelling occurred, from approximately 48 to 55%, for the lowest concentration of TPGDA (1 mol%), and from 40 to 80% for the highest concentration (10 mol%). Fourier transform infrared (FTIR) and differential scanning calorimetry (DSC) measurements were made after the equilibrium swelling of the gels at different pH values, to explain these results. The advantage of using these gels as controlled drug delivery systems is illustrated using salicylic acid (SA) as a model drug. The loading and the release of the SA were made at different pH values and the results obtained showed that it is possible to modulate the hydrogel performance by controlling an external factor, the pH at which the drug loading and release were performed.
针对一系列不同浓度的三丙二醇二丙烯酸酯（TPGDA），开展了与三丙二醇二丙烯酸酯（TPGDA）交联的聚甲基丙烯酸2-羟乙酯（pHEMA）凝胶的动态和平衡溶胀、结构表征及溶胀状态下溶质传输的研究。评估了pH对这些pHEMA性质的影响。在溶胀研究中发现，将pH从6.5改变至12.0时，对于最低TPGDA浓度（1摩尔%），溶胀大幅增加，从约48%增至55%，而对于最高浓度（10摩尔%），则从40%增至80%。在凝胶于不同pH值达到平衡溶胀后，进行了傅里叶变换红外光谱（FTIR）和差示扫描量热法（DSC）测量，以解释这些结果。以水杨酸（SA）作为模型药物，说明了将这些凝胶用作控释给药系统的优势。在不同pH值下进行了SA的负载和释放，所得结果表明，通过控制一个外部因素，即进行药物负载和释放时的pH值，可以调节水凝胶的性能。
