Chauhan C S, Choudhury P K
Department of Pharmacy, MLS University, Udaipur (Raj.), India.
Curr Drug Deliv. 2006 Apr;3(2):193-8. doi: 10.2174/156720106776359203.
Controlled porosity osmotic pump contains water-soluble additives in the coating membrane, which in contact with aqueous environment dissolves and results in formation of micro porous membrane. The resulting membrane is substantially permeable to both water and dissolved drug. The drug release from this type of system is independent of pH and follows zero order kinetics. In the present investigation, effort has been made to study release mechanism of drug having low water solubility by means of controlled porosity osmotic pump. The capsule membrane was prepared by phase inversion technique. The phase inversion was carried by dipping the stainless steel mould in a 15% solution of cellulose acetate containing varying amounts of pore-forming agent, glycerol (50% to 70% w/w), followed by quenching in an aqueous solution (10% w/v glycerol), which resulted in the formation of the asymmetric membrane. The delivery orifices so formed were confirmed by release of an encapsulated dye from the capsule and scanning electron microscope (SEM). The drug selected for this study, Flurbiprofen, has low water solubility and hence is unable to create osmotic pressure to cause drug release. To enhance the solubility and its osmotic pressure, this study was conducted with a solubility enhancer sodium lauryl sulfate (SLS). The quantity of SLS was predetermined by conducting a solubility study of flurbiprofen with SLS. Release rate studies revealed that less than 10% of drug was released from the system without SLS, while about 75% release was observed from systems containing SLS. The release rate increased as the concentration of pore forming agent increased.
控释微孔渗透泵在包衣膜中含有水溶性添加剂，其与水性环境接触时溶解并导致形成微孔膜。所形成的膜对水和溶解的药物都具有基本的渗透性。这种类型系统中的药物释放与pH无关，并遵循零级动力学。在本研究中，已努力通过控释微孔渗透泵研究低水溶性药物的释放机制。胶囊膜通过相转化技术制备。通过将不锈钢模具浸入含有不同量成孔剂甘油（50%至70% w/w）的15%醋酸纤维素溶液中进行相转化，随后在水溶液（10% w/v甘油）中骤冷，这导致形成不对称膜。通过从胶囊中释放包封的染料和扫描电子显微镜（SEM）确认如此形成的给药孔。本研究选择的药物氟比洛芬具有低水溶性，因此无法产生渗透压以导致药物释放。为了提高其溶解度及其渗透压，本研究使用了溶解度增强剂月桂基硫酸钠（SLS）进行。通过进行氟比洛芬与SLS的溶解度研究预先确定SLS的量。释放速率研究表明，不含SLS的系统中不到10%的药物从系统中释放，而含有SLS的系统中观察到约75%的释放。释放速率随着成孔剂浓度的增加而增加。
