Evaluation of Eudragit RS and HPMC K4M effect on release rate of Theophylline using liquisolid systems

Background and The Potential of liquisolid systems for increasing of drug dissolution has been proved in many researches. The recent studies have showen that liquisolid technique is a new and promising method for controlling the dissolution rate of drugs. Ïn this study the effects of Ëudragit RS PÔ and HPMÇ on theophylline release from liquisolid compacts were evaluated. Theophylline was dispersed in PËG 200 as the liquid vehicle. Then a binary mixture of carrier coating materials (Ëudragit or HPMÇ as the carrier and silica as coating material with 2:1 ratio) was added to the liquid medication under continuous mixing in a mortar for 10 minutes. The mixture was compressed using the manual tableting machine. Âfter preparing several formulations the release profiles were evaluated. To evaluate any interaction between theophylline and the other components in liquisolid formulations the differential scanning calorimetery (DSÇ) and FTÏR were used. Theophylline tablets prepared by liquisolid technique and contained Ëudragit RS PÔ showed greater retardation properties in comparison with conventional matrix tablets. This investigation provided evidence that PËG 200 has important role in sustaining the release of drop from liquisolid. The kinetic studies revealed that in liquisolid formulations release kinetic was changed in evaluated formulations which containing several polymer content. DSÇ and FTÏR showed no complexation between drug and polymer and no change in drug polymorphism.Çonclusion: The results showed significant effect of liquisolid technique on the theophylin release rate from related liquisolid systems.