THE EFFECT OF EUDRAGIT RL-100 ON THE MECHANICAL AND MUCOADHESION PROPERTIES OF POLYCARBOPHIL DOSAGE FORMS

Polycarbophil is a high molecular weight acrylic polymer which posses enzymatic inhibition and absorption enhancement properties. However, i ts use is limited because of poor mechanical properties. In this study Eudragit(R) RL-100 was tested as a possible regulating agent for poly carbophil solid formulations. Although swelling of polycarbophil-Eudra git(R) RL-100 films was lower in PBS pH=5.0 than in PBS pH=7.4, in bot h cases there was a profound difference between the swelling of pure p olycarbophil films and films made of mixtures of polycarbophil and inc reasing amounts of Eudragit(R) RL-100. Eudragit(R) RL-100 was able to significantly decrease the swelling of polycarbophil films in a concen tration-dependent manner. The incorporation of Eudragit(R) RL-100 into polycarbophil also affected the mechanical properties of the films, a s was evident from the torsion force and modulus of elasticity measure ments. The higher the amount of Eudragit(R) RL-100 in the mixtures wit h the polycarbophil, the larger the values of torsion force and modulu s of elasticity. In the case of tablets made of different ratios of Eu dragit(R) RL-100 and polycarbophil, the larger the amount of Eudragit( R) RL-100 the higher the rate of erosion of the tablet. Tablets contai ning predetermined ratios of polycarbophil and Eudragit(R) RL-100 were able to synchronize the release rate of sodium cefazolin and ibuprofe n. It was found that the similarity in the release rates resulted from a controlled erosion process governed by balancing the ratio of Eudra git(R) RL-100 and polycarbophil. The mucoadhesion properties of polyca rbophil-Eudragit(R) RL-100 tablets with increasing amounts of Eudragit (R) RL-100 was measured in different regions of the GI tract of the ra t. It was found that tablets containing up to 20%w/w of Eudragit(R) RL -100 adhered significantly better to the cecum of the rat and that the ir adherence to the stomach, jejunum and colon did not differ from eac h other. Eudragit(R) RL-100 concentrations of 50%w/w and above signifi cantly reduced the ability of polycarbophil to adhere to the GI epithe lium. Based on the reported findings it is suggested that solid dosage forms made of mixtures of polycarbophil and Eudragit(R) RL-100 may be suitable for the oral delivery of drugs, such as proteinaceous drugs, susceptible to enzymatic degradation.