Učinak molekulske mase karboksimetilceluloze i nekih polimera na usporeno oslobađanje teofilina iz hidrofilnih matriksa

The objective of this study was to investigate the influence of the molecular size of carboxymethylcellulose (cmc) and some hydrophobic polymer additives on the release properties of theophylline from the tablet matrices. The cmc matrices were prepared by the conventional wet granulation method. The granules were evaluated for angles of repose, bulk density, compressibility index, and porosity, while the tablets were subjected to hardness, friability and compression characteristics. All the tablet formulations showed acceptable pharmacotechnical properties. Low molecular size cmc (cmc-L) had the fastest drug release t50% values of 27 min, for medium size cmc (cmc-M) 55 min and high molecular size cmc (cmc-H) 200 min. Overall, results showed that drug release rate decreases with increase in molecular size of cmc. All the polymer additives ethylcellulose (ETC), cellulose acetate phthalate (CAP) and Eudragit l-100 (EUD) retarded theophylline release from cmc-L and cmc-H, with ethylcellulose having the most pronounced effect on cmc-L. Kinetic studies using Hixson-Crowell and Peppas-Ritger equations showed that different drug release mechanisms were involved in controlling drug dissolution from the tablets. Drug release mechanism was influenced by both the molecular size of cmc and the presence of polymer additives.U radu je ispitivan učinak molekulske mase karboksimetilceluloze (cmc) i nekih hidrofobnih polimera kao aditiva na profil oslobađanja teofilina iz tabletnih matriksa. Matriksi s cmc pripremljeni su uobičajenom metodom vlažne granulacije. Granulama je određivana sipkost, gustoća, poroznost i indeks kompresivnosti, dok je tabletama ispitivana tvrdoća, rastrošljivost i kompresibilnost. Sve priređene tablete imala su prihvatljiva farmakotehnološka svojstva. Najbrže vrijeme oslobađanja t50% od 27 min postignuto je iz pripravka cmc male molekulske mase (cmc-L), 55 min iz pripravka cmc srednje molekulske mase (cmc-M) 55 min i 200 min iz pripravka cmc velike molekulske mase (cmc-H). Rezultati ukazuju da se brzina oslobađanja smanjuje povećanjem molekulske mase cmc. Svi polimerni aditivi, etilceluloza, celuloza acetat ftalat i Eudragit l-100 usporili su oslobađanje teofilina iz cmc-L i cmc-H pripravka, a najveći učinak imala je etilceluloza na cmc-L. Kinetičke studije provedene pomoću Hixson-Crowell-ove i Peppas-Ritger-ove jednadžbe ukazuju da su u oslobađanju teofilina iz tableta uključeni različiti mehanizmi. Na mehanizam oslobađanja utjecali su i molekulska masa cmc i prisutnost polimernih aditiva