Akademik Veri Yönetim Sistemi
Ankara Üniversitesi Eczacılık Fakültesi Dergisi, cilt.47, sa.2, ss.588-600, 2023 (Scopus)
Objective: Ion-exchangers are inert, water-insoluble polymers with ionizable functional groups on their surface. They can be used for purposes such as disintegrating or taste masking in orally disintegrating dosage forms, or they can provide a pH-dependent controlled release. Material and Method: The loading and release properties of different cation exchangers were investigated by loading Atenolol to Amberlite CG50, Dowex 50W-X2 and Smopex 101 as weak or strong resin and strong fiber, respectively. The effect of the ionic strength of the medium on the loading capacities of these materials were investigated in water and pH 7.4 HEPES buffer using batch method and loading was monitored by pH, zeta potential, FTIR and SEM analysis. Loading capacity was calculated UV spectrophotometrically. The effect of pH and ionic strength on the atenolol release was investigated by the dialysis bag method in pH 1.2 HCl, pH 6.8 PBS and pH 6.8 HEPES media. Result and Discussion: Due to its low molecular weight and high pKa atenolol was successfully loaded with a capacity over 93%. As the pH could be balanced a higher loading capacity was achieved in HEPES buffer. The decrease in zeta potential values proved that the complexes were successfully obtained and the ionic complex formation was also monitored with FTIR and SEM micrographs. Atenolol did not get released in pH 1.2 medium, contrarily to pH 6.8 in which the functional groups are ionized. The higher amount of counter ions in PBS buffer also affected the release. The highest release rate was obtained with Amberlite. All ion-exchangers provided a pH-dependent release fitting to Higuchi or Zero order kinetics that shows diffusion. Boyd equation results also showed that diffusion mechanism was particle controlled.