تهيه و مشخصه‌يابي چارچوب فلز–آلي Zn-Glu Bio-MOF و بارگذاري داروي ريبوفلاوين و بررسي رهايش آن

In this study, a zinc–glutamate bio-metal–organic framework (Zn-Glu Bio-MOF) was prepared, an‎d its potential for riboflavin loading an‎d in vitro release was investigated. The framework was synthesized from zinc chloride an‎d L-glutamic acid hydrochloride in an aqueous medium. Following activation, riboflavin was loaded onto the framework using a post-synthetic method. The samples were characterized using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), an‎d energy-dispersive X-ray spectroscopy coupled with elemental mapping (EDX-MAP). The specific surface area an‎d pore characteristics of the framework were also eva‎luated using nitrogen adsorption–desorption measurements. The results indicated that the synthesized framework exhibited a crystalline structure an‎d predominantly rod-like to prismatic morphology. The BET specific surface area was 18.88 m²/g, an‎d the predominant pore diameter determined using the BJH method was approximately 3–4 nm. Comparative characterization before an‎d after loading was consistent with the presence of riboflavin in the loaded sample an‎d the retention of the principal crystalline an‎d morphological features of the carrier. Initial riboflavin concentrations of 50, 100, 150, 200, an‎d 250 ppm were examined to identify suitable loading conditions. Given the limited increase in loading efficiency at concentrations above 100 ppm, this concentration was selec‎ted for loading. Riboflavin was quantified using ultraviolet–visible spectroscopy at a wavelength of 445 nm. Riboflavin release from the loaded sample was studied using a dialysis bag in phosphate-buffered saline at 25 an‎d 37 °C an‎d pH values of 7.4 an‎d 5.7. Under all four conditions, release was faster during the initial hours an‎d subsequently continued at a slower rate. At the end of the experiment, cumulative release at 25 °C was approximately 49.8% an‎d 62.8% at pH 7.4 an‎d 5.7, respectively. The corresponding values at 37 °C were approximately 90.7% an‎d 86.5%. Increasing the temperature enhanced release in both media, whereas the effect of pH differed between the two temperatures. Overall, the findings demonstrated the potential of the zinc–glutamate framework for riboflavin loading an‎d gradual release under in vitro conditions.

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غلامحسين محمدنژاد شيرازي , حسن حداد زاده