QUANTIFYING MAGNETITE IN CHITOSAN MICROSPHERES LOADED WITH 5-FLUROURACIL USING MODIFIED COLORIMETRIC METHOD: A COMPARATIVE STUDY WITH THERMOGRAVIMETRIC ANALYSIS

Abstract

Objective: The purpose of the present investigation is to develop a simple colorimetric estimation of magnetite from magnetic microspheres.

Methods: Emulsification and cross-linking technique was used to prepare 5-fluorouracil loaded chitosan magnetic microspheres. The microspheres were evaluated using optical microscopy, scanning electron microscopy and X-ray diffraction. A modified colorimetric method was employed to determine magnetite content of chitosan microspheres with and without the drug. Microspheres were digested by HCl to convert magnetite into ferrous/ferric ions. Absorbance of yellow coloured complex of these ions with sulfosalicylic acid at alkaline pH was measured to quantify magnetite at 425 nm. The determination of magnetite by the colorimetry validated through a thermogravimetric analysis of the same samples.

Results: The presences of magnetite in the microspheres were qualitatively confirmed by the photomicrograph, scanning electron microscopy, and X-ray diffraction studies. Colorimetric determination of magnetite content of the drug loaded, and unloaded chitosan microspheres were 21.5 and 20.6%w/w, respectively. The magnetite content of the same samples estimated by thermogravimetric analysis was 22.5 and 19.1%w/w, correspondingly, which were much closer to the colorimetric estimation. The drug loading in the microsphere was 12.35% w/w, and the X-ray diffraction analysis confirms amorphous nature of the loaded drug.

Conclusion: The proposed colorimetric quantification of magnetite is simple cost-effective and could be useful in determining magnetite content of magnetically targeted drug-delivery systems.