Crosslinked Biodegradable Alginate Hydrogel Floating Beads for Stomach Site Specific Controlled Delivery of Metronidazole

The retention of drug delivery systems in the stomach for longer time is required to improve the bioavailability and therapeutic efficacy of the drugs used for the diseases associated with the stomach. In the present work, gastro-retentive floating beads of sodium alginate (SA) were prepared through ionotropic gelation with divalent Ca ions and covalent cross-linking with glutaraldehyde (GA). Metronidazole (MZ) was successfully encapsulated into beads by varying the amount of SA, xanthan gum, magnesium stearate, and GA. Encapsulation of MZ was up to 79.17%. However, with an increasing amount of GA in the matrix, the encapsulation efficiency was found to decrease significantly. Beads prepared without GA released 50% of the drug in 2.76h. GA treatment suppressed the drug release significantly. Compatibility of the drug with the polymers was examined using Fourier transform infrared (FTIR) spectroscopy. Differential scanning colorimetry (DSC) and X–ray diffraction studies (XRD) were carried out to examine the crystalline nature of the encapsulated drug. The drug was relatively stable and amorphous in the beads.