Formulation of clarithromycin floating microspheres for eradication of Helicobacter pylori

The aim of this study was to develop floating microspheres for gastroretentive delivery of clarithromycin for eradication of Helicobacter pylori. The microspheres were prepared by solvent evaporation using ethyl cellulose (EC) at different weight ratio with clarithromycin with hydroxypropyl methyl cellulose (HPMC E5) acting as secondary polymer. The emulsifier employed either polyvinylpyrrolidone (PVP) or polyvinyl alcohol (PVA). The microspheres were evaluated for floatation, drug entrapment and release, particle size, shape and surface morphology. The physical form of clarithromycin was monitored using FTIR, DSC and X-ray diffraction. The microspheres were in micron range with particle size reducing when replacing PVP with PVA. Further size reduction was recorded in presence of HPMC. The entrapment efficiency increased at high EC concentration especially in presence of HPMC. Immediate floatation was seen with at least 56% of the particles remaining on the surface after 8 h. Physical characterization reflected amorphousization or solubilization of clarithromycin after entrapment in the microspheres. The release pattern followed Higuchi matrix kinetic model in most formulations except those containing low concentration of EC or those containing high HPMC content with HPMC increasing the rate of drug release. The study presented floating microspheres with different release pattern depending on the composition.

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