Formulation and stability study of palatable norfloxacin dry syrup: comparison among different preparation methods

Purpose: The aim of this work is to prepare stable and palatable norfloxacin suspension formulation for oral administration. Hence an attempt is made to develop norfloxacin dry syrup. Methods: Methods employed for formulations are: a) preparation of norfloxacin granules by coating with different levels of acrycoat E100–40 and b) preparation of norfloxacin microspheres using Eudragit E100 and subsequent adsorption on different carriers such as lactose, microcrystalline cellulose and mannitol. The interaction between norfloxacin and Eudragit E100 was analyzed by FTIR spectroscopy and X-ray powder diffractrometry. Gustatory sensation tests were conducted on six healthy human volunteers to assess the palatability of liquid syrup. Results: FTIR studies and X-ray powder diffractions indicate compatibility of drug with polymers used in the work. The microspheres were smoother and more regular in their shape compared to granules. Rheological studies reveal plastic thixotropy of the reconstituted syrup. In vitro dissolution studies performed at pH 1.2 showed satisfactory dissolution rate for all the formulations. Drug content of reconstituted liquid suspension on day 1 and at day 5 were within the limits of 93.42% and 90.4% respectively. Stability studies of dry suspension formulation conducted at 40 ± 2˚C for three months were found to be stable and percentages of drug remaining were higher than 98% of initial concentration. Conclusion: Microspheres prepared with increased concentrations of MCC and mannitol improves physical stability and they were palatable with slight or no bitter aftertaste.