The aim of this study was to develop and validate a rapid, accurate, and exact method for the quantitative determination of famotidine in pharmaceutical products. The HPLC analyses were performed by using a mobile phase containing methanol:1% acetic acid solution=30:7 (v/v), at a flow rate of 0.4 mL/min.The total time of the method was 10 min, and the retention time of famotidine was 4.16 min. The detection was evaluated at l=267 nm. The method has been validated by using different validation parameters. The linear response of the detector for famotidine peak area was observed at concentrations ranging from 0.1 to 0.0001 mg mL-1 , resulting in a correlation coefficient of 0.99998. The values of the detection limit and of the quantification limit are 0.00048 mg mL-1 and 0.00148 mg mL-1, respectively. The method proposed allowed accurate (with a relative error of less than 2%) and precise (RSD values less than 2.0%) determination of famotidine content in pharmaceutical products and can be used for its rapid quantitative analysis.

The aim of this study was to obtain and to characterize some inclusion complexes of famotidine and nizatidine with b-cyclodextrin (b-CD) in solution. The formation of famotidine- and nizatidine - b-CD complexes were evaluated by means of 1H-NMR spectroscopy. Thereafter, the stoichiometry and association constants of the complexes obtained were calculated via a continuous variation method by using the chemical shifts of specific protons from both host and guest molecules. The association constants calculated are 179.6 M--1for famotidine - b-cyclodextrin complex, and 74.9 M-1 for nizatidine - b-cyclodextrin complex, at 295 K. Due to their better stability, these complexes could be use as oral pharmaceutical preparations with better taste compared with that of free drugs.