Stability-Indicating HPTLC Method for Determination of Remogliflozin Etabonate and Vildagliptin in Tablets.

A sensitive, selective, precise and stability-indicating high-performance thin-layer chromatographic (HPTLC) method is developed for the simultaneous estimation of remogliflozin etabonate and vildagliptin in the presence of their degradation products. The separation was performed in thin layer chromatography plate precoated with silica gel G60F254. The mobile phase consists of methanol:ethyl acetate:toluene:ammonia (1.5:4:4.5:0.1, v/v/v/v). Detection and quantification are performed with densitometer at 212 nm. The Rf values of remogliflozin etabonate and vildagliptin are 0.53 and 0.42, respectively. Degradation studies for the two drugs were carried out in acidic, alkaline, neutral, oxidative, photolytic and thermal stress conditions and analyzed. The suitability of this method for the quantitative determination of the compounds is proved by validation in accordance with the requirements laid down by International Conference on Harmonization (ICH). Linearity was found over the concentration range of 200-1000 ng/band with correlation coefficient of 0.9936 for remogliflozin etabonate and 100-500 ng/band with correlation coefficient of 0.9912 for vildagliptin. The method was successively applied to tablets containing two drugs and found to have no chromatographic interferences from the tablet excipients. The degradant formed was not interfering with estimation of two drugs makes the method more selective for the purpose intended.

Interaction study of moxifloxacin and lomefloxacin with co-administered drugs.

Moxifloxacin and lomefloxacin are fluoroquinolone antibiotics used in treating urinary and respiratory tract infections. Fluoroquinolones are known to have interactions with drugs that are active in gastro intestinal tract. Being moxifloxacin and lomefloxacin fluoroquinolones the interaction study of was carried out with sucralfate, gelusil, erythromycin and multi minerals. The interaction was studied at neutral, acidic and basic conditions both at room temperature and 37°C. The effect of dissolution medium simulating various body environments with response to pH has been examined in order to elucidate the interactions. The response of moxifloxacin and lomefloxacin after interaction with co-administered drugs at different conditions and temperature were noted using a Shimadzu HPLC system with PDA detector. It was seen that interaction of these fluoroquinolones was more at 37°C than at room temperature. Moxifloxacin and Lomefloxacin reacts faster with sucralfate and gelusil in acidic media whereas with erythromycin in basic media and multi-minerals in neutral media. The study ensures the interaction of fluoroquinolones with selected class of drugs. In order to achieve the effective therapeutic effect appropriate time intervals between administrations of drugs is essential.