spectrophotometry

The inhibitory activity of bacteriocins produced by Lactic acid bacteria isolated from raw cattle and goat milk and other processed milk products against Mycobacterium bovis and Mycobacterium tuberculosis in milk was studied using spectrophotometry. Six bacteriocin positive strains of LAB were isolated and identified as Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus fermentum, Lactobacillus brevis, Lactococcus lactis and Streptococcus thermophilus. The antimycobacterial activity of the bacteriocins in milk showed that the bacteriocins from Lactobacillus inhibited the growth of the mycobacterium over a period of 15 days while bacteriocin from Streptococcus did not inhibit the Mycobacteria in milk.  However, the activity of the bacteriocin were lost after the 15th day as shown by increase in absorbance on day 18. The bacteriocin mix from all six bacteriocins against Mycobacteria was the most efficient when compared to that of individual bacteriocins, recording a significant decline in absorbance at from 0.79 to 0.026 even on day 18.

Two sensitive, precise and cost-effective UV-spectrophotometric methods are described for the determination of flunarazine dihydrchloride (FNH) in bulk drug and tablets. The proposed methods are based on the measurement of the absorbance of FNH either in 0.1 M HCl (method A) or in acetonitrile (method B) at 253 nm. As per the International Conference on Harmonization (ICH) guidelines, the methods were validated for linearity, accuracy, precision, limits of detection (LOD) and quantification (LOQ) and robustness and ruggedness. Beer’s law is obeyed over the concentration ranges of 2.5-30.0 µg mL-1 in method A and 1.0-20.0 µg mL-1 in method B. The calculated molar absorptivity values are 2.12×104 and 2.47×104 L mol-1 cm-1 for method A and method B, respectively. The proposed methods were applied successfully to the determination of FNH in tablets with good accuracy and precision without any detectable interference from common excipients. The accuracy of the proposed methods was further assessed by the recovery studies via a standard addition method. In addition, forced degradation of FNH was conducted in accordance with the ICH guidelines. Acidic and basic hydrolysis, thermal stress, peroxide and photolytic degradation were used to assess the degradation behavior of the drug. Substantial degradation was observed during oxidative degradation and no degradation was observed under other stress conditions.