The extent of tobacco cultivation remains substantially high in Bangladesh, which is the 12th largest tobacco producer in the world. Using data from a household survey of current, former, and never tobacco farmers, based on a multi-stage stratified sampling design with a mix of purposive and random sampling of households, this study estimated the financial and economic profitability per acre of land used for tobacco cultivation. The environmental effects of tobacco cultivation on land and water resources were estimated using laboratory tests of sample water and soil collected from tobacco-cultivating and non-tobacco cultivating areas. The study finds that tobacco cultivation turns into a losing concern when the opportunity costs of unpaid family labour and other owned resources, and the health effects of tobacco cultivation are included. Tobacco cultivation poses a significantly high environmental cost that causes a net loss to society. Nevertheless, the availability of unpaid family labour and the options of advanced credit as well as a buy back guarantee from the tobacco companies attract farmers to engage in and continue tobacco cultivation. Therefore, supply side interventions to curb the tobacco epidemic in Bangladesh need to address major drivers of tobacco cultivation to correct the wrong incentives and motivate tobacco farmers to switch to alternative livelihood options.

Objective: This study was conducted to synthesise some 2-substituted-5-nitro benzimidazole derivatives to evaluate their antioxidant activity.Methods: The titled compounds were synthesised by sodium metabisulfite mediated reaction of 4-nitro-1, 2-phenylenediamine with a number of para-substituted benzaldehydes. The antioxidant activity was evaluated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method.Results: All the compounds exhibited good antioxidant activity having IC50 values in the range of 3.17 to 7.59 µg/ml while that of standard butylated hydroxytoluene (BHT) was 18.42 µg/ml.Conclusion: Among the synthesised compounds, compounds 3a-c have been shown to possess the most prominent antioxidant activity which might be attributed due to the presence of chloro, bromo and fluoro substituents in the molecule. The compounds may act as the future lead(s) for the development of potential antioxidant compounds.

A series of 2-substituted-5-methylbenzimidazole derivatives (3a-e) were synthesized by reacting 4-methyl-1,2-phenylenediamine (1) with a number of p-substituted benzaldehydes (2a-e) in moderate yields (25.51- 40.21%). The synthesized compounds (3a-e) were characterized by spectroscopic data and were evaluated for antioxidant activity using DPPH free radical scavenging assay. The compounds showed significant antioxidant activity having IC50 value of 1.054-19.05 μg/ml as compared to the standard BHT (26.96 μg/ml).Dhaka Univ. J. Pharm. Sci. 16(2): 245-249, 2017 (December)

A novel reversed phase ultra-high performance liquid chromatographic (RP-UHPLC) method was developed for the estimation of sitagliptin in pharmaceutical dosage form. Separation was done by a X-bridge C18 column (4.6 i.d.× 150 mm, 5 μm particle size) with a flow rate of 1 ml/min using phosphate buffer (pH 6) and acetonitrile (70:30, v/v) as mobile phase at 268 nm using photodiode array plus (PDA+) detector. The retention time was found at 4.607 min. The developed method was validated as per the requirements of ICH-Q2B guidelines for specificity, system suitability, linearity, precision, accuracy, sensitivity and robustness. The linear regression analysis data for the linearity plot showed correlation coefficient values of 0.999 with LOD value of 0.06 μg/ml and LOQ of 0.225 μg/ml. The relative standard deviation (%RSD) for inter-day and intra- day precision was not more than 2.0%. The method was found to be accurate with percentages recovery of 98.50±0.03 to 99.70±0.05 and the % RSD was less than 2. The results showed that the proposed method is highly convenient for routine analysis of sitagliptin.Dhaka Univ. J. Pharm. Sci. 17(1): 123-129, 2018 (June)

The aim of this study was to investigate whether fruit juices available in markets of Bangladesh contain any preservative. A specific RP-HPLC method was developed, validated and applied to identify and quantify preservatives including benzoic acid, sorbic acid, methyl paraben and propyl paraben simultaneously in 50 different products. These additives were separated by C18 column in mobile phase composed of methanol and acetate buffer (pH 4.4) in the ratio of 50:50 with a flow rate of 0.7 mL/min, and detected at 254 nm. Linearities for benzoic acid, sorbic acid, methyl paraben and propyl paraben were determined in the range of 20-170 ppm (r2 0.997), 12-42 ppm (r2 0.994), 10-60 ppm (r2 0.993) and 10-60 ppm (r2 0.992) respectively. Limit of detection (LOD) and limit of quantification (LOQ) were 5.46 ppm and 16.5 ppm for benzoic acid while for sorbic acid they were 1.08 ppm and 3.30 ppm, respectively. Benzoic acid was detected in a range of 96.1 to 441 ppm in 9 fruit juices while in 7 fruit juices sorbic acid was found in a range of 105 - 444 ppm. The values were within the maximum allowable ranges for fruit juice (1000 ppm for both benzoic acid and sorbic acid) as suggested by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). None of the juice product was found to contain methyl paraben or propyl paraben Dhaka Univ. J. Pharm. Sci. 18(2): 195-208, 2019 (December)

The present work describes a quality by design (QbD)-based rapid, simple, precise and robust RPUHPLC method for the routine analysis of vildagliptin in bulk drug and in pharmaceutical dosage forms. Chromatographic separation was achieved by a X-bridge C18 column with isocratic elution of mobile phase containing mixture of phosphate buffer (pH 6.8) and acetonitrile in the ratio of 67:33(v/v). The flow rate was 1.0 ml/min and the detection was done at 239 nm with photo-diode array plus (PDA+) detector. The optimization of chromatographic method was carried out by QbD approach using design of experiments (DoE). Two factors utilized for the experimental design of the method were (i) independent variables which comprise percentages of acetonitrile in mobile phase and flow rate and (ii) co-variates which include the retention time, tailing factor and theoretical plates. This design was statistically analyzed by ANOVA, normal plot of residual, box-cox plot for power transform, perturbation, counter plot and 3D response surfaces plots. This was further validated as per the requirements of ICHQ2B guidelines for linearity, LOD, LOQ, accuracy, precision, specificity and robustness. The results showed that proposed method is simple, sensitive and highly robust for routine analysis of vildagliptin.Dhaka Univ. J. Pharm. Sci. 16(1): 107-117, 2017 (June)