The behavior of bispyribac-sodium and metribuzin herbicides was investigated into alluvial soil. Effect of pH, temperature, and particle size of soil on the sorption process was studied. Sorption isotherms by bulk soil and its sand, silt, clay and humic acid (HA) fractions were quantified using the batch equilibration technique. The results showed that sorption of herbicides tested was significantly affected by temperature and was a spontaneous interfacial process into soil. Freundlich equation accurately predicted the sorption behavior of two herbicides. Thermodynamic parameters summarized that the negative values of the standard free energy changes (ΔG˚) were obtained therefore, the adsorption of tested pesticides in soil was spontaneous and small negative values indicate the sorption is physical in nature involving weak forces of attraction. The negative ΔH˚ value, indicating metribuzin and bispyribac-sodium interactions are exothermic processes and products are energetically stable with a high binding of compound to soil sites. There was an increase in the entropy of tested pesticides-soil systems as shown by positive values of ΔS˚. The highest adsorption in soil was at pH 5 for bispyribac-sodium and at pH 7 for metribuzin. The sorption of metribuzin and bispyribac-sodium were significantly greater on HA fraction followed by clay fraction than the bulk soil. The KF and Kd values increase with decreasing particle size particularly in the case of adsorption of metribuzin.

Theories working in the developed world sometimes fail to prove their accuracy in the developing world. So, researchers study these theories based on various countries, on different timelines as the real world is not so straight forward as theories & assumptions. In Bangladesh, very little work has been done regarding the effect of directors’ compensation on firm performance. So, this study has been undertaken to examine the relationship between these two. To test the theory a model comprising the age of the firm, log value of its assets, total asset turnover, firm size, and firm performance was developed. Using a sample of 38 listed firms of DSE from the Pharmaceutical & Chemical and Paper & Printing Industry as per the DSE website fixed-effect model & random effect model was run on the data from 2015 to 2021. And as the Hausman test suggested, the fixed-effect model is chosen to be more fit for BEP (Basic Earning Power). The focus of the study was the impact of directors’ compensation on firm performance. According to the analysis, it showed a negative correlation between directors’ compensation and firm performance. Firm size and asset turnover ratio have moderately positive correlation to the firm’s performance. On the other hand, board independence holds an opposite relation. It was also found that the firm’s age and board size have little to no correlation to the firm’s performance.

Lamotrigine (LMT), chemically known as [6-(2,3-dichlorophenyl)-1,2,4-triazine-3,5-diamine], is a broad spectrum antiepileptic drug, used as monotherapy and as an adjunct with other antiepileptic drugs for treatment of partial and generalized toxic-clonic seizures. It is used to treat neurological lesions and as a tranquilizer. A selective electrochemical membrane sensor has been developed and validated for determination of LMT. The membrane constructed using LMT and molybdophosphoric acid in THF and PVC is applicable for the detection of 5 × 10^-4 to 9 × 10^-3 M LMT in the pH range between 4.6 and 5.8 with the Nernstian slope of 57.14±1 mV/decade. The regression coefficient value of 0.9932 showed a good linear correlation between the concentrations of LMT and measured cell potentials. The limits of detection (LOD) and quantification (LOQ) values for the fabricated sensor were 1.3 × 10^-5 and 4 × 10^-5 M LMT, respectively. Various experimental conditions were optimized to reach the effective performance characteristics of the sensor. The effect of various cations, anions and organic species on the performance of sensor was studied by following standard-addition procedure. The results revealed no such variations due to presence of foreign ions or species. The fabricated sensor was subjected to validation to check accuracy, precision, robustness and ruggedness. The mean accuracy for determination of LMT was found to be 99.16%. The developed sensor was successfully used to determine LMT in tablets and in spiked human urine.

Pioglitazone hydrochloride (PGH) is an oral anti-hyperglycemic agent used in the treatment of type-2 diabetes mellitus. Potassium permanganate was found to oxidize PGH both in acidic and basic conditions, based on which two simple and sensitive methods were developed for its determination in bulk sample and tablets, and validated. In the first method (indirect method), PGH was reacted with a measured excess of standard permanganate in H₂SO₄ medium, and the residual oxidant was determined by measuring its absorbance at 550 nm. The second method (Direct method) entails treating PGH with permanganate in NaOH medium, followed by the measurement of the resulting bluish-green manganite at 610 nm. Experimental variables affecting the reactions were studied and optimized. Under optimum conditions, linear relationships with good correlation coefficients were found between absorbance and concentration in the ranges, 1.25 – 25 µg mL^-1 (Indirect method) and 1-12 µg mL^-1 (Direct method) with respective molar absorptivity values of 1.10 × 10⁴ and 2.77 × 10⁴ l mol^-1 cm^-1. The limits of detection (LOD) and quantification (LOQ) were 0.36 and 1.08 (Indirect method) and 0.23 and 0.69 µg mL^-1 (Direct method). Intra-day and inter-day precisions were satisfactory, with %RSD values of ≤2.11, and the respective accuracies were excellent with %RE values of ≤2. The methods were also validated for robustness, ruggedness and selectivity. The methods were applied to the determination of PGH in its tablets with good accuracy and precision, and no interference from the tablet additives was encountered. The results were also compared with those obtained by a reference method.

Piroxicam (POC) and oxfendazole (OFA) are two widely used veterinary non-steroidal anti-inflammatory and anthelmintic medicines, respectively. Simple, precise and accurate and cost-effective methods for the determination of POC and OFZ in bulk drug and in its dosage forms have been developed and validated. The methods are based on the potentiometric titration of compound with acetous perchloric acid in glacial acetic acid medium using modified glass-saturated calomel electrode system. The methods are applicable over the ranges 1.5 - 15 mg and 7.5-15 mg, for POC and OFA, respectively. The proposed methods were successfully applied to the determination of active substances in their pharmaceutical dosage forms. A statistical comparison was made on the results of proposed methods with those obtained for reference method. The intra-day and inter-day precision and accuracy values obtained were satisfactory with RSD and RE values less than 3%. Excipients in tablets did not interfere to the assay as shown by the recovery study via standard addition technique with mean percentage recoveries in the range 97.8 – 100.6%.