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).

ABSTRACT:The present work describes a quality by design (QbD)-based rapid, simple, precise and robust RP-UHPLC method for the routine analysis of vildagliptin in bulk drug and in pharmaceutical dosage forms. Chromatographic separation was achieved by a X-bridge C 18 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 ICH-Q2B 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.

The main objective of the study was to formulate fast dissolving tablets of allopurinol to achieve better dissolution rate and further improving the bioavailability to provide a quick onset of action. Nine formulations of fast dissolving tablets of allopurinol were prepared by direct compression technique using croscarmellose sodium (Group A), sodium starch glycolate (Group B) and crospovidone (Group C) as superdisintegrants in different concentrations. All formulations showed satisfactory mechanical strength, uniform weight & drug content, and lesser wetting time & dispersion time. In vitro disintegration time, dispersion time, wetting time of all nine formulations were obtained from 11.67±0.88 to 40.67±1.20 seconds, 32.67±0.88 to 65.33±1.45 seconds and 21.67±0.33 to 50.00±1.53 seconds respectively. Amongst all formulations, formulation F-9 prepared by 4.17% crospovidone showed least disintegrating time of 11.67±0.88 seconds along with rapid drug release (98.88% within 15 minutes).Dhaka Univ. J. Pharm. Sci. 15(1): 73-81, 2016 (June)

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The intent of the research work was to develop and validate a simple, selective and precise reversed phase ultra-high performance liquid chromatography (RP-UHPLC) method for the determination of ledipasvir. A forced degradation study was performed as per International Conference on Harmonisation (ICH) guidelines Q1A (R2) and Q1B. Ledipasvir was found to be well separated from degradation products using an analytical C18 column (150 mm × 4.6 mm i.d., 5 μm particle size) with a ratio of mobile phase (75:25 v/v) consisting of methanol and 0.1% trifluoroacetic acid (TFA) kept at ambient temperature. The average retention time of ledipasvir was found 4.45 min at 254 nm wavelength with 1.6 mL/min isocratic flow rate and 10 µL injection volume. Linearity, accuracy, precision, sensitivity, robustness, and ruggedness were studied according to ICH guideline Q2 (R1) to validate the method. Then, this validated method was applied for forced degradation studies of ledipasvir. In conclusion, the developed method has been successfully used to study degradation behaviour of ledipasvir and may be useful to quantify the drug in different pharmaceutical dosage forms.