Evaluation of antioxidant and antimicrobial activities on various extracts of Himalayan medicinal plants.

The DPPH radical scavenging potentials of the fractions were determined in comparison to positive controls such as quercetin with EC50 = 4.12±1.27, ascorbic acid with EC50 = 6.20±1.67, gallic acid with EC50 = 4.75±1.24 and α-tocopherol with EC50 = 32.50±1.57 µg/mL. The experiment showed that aqueous fractions of the bark extracts of Abies pindrow (fraction: C2) and Cedrus deodara (fraction: E2) showed significantly lower EC50 values of 2.5±0.5 and 2.5±0.6 µg/mL, respectively. In reducing power assay, lower EC50 values of 5.5 and 4.5µg/mL were recorded for the aqueous fraction (fraction: C 2) and final residue (fraction: C5), of Abies pindrow, respectively. The ethyl acetate, acetone and final fractions of knot wood of Picea smithiana were found significantly active against all bacterial strains. Of the most sensitive fractions towards all the fungal strains was ethyl acetate fraction obtained from the bark of Cedrus deodara with a zone of inhibition ranging from 75 to 88 % that was more than the standard fluconazole.

Formulation and in vitro evaluation of directly compressed controlled release tablets designed from the Co-precipitates.

Controlled release dosage forms provide sustained therapeutics effects for prolonged period of time and improve patient compliance. In present study, controlled release co-precipitates of Metoprolol Tartrate and Losartan Potassium were prepared by solvent evaporation method using polymers such as Eudragit RL 100 and Carbopol 974PNF and controlled release tablets were directly compressed into tablets. In-vitro dissolution of controlled release co-precipitates were performed by USP Method-II (paddle method) and tablets were evaluated by USP Method-I (rotating basket method) in phosphate buffer (PH 6.8) using pharma test dissolution apparatus. The temperature was maintained constant at 37±1.0°C and the rotation speed of paddle and basket was kept constant at 100rpm. Drug release mechanisms were determined by applying Power Law kinetic model. The difference and similarity of dissolution profiles test formulations with reference standards were also determined by applying difference factor (f1) and similarity factor (f2). The results showed that the controlled release co-precipitates with polymer Eudragit RL 100 of both the drug extended the drug release rates for 10 hours and those having polymer Carbopol 974P NF extended the drug release rates for 12 hours. The controlled release tablets prepared from controlled release co-precipitates extended the drugs release up to 24 hours with both the polymers. The drug was released by all tests anomalous non fickian mechanism except F1 and F5 do not follow Power Law. The f1 and f2 values obtained were not in acceptable limits except F15 whose values were in acceptable limits. It is concluded from the present study that polymers (Eudragit RL 100 and Carbopol 974P NF) can be efficiently used in development of controlled release dosage forms having predictable kinetics.