562 research outputs found
Nematic - Isotropic Transition in Porous Media - a Monte Carlo Study
We propose a lattice model to simulate the influence of porous medium on the
Nematic - Isotropic transition of liquid crystal confined to the pores. The
effects of pore size and pore connectivity are modelled through a disorder
parameter. Monte Carlo calculations based on the model leads to results that
compare well with experiments.Comment: 11 pages; 4 figure
DEVELOPMENT OF SELF NANO-EMULSIFYING DRUG DELIVERY SYSTEM FOR AN ANTI-HYPERTENSIVE AGENT FELODIPINE: A SYSTEMATIC APPROACH FOR LIPID NANO-FORMULATION WITH IMPROVED ORAL BIOAVAILABILITY IN RATS
Objective: The present study involves the development of SNEDDS employing essential oils for enhancing biopharmaceutical performance.
Methods: Preliminary investigations suggested the selection of cinnamon oil as an essential oil, tween 60 as a surfactant, while transcutol HP as a cosolvent for formulating SNEDDS. Formulations evaluated for stability, robustness to dilution, and emulsification time, droplet size, zeta potential (ζ), cloud point, in vitro drug release, drug excipient compatibility, TEM, stability assessment and in vivo pharmacokinetic performance in rats.
Results: All formulations were robust, stable, and revealed excellent emulsification time<40 s, with fine droplet size (11.41±2.41 nm), lower PDI (0.028-0.277). Formulation F(FLD)6 exhibited a release of 97.7% within 4h, and TEM photograph confirmed spherical droplets. The bioavailability results revealed a higher rate and extent of absorption, AUC, and Cmax for the formulations found to be 1212.4 and 355.40±13.67 (p<0.05). The results recommend that the developed formulation approach offers bioavailability enhancement of FLD.
Conclusion: The study concluded that SNEDDS would be an effective formulation system in increasing the aqueous solubility and potentially bioavailability. Furthermore, it can be applied for other therapeutic categories of drugs belonging to BCS class II and IV that show comparable biopharmaceutical challenges
New mixed ligand complexes of ruthenium(II) that incorporate a modified phenanthroline ligand: synthesis, spectral characterization and DNA binding
The hexafluorophosphate and chloride salts of two ruthenium(II) complexes, viz. [Ru(phen)(ptzo)2]2 and [Ru(ptzo)3]2+, where ptzo = 1,10-phenanthrolino[5,6-e]1,2,4-triazine-3-one (ptzo) - a new modified phenanthroline (phen) ligand, have been synthesised. These complexes have been characterised by infrared, UV-Vis, steady-state emission and1H NMR spectroscopic methods. Results of absorption and fluorescence titration as well as thermal denaturation studies reveal that both thebis- and tris-complexes of ptzo show moderately strong affinity for binding with calf thymus (CT) DNA with the binding constants being close to 105M-1 in each case. An intercalative mode of DNA binding has been suggested for both the complexes. Emission studies carried out in non-aqueous solvents and in aqueous media without DNA reveal that both [Ru(phen)(ptzo)2]2+ and [Ru(ptzo)3]2+ are weakly luminescent under these solution conditions. Successive addition of CT DNA to buffered aqueous solutions containing [Ru(phen)(ptzo)2]2+results in an enhancement of the emission. These results have been discussed in the light of the dependence of the structure-specific deactivation processes of the MLCT state of the metallo-intercalator with the characteristic features of its DNA interaction. In doing so, attempts have been made to compare and contrast its properties with those of the analogous phenanthroline-based complexes including the ones reported by us previously
Kinetics of thermal decomposition of some metal oxalates
The thermal decomposition kinetics of oxalates of ZnII, NiII and ThIV have been studied in air by isothermal and non-isothermal thermogravimetry. The isothermal kinetic results suggest that the mechanism of decomposition of the zinc compound involves rapid nucleation followed by two dimensional growth in the acceleratory region, while in the case of thorium oxalate, the initial nucleation occurs by a chain mechanism on the surface of the reactant followed by the growth of the product from the surface towards the interior. The results on nickel oxalate could not be interpreted in an unambiguous manner. The activation energy and the frequency factor obtained from TG curves compare well with those obtained from the isothermal method. The activation energies for the dehydration of these oxalates have also been evaluated from the thermogravimetric curves
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