Apparent Solubility of Ibuprofen in Dimethyl Dodecyl Ammonium-Propane Sulfonate, DDAPS, Micelles, DDAPS/Butanol Mixtures and in Oil-in-Water Microemulsions Stabilized by DDAPS

Solubility of drugs in aqueous media is a real issue for scientists and a lot of work is going on to resolve the issue. The same is the case for ibuprofen, which is a derivative of propionic acid, belongs to the NSAIDs family and has low solubility in pure water. Therefore, its solubility has been investigated in dimethyl dodecyl ammonium-propane sulfonate, DDAPS, micellar solution, DDAPS/butanol mixtures and in various (hexane, decane and tetradecane) oil-in-water microemulsions to find out a suitable vehicle. The aggregation number, size and flow ability of micelles and microemulsions were estimated using refractive index, viscosity and light scattering measurements. It has been observed that these microemulsions have a higher ability to solubilize ibuprofen than DDAPS/butanol mixtures or DDAPS micelles.     

Viscometric Estimation of Unperturbed Chain Dimensions of Polymers

A new expression is proposed to determine the unperturbed dimensions of coil-like polymers viscometrically by use of the Flory and Kratky expression. The unperturbed dimensions so estimated are compared with the results obtained by using different expressions available in the literature. The results are comparable even for stiff chain polymers. The data obtained under theta conditions also fit this expression very well. The effect of molecular weight, its distribution, and that of the solvent has also been studied. It is concluded that the unperturbed dimensions are independent of molecular weight and solvent but depend on the heterogeneity of the system.     

Enhancement in Aqueous Solubility of Mefenamic Acid using Micellar Solutions of Various Surfactants

Journal of Solution Chemistry - The development of a meaningful dissolution procedure for drug products with limited water solubility has been a challenge to both the pharmaceutical industry and...     

Miscibility between PS and PSAN Affected by Solvent and Temperature of the System

The influence of solvent on the miscibility of polystyrene（PS） and poly（styrene-co-acrylonitrile）（PSAN） blends has been investigated viscometrically. The miscibility of different PS/PSAN blend（30/70, 50/50 and 70/30） compositions in acetone and benzene at 20, 30, and 40 °C was investigated on the basis of the sign of Chee（ΔB and ）, and Sun’s（α） criteria. The values of these parameters were evaluated from the analyses of reduced viscosity data of binary（solvent/polymer） and ternary（solvent/polymer1/polymer2） polymer systems. These investigations indicated partial miscibility for both the blend systems. However, PS/PSAN/acetone blend system showed somewhat higher partial miscibility than the PS/PSAN/Benzene blend system highlighting the impact of solvent over the polymer-polymer interactions and hence their miscibility. The results obtained through viscometry were also corroborated by the refractive index and density results for the blends under study. The effect of temperature on miscibility in both the cases was almost negligible.     

Water Pollution Threat to the Environment by a Urea Plant

Disposal of untreated industrial effluents is drastically deteriorating the quality of underground water. Research work has been conducted to analyze the effect of disposal of urea plant effluent on the quality of ground water of the District Mianwali Daudkhail, Pakistan. For this purpose the effluent and ground water samples were analyzed for pH, TDS, TSS, Cl, F, COD, BOD, Fe, Zn, Pb, Cu, Cr, Cd, Mn, and As. Results obtained were compared with WHO and NEQS standards for drinking and effluent emission limits, respectively. Moreover, effluent samples were also evaluated for irrigation purposes and results compared with criteria recommended for irrigation water. Results showed though the effluents were according to the standards given by National Environmental Quality Standards (NEQS) for liquid emission and fit for irrigation purposes, the quality of underground water was below standard due to having a higher quantity of total dissolved solids than permissible.     

A hybrid projective method for solving system of equilibrium problems with demicontractive mappings applicable in image restoration problems

In this paper, we propose a general iterative scheme based on CQ projection method for finding a common solution of system of equilibrium problems and the fixed point set of a finite family of demicontractive mappings. We also prove strong convergence of the scheme to a common element of the two above-described sets. We then give a numerical example to justify our main result. An example is given in an infinite dimensional space for supporting our main result. Moreover, we apply our main result to solve the unconstrained image restoration problems with a finite family of blurring operators. Our results extend and improve some existing results in the literature.     

The influence of Sr and Fe on the conductance of magnetoresistant compounds

Single-phase giant magnetoresistance (GMR) compounds were prepared by doping the parent compound, NdMnO₃, with Sr at Nd sites. The resistivity of the doped samples showed two prominent regions (Δρ/ΔT < 0, insulating and Δρ/ΔT > 0, metallic). The doped samples exhibited an enhancement in double exchange (DE) interactions causing an increase in T _c (transition temperature). Magnetic field decreased the resistance of all the samples because of the suppression of spin fluctuations and an increase in disorder in the system. The polaron and variable range hopping (VRH) models were good for studying the transport mechanism of electrons and understand their behavior at T > T _c.     

Isolation and characterisation of new bio-active compounds from Euphorbia cornigera: cytotoxic ingenol esters

The aerial parts of Euphorbia cornigera Boiss., on extraction with MeOH, yielded new bio-active constituents (1, 2) and known compounds (3 and 4) after MTT cytotoxicity assay-guided fractionation and chromatographic separation were conducted. From the aerial parts of E. cornigera Boiss., new bio-active constituents were extracted in methanol. The extract was partitioned in different organic solvents and the ethylacetate-soluble portion was subjected to Craig's distribution. The MTT cytotoxicity assay-guided chromatographic separation yielded four (1-4), out of which two (1, 2) were new and two known (3, 4) bio-active compounds, and they are reported for the first time from this source. Their structure and relative stereochemistry were established by analysing spectroscopic and mass measurement data. The isolates were named as: 13-O-[(2Z ,4 E ,6 Z)]-deca-2,4,6-trienoylingenol (1), 13-O-( 2 Z ,4 E ,6 Z)-deca-2,4,6-trienoyl-20-O-angeloylingenol (2), 13-O-dodecanoyl-20-O-hexanoylingenol (3) and 3-O-(2,3-dimethylbutanoyl)-13-O-dodecanoyl-20-O-hexadecanoylingenol (4). Literature revealed that compounds 1 and 2 are new metabolites, while 3 and 4 are known, and are reported for the first time from this source. Cytotoxicities of isolates were evaluated in terms of IC(50) against RAW and HT-29 cell lines through MTT assay using ambrucin hydrochloride as a control. Compound 3 showed more activity than control, while 1, 2 and 4 were moderate.     

Novel antifungal janthinopolyenemycins A and B from a co-culture of marine-associated Janthinobacterium spp. ZZ145 and ZZ148

Two rare polyketides, named as janthinopolyenemycins A (1) and B (2), were isolated from a co-culture of two marine-sourced bacteria Janthinobacterium spp. ZZ145 and ZZ148. Their structures were established by a combination of extensive NMR spectroscopic analyses, HRESIMS data, and ECD calculation. Both janthinopolyenemycins A and B showed activity in inhibiting the growth of Candida albicans with a MIC value of 15.6?μg/mL and a MBC value of 31. 25?μg/mL.