In the practice of "osmotic stress," the effect of excluded cosolvents on a biochemical equilibrium is interpreted as the number of water molecules participating in the reaction. This action is attributed to lowering of solvent water activity by the cosolvent. This concept of osmotic stress in disperse solution is erroneous: (i) A cosolvent cannot be both excluded and inert, i.e., noninteractin...

OBJECTIVES The purpose of these studies was to understand the influence of cosolvent and surfactant contributions to particle size distributions emitted from solution metered dose inhalers (pMDIs) based on the propellant HFA 227. METHODS Two sets of formulations were prepared: (a) pMDIs-HFA 227 containing cosolvent (5-15% w/w ethanol) with constant surfactant (pluronic) concentration and (b) ...

Tabernaemontana catharinensis is a tree rich in indole alkaloids, such as coronaridine and voacangine that have antileishmanial activity. SFE from T.catharinensis using CO2 + 5.1% (m/m) of cosolvent (ethanol, isopropyl alcohol, methanol, water and their mixtures) was studied. The global yields and the compositions of extracts were determined. The data were taken at 250 bar, 45oC, and total solv...

The effects of cosolvents on the solubility and hydration of small nonpolar solutes in solution has been investigated using a combination of molecular dynamics simulation and Widom particle insertion calculations. Results were obtained for helium, neon, argon, and methane solutes in solutions of sodium chloride, ammonium sulfate, calcium chloride, ammonium acetate, tetramethylammonium chloride,...

Solvent additives (cosolvents, osmolytes) modulate biochemical reactions if, during the course of the reaction, there is a change in preferential interactions of solvent components with the reacting system. Preferential interactions can be expressed in terms of preferential binding of the cosolvent or its preferential exclusion (preferential hydration). The driving force is the perturbation by ...

Griseofulvin (GF) is an antifungal drug whose pharmaceutical activity can be improved by particle size reduction. In this study the rapid expansion of supercritical solution (RESS) was employed to micronize GF. Carbon dioxide (CO2) with cosolvent acetone was chosen as a supercritical mixed solvent. The solubility of GF in supercritical CO2 with cosolvent acetone was measured using a dynamic app...

The influence of poor solvent quality on fluid demixing of a model mixture of colloids and nonadsorbing polymers is investigated using density functional theory. The colloidal particles are modeled as hard spheres and the polymer coils as effective interpenetrating spheres that have hard interactions with the colloids. The solvent is modeled as a two-component mixture of a primary solvent, rega...

The deconstruction of cellulose is an essential step in the production of ethanol from lignocellulosic biomass. However, the presence of lignin hinders this process. Recently, a novel cosolvent based biomass pretreatment method called CELF (Cosolvent Enhanced Lignocellulosic Fractionation) which employs tetrahydrofuran (THF) in a single phase mixture with water, was found to be highly effective...

Cosolvent effects on the coil–globule transitions in aqueous polymer solutions are not well understood, especially case of amphiphilic cosolvents that preferentially adsorb and lead to both swelling collapse. Although a predominant focus literature has been placed role polymer–cosolvent attractive interactions, our recent work shown excluded-volume interactions (repulsive interactions) can driv...

Solubility of lornoxicam in various pure solvents and solvent-cosolvent mixtures was studied to understand drug vehicle interactions and in order to get the required solubility equal to the dose of lornoxicam, i.e., 4 mg/ml for development of solution formulation. Polyethylene glycol (PEG) 400, propylene glycol, ethanol, water, dimethyl formamide, dimethyl sulfoxide, and ethyl acetate were used...