Search results for "solubility"

A New Type of Artificial Oxygen Carrier: Soluble Hyperpolymeric Haemoglobin with Negligible Oncotic Pressure—Production of Thermally Stable Hyperpoly…

1992

Role of oxygen fugacity on the solubility of chlorine in peralkaline magmas.

2007

Experimental investigation on peralkaline silicic magmas of Pantelleria Island: inferences on pre-eruptive conditions, magma evolution and water solu…

2017

Skin permeation model of phenyl alcohols: comparison of experimental conditions

1998

Abstract This study was conducted primarily to establish the significance of the experimental conditions in the determination of permeability coefficients. In order to do this, standard in vitro skin permeation methods were used to determine the permeability coefficient (kp) of a homologous series of phenyl alcohols, with a wide range of lipophilicity, by two different experimental conditions through rat skin; first, using solutions (at 75% saturation concentration) of the penetrants in the donor compartment and second using saturated solutions added with an excess of the penetrant. The kp values obtained by these techniques were compared. Solubility of the phenyl alcohols in the donor phas…

Simultaneous dissolution profiles of two drugs, sulfadiazine-trimethoprim and amitriptyline-perphenazine, in solid oral dosage forms by a FIA manifol…

2002

The simultaneous determination of two dissolution profiles with the aid of a Flow Injection Analysis assembly has been applied to: (a) sulfadiazine-trimethoprim in tablets and (b) amitriptyline-perphenazine in sugar coated pills. The selected combinations are drugs which have overlapping UV-vis spectra. The officially proposed procedure from the pharmacopoeias has been adapted for the FIA methodology and derivative spectrophotometry and zero crossing. Preliminary experiments on the suitability of the simultaneous determination of both drugs were performed. The empirical profiles were adjusted by regression analysis using different approaches. The 3-parameter plot method was finally selected…

Biowaiver Monographs for Immediate-Release Solid Oral Dosage Forms: Folic Acid.

2018

This work presents a review of literature and experimental data relevant to the possibility of waiving pharmacokinetic bioequivalence studies in human volunteers for approval of immediate-release solid oral pharmaceutical forms containing folic acid as the single active pharmaceutical ingredient. For dosage forms containing 5 mg folic acid, the highest dose strength on the World Health Organization Essential Medicines List, the dose/solubility ratio calculated from solubility studies was higher than 250 mL, corresponding to a classification as "not highly soluble." Small, physiological doses of folic acid (≤320 μg) seem to be absorbed completely via active transport, but permeability data f…

Computational Fluid Dynamics Simulation of Hydrodynamics and Stresses in the PhEur/USP Disintegration Tester Under Fed and Fasted Fluid Characteristi…

2015

ABSTRACT: Disintegration of oral solid dosage forms is a prerequisite for drug dissolution and absorption and is to a large extent dependent on the pressures and hydrodynamic conditions in the solution that the dosage form is exposed to. In this work, the hydrodynamics in the PhEur/USP disintegration tester were investigated using computational fluid dynamics (CFD). Particle image velocimetry was used to validate the CFD predictions. The CFD simulations were performed with different Newtonian and non-Newtonian fluids, representing fasted and fed states. The results indicate that the current design and operating conditions of the disintegration test device, given by the pharmacopoeias, are n…

Influence of poloxamers on the dissolution performance and stability of controlled-release formulations containing Precirol® ATO 5

2005

Abstract Lipid excipients are usually used for the development of sustained-release formulations. When used in relatively high quantities, Precirol ® ATO 5 imparts sustained-release properties to solid oral dosage forms, by forming a lipid matrix. To control or adjust the drug release kinetics from such lipid matrix however, one must often resort to complementary ingredients or techniques. This study investigates the influence of poloxamers (Lutrol ® ) included in lipid matrices composed of glyceryl palmitostearate (Precirol ® ATO 5) on their dissolution performance and their stability. The addition of these hydrophilic polymers in the lipid matrix increased the amount of theophylline relea…

Mechanistic investigation of food effect on disintegration and dissolution of BCS class III compound solid formulations: the importance of viscosity

2012

A negative food effect, i.e. a decrease in bioavailability upon the co-administration of compounds together with food, has been attributed particularly with high solubility/low permeability compounds (BCS class III). Different mechanisms have been proposed including intestinal dilution leading to a lower concentration gradient across the intestinal wall as well as binding of the active pharmaceutical ingredient to food components in the intestine and thereby decreasing the fraction of the dose available for absorption. These mechanisms refer primarily to the compound and not to the dosage form. An increase in viscosity of the dissolution fluid will in particular affect the absorption of BCS…

Methods of protein surface PEGylation under structure preservation for the emulsion-based formation of stable nanoparticles

2016

Proteins show remarkable versatility as multifunctional materials for therapeutic applications. They can be easily modified with the toolkit of bioorganic chemistry and are particularly attractive because of their degradability and biocompatibility. Herein, we evaluate different methods for the attachment of multiple PEG chains on the surface of the enzyme lysozyme. For this, we activated standard 2 kDa mPEG chains with four different electrophilic groups and tested their ability to react with different amino acids on the surface of our model protein. The aim was to find an effective and at the same time mild modification method that preserves the native structure and activity of the enzyme…