Thermodynamics
Sarah Armstrong, Barry Clifton, Lionel Davis in Primary FRCA in a Box, 2019
Colligative properties of a solution are the change in its properties due to the number of solute particles present. As the molar concentration of solute increases, there is a proportional increase in osmotic pressuredecrease in freezing point (1.86 K per osmol of solute per kg solvent); hence, salting the roads in winter and the principle of how an osmometer worksincrease in boiling point (0.52 K per osmol per kg)decrease in vapour pressure of solvent – this is Raoult's law
Chapter Paper 4 Questions
James Day, Amy Thomson, Tamsin McAllister, Nawal Bahal in Get Through, 2014
Regarding the colligative properties of solutions:Increasing individual solute concentration has no effect on osmotic pressureIncreasing solute concentration elevates the freezing point of a solventReduction of vapour pressure of a solvent in presence of a solute also elevates the boiling pointRaoult’s law relates molar concentration of a solute to depression of the freezing pointIncrease in vapour pressure of a solvent occurs proportionally to increase in molar concentration of the solute
The Scientific Basis of Urinary Stone Formation
Anthony R. Mundy, John M. Fitzpatrick, David E. Neal, Nicholas J. R. George in The Scientific Basis of Urology, 2010
The overriding factor that is common to all types of stone is the relative insolubility of their respective mineral component(s) in urine. When a substance is allowed to dissolve in water, dissolution proceeds until the rate of return of the dissolved material to the solid phase equals the rate at which the solid phase goes into solution. The concentration of the substance in solution at this equilibrium point is known as the substance’s solubility under the conditions of temperature and ionic strength concerned. Examples of the solubilities in water at 37°C and at pH 6 of various salts and acids present in urine are shown in Table 1. Clearly, the substances that turn up in kidney stones have much lower solubilities than those that do not. For a sparingly soluble substance, it is usual to express this equilibrium value as a product of the concentrations (or more correctly activities) of the constituent ions rather than as the absolute solubility of the substance in mass per unit volume. This equilibrium activity product is known as the thermodynamic solubility product of the substance concerned and is a constant at a given temperature.
Central composite rotatable design for optimization of budesonide-loaded cross-linked chitosan–dextran sulfate nanodispersion: characterization, in vitro diffusion and aerodynamic study
Published in Drug Development and Industrial Pharmacy, 2019
Divyanka Shrikant Bodas, Pradum Pundlikrao Ige
Solubility is a property of a solid, liquid, or gaseous chemical substance called solute which is to be dissolved in a solid, liquid, or gaseous solvent to form a homogenous solution of the solute in the solvent. The solubility of substance primarily depends on the solvent used as well as on temperature and pressure. The solubility of budesonide was studied in different solvents. The solubility of drug in dichloromethane, ethanol, PBS (pH 7.4 and pH 6.8) and purified water was found to be 102.66 ± 4.03 mg/mL, 92 ± 1.36 mg/mL, 0.017 ± 0.0008 mg/mL, 0.0216 ± 0.0001 mg/mL, and 0.0450 ± 0.0005 mg/mL, respectively. Solubility results showed highest solubility in dichloromethane and ethanol. The extent of solubility of a substance in a specific solvent is measured as the saturation concentration where adding more solute does not increase its concentration in the solution.
Transdermal delivery via medical device technologies
Published in Expert Opinion on Drug Delivery, 2022
Shubhangi Shukla, Ryan H. Huston, Blake D. Cox, Abhay R. Satoskar, Roger J. Narayan
While drugs come in innumerable structural combinations, one way to classify them easily is using two main characteristics which provide unique advantages or challenges to their use, specifically drug permeability and drug solubility; hence, these two traits define the Biopharmaceutics Classification System taxonomy [111]. Iontophoresis has been shown to benefit many drugs with varying combinations of these traits; however, the most challenging drugs to deliver are those with low permeability and low solubility. Compared to water-soluble drugs, iontophoresis has not been thoroughly researched for use with lipophilic/hydrophobic or otherwise water-insoluble drugs. The current research has been largely focused on delivery of drugs via iontophoresis using water-based buffers and water-soluble ions; however, the principle of electroosmosis clearly supports the penetration of nonpolar or uncharged molecules as well [100]. In addition, creative drug formulations can enhance iontophoretic delivery by (a) placing drugs in liposomes or micelles; (b) mixing solutes with surfactants, cosolvents, or complexion solutes; or (c) substituting the solvent altogether [112].
Smart systems for determination of drug’s solubility
Published in Drug Development and Industrial Pharmacy, 2019
Vahid Jouyban-Gharamaleki, Abolghasem Jouyban, William E. Acree, Elaheh Rahimpour
In the pharmaceutical sciences, drug solubility not only has remedial implications but also is one of the challenging topics in the drug discovery and development studies. Approximately one-half of the newly synthesized materials have been abandoned from the process of discovering due to the low aqueous solubility. The methods used for estimating the solubility of drugs are classified as (i) manual experimental methods, (ii) mathematical predictive methods, and (iii) experimental smart/synthetic methods. The manual methods are tedious and time-consuming, which may cause some limitations in the discovering and development of new drugs. Mathematical methods are the easy and fast ways to describe the solute solubility behavior. These models can be categorized in two classes: (a) theoretical and (b) semi-theoretical or empirical approaches [1]. Theoretical models are useful for better understanding of the drug solubility. Empirical models, on the other hand, are used for correlating experimental data. Empirical models are also categorized into two groups: predictive models and correlative equations. The important remark for a totally predictive model is that no additional experimental data are required for using these models while the correlative equations employ curve-fitting parameters to correlate the experimental solubility data as a function of the solvent composition and/or temperature [2].
Related Knowledge Centers
- Chemistry
- Filtration
- Rayleigh Scattering
- Solvation
- Mixture
- Chemical Polarity
- Suspension
- Scattering
- Tyndall Effect
- Relative Density