Table of Contents
What does the partition coefficient determine?
A partition coefficient is used to describe how a solute is distributed between two immiscible solvents. They are used in drug design as a measure of a solute’s hydrophobicity and a proxy for its membrane permeability.
Why is it important to define the partition coefficient in an extraction experiment?
The partition coefficient is the ratio of the moles of solute in the two phases, and is a more effective means of measuring whether you have achieved the desired goal. The larger the value of DM, the more of the solute we have extracted or partitioned into the organic phase.
What is the application of partition coefficient in pharmacology?
Partition coefficients are used in the pharmaceutical industry to estimate how a drug may transfer between different biological environments4,20 and are regularly used to predict a molecule’s hydrophobicity.
What are the factors affecting partition coefficient?
The greater the solubility of a substance, the higher its partition coefficient, and the higher the partition coefficient, the higher the permeability of the membrane to that particular substance. For example, the water solubility of hydroxyl, carboxyl, and amino groups reduces their solubility…
What is a partition coefficient in chemistry?
In the physical sciences, a partition coefficient (P) or distribution coefficient (D) is the ratio of concentrations of a compound in a mixture of two immiscible solvents at equilibrium. This ratio is therefore a comparison of the solubilities of the solute in these two liquids.
How is apparent partition coefficient calculated?
The apparent partition coefficient is (drug in organic phase / total drug in water phase) = (0.8/1.2) = 0.67.
What is difference between partition coefficient and distribution coefficient?
The partition coefficient generally refers to the concentration ratio of un-ionized species of compound, whereas the distribution coefficient refers to the concentration ratio of all species of the compound (ionized plus un-ionized). In the chemical and pharmaceutical sciences, both phases usually are solvents.
Why is sodium bicarbonate used in extraction?
This phenomenon will often be observed if sodium bicarbonate is used for the extraction in order to neutralize or remove acidic compounds. The reaction affords carbon dioxide (CO2), which is a gas at ambient temperature. Pressure builds up that pushes some of the gas and the liquid out.
Which of the following solvent is most suitable for determining partition coefficient?
The partition coefficient is determined by the shake flask method using two immiscible solvents, the most common hydrophilic solvent is water or phosphate buffer of pH 7.4, and for oil phase is octanol.
What are the limitations of partition coefficient?
Limitations. LogP is not an accurate determinant of lipophilicity for ionizable compounds because it only correctly describes the partition coefficient of neutral (uncharged) molecules.
How does pH affect partition coefficient?
The study showed that both solubility and partition coefficient are pH-dependent, whereby solubility increases with increasing pH value above the pKa value, while partition coefficient decreases in the same conditions.
What is the method of measuring distribution coefficient?
A number of methods of measuring distribution coefficients have been developed, including the shake-flask, separating funnel method, reverse-phase HPLC, and pH-metric techniques.
What is partition coefficient in analytical chemistry?
The partition coefficient (P) is defined as the ratio of the equilibrium concentrations of a dissolved substance in a two-phase system consisting of two largely immiscible solvents.
Is partition coefficient same as solubility?
The difference between the two is that solubility measures the amount of solute that can be dissolved in one solvent, while partition coefficient measures the ability of the solute to go into two immiscible phases.
What is the partition coefficient of a substance?
A partition coefficient is the ratio of the concentration of a substance in one medium or phase (C 1) to the concentration in a second phase (C 2) when the two concentrations are at equilibrium; that is, partition coefficient = (C 1 /C 2) equil.
Is blood partitioning coefficient unitless?
(In principle all partition coefficients are unitless, since they represent the ratio of two concentrations and for internal tissue:blood partitioning are usually listed as such.
What is the organic carbon water partition coefficient?
The organic carbon water partition coefficient is a dimensionless number defined as the ratio of a chemical’s concentration absorbed per unit mass of soil, to its concentration in the aqueous phase. It represents the distribution coefficient (Kd) normalized to total organic carbon content.
What is the partition coefficient of general anesthetic?
For example, the blood/gas partition coefficient of a general anesthetic measures how easily the anesthetic passes from gas to blood. Partition coefficients can also be defined when one of the phases is solid, for instance, when one phase is a molten metal and the second is a solid metal, or when both phases are solids.