What do log Kow values mean?

octanol/water partition coefficient
Definition. “log Kow” is a ratio value without a unit and is normally used in the decadic logarithm (“log” in log Kow). This value stands for the octanol/water partition coefficient. Consequently, this means the higher the log Kow, the more soluble the substance is in fatty (nonpolar) substances.

What does a high Kow value mean?

Substances with high logKow values tend to adsorb more readily to organic matter in soils or sediments because of their low affinity for water (see Kd/Koc). Chemicals with very high logKow values (i.e, >4.5) are of greater concern because they may have the potential to bio-concentrate in living organisms.

What does a low log P mean?

A negative value for logP means the compound has a higher affinity for the aqueous phase (it is more hydrophilic); when logP = 0 the compound is equally partitioned between the lipid and aqueous phases; a positive value for logP denotes a higher concentration in the lipid phase (i.e., the compound is more lipophilic).

What does log p tell you about a drug?

Lipophilicity is a valuable parameter of the drug which affects its activity in the human body. The Log P value of the compound indicates the permeability of the drugs to reach the target tissue in the body.

How does Kow relate to bioaccumulation?

BIOACCUMULATION METRICS The octanol–water partition coefficient (KOW) is widely used as an indicator of hydrophobicity and thus the partitioning of a chemical from water into lipids and other organic phases such as protein [10].

What does a high partition coefficient mean?

unit of measure called the 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.

Is log P the same as log Kow?

The KOW values of organic compounds span many orders of magnitude, and this is one reason why often the decadic logarithm of KOW (log KOW, also called log P) is listed rather than KOW itself; a more fundamental reason is shown below.

What does a negative log D mean?

Predicted logP is 2.7 ± 0.3. Negative values of logD (-1.44 to 0) in the physiologically relevant pH range (pH 1–8) lead us to conclude that this compound would be more susceptible to higher aqueous solubility and of lower lipophilicity in the body. As a result we would expect membrane permeability to be poor.

Why is bioaccumulation a problem?

“What is the problem with bioaccumulation?” When toxins gets absorbed at a higher rate than the body can get rid of it, the organism is at risk of chronic poisoning. Even if the environment doesn’t have a high amount of toxin in it, accumulation through the food chain can be devastating for organisms.

What is log Koc?

Thus a normalised organic carbon to water partition coefficient (KOC), described as the ratio between the sorption coefficient Kd, and the organic carbon content of the sorbent, in units of mass of organic carbon (OC) per mass of soil (g OC/g soil) is commonly used to assess the extent to which an organic chemical is …

How does log p affect absorption?

High lipophilicity (logP>5) often contributes to high metabolic turnover, low solubility, and poor oral absorption. In addition, highly lipophilic compounds tend to bind to hydrophobic targets other than the desired target, and, therefore, there is an increased risk of promiscuity and toxicity.

What does log P value means?

The log P value for a compound is the logarithm (base 10) of the partition coefficient (P), which is defined as the ratio of the. compound’s organic (oil)-to-aqueous phase concentrations: Partition Coefficient (P) = [Organic] / [Aqueous], where [ ] is the compound’s concentration in that solvent phase.