What is log D of a drug?

Log D, a pH dependent version of log P, is a descriptor of the octanol−water distribution coefficient for partitioning of ionizable species in biphasic media. It reflects the true behavior of ionizable compounds in solution at a given pH value or range.

What is log p QSAR?

The partition coefficient (log P) is a physicochemical parameter widely used in environmental and health sciences and is important in REACH and CLP regulations. In this regulatory context, the number of existing experimental data on log P is negligible compared to the number of chemicals for which it is necessary.

What is log P value of 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. The most lipophilic compounds are flurbiprofen and ibuprofen.

How do you calculate log P?

Log P calculations are based on a pool of fragments predefined in the log P calculator. This set is based on the data set in Viswanadhan et al. Every fragment is assigned a unique name and a value. The log P value of a molecule is the sum of the fragment values that are present in the molecule.

What is the difference between log D and LogP?

LogD is a distribution coefficient widely used to measure the lipophilicity of ionizable compounds, where the partition is a function of the pH. For non-ionizable compounds LogP = LogD throughout pH range, whereas for ionizable compounds LogD takes into account the partition of both ionized and non-ionized forms.

What does negative log D mean?

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.

What is a high logP value?

A drug targeting the central nervous system (CNS) should ideally have a logP value around 2;2 for oral and intestinal absorption the idea value is 1.35–1.8, while a drug intended for sub-lingual absorption should have a logP value >5. Not only does logP help predict the likely transport of a compound around the body.

What is log Kow value?

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 is the difference between LogP and log D?

How do you know if a drug is lipophilic?

Lipophilicity can be measured by the distribution of a drug between the organic phase, which is generally n-octanol pre-saturated with water, and the aqueous phase, which is generally water pre-saturated with n-octanol.

What is log p water?

Partition coefficient of a solvent1/ water system might be defined as the ratio of a chemical’s concentration in the solvent1 phase to its concentration in the aqueous phase. Log of this partition coefficient, log P is used to measure the hydrophobicity. …

How is log P value calculated theoretically?

It has been shown that the log P of a compound can be determined by the sum of its non-overlapping molecular fragments (defined as one or more atoms covalently bound to each other within the molecule).

What is logP and log d?

logD is a log of partition of a chemical compound between the lipid and aqueous phases . The most popular lipid phase is octanol. LogP is equivalent to logD for non-ionisable compounds and represents the partition of the neutral form for ionizable compounds (and, hence, is a virtual, unmeasurable, property).

What is log p value?

The logP value of a compound, which is the logarithm of its partition coefficient between n-octanol and water log(c octanol/c water), is a well established measure of the compound’s hydrophilicity. Low hydrophilicities and therefore high logP values cause poor absorption or permeation.

What is log P?

Log P (or partition co-efficient) is a measure of the lipophilicity of a compound. Cyprotex’s pK a and log P determination uses UV-metric and pH-metric technology developed by Sirius. This is considered to be a ‘gold standard’ method for determining these properties.