LYPOPHILICITY

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Certain amount of lipophilicity is needed for the compounds to permeate across biological membrane. Lypophilicity is especially important for compounds of oral administration. 

The typical measurement of lipophilicity is the partition coefficient (logP) of compounds between non-aqueous (Octanol) and aqueous (water) phases. A desired logP value is less than 5 (Lipinski rule of five).

Lipophilicity can also be measured as distribution coefficient, logD. LogD measurement takes into account the ionized and non ionized forms of the compounds and is measured at different pHs. Typically the most relevant pH for lipophilicity measurement is the physiological pH 7.4.

Lypophilicity assay protocol:

Method: Octanol:buffer shake flask method 

Test article concentration: 5 µM (other upon request) 

Incubation time: Overnight 

Incubation temperature: Ambient temperature 

Number of Replicates: n = 2 (aliquots from aqueous and organic phases) 

Assay condition: n-Octanol, PBS - pH 7.4 (other buffers upon request) 

Positive control: Propranolol 

Analysis Method: LC/MS/MS

Data Delivery: LogP; LogD (as per request)