{"id":13478,"date":"2026-02-02T15:14:30","date_gmt":"2026-02-02T15:14:30","guid":{"rendered":"https:\/\/www.sygnaturediscovery.com\/?post_type=technical-note&p=13478"},"modified":"2026-02-02T15:19:46","modified_gmt":"2026-02-02T15:19:46","slug":"logd7-4-assay-validation-shake-flask","status":"publish","type":"technical-note","link":"https:\/\/www.sygnaturediscovery.com\/fr\/technical-note\/logd7-4-assay-validation-shake-flask\/","title":{"rendered":"LogD7.4<\/sub>"},"content":{"rendered":"\n

About the Assay<\/h2>\n\n\n\n

Sygnature Discovery\u2019s LogD7.4 <\/sub>assay quantifies compound lipophilicity using a classical shake\u2011flask partitioning approach between 1\u2011octanol and pH\u202f7.4 phosphate buffer. Lipophilicity expressed as the Log of the distribution coefficient (LogD), is a key determinant of solubility, distribution, permeability and metabolic stability, making its accurate measurement essential for early\u2011stage drug discovery. The assay is designed to provide reliable LogD measurements across a broad chemical diversity, from hydrophilic to highly lipophilic compounds.<\/p>\n\n\n\n

Protocol Summary<\/h2>\n\n\n\n

The LogD7.4 <\/sub>workflow involves partitioning of test compounds between 1-octanol and pH 7.4 buffer to quantify the relative distribution between polar and non\u2011polar environments. Test compound solutions utilizing 10 mM DMSO stocks are prepared in 1-octanol, equilibrated to ensure complete dissolution, and mixed with buffer in a defined phase ratio. Mechanical shaking ensures efficient mixing and enables the compound to distribute between the two phases.

Once equilibrium is reached, the two phases are separated by centrifugation, and aliquots are taken from each layer. Samples undergo appropriate dilution to fall within the analytical calibration range, and quantification is performed using LC\u2013MS\/MS. Measurements from multiple dilutions of buffer samples and nominal octanol standards are combined to generate a set of LogD ratios, from which accepted values are averaged to provide a final reported LogD7.4<\/sub>.

This structured workflow emphasizes reproducibility, minimizes handling variability and supports consistent data across compound classes. The standardised dilution and calibration strategy ensures robust quantification, enabling confident assessment of compounds spanning a wide range of lipophilicities.<\/p>\n\n\n\n

Validation Results<\/h2>\n\n\n\n
\"Graph<\/figure>\n\n\n\n

Figure 1.<\/strong> Graph illustrating the mean measured LogD values for reference compounds vs literature data (1,2,3)<\/sup> in pH7.4 phosphate buffer:1-octanol<\/em><\/p>\n\n\n\n

A subset of five compounds was further assessed in a dedicated intra\u2011assay evaluation (n\u202f=\u202f6 incubations). The results demonstrated outstanding consistency, with coefficients of variation ranging from 0.9% to 8.7%, confirming reproducible performance within a single experimental run.<\/p>\n\n\n\n

Summary<\/h2>\n\n\n\n

The assay delivers robust and reproducible partitioning across two immiscible phases following controlled equilibration, enabling accurate determination of concentration ratios. LC\u2013MS\/MS quantification ensures high sensitivity and broad dynamic range, supporting measurement of both polar and lipophilic molecules. The method supports high confidence in LogD7.4 <\/sub>characterization, facilitating medicinal chemistry optimization and enabling reliable structure\u2011property relationship interpretation.<\/p>\n\n\n\n

Overall, the shake\u2011flask LogD7.4 <\/sub>assay provides high\u2011quality lipophilicity data aligned with industry standards and literature values, making it a powerful tool within early\u2011stage ADME screening workflows.<\/p>\n\n\n\n

References<\/h3>\n\n\n\n
    \n
  1. F. Lombardo, M.Y.Shaleva, K.A.Tupper, F.Gao, A tool for lipophilicity determination in drug discovery. 2. Basic and neutral compounds, J. Med. Chem. 44 (2001) 2490-2497<\/li>\n\n\n\n
  2. G. Morikawa, C. Suzuka, A. Shoji, Y. Shibusawa, A. Yanagida, High-throughput determination of octanol\/water partition coefficients using a shake-flask method and novel two-phase solvent system. Journal of Pharmaceutical and Biomedical Analysis 117 (2019) 338-344<\/li>\n\n\n\n
  3. M. Wenlock, T. Potter, P. Barton, and R.P. Austin, A Method for Measuring the Lipophilicity of Compounds in Mixtures of 10. Society for Laboratory Automation and Screening (2011)<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"

    Sygnature Discovery\u2019s LogD7.4<\/sub> validation confirms the assay\u2019s accuracy and reproducibility across a wide range of compound lipophilicities. Using a classical shake\u2011flask approach with LC\u2013MS\/MS quantification, the method shows strong alignment with literature values and low variability across repeat assays, providing high\u2011quality lipophilicity data to support confident early\u2011stage ADME decision\u2011making.<\/p>\n","protected":false},"featured_media":0,"template":"","category":[683,719],"resource_tag":[],"class_list":["post-13478","technical-note","type-technical-note","status-publish","hentry","category-dmpk","category-physicochemical-profiling"],"acf":[],"yoast_head":"\nLogD7.4 Assay Validation: Accurate Lipophilicity Measurement<\/title>\n<meta name=\"description\" content=\"LogD7.4 data validated across diverse chemistries, demonstrating high accuracy and low variability for confident early\u2011stage ADME decisions.\" \/>\n<meta name=\"robots\" content=\"noindex, follow\" \/>\n<meta property=\"og:locale\" content=\"fr_CA\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta 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