A new automated instrument for rapid measurement of pKa during early stage pharmacokinetic tests has been introduced by Sirius Analytical Instruments
A new automated instrument for rapid measurement of pKa during early stage pharmacokinetic tests has been introduced by Sirius Analytical Instruments.
Innovative software uniquely enables the calculation of pKas of several species where UV absorbance peaks are close or overlap.
Physico-chemical properties such as lipophilicity (logP), solubility and permeability are regularly used to predict properties of molecules in biological systems such as oral absorption.
If a molecule is ionisable, its properties are pKa dependent.
Approximately 75% of all physiologically active compounds are ionisable.
Knowledge of pKa is essential for completing a full physicochemical profile of a compound.
The new ProfilerSGA provides a fast, automated method of pKa measurement.
It measures 300 assays per day, using 10-20 microlitres of 10mM sample solution (about 50 micrograms of sample) per assay.
Measuring samples direct from microplates, the ProfilerSGA uses multi-wavelength UV spectroscopy and a linear 2-12 pH unit gradient for rapid pKa determination.
Poorly soluble samples are analysed by starting the gradient at the pH where the sample is most soluble (low pH for bases, high for acids). According to Technical Director John Comer: "Results are automatically calculated by our ProfilerRefine software using a method based on Target Factor Analysis.
This powerful technique deconvolutes the multi-wavelength spectra to give accurate pKa values, even when UV absorbance peaks of different species in solution are close together or overlap and conventional first derivative spectral analysis is inadequate." Finding the right balance between physicochemical properties and biological activity of a drug candidate is a difficult and expensive process.
The Sirius ProfilerSGA provides the solution for rapid pKa measurement: * Hands-off pKa analysis of samples in 96-well plates; * 300 assays measured in 24 hours; *50 micrograms of sample per assay; * Multi-wavelength spectrophotometric technique; * Secure user IDs for open access option; * Automated data handling and processing; and * Full computer control
