At Sirius Analytical we design and manufacture highly automated instruments to measure physicochemical parameters - pKa, logP & logD, solubility and dissolution. We also operate as a CRO providing a wide range of physical chemistry analytical services.
Sirius Analytical Gold Standard assays are definitive physchem analyses in which the analysis conditions are optimised to give the best data quality. We perform repeat analyses until the best result is achieved. The assays are typically designed for solids, although solutions can also be accommodated.
Additionally, extended investigations are available by special request to test for changes in polymorph/crystal form where relevant.
The Sirius Gold Standard pKa assay is a definitive PhysChem assay that is customised for each compound using either a pH-metric or UV-metric approach. It may therefore be used for compounds which are non UV active. The pH-metric pKa range is 2-12 and the dual vial UV method measures pKas in the range 1.5 to 13.5. Either aqueous or cosolvent approaches are adopted depending upon the compound solubility. A detailed report is provided including:
Samples are typically provided as solids for Gold Standard pKa assays. We normally request 5mg for this assay, but smaller amounts can be accommodated, so please talk to Sirius if you intend to submit less.
Our pH-metric LogP assay is a definitive Physchem assay for compounds which are ionisable. The assay yields the LogP of neutral and ionic forms of an ionisable compound. This assay also delivers an extrapolated pH vs. LogD profile. Ocan-1-ol is used as our standard partition solvent but alternative partition solvents can be accommodated at additional cost. The method will accommodate compounds having a LogP value between -1 and 6.
Samples are typically provided as solids for Gold Standard LogP assays. We normally request 5mg for this assay, but smaller amounts can be accommodated, so please talk to Sirius if you intend to submit less.
Sirius offers both the Cheqsol assay for measuring kinetic and intrinsic solubility and classical shake flask equilibrium solubility measurements. Our Cheqsol assay is a pH-metric assay suitable for ionisable compounds which provides information on supersaturation, excipient profiling and measurements in biorelevant media. This assay delivers an extrapolated pH vs. solubility profile.
Shake flask solubility measurements are conducted at fixed pH and may be performed in the presence of excipients and biorelevant buffers. This assay is suitable for ionisable and non-ionisable compounds.
Our dissolution assay is a small volume assay which uses in-situ tools to monitor the release of drug into solution over time. Our capabilities include real-time pH control in the vessel and measurement in the presence of excipients and bio-relevant buffer media including FaSSIF and FeSSIF simulated intestinal fluids. This assay is ideal for formulation development work and gives valuable insight into the impact of pH and the presence of additives on drug dissolution.
We partner with a leading UK university who employs cutting edge solid state techniques including X-ray powder diffraction (XRPD), microscopy, Differential Scanning calorimetry (DSC) and thermogravimetric (TGA) analyses directly to samples provided by customers, or to precipitates generated during solubility or dissolution experiments.
