Pre-Formulation
These assays are designed to provide extensive information on specific drug compounds. They provide rich, detailed information and can be optimized based on the structural properties of the compounds under study.
We refer to our assays in this area as "Gold Standard". They provide reference-quality data and are our most detailed studies available for PhysChem parameters. Assays are designed for solids and/or DMSO stock solutions. Our chemists will advise about the most appropriate method based on the compound's structure and/or predicted properties. Also, we will run multiple assays to optimize the results, with the final results being the best possible with these techniques.
Objectives:
- Assays designed for solids or stock solutions
- Each experiment optimized for best quality data
- Repeat experiments performed until best result is achieved
Note: If you think you may not have enough compound for such detailed assays then please see our plate based assays or contact us to discuss your requirements
Assays Available:
Detailed Assay Information:
Gold Standard pKa
pKa measured either potentiometrically, or spectroscopically, using our industry standard pH-metric and pH-UV methods. Assays can be run under aqueous or cosolvent conditions. Our standard practice is to attempt an aqueous determination first, and only if the compound fails under aqueous conditions do we proceed to a cosolvent determination. In such cases, only the cosolvent price is charged. Real-time turbidity detection is used to detect whether the compound is dissolved or not. If the compound does precipitate, the exact pH of precipitation is reported.
Requires:
- 5 to 10mg of solid
- Structural information (Full structure, partial structure, or list of ionizable groups)
Delivers:
- pKa results
- Method overview
- Titration curves
- Distribution of species plot
- Ionic strength profile
- Buffer capacity profile
- Molar absorption profiles (in cases where the pH-UV method is applied).
Gold Standard LogP/D
Measures the logP of the compound, by titrating it in water/octanol mixtures. Measures neutral logP and ion‐pair logP. LogD vs. pH profile generated for pH 2 to 12. Determination is performed in triplicate.
Requires:
- 5 to 10mg of solid
- Structural information (Full structure, partial structure, or list of ionizable groups)
- Measured pKa(s)
Delivers:
- logP results
- logD results extrapolated at specified pH values
- Method overview
- Titration curves
- Distribution of species plot
- Lipophilicity (pH vs. logD) plot
- Ionic strength profile
Gold Standard Solubility
Intrinsic & Kinetic Solubility measurement using pH-metric methods. Degree of supersaturation also determined. Real-time monitoring of pH change can sometimes reveal polymorph formation during precipitation and dissolution cycles.
Requires:
- 5 to 20mg of solid
- Structural information (Full structure, partial structure, or list of ionizable groups)
- Measured pKa(s)
Delivers:
- Intrinsic Solubility result
- Kinetic Solubility result
- pH dependent solubility results extrapolated from pH 2 to pH 12
- Method overview
- Titration curves
- Distribution of species plot
- Solubility (pH vs. logS) plot
- Ionic strength profile
Gold Standard GI Dissolution
Dissolution measured by UV absorbance in our unique GI simulator cell, where the pH of the bulk solution can be varied to simulate passage of a drug through the GI tract.
Requires:
- 5 to 20mg of solid
- Structural information (Full structure, partial structure, or list of ionizable groups)
Delivers:
- Dissolution rates in each pH zone
- Time vs. Concentration profile
- Method overview
Gold Standard PhysChem Bundle
pKa, logP, solubility and dissolution measurement by our pH-metric and UV-hybrid methods
Requires:
- 20 to 80mg of solid
- Structural information (Full structure, partial structure, or list of ionizable groups)
Delivers:
- All Gold-Standard information detailed above.
Sirius appointed as distributors for Kibron Delta-8
24.7.08
Sirius are now the exclusive distributors in UK, USA and Canada for the Kibron Delta-8 system for measurement of surface tension and phospholipidosis.
Cambridge scientists set solubility challenge
11.8.08
A new paper from scientists using Sirius solubility techniques at the University of Cambridge asks "can you predict solubilities of 32 molecules using a database of 100 reliable measurements?".
BPC 2008
09.9.08
John Comer from Sirius is giving a presentation on solubility and supersaturation, and their effects on predicting oral absorption.
AAPS Annual Meeting
16.11.08
Sirius will have a booth at this years AAPS Annual Meeting in Atlanta, Georgia.