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 screening 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 (contact us if you have smaller quanities)
- Structural information (Full structure, partial structure, or list of ionizable groups)
Delivers:
- pKa results (triplicate determination as standard)
- 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 (contact us if you have smaller quanities)
- Structural information (Full structure, partial structure, or list of ionizable groups)
- Measured pKa(s)
Delivers:
- logP results (triplicate determination as standard)
- 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 (contact us if you have smaller quanities)
- 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 Dissolution Assay, 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 (contact us if you have smaller quanities)
- 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 and solubility measurement by our pH-metric and UV-hybrid methods
Requires:
- 20 to 50mg of solid
- Structural information (Full structure, partial structure, or list of ionizable groups)
Delivers:
- All Gold-Standard information detailed above.
Latest Sirius Posters Available for download
01.08.09
Our latest posters, including Solubility & Dissolution measurements in excipients and FaSSIF/FeSSIF media and high throughput pKa measurements, are available for download.
New Scientific Paper Published
07.12.09
New paper from Sirius explains how our solubility measurements work, and introduces new methods for evaluating supersaturation.
PhysChem Forum 8
23.03.10
Sirius are sponsors and exhibitors at the next PhysChem Forum being held at Pfizer in Sandwich, UK.
ADMET Europe 2010
08.04.10
Sirius will be exhibiting and speaking at ADMET Europe 2010 in Munich. Visit us on booth #12.