OpenEye have just announced the release of pKa Prospector v1.0 a database of high quality experimental pKa determinations. The ionisation state of a drug molecule can have profound effects on affinity, dissolution, absorption, distribution, metabolism and off-target activity. The ability to predict pKa is often compromised by the lack of relevant experimental data, pKa Prospector is intended to address that issue.
The built-in experimental pKa database was compiled by Tony Slater of pKaData Limited from a collection of IUPAC sources. Each measurement has been individually verified, curated, and assigned a metric of quality. There are more than 30,000 experiments across 12,000 molecules represented. The database is particularly relevant for medicinal chemistry due to the strong preponderance of room temperature aqueous measurements, the many molecules with multiple experimental records, and the presence of over three hundred different heterocycles.
It is also possible to add additional experimental results and have them integrated into the application thus expanding the chemical space covered. The search uses rooted maximum common substructure (MCS) with "electronically-aware" scoring, alternatively it can be searched by similarity or substructure. Ionizable groups are automatically identified and highlighted.