title: Assessing the issue of instability due to Michael adduct formation in novel chemical entities possessing a carbon-carbon double bond during early drug development--applicability of common laboratory analytical protocols.
abstract: The discovery of small-molecule novel chemical entities (NCEs) is often a complex play between appropriate structural requirements and optimization of the desired efficacy, safety and pharmacokinetic properties. One of the typical structural variants such as having an active carbon-carbon double bond (alpha, beta-unsaturated carbonyl group) in xenobiotics may lead to stability issues. Such functionalities are extremely reactive, paving way to nucleophilic attack by endogenously occurring and ubiquitous nucleophiles like thiols. While it is easy to make a unilateral decision to not pursue the development of xenobiotics with such functionalities, we question the wisdom of such a decision. In this report, we present in vitro methodologies with appropriate examples to illustrate the ease of assessing the reactivity of the xenobiotics containing double bonds with a known nucleophile. The protocols involve simple reaction procedures followed by measurements using standard laboratory equipments (UV spectrophotometer, HPLC and LC-MS). Our data suggests that not all xenobiotics with carbon-carbon double bonds readily form a Michael's adduct product with glutathione. Hence, the criterion for dropping discovery compounds because of alpha,beta-unsaturated double bonds needs to be reconsidered.
authors.affiliation: Discovery Research, Dr Reddy's Laboratories Ltd, Miyapur, Hyderabad- 500 049, India.
authors.forename: Akshanth Reddy
authors.initials: AR
authors.lastname: Polepally
authors.forename: Venkata V Pavan
authors.initials: VV
authors.lastname: Kumar
authors.forename: Ravikanth
authors.initials: R
authors.lastname: Bhamidipati
authors.forename: Jagannath
authors.initials: J
authors.lastname: Kota
authors.forename: Shaik Abdul
authors.initials: SA
authors.lastname: Naveed
authors.forename: Karnati Harinder
authors.initials: KH
authors.lastname: Reddy
authors.forename: Rao N V S
authors.initials: RN
authors.lastname: Mamidi
authors.forename: N
authors.initials: N
authors.lastname: Selvakumar
authors.forename: Ramesh
authors.initials: R
authors.lastname: Mullangi
authors.forename: Nuggehally R
authors.initials: NR
authors.lastname: Srinivas
mesh_terms: D002244:Carbon; D002853:Chromatography, Liquid / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D015262:Xenobiotics / Q000032:analysis* / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D015262:Xenobiotics; D002244:Carbon