Project 1 Freshly ejaculated mammalian sperm are unable to fertilize an egg. They acquire fertilizing capacity in the hours following ejaculation, as they pass through the female reproductive tract, in a process known as capacitation. Soluble adenylyl cyclase (sAC: ADCY10) is a non-hormonal target essential for sperm capacitation and male fertility. Pharmacological sAC inhibitors block sperm functions in vitro and two distinct sAC knockout (KO) mouse strains exhibit male-specific sterility without exhibiting other overt phenotypes. The overall hypothesis tested in this Contraception Research Center (CRC) is that sAC inhibitors can be designed which can be appropriately dosed to block sperm functions while minimizing undesirable side effects. In this Contraception Development Research Project, we will perform additional medicinal chemistry optimization of a series of potent, selective sAC inhibitors, along with in vivo studies of efficacy, safety, and pharmacokinetics, to ultimately produce well-developed, potent, selective, drug-like, non-toxic sAC inhibitors. The goal of this Project is to advance a compound from this series into preclinical development candidates suitable for development partners to apply for an FDA Investigational New Drug (IND) for a novel oral, non-hormonal contraceptive.