Heterocyclic compounds of Formula (I), (II), and (III) are described herein along with their polymorphs, stereoisomers, prodrugs, solvates, co-crystals, intermediates, pharmaceutically acceptable salts, and metabolites thereof. The compounds described herein, their polymorphs, stereoisomers, prodrugs, solvates, co-crystals, intermediates, pharmaceutically acceptable salts, and metabolites thereof are PAD4 inhibitors and may be useful in the treatment of various disorders, for example rheumatoid arthritis, vasculitis, systemic lupus erythematosis, cutaneous lupus erythematosis, ulcerative colitis, cancer, cystic fibrosis, asthma, multiple sclerosis and psoriasis. The process of preparation of the compounds of Formula (I), (II), and (III), their polymorphs, stereoisomers, prodrugs, solvates, co-crystals, intermediates, pharmaceutically acceptable salts, and metabolites thereof, along with a pharmaceutical composition comprising a compound of Formula (I), Formula (II), Formula (III), or a pharmaceutically acceptable salt thereof have also been described.
