definiens: means a derivative of a uridine nucleoside or nucleotide or a derivative of a cytidine nucleoside or nucleotide in which an acyl substituent derived from a carboxylic acid is attached to one or more of the free hydroxyl groups of the ribose moiety of the nucleoside with an ester linkage and/or where such a substituent is attached to the amine substituent of the pyrimidine ring of cytidine, with an amide linkage . Such acyl substituents are derived from carboxylic acids which include, but are not limited to, compounds selected from the group consisting of a fatty acid, an amino acid, nicotinic acid, dicarboxylic acids, lactic acid, p - aminobenzoic acid and orotic acid . A compound is included in based on its chemical structure, regardless of the manner in which it is made . By way of example and not limitation, Acylated Pyrimidines include, but are not limited to 2 ', 3 ', 5 ' -tri - O­acetyluridine, 2 ' -O - propanoyluridine, N4 - acetylcytidine, 2 ' -0 - acetyl-3'­O - ethoxyuridine, uridine 2 ' -O - malonate, and 2 ', 3 ' -diacetyluridine-5 ' -mono phosphate . By way of example and not limitation, Acylated Pyrimidines exclude uridine, cytidine, acyl derivatives of 6 - -3 - sf-1579227 .~ j, \