1. A composition comprising a prostanoid agonist ester, a carboxylic acid, dibasic sodium phosphate, sodium chloride, a solubilizer and a water residue, where the pH of the composition is adjusted to a value from about 4 to about 8.2. The composition according to claim 1, wherein the carboxylic acid is C-Scarboxylic acid. The composition according to claim 1, wherein the carboxylic acid is citric acid. The composition according to claim 1, characterized in that it contains from about 0.05% to about 0.2% carboxylic acid. The composition according to claim 1, containing from about 0.1% to about 0.15% carboxylic acid. The composition according to claim 1, characterized in that it contains 0.135% carboxylic acid. The composition according to claim 1, characterized in that it has a pH from about 4.5 to about 6.5.8. The composition according to claim 1, characterized in that it has a pH of about 6.0.9. The composition according to claim 1, characterized in that the prodrugs of the prostanoid agonist have the structure: where each of Z-Z is independently C, N, O or S； A is - (CH) - or cis-CHCH = CH- (CH) -, where 1 or two carbon can be substituted by S or O； or A is - (CH) -Ar- (CH) -, where Ar is arylene or heteroarylene, the sum of m and o is from 1 to 4, and where one CH: may be substituted with S or O； R is alkyl, cycloalkyl, hydroxyalkyl , hydroxyalkyl, alkenyl, oxyalkenyl or hydroxyalkenyl； R is alkyl, alkenyl, hydroxyl, halide, piano or oxo； J is alkyl, cycloalkyl, hydroxyalkyl, hydroxyalkyl； E is C1-6 alkyl, R or -YR, where Y is CH, S or O, and R is aryl or heteroaryl； n is 0 or 1； and where the dashed line represents the presence or absence of a bond .10. The composition of claim 9, wherein n is 0.11. The composition according to claim 9, characterized in that R1. Композиция, включающая сложный эфир простаноидного агониста, карбоновую кислоту, двухосновный фосфат натрия, хлорид натрия, солюбилизатор и остаток воды, где рН композиции доведен до значения от около 4
