| Abstrakt: |
The stability of prostaglandin E1 and dinoprostone was investigated at the extremes of the pH range (less than or equal to 3 and greater than or equal to 10) in the sequence prostaglandin E leads to prostaglandin A leads to prostaglandin B. The degradation rate is first order with hydrogen-ion and hydroxide-ion concentrations. Separation and analysis of the E prostaglandins were accomplished by TLC and UV spectrophotometry. At the lowest pH values and at elevated or low temperatures, significant amounts of 15-epiprostaglandin E were present. Apparent activation energies for the total dinoprostone loss, calculated from elevated temperature data, were 21 kcal/mole in the strongly acidic region and about 18 kcal/mole at pH 3. Corresponding studies in the alkaline region led to a derived arrhenius activation energy of 15 kcal/mole with the appearance of significant amounts of 8-isoprostaglandin E. This difference in activation energies may reflect the different mechanisms operant at high and low pH values. |
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