Dexa: Soluble in ethanol (25 mg/ml), and DMSO (25 mg/ml). Insoluble in water.
Beta: methanol, DMSO (79 mg/ml at 25 °C), and ethanol (10 mg/ml at 25 °C). Insoluble in water.
The major difference I mean the water solubility. Although of the two are flourinated derivatives of methyl predinsolone, but their solubilities in water are not identical. A steric effect may be the reason of this difference where water molecules being less able to move close to the 17-OH group in case of dexamethasone than betamethasone. This case is called isomeric solubility like in case of o,m, p dihydroxy benzene where p form is the most stable form so it has the lowest solubility in water but the ortho form may lead to formation of intramolecular hydrogen bond causing less liability of OH group to water molecules. So, we can see the difference in solubility between them where they are 4, 9, 0.6 mole/dm3 for o, m, p respectively.
- Badges
- Science topic