Question
Posted on: March 6 2013The following formula forms crystals:
We have already found out that the prednisolone is precipitating, and were recommended to propel the amount of propylene glycol. But also when using 30 ml propylene glycol (no more grains to see when rubbing) a precipitate formed.
since prednisolone is soluble in alcohol, we now dissolved 200mg in 10ml ethanol 96% and 200mg in 10ml ethanol, laid out up to 500ml with water in a second Test setup. After a night of storage at room temperature, a precipitation occurs in both solutions. In pure ethanol, needles form a flaky precipitate in the diluted trial.
on the website is mentioned to dissolve prednisolone with semipolar solvents, but this proved so far no success yet.
do you have any other suggestions?
Answer
The solubility of prednisolone in water is 0.25 mg/ml, in ethanol 1 to 30 and in PEG 400 2.16 g per 100ml. I have not been able to find the solubility in propylene glycol, although this solvent is known as a good solvent for corticosteroids. To dissolve 200 mg prednisolone in ethanol, 6 ml is required. You used 10ml so that a precipitation happens to me peculiar? If I take into account the solubility in water then it should dissolve about 100mg prednisolone. We can of course figure out to what extent the amount of propylene glycol needs to be increased in order to bring everything into solution. Now here we will not improve the taste of the preparation. Both Prednisolone and propylene glycol will give an unpleasant taste to the preparation. In the composition, hydroxyethylcellulose occurs because also nystatin is insoluble in water. Hydroxyethylcellulose will of course also have an influence on the sticking of the oral mucosa? So the preparation of a suspension is the most obvious. Special problems are not linked here. Perhaps an aroma should be added? In the TMF, 10mg of mint oil is added per 100ml of suspension. It is dissolved in ethanol beforehand.