Question
Posted on: February 29 2016Chlorhexidine 0.5%-betamethasonedipropionate 0.64% AD 100ml isopropyl alcohol gives precipitation
Chlorhexidinedigluconate 20% solution (PANNOC) used. Also without betamethasone it gives direct precipitation when adding isopropyl alcohol. If Hibitane 5% is used to dilute with isopropyl alcohol this DOES NOT give precipitation (pink coloured, so dermatologically less appropriate).
Hibitane 5% has the following composition: Chlorhexidinedigluconate 5% m/V, alcoholpropoxylate ethoxylate, Linalylacetate, D-gluconolactone, isopropyl alcohol, Kamois (E122), purified water.
Answer
A comparison of the composition of Hibitane 5% with the Chlorhexidinedigluconate solution 20% (PANNOC) suggests to me that the final product contains more water when the Hibitane 5% of the PANNOC solution is assumed.
For trials (thanks to Apoth Sven Lenaerts) showed that after adding 10 ml of water the formed precipitation disappears.
So the prescribed composition can be amended as follows: Chlorhexidinedigluconate solution 20% 2.5 ml (2, 65g), water 10 ml, Betamethasone Dipropionate 640 mg and isopropanol AD 100 ml