Diphenhydramine Hydrochloride → Diphenhydramine

Participants

Reaction Steps

Another typical combination composition was formulated as follows. Diphenhydramine hydrochloride 58 g (0.2 mole) was dissolved in water 100 ml, and 5N NaOH 40 ml (0.2 mole) was added slowly with stirring. Diphenhydramine free base was formed as oily white precipitates. Without isolation of the free base, N-acetyl-L-proline 48 g (0.3 mole) and N-acetyl-D-glucosamine 44 g (0.2 mole) were added with stirring into the oily mixture, and the mixture became a clear solution. Propylene glycol 100 ml and water 50 ml were added to make total volume 400 ml (444 g). This formulation contained diphenhydramine 14.5%, N-acetyl-L-proline 12% and N-acetyl-D-glucosamine 11% in a propylene glycol/water solution. The above formulation 22 g and tribenzyl citrate 10 g were mixed with hydrophilic ointment or oil-in-water cream 68 g. The composition thus prepared had pH 3.8 and contained 10% tri-benzyl citrate, 3% diphenhydramine, 2.6% N-acetyl-L-proline and 2.4% N-acetyl-D-glucosamine in a water-washable cream.

Provenance & Evidence