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Question

Posted on: May 27 2013

Shelf life of benzyl benzoate Cream

Are there other formulations with BB between 10% to 30% in cream base, whose stability is documented for a longer period: 2 to 3 months or more? The intention is to set up a minimum inventory on the emergency service and to avoid the expiry date of destruction. The frequency of necessity is variable, sometimes 3-4 times after each other in our "patient", sometimes weeks nothing. With best thanks for your response

Answer

Benzyl benzoate degrades to benzoic acid and Benzyl alcohol. These degradation products are less active against scabies mites. They are relatively non-toxic and act as preservatives in the lotion. Baker and co-workers found low contents of benzyl benzoate in some emulsions (formulated according to the British Pharmacopoeia) but only small amounts of the degradation products. They assumed that the low concentrations of benzyl benzoate did not result from degradation, but from partial separation of the emulsion at the time of dispensing (13). Benzyl benzoate emulsion should always be well mixed before dispensing and before application. Hydrolysis or benzyl benzoate in emulsions is expected but is limited as there is little contact with water. The only possible contact of Benzyl benzoate is at the interface of the oil and aqueous phases, because Benzyl benzoate is not dissolved in the water but in the oil phase. The emulsion is therefore suitable for storage during longer periods of times. However, for reasons of physical and microbial stability, we recommend to use Benzyl Benzoate emulsion within 3 months after production.

This term will also apply to one "stable" cream. Maybe six months, but data is not available. Very important in this context are the hygienic measures, which are used in the preparation and packaging of the cream. No stock pots!