Risk of contamination of lidocaine hydrochloride and phenylephrine hydrochloride topical solution: in vivo and in vitro analyses

Abstract

AbstractObjective:To investigate the risk of contamination of lidocaine hydrochloride 5 per cent weight/volume and phenylephrine hydrochloride 0.5 per cent weight/volume topical solution, both in patients (in vivo) and in the laboratory setting (in vitro).Methods:This paper reports a prospective study involving 10 samples of the lidocaine hydrochloride and phenylephrine hydrochloride topical anaesthetic spray. The samples were assessed for microbiological contamination after a single use on patients in a controlled laboratory environment. Additional samples were assessed for baseline contamination and later assessed for contamination in an in vitro setting.Results:In the in vivo setting, 2 of the 10 samples were positive for cultures from both the pump and the bottles. However, in the in vitro setting, the pump and the contents of the bottles were contaminated after a single use when the sterile solution was sprayed from distances of 1 and 2 cm.Conclusion:The lidocaine hydrochloride and phenylephrine hydrochloride topical solution assembly was contaminated in both in vivo and in vitro settings after a single use.