In-office compounding of buffered lidocaine and epinephrine - A stability and safety review

Buffered lidocaine is widely used in dermatologic and other in-office procedures to reduce injection pain and expedite onset of anesthesia. Current United States Pharmacopeia <797> standards limit immediate-use compounded sterile preparations to administration within 4 hours, creating significant barriers for dermatology practices where buffered lidocaine is routinely prepared in advance of patient visits. In collaboration with the U.S. Food and Drug Administration, Centers for Disease Control and Prevention, and United States Pharmacopeia, the American Academy of Dermatology Association, American College of Mohs Surgery, American Society for Dermatologic Surgery, and American Society for Mohs Surgery initiated development of a United States Pharmacopeia monograph to establish evidence-based beyond-use dates for buffered lidocaine. Stability and sterility testing were conducted on multiple lots of buffered lidocaine with epinephrine prepared in syringes. Analytical methods validated potency, purity, pH, antimicrobial effectiveness, endotoxin, particulate matter, and container/closure integrity. Results demonstrated that preparations remained within specifications for potency, sterility, and safety parameters. Based on regression analysis, buffered lidocaine maintained stability for 24 hours at room temperature and up to 7 days under refrigeration when stored in capped syringes. These findings support evidence-based standards for safe in-office preparation of buffered lidocaine and provide a model for future compounded dermatologic preparations.