3PC-027 Long term stability of a ready to use topical anaesthetic gel kit

Background and importance Undergoing small surgeries, aesthetic procedures or needle injections can be stressful, especially for paediatric patients. Various local anaesthetics have therefore been developed to numb the skin, including commercially available medications. Unfortunately, shortage of medicines, including for local anaesthesia, remains a widespread and persistent problem. LETS GEL KIT is a ready to use kit developed by Fagron to compound a topical anaesthetic gel. LETS GEL KIT contains lidocaine hydrochloride (4% w/w), epinephrine bitartrate (0.18% w/w), tetracaine hydrochloride (0.5% w/w) and sodium metabisulfite (0.075% w/w). LETS has been shown to be equivalent in providing and maintaining anaesthesia in the treatment of facial lacerations, with up to 10-fold less systemic exposure, compared with a 2.5% lidocaine/2.5% prilocaine solution. Aim and objectives To evaluate the chemical stability of the LETS GEL KIT when stored in syringes. Material and methods Samples were stored in plastic syringes (Comar, USA) under controlled refrigeration (2–8°C) and controlled room temperature (20–25°C). Stability was assessed by examining colour, odour and pH, and by measuring the active content at varying time points (0, 30, 60, 90, 120 and 150 days) over a 150 day period. API quantification was performed by validated high performance liquid chromatography (HPLC-UV). Results Throughout the whole study, no phenomena, such as turbidity, macroscopically visible crystal growth or phase separation, were observed. Colour, odour and pH showed no significant change. Drug content (%) after 150 days were (for refrigerated and room temperature, respectively): lidocaine hydrochloride 94.47±0.25 and 94.86±0.70; epinephrine bitartrate 97.90±0.33 and 98.82±0.20; and tetracaine hydrochloride 102.09±0.70 and 102.18±1.15. Conclusion and relevance In the current study, LETS GEL KIT showed excellent stability under both controlled refrigerated conditions (2–8°C) and at room temperature (15–25°C) for up to 150 days. Therefore, prefilled compounded syringes using LETS GEL KIT can be a valuable alternative when commercial medication is not suitable or available. References and/or acknowledgements Conflict of interest Corporate sponsored research or other substantive relationships: The study was sponsored by Fagron BV.