Magistal Preparation "Pliaglis Cream" (Lidocaine and Tetracaine)

Lidocaine 70.000 mg Tetracaine 70.000 mg Methylparahydroxybenzoate 0.500 mg Propylparahydroxybenzoate 0.100 mg Calcium hydrogen phosphate Purified water Polyvinyl alcohol Petroleum jelly (white) Sorbitanpalmitate This composition was on the market under the brand name "Pliaglis", now not available. We were given the request of a dermatologist to prepare this magijet for anesthesia of a large surface area (the back) for maximum anesthesia in laserdermatological treatment. What proportion of water/petroleum jelly do we use best? Or can we use AVA with equally strong numbing effect on the skin? The alternatives "Emla" and "Xylocaine gel" have a different basic composition and can probably not give sufficient pain relief.