- A new composition of analgesic bioadhesive healing microspheres in which each microsphere comprises at least:a.- a layer of a polyanion, where the polyanion may be an alginate.b.- a core coated with a polyanion consisting of a triblock copolymer non-ionic surfactant； polexamer 188 or a mixture of them； and a volatile halogenated by-product anaesthetic ether agent of methyl-isopropyl-ether in contact with the internal part of the polyanion layer, which may be sevoflurane.c.- a coating of a polycation in contact with the external part of the polyanion layer, which may be chitosan.
