title: Liposomal delivery system for topical anaesthesia of the palatal mucosa.
abstract: An effective topical agent to reduce pain during local anaesthesia of the palate is not yet available. The aim of the present study was to evaluate the efficiency of liposome-encapsulated ropivacaine in different concentrations for topical anaesthesia of the palatal mucosa. In this single-blinded, placebo-controlled, crossover study 40 (20 male) healthy volunteers were randomised to be given: liposome-encapsulated 2% ropivacaine, liposome-encapsulated 1% ropivacaine, a eutectic mixture of 2.5% lidocaine and 2.5% prilocaine (EMLA), and liposomal placebo gel, topically on to the palatal mucosa of the right canine region for 5 min each, at four different sessions. Pain associated with insertion of a 30G needle, and with injection of a local anaesthetic, was rated on a visual analogue scale (VAS). The effect of liposomal ropivacaine 1% and 2% did not differ from that of placebo (p=0.3 and p=0.1, respectively) in reducing pain during insertion of the needle. Lower VAS were obtained with EMLA. In this group VAS were lower in women than men (p=0.007). There was no difference in VAS among groups (p=0.3) as far as injection of the local anaesthetic was concerned. In conclusion, liposomal-encapsulated ropivacaine formulations did not reduce the pain of insertion of a needle into the palatal mucosa. None of the anaesthetic formulations tested, including the positive control (EMLA), were effective in reducing the pain of an injection of local anaesthetic compared with placebo.
authors.affiliation: Department of Biochemistry, Institute of Biology, University of Campinas - UNICAMP, Campinas, São Paulo, Brazil. franzmontan@hotmail.com
authors.forename: M
authors.initials: M
authors.lastname: Franz-Montan
authors.forename: E
authors.initials: E
authors.lastname: de Paula
authors.forename: F C
authors.initials: FC
authors.lastname: Groppo
authors.forename: A L R
authors.initials: AL
authors.lastname: Silva
authors.forename: J
authors.initials: J
authors.lastname: Ranali
authors.forename: M C
authors.initials: MC
authors.lastname: Volpato
mesh_terms: D000287:Administration, Topical; D000328:Adult; D000577:Amides / Q000008:administration & dosage*; D000766:Anesthesia, Dental / Q000379:methods*; D019162:Anesthetics, Combined / Q000008:administration & dosage; D000779:Anesthetics, Local / Q000008:administration & dosage*; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007267:Injections / Q000295:instrumentation; D008012:Lidocaine / Q000008:administration & dosage; D000077442:Lidocaine, Prilocaine Drug Combination; D008081:Liposomes; D008297:Male; D009061:Mouth Mucosa / Q000187:drug effects*; D009339:Needles / Q000009:adverse effects; D010146:Pain / Q000517:prevention & control; D010147:Pain Measurement; D010159:Palate / Q000187:drug effects*; D010919:Placebos; D011318:Prilocaine / Q000008:administration & dosage; D000077212:Ropivacaine; D012737:Sex Factors; D016037:Single-Blind Method; D055815:Young Adult
chemical_list: D000577:Amides; D019162:Anesthetics, Combined; D000779:Anesthetics, Local; D000077442:Lidocaine, Prilocaine Drug Combination; D008081:Liposomes; D010919:Placebos; D011318:Prilocaine; D000077212:Ropivacaine; D008012:Lidocaine