title: Drug-coated microneedles for rapid and painless local anesthesia.
abstract: This study showed that drug-coated PLLA (Poly (L-lactide)) microneedle arrays can induce rapid and painless local anesthesia. Microneedle arrays were fabricated using a micro-molding technique, and the needle tips were coated with 290.6 ± 45.9 μg of lidocaine, the most widely used local anesthetic worldwide. A dip-coating device was newly designed for the coating step using an optimized coating formulation. Lidocaine coated on the arrays was released rapidly into PBS within 2 min, and its stability in storage lasted 3 weeks at 4, 25, and 37°C. Furthermore, the microneedle arrays showed consistent in vitro skin penetration and delivered 200.8 ± 43.9, 224.2 ± 39.3, and 244.1 ± 19.6 μg of lidocaine into the skin 1, 2, and 5 min after application with a high delivery efficiency of 69, 77, and 84%. Compared to a commercially available topical anesthetic EMLA® cream, a 22.0, 13.6, and 14.0-fold higher amount of lidocaine was delivered into the skin. Note, in vitro skin permeation of Lidocaine was also notably enhanced by a 2-min-application of the lidocaine-coated microneedle arrays. Altogether, these results suggest that the biocompatible lidocaine-coated PLLA microneedle arrays could provide significantly rapid local anesthesia in a painless manner without any of the issues from topical applications or hypodermic injections of local anesthetics.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
authors.forename: Sung-Hyun
authors.initials: SH
authors.lastname: Baek
authors.affiliation: Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
authors.forename: Ju-Hyung
authors.initials: JH
authors.lastname: Shin
authors.affiliation: Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea. dohnanyi@kaist.ac.kr.
authors.forename: Yeu-Chun
authors.initials: YC
authors.lastname: Kim
mesh_terms: D000287:Administration, Topical; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000378:metabolism; D000818:Animals; D016503:Drug Delivery Systems / Q000295:instrumentation*; D065546:Drug Liberation; D008012:Lidocaine / Q000008:administration & dosage / Q000378:metabolism; D055616:Microtechnology / Q000295:instrumentation*; D009339:Needles; D010146:Pain / Q000517:prevention & control; D010539:Permeability; D011091:Polyesters; D012867:Skin / Q000378:metabolism; D013552:Swine; D013997:Time Factors
chemical_list: D000779:Anesthetics, Local; D011091:Polyesters; C033616:poly(lactide); D008012:Lidocaine
keywords: Coated-microneedles; Lidocaine; Local anesthesia; Poly (L-lactide); Transdermal drug delivery