» Articles » PMID: 39204403

A Buffered Local Anesthetic Without Epinephrine: Development, Characterization, and In Vivo Efficacy and Toxicity Analysis

Overview
Journal Pharmaceutics
Publisher MDPI
Date 2024 Aug 29
PMID 39204403
Authors
Affiliations
Soon will be listed here.
Abstract

Lidocaine hydrochloride (HCl) 2% with 1:100,000 epinephrine (LW/E) is widely used to prevent pain during dental procedures and has been associated with injection sting, jittering effects, slow onset, and a bitter aftertaste. Since LW/E's introduction in 1948, no significant modifications have been proposed. This study aims to design and characterize an improved dental lidocaine HCl injectable formulation without epinephrine (LW/O/E) via buffers, sweeteners, and amino acids. LW/O/E injections were prepared with pH and osmolality values of 6.5-7.0 and 590-610 mOsm/kg. Using the electronic tongue (ETongue), the LW/O/E injectable formulations were characterized for viscosity, injectability, and taste analysis. The results were compared with the LW/E control. In vivo efficacy and anesthetic duration of the samples were measured through radiant heat tail-flick latency (RHTFL) and hot plate (HP) tests and local toxicity was assessed after a single intra-oral injection in Sprague Dawley rats (SDR). The viscosity and injectability values of the LW/O/E samples were found to be comparable to the LW/E injection. ETongue taste analysis showed an improvement in bitterness reduction of the LW/O/E samples compared to the LW/E formulation. Toxicity studies of samples in SDR showed minor and transient signs of erythema/eschar and edema. Anesthetic duration via RHTFL and HP paw withdrawal latency time in SDR were found to be comparable for the LW/O/E Sample 3A and the LW/E injection ( < 0.05). In conclusion, the buffered, higher osmolality and reduced bitterness developed LW/O/E formulation (Sample 3A) could be considered a promising alternative to the LW/E formulation for dental use.

References
1.
Rachid O, Rawas-Qalaji M, Simons K . Epinephrine in Anaphylaxis: Preclinical Study of Pharmacokinetics after Sublingual Administration of Taste-Masked Tablets for Potential Pediatric Use. Pharmaceutics. 2018; 10(1). PMC: 5874837. DOI: 10.3390/pharmaceutics10010024. View

2.
Crawford S, Niessen L, Wong S, Dowling E . Quantification of patient fears regarding dental injections and patient perceptions of a local noninjectable anesthetic gel. Compend Contin Educ Dent. 2006; 26(2 Suppl 1):11-4. View

3.
Kim H, Hwang K, Yun S, Kim D . Usage of Epinephrine Mixed With Lidocaine in Plastic Surgery. J Craniofac Surg. 2020; 31(3):791-793. DOI: 10.1097/SCS.0000000000006156. View

4.
Bhusal P, Sharma M, Harrison J, Procter G, Andrews G, Jones D . Development, Validation and Application of a Stability Indicating HPLC Method to Quantify Lidocaine from Polyethylene-co-Vinyl Acetate (EVA) Matrices and Biological Fluids. J Chromatogr Sci. 2017; 55(8):832-838. DOI: 10.1093/chromsci/bmx043. View

5.
Kaufman E, Goharian S, Katz Y . Adverse reactions triggered by dental local anesthetics: a clinical survey. Anesth Prog. 2001; 47(4):134-8. PMC: 2149031. View