Related Experiment Video
Updated: Jun 13, 2026

Development, Characterization, and Evaluation of CAGE-based Ionic Liquid Systems for Transdermal Delivery
Published on: September 26, 2025
Effect of ionic and non-ionic polymer on the pH of lidocaine hydrochloride preparation assessed below and over human
Witold Musial1, Vanja Kokol, Bojana Voncina
1University of Maribor, Department for Textile Materials and Design, Laboratory for Chemistry Dyes and Polymers, Slovenia. witold@ktpl.am.wroc.pl
Abstract:
Lidocaine is widely accepted local anesthetic, which is applied in the form of freely soluble hydrochloride salt. In this study we evaluated the pH of respective solutions of lidocaine hydrochloride with ionic polymer--polyacrylic acid or non-ionic polymer--methylcellulose, and compared to physiological skin conditions in the range between 22 degrees C and 41 degrees C. In microscopic observation of lidocaine hydrochloride preparations with polyacrylic acid the micro-sedimentation was revealed, however obtained mixture was opalescent, and homogenously dispersed in aqueous environment. The pH was maintained on the level not higher then 4,0 in the period of 12 hours for polyacrylic acid formulation, whereas in the case of preparation with methylcellulose, the pH increased from acceptable pH of ca. 4,5 to the level of above 6,0. The polyacrylic acid derivatives should be further studied as vehicles forming preparations with stable pH value during application on the skin, with more specific methods including pH microelectrodes, sufficient for assessments in small quantities of liquids of skin surface.
Related Concept Videos
Local Anesthetics: Mechanism of Action
Local anesthetics are amphiphilic molecules consisting of a hydrophobic aromatic part linked to a hydrophilic group by an ester or amide linkage. They are weak bases and are usually available as salts, which increases their solubility and stability. Once administered, LAs exist in the body either...
Local Anesthetics: Chemistry and Structure-Activity Relationship
Local Anesthetics: Pharmacokinetics
Local Anesthetics: Clinical Application as Surface, Infiltration, and Conduction Block Anesthesia
Factors Affecting Dissolution: Drug pKa, Lipophilicity and GI pH
A drug's pKa and the pH of the gastrointestinal (GI) tract play crucial roles in drug...
Local Anesthetics: Common Agents and Their Applications
Cocaine is an ester of benzoic acid and methylecgogine. It is used to anesthetize and vasoconstrict locally. Currently, it is used primarily for topical applications. It is beneficial for surgeries on the upper respiratory tract, providing anesthesia and shrinking the mucosa. Cocaine in the form of cocaine hydrochloride is...

