Preliminary clinical assessment of polyvinyl alcohol-tetrahydroxyborate hydrogels as potential topical formulations for local anesthesia of lacerations.

Objectives: The aim of this study was to assess a novel semisolid material as a potential topical drug delivery system for acute laceration. The objectives were to correlate physical characterization data using rheologic studies and to compare with clinical assessment of performance in an emergency department (ED).
Methods: Polyvinyl alcohol (PVA) hydrogels, cross-linked using tetrahydroxyborate (THB), were characterized using texture profile analysis. Formulation samples were applied to acute lacerations presented to the ED and factors, such as in vivo residency time and cohesive removal, were assessed.
Results: Viscosity was shown to be related to mechanical characteristics, whereas adhesiveness depended on the THB concentration. Residence in, and clean removal from, lacerations was evaluated on 29 patients. Formulation F3 (10.0% PVA, 2.5% w/w THB) displayed the most appropriate characteristics for clinical use by scoring highest in qualitative assessments. Other formulations exhibited difficulties in application and removal due to excessive adhesiveness. The release of a model local anesthetic drug was proportional to the concentration of drug incorporated, but was not substantially affected by small changes in the formulation constituents.
Conclusions: Using a combination of pharmaceutical evaluation and clinical assessment, it was shown that cross-linked PVA semisolids are a suitable formulation for drug administration to acute lacerations, with potential for induction of anesthesia prior to wound repair.
(© 2011 by the Society for Academic Emergency Medicine.)