Search Results (3)

Gel-based depots are increasingly recognized as platforms to extend the intratissue residence of local anesthetics (LAs) while reducing systemic exposure. Hydrogels, organogels, and emerging bigels represent three distinct architectures defined by their continuous phases and drug–matrix interactions. Hydrogels provide hydrated polymer networks with predictable injectability, tunable degradation, and diffusion- or stimulus-responsive release, enabling sustained analgesia in perineural, peri-incisional, intra-articular, and implant-adjacent settings. Organogels, formed by supramolecular assembly of low-molecular-weight gelators in lipids or semi-polar solvents, strongly solubilize lipophilic LA bases and enhance barrier partitioning, making them suitable for dermal, transdermal, and mucosal applications in outpatient or chronic pain care. Bigels integrate aqueous and lipid domains within biphasic matrices, improving rheology, spreadability, and dual-solubilization capacity, although their use in LA delivery remains at the formulation stage, with no validated in vivo pharmacology. This narrative review synthesizes the design principles, release mechanisms, and translational evidence across these platforms, highlighting domain-specific advantages and barriers related to mechanical robustness, sterilization, reproducibility, and regulatory feasibility. We propose a platform-level framework in which depot selection is aligned with LA chemistry, anatomical context, and clinical objectives to guide the development of workflow-compatible next-generation LA depots. Full article

Background/Objectives: Lidocaine is a widely used local anesthetic, but injections and topical creams are often painful or slow in onset. This study aimed to develop dissolving microneedles incorporating lidocaine hydrochloride for rapid and convenient local anesthesia. Methods: Six formulations were prepared with polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA) and evaluated for mechanical strength, skin insertion, drug release, and transdermal permeability. Results: Sharp pyramidal microneedles were successfully fabricated, with PVP–PVA mixtures producing stronger needles than single polymers. The optimized F5 formulation showed high strength (>32 N), efficient skin insertion (four parafilm layers), and rapid release (>80% within 15 min). In ex vivo studies, F5 delivered >600 µg/mL lidocaine in 15 min, over three times the therapeutic level and much faster than Emla cream (5%). Conclusions: PVP–PVA microneedles represent a promising platform for painless, rapid local anesthesia, combining the benefits of injections and topical creams while minimizing their drawbacks. Full article

The pain and fear caused by direct local injection of anesthetic or the poor experience with surface anesthetic cream increase the difficulty of clinical treatment for oral diseases. To address this problem, a hyaluronic acid microneedle patch (Li-HAMNs) that consists of fast-dissolving lidocaine hydrochloride (LDC)-loaded tips and a wet-adhesive backing layer made of polyvinyl alcohol (PVA)/carboxymethylcellulose sodium (CMC-Na) was fabricated to explore its potential use in dental topical anesthesia. Li-HAMNs could puncture the stratum corneum with an insertion depth of about 279 μm in the isolated porcine oral mucosal. The fast-dissolving tips could release LDC to improve the patients’ convenience and compliance. Importantly, the backing layer, which has good adhesion ability and water-absorbing properties, could surmount the contraction and extension of oral masticatory muscles and the saliva scour. In the tail flick test, the topical anesthesia efficacy of the Li-HAMNs group was much better than clinical lidocaine cream (EMLA cream, LDC, 1.2 mg) in spite of a relatively lower LDC dose with Li-HAMNs (LDC, 0.5 mg). It is believed that the proposed adhesive microneedle patch could enhance transmucosal delivery of anesthetics and thus open a new chapter in the painless treatment of oral diseases. Full article