Topical hyalubilosomes of dantrolene sodium as muscle targeted nanocarrier for muscle spasms: fabrication, <i>ex-vivo</i> permeation and behavioral animal model

Topical muscle relaxants are gaining interest in pharmaceuticals. Dantrolene sodium (DS), an FDA-approved relaxant targeting ryanodine receptors, is limited in topical use by poor physicochemical properties, delayed onset, and hepatotoxicity. This study introduces the first optimized hyalubilosome-based nanocarrier for non-invasive DS delivery. Two anionic surfactants were used as edge activators to improve drug encapsulation and permeation. The optimized nanocarrier had a spherical shape, 165 nm particle size, -31.2 mV zeta potential, and 97.47% entrapment efficiency. Ex vivo studies showed superior permeation compared to DS suspension (10% in water, pH 6.8), with 30% of the dose permeating within 15 min. In vivo, efficacy was tested in Wistar mice using the Straub tail test with a single 30 mg/kg topical dose. Behavioral analysis showed a fivefold increase in muscle relaxation vs. untreated controls (p < 0.0001). The formulation had an onset within one minute and complete relief within two minutes, unlike the conventional topical DS, which showed no effect for 90 min. This highlights hyaluronic acid-based transbilosomes as a promising nanoplatform for fast, effective topical DS delivery and potential muscle spasm treatment.