Development and Evaluation of Nanoemulsion Loaded Metaxalone for the Treatment of Pain and Injury

Spasticity is a disorder characterized by an unnatural rise in muscular tone or stiffness, which may impair speech or movement and be accompanied by discomfort or pain. Spasticity can occur due to upper motor neuron dysfunction, which comes about when there is a disturbance of the inhibitory descending spinal motor pathways. The aim of the present work is to formulate nanoemulsion-loaded metaxalone and evaluate it for various parameters. Metaxalone is used with rest, physical therapy, and other measures to relax muscles and relieve pain and discomfort caused by strains, sprains, and other muscle injuries. The phase titration method was used to plot a pseudo ternary phase diagram to select the ratio of the oil to surfactant. The nanoemulsion was prepared using the high-speed homogenization method and an in vitro drug release study was conducted using a Franz diffusion cell. The optimized batch showed the highest entrapment efficiency, up to 93%, and the zeta potential −33 mV and PDI 0.321 showed the stable and homogenous behavior of the globule formed. It also showed an in vitro release of up to 8 h following a zero-order release. Therefore, we conclude that the nanoemulsion containing metaxalone showed a prolonged effect compared to plain metaxalone and can effectively work to improve the muscle conditions to relieve pain and injury.