Eudragit coated microemulsion for enhanced efficacy of spiramycin against toxoplasmic encephalitis

The study investigated Eudragit coated microemulsion (ME) for oral delivery of spiramycin in treatment of toxoplasmic encephalitis. The goal was to augment the efficacy of ME by protection from gastrointestinal conditions and/or providing bioadhesion. Uncoated and coated MEs comprise labrafil as oil, cremophore EL as surfactant and labrasol as cosurfactant were prepared. The MEs were characterized with respect to shape, droplet size and in vitro drug release. Optimum formulations were assessed against cerebral toxoplasmosis. This involved oral administration of spiramycin solution, uncoated and coated MEs to Me49 Toxoplasma gondii infected mice at early and late stages.

Highlights

• Spiramycin was successfully encapsulated in uncoated and eudragit coated microemulsions for controlled drug release.

• Eudragit coated microemulsion was more efficient against toxoplasmic encephalitis.

• Histopathological features significantly improved after treatment with spiramycin loaded microemulsions.

• Treatment of toxoplasmic encephalitis with spiramycin loaded microemulsions was more valuable in late stage of infection.

• Coated and uncoated microemulsions are promising oral delivery system for enhanced efficacy of spiramycin.

The uncoated ME droplets were spherical with average size of 147 nm. The coated ME droplets were polygonal with average size of 142 nm. Spiramycin release rate was significantly higher from uncoated ME. The parasitic load and histopathology reflected superiority of spiramycin coated ME over uncoated ME and both were more effective than spiramycin solution. The same trend was evident in early and late stages of infection. Interestingly, all formulations showed better efficiency in late stage of infection. The study introduced eudragit coating of ME as a tool to augment oral delivery from microemulsions. The developed system hastened the efficacy of spiramycin against toxoplasmic encephalitis.

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Rania K. Eid, Mona F. Arafa, Dalia S. Ashour, Ebtessam A. Essa, Hager S. Zoghroban, Yasmine A. Issa, Hanan M. Nomeir, Hend S. Abo Safia, Gamal M. El Maghraby,
Eudragit coated microemulsion for enhanced efficacy of spiramycin against toxoplasmic encephalitis,
Journal of Drug Delivery Science and Technology, Volume 69, 2022, 103137, ISSN 1773-2247,
https://doi.org/10.1016/j.jddst.2022.103137.