Formulation and in vitro characterization of nanoemulsions containing remdesivir or licorice extract: A potential subcutaneous injection for coronavirus treatment

The management of coronavirus necessitates that medicines are available, reasonably priced, and easy to administer. The work aimed at formulating and characterizing remdesivir and licorice extract nanoemulsions and comparing their efficacy against coronavirus for further subcutaneous injection. First, the solubility of remdesivir was determined in different oils, surfactants, and co-surfactants to choose the optimal nanoemulsion components. Nanoemulsions were optimized concerning surfactant: co-surfactant ratio (5:1, 4:1, 3:1, 2:1, and 1:1) and oil to surfactant: co-surfactant ratio (1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, and 1:1). The formulations were evaluated concerning % transmittance, emulsification time, pH, viscosity, droplet size, polydispersity index, zeta potential, drug content, transmission electron microscopy, in-vitro drug release, stability (of the optimal formulas), and antiviral effect against coronavirus. The optimal nanoemulsion formula was F7, exhibiting an acceptable pH level, a rapid emulsification rate, a viscosity of 20 cP, and 100% drug content. The formulation droplet size was 16 and 17 nm, the polydispersity index was 0.18 and 0.26, and the zeta potential was - 6.29 and - 10.34 mV for licorice extract and remdesivir nanoemulsions, respectively. However, licorice extract nanoemulsion exhibited better release and physical stability. Licorice extract nanoemulsion may be a potential subcutaneous injection for combating mild to moderate coronavirus.

Oral bioavailability enhancement of doxazosin mesylate: Nanosuspension versus self-nanoemulsifying drug delivery systems

Background and purpose

Doxazosin mesylate (DOX) is an antihypertensive drug that possesses poor water solubility and, hence, poor release properties. Both nanosuspensions and self-nanoemulsifying drug delivery systems (SNEDDS) are becoming nanotechnology techniques for the enhancement of water solubility of different drugs.

Experimental approach

The study's goal was to identify the best drug delivery system able to enhance the release and antihypertensive effect of DOX by comparing the physical characteristics such as particle size, zeta potential, entrapment efficiency, release rate, and main arterial blood pressure of DOX-loaded nanosuspensions and SNEDDS in liquid and solid form.

Key results

DOX nanosuspension preparation had a particle size of 385±13 nm, poly-dispersity index of 0.049±3, zeta potential of 50 ± 4 mV and drug release after 20 min (91±0.43 %). Liquid SNEDDS had a droplet size of 224±15 nm, poly-dispersity index of (0.470±0.01), zeta potential of -5±0.10 mV and DR20min of 93±4 %. Solid SEDDS showed particle size of 79±14 nm, poly-dispersity index of 1±0.00, a zeta potential of -18 ±0.26 mv and DR20min of 100 ±2.72 %.

Conclusion

Finally, in terms of the mean arterial blood pressure lowering, solid SNEDDS performed better effect than both liquid SNEDDS and nanosuspension (P >0.05).