Enhancing encapsulation of hydrophobic phyto-drugs naringenin and baicalein in polymeric nano-micelles

Pluronic micelles hold great potential to act as hydrophobic drug delivery carriers; however, there is a pressing need to optimize their use in commercial formulations. This is the first report that describes the loading of phyto-drugs naringenin (NAR) and baicalein (BAC) in different Pluronics F108, F127 and P84 using solvent evaporation method (S.Ev.M) and Direct dissolution method (D.D.M.). Pluronic P84 micelles were able to encapsulate significantly higher amount of both phyto-drugs as compared to other Pluronic micelles. S.Ev.M appreciably enhanced the encapsulation of NAR (19.2 ± 0.438 mg/mL) and BAC (2.593 ± 0.223 mg/mL) compared to D.D.M. (NAR, 10.95 ± 0.212 mg/mL, and BAC, 1.058 ± 0.049 mg/mL) in 5% w/v and 12% w/v Pluronic P84, respectively. SEM (Scanning Electron Microscopy) results showed a spherical morphology after the incorporation of NAR into Pluronic micelles and evidenced that S.Ev.M did not affect the morphology. Sustained release behavior of phyto-drugs was observed from the loaded Pluronic micelles, which was conformed via in vitro release studies. Finally, antioxidant activity was analyzed by ABTS ^•+ (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) scavenging assays, with both NAR and BAC loaded P84 micelles (IC ₅₀ 7.185 and 28.90 μg/mL) showcasing a marked increase in antioxidant properties compared to the pure phyto-drugs NAR and BAC (IC ₅₀ 13.25 and 53.68 μg/mL) or other Pluronic formulations. Interaction of phyto-drugs and Pluronic P84 has been screened using ¹H NMR Spectroscopy (proton nuclear magnetic spectroscopy) and revealed that the whole NAR molecule was encapsulated within the Pluronic micelles. These phyto-drugs hold great potential for use as nutraceuticals and other pharmaceutical applications but currently can't be used due to poor solubilization. Therefore, it can be suggested that preparation of drug loaded Pluronic formulations using S.Ev.M. would be more convenient, fast, and efficient method over D.D.M.