Liposomal Formulation of a PLA2-Sensitive Phospholipid–Allocolchicinoid Conjugate: Stability and Activity Studies In Vitro

Abstract

To assess the stability and efficiency of liposomes carrying a phospholipase A2-sensitive phospholipid-allocolchicinoid conjugate (aC-PC) in the bilayer, egg phosphatidylcholine and 1-palmitoyl-2-oleoylphosphatidylglycerol-based formulations were tested in plasma protein binding, tubulin polymerization inhibition, and cytotoxicity assays. Liposomes L-aC-PC10 containing 10 mol. % aC-PC in the bilayer bound less plasma proteins and were more stable in 50% plasma within 4 h incubation, according to calcein release and FRET-based assays. Liposomes with 25 mol. % of the prodrug (L-aC-PC25) were characterized by higher storage stability judged by their hydrodynamic radius evolution yet enhanced deposition of blood plasma opsonins on their surface according to SDS-PAGE and immunoblotting. Notably, inhibition of tubulin polymerization was found to require that the prodrug should be hydrolyzed to the parent allocolchicinoid. The L-aC-PC10 and L-aC-PC25 formulations demonstrated similar tubulin polymerization inhibition and cytotoxic activities. The L-aC-PC10 formulation should be beneficial for applications requiring liposome accumulation at tumor or inflammation sites.

Biological Activities and Solubilization Methodologies of Naringin

“…Recent studies have demonstrated that the attachment of polymers, antibodies, or phospholipid derivatives to the surface of liposomes effectively improves liposome properties and their storage stability [ 112 , 113 , 114 ]. Frequently used liposome modifiers include chitosan, alginate, polyethylene glycol, pectin, and silica.…”

Protein Corona Attenuates the Targeting of Antitumor Sialyl Lewis X-Decorated Liposomes to Vascular Endothelial Cells under Flow Conditions

“…Liposomes (large unilamellar vesicles) were prepared by lipid film hydration followed by extrusion as described earlier [ 37 , 52 ]. Mixtures of ePC, PI, SiaLe X -conjugate and MlphDG in the required molar ratios ( Table 1 ) in chloroform–methanol (2:1) were dried by rotary evaporation in round-bottomed tubes and then in vacuum at 7 Pa for at least 1.5 h. The lipid films were hydrated with PBS (unless otherwise specified) under shaking at room temperature for 2 h. Then, the suspensions were subjected to 5–7 cycles of freezing/thawing (N 2 liquid/+40 °C) and extruded 20 times through polycarbonate Whatman Nuclepore membrane filters (Cytiva, Marlborough, MA, USA) with a pore size of 100 nm using a Mini-Extruder setup (Avanti Polar Lipids, Alabaster, AL, USA).…”

“…Phospholipid concentrations in liposome dispersions were measured by the enzymatic colorimetric phosphatidylcholine assay (Sentinel Diagnostics, Milan, Italy), as described in [ 52 ]. Prodrug concentrations were measured by UV spectrophotometry after liposome disruption with ethanol (λ max MlphDG 260 nm, ε 16,100 M −1 cm −1 ).…”

“…Delipidization was performed as described in [ 60 ] and in our recent study [ 52 ]. The resulting protein samples were dissolved in 36 μL of 2× standard reducing buffer for SDS-PAGE and boiled 2 × 2 min.…”