A series of linear and star-shaped amphiphilic polyethylene glycol block polylactide (PEG-b-PLA) and β-cyclodextrin (CD) conjugated PEG-b-PLA (PEG-b-PLA-CD) copolymers were synthesized. Bovine serum albumin (BSA) aqueous solution was emulsified in the copolymer organic solutions to fabricate reverse micelles (RMs), and was then further transferred into ethyl oleate (EO), a pharmaceutically acceptable vehicle, by the RMs. As identified by 1H NMR, the RMs were formed with a hydrophilic core of PEG and CD, covered with a hydrophobic corona of PLA moiety, and were spherical in shape, as observed by a scan electronic microscope. Compared with the PEG-b-PLA RMs, the PEG-b-PLA-CD RMs presented higher encapsulation efficiency. The release of BSA was influenced by the copolymer composition and architecture. BSA stability in the release aqueous phase was confirmed by circular dichroism spectroscopy. The oil-based formulation fabricated from biodegradable copolymers with high drug loading showed a great potential for protein delivery.
Polymeric nanoparticles (NPs) are an important category of drug delivery systems, and their in vivo fate is closely associated with delivery efficacy. Analysis of the protein corona on the surface of NPs to understand the in vivo fate of different NPs has been shown to be reliable but complicated and time-consuming. In this work, we establish a simple approach for predicting the in vivo fate of polymeric NPs. We prepared a series of poly(ethylene glycol)-block-poly(d,l-lactide) (PEG-b-PLA) NPs with different protein binding behaviors by adjusting their PEG densities, which were determined by analyzing the serum protein adsorption. We further determined the protein binding affinity, denoted as the equilibrium association constant (KA), to correlate with in vivo fate of NPs. The in vivo fate, including blood clearance and Kupffer cell uptake, was studied, and the maximum concentration (Cmax), the area under the plasma concentration–time curve (AUC), and the mean residence time (MRT) were negatively linearly dependent, while Kupffer cell uptake was positively linearly dependent on KA. Subsequently, we verified the reliability of the approach for in vivo fate prediction using poly(methoxyethyl ethylene phosphate)-block-poly(d,l-lactide) (PEEP-b-PLA) and poly(vinylpyrrolidone)-block-poly(d,l-lactide) (PVP-b-PLA) NPs, and the linear relationship between the KA value and their PK parameters further suggests that the protein binding affinity of polymeric NPs can be a direct indicator of their pharmacokinetics.
危险品化学品经营许可证（带存储）