Colloidal carriers for intravenous drug targeting: Plasma protein adsorption patterns on surface‐modified latex particles evaluated by two‐dimensional polyacrylamide gel electrophoresis

Abstract

Targeting to specific sites of the body via colloidal carriers is sought in order to reduce drug side effects. The adsorption of plasma proteins on intravenously injected particles is regarded as the key factor in explaining their organ distribution: total bound protein, or, more likely, the presence of specific proteins and their conformation, are expected to influence macrophage uptake. Polystyrene beads, 60 nm in diameter, were used as model carriers; their surface was differentially modified by adsorption of increasingly hydrophilic block copolymers, poloxamers 184, 188 and 407. After incubation in plasma, the patterns of protein adsorption onto coated beads were analyzed by highresolution two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). The behavior of some representative proteins was monitored, including albumin, fibrinogen, IgG, factor B and the apolipoproteins, A-I, A-IV, C-111, E and J. The more hydrophobic the particles, the larger the total amount of bound protein. However, this correlation was not valid for all of the analyzed protein species, which proves that it is insufficient to look only at physicochemical data to predict organ distribution. On the contrary, it is essential to use 2-D PAGE to establish the correlation between adsorbed proteins and carrier behavior in vivo.

Nanosuspensions: a promising drug delivery strategy

“…The establishment of an in-vitro/in-vivo correlation and the monitoring of the in-vivo performance of the drug is an essential part of the study, irrespective of the route and the delivery system employed. It is of the utmost importance in the case of intravenously injected nanosuspensions since the in-vivo behaviour of the drug depends on the organ distribution, which in turn depends on its surface properties, such as surface hydrophobicity and interactions with plasma proteins (Blunk et al 1993(Blunk et al , 1996Lu¨ck et al 1997a,b). In fact, the qualitative and quantitative composition of the protein absorption pattern observed after the intravenous injection of nanoparticles is recognized as the essential factor for organ distribution (Mu¨ller 1989;Blunk et al 1993Blunk et al , 1996Lu¨ck et al 1997a,b).…”

“…Hence, suitable techniques have to be used in order to evaluate the surface properties and protein interactions to get an idea of in-vivo behaviour. Techniques such as hydrophobic interaction chromatography can be used to determine surface hydrophobicity (Wallis & Mu¨ller 1993), whereas 2-D PAGE (Blunk et al 1993) can be employed for the quantitative and qualitative measurement of protein adsorption after intravenous injection of drug nanosuspensions in animals.…”

Maghemite Functionalization for Antitumor Drug Vehiculization

“…This type of adsorption is very important for the biological destiny of the magnetic colloids (e.g. biodistribution and clearance process) (Blunk et al, 1993).…”

Understanding the nanoparticle–protein corona using methods to quantify exchange rates and affinities of proteins for nanoparticles

“…A central methodological problem is to separate free protein from protein bound to nanoparticles, ideally employing nonperturbing methods that do not disrupt the protein-particle complex or induce additional protein binding. The preferred method to-date has been centrifugation, identifying the major serum proteins albumin, IgG and fibrinogen as being associated with a wide range of particles of seemingly disparate molecular composition (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). Due to its high abundance, albumin is almost always observed on particles and may be retrieved even if it has relatively low affinity.…”