Intravitreal Administration of Adalimumab-Loaded Poly(Lactic-co-Glycolic Acid) Nanoparticles: Effects on Biodistribution and Pharmacokinetics

Abstract

Adalimumab, a monoclonal antibody used for treating inflammatory diseases, including eye diseases, faces challenges in biodistribution and targeted delivery. Nanoparticle (NP)-based drug delivery systems have shown promise in enhancing the pharmacokinetic profiles of biologic drugs. This study aims to develop, and characterize intravitreal adalimumab-loaded poly(lactic-co-glycolic acid) (PLGA) NPs to improve antibody distribution and therapeutic efficacy. Characterization studies, morphological examination, and quantitative, stability, and physical properties are conducted. In vitro release kinetics are assessed using a dialysis membrane method. In vivo biodistribution is studied in rats after intravitreal administration by Positron Emission Tomography/Computed Tomography imaging. The optimized NPs were spherical (around 300 nm) with a surface charge of about -20 mV. Encapsulation efficiency and drug loading reach values close to 100%. Stability studies showed minimal changes in particle size and drug content. In vitro release showed a biphasic pattern with an initial burst release followed by sustained release. Safety studies indicated no significant cytotoxicity or adverse effects. The adalimumab-loaded PLGA NPs demonstrate favorable physicochemical characteristics, stability, and release profiles. In vivo distribution revealed a change in the antibody's distribution pattern after intravitreal administration via NPs encapsulation. These findings suggest the potential for enhanced therapeutic outcomes and warrant further investigation in disease-specific models to explore the clinical potential of this NP-based delivery system.

Keywords: adalimumab; controlled releases; in vivo distribution and pharmacokinetics; nanoparticles; poly(lactic‐co‐glycolic acid).

Figure 1

Study timeline for both groups (mAb and encapsulated mAb NPs group): intravitreal injections of ⁸⁹Zr–adalimumab (data obtained from our previous work^{[ 21 ]}) and encapsulated ⁸⁹Zr–Adalimumab Gelled‐Core NPs (⁸⁹Zr–ADA–GC NPs), PET acquisitions, blood sample collection, and autoradiography. Designed with BioRender.com.

Figure 2

TEM images of adalimumab‐loaded PLGA nanoparticles.

Figure 3

Resulting data of PY, EE, and LC of adalimumab‐loaded PLGA nanoparticles. a) Graph shows the quantitative data for the ADA PLGA NPs while b) the graph displays the results for the ADA–GC PLGA NPs.

Figure 4

Size, size distribution, and ζ potential of the PLGA‐based NPs.

Figure 5

Resulting data of the stability‐to‐storage study for PLGA‐based NPs, where size and PDI changes were studied at three different temperature conditions. Graph a) displays the results for the ADA PLGA NPs while the graph b) shows the resulting data for the ADA–GC PLGA NPs.

Figure 6

Resulting data of the stability‐to‐pH study. a,c) Graphs show the size and PDI changes over the studied pH interval for ADA PLGA NPs and ADA–GC PLGA NPs, respectively, while b,d) the graphs display the size and ζ potential variations along the same pH interval for the same type of formulations.

Figure 7

Resulting data of the stability‐to‐ionic strength study. a,c) Graphs show the size and PDI changes over the studied ionic strength interval for ADA PLGA NPs and ADA–GC PLGA NPs, respectively, while b,d) the graphs display the size and ζ potential variations along the same ionic strength interval for the same type of formulations.

Figure 8

Differential scanning calorimetry (DSC) analysis of adalimumab‐loaded PLGA‐based NPs.

Figure 9

FTIR analysis of the adalimumab‐loaded PLGA‐based NPs.

Figure 10

X‐ray diffraction analysis of the adalimumab‐loaded PLGA‐based NPs. a) Graph displays the results for the ADA PLGA NPs, while b) the graph shows the resulting data for the ADA–GC PLGA NPs.

Figure 11

In vitro release study of adalimumab‐loaded PLGA‐based NPs.

Figure 12

Evolution of the changes on the corneal transparency along the bovine corneal opacity and permeability (BCOP) study of adalimumab‐loaded PLGA‐based NPs.

Figure 13

Hen's egg test on the chorioallantoic membrane (HET–CAM) study of adalimumab‐loaded PLGA‐based NPs.

Figure 14

Coronal‐plane‐fused PET/CT images showing rat's head at different time points (initial, 24 h, 3 days, and 9 days) following intravitreal administration of ⁸⁹Zr–adalimumab in both groups (adalimumab‐ and adalimumab‐loaded NPs). The color scale represents the radioactive uptake of ⁸⁹Zr–adalimumab, ranging from lower (blue) to higher (red) intensity.

Figure 15

Percentage of remaining radioactivity in the eye overtime after intravitreal injection of ⁸⁹Zr–adalimumab (n = 6 eyes) and ⁸⁹Zr–labeled NPs (n = 4 eyes), α < 0.05 between 24 and 120 h.

Figure 16

Percentage of blood radioactivity overtime after intravitreal injection of ⁸⁹Zr–adalimumab in both rat groups (adalimumab (n = 6) and adalimumab‐loaded GC NPs (n = 4)), α < 0.05 at all‐time points, statistical analysis: two‐way ANOVA analysis.

Figure 17

Rat whole‐body PET/CT images displayed in coronal (up) and sagittal (down) plane for ⁸⁹Zr–adalimumab (left) and ⁸⁹Zr–adalimumab‐loaded GC NPs (right), representing the antibody distribution in the organs with the highest uptake 3 days after intravitreal injection. The color scale represents the radioactive uptake of ⁸⁹Zr–adalimumab, ranging from lower (blue) to higher (red) intensity.

Figure 18

Activity (SUV) in the different organs (liver, kidney, and cervical lymph nodes) overtime after intravitreal injection of ⁸⁹Zr–adalimumab in both rat groups (adalimumab‐ and adalimumab‐loaded GC NPs).

Figure 19

a) Autoradiography image of ⁸⁹Zr–adalimumab‐loaded GC NPs eye distribution 9 days after intravitreal injection (right) and the same histological section (left). b) Percentage of ocular activity after 9 days of ⁸⁹Zr–adalimumab GC NPs distribution in both anterior and posterior ocular segments.