In vivo effect of bevacizumab-loaded albumin nanoparticles in the treatment of corneal neovascularization.

Corneal neovascularization (CNV) is associated with different ocular pathologies, including infectious keratitis, trachoma or corneal trauma. Pharmacological treatments based on the topical application of anti-VEGF therapies have been shown to be effective in the treatment and prevention of CNV. The aim of this work was to evaluate the effect of bevacizumab-loaded albumin nanoparticles in a rat model of CNV. Bevacizumab-loaded nanoparticles, either "naked" (B-NP) or coated with PEG 35,000 (B-NP-PEG), were administered once a day in the eyes of animals (10 µL, 4 mg/mL every 24 h) during 7 days. Bevacizumab and dexamethasone were employed as controls and administered at the same dose every 12 h. At the end of the study, the area of the eye affected by neovascularization was about 2-times lower for animals treated with B-NP than with free bevacizumab. In the study, dexamethasone did not demonstrate an inhibitory effect on CNV at the employed dose. All of these results were confirmed by histopathological analysis, which clearly showed that eyes treated with nanoparticles displayed lower levels of fibrosis, inflammation and edema. In summary, the encapsulation of bevacizumab in human serum albumin nanoparticles improved its efficacy in an animal model of CNV.

Human serum albumin nanoparticles for ocular delivery of bevacizumab.

Bevacizumab-loaded nanoparticles (B-NP) were prepared by a desolvation process followed by freeze-drying, without any chemical, physical or enzymatic cross-linkage. Compared with typical HSA nanoparticles cross-linked with glutaraldehyde (B-NP-GLU), B-NP displayed a significantly higher mean size (310 nm vs. 180 nm) and a lower negative zeta potential (-15 mV vs. -36 mV). On the contrary, B-NP displayed a high payload of approximately 13% when measured by a specific ELISA, whereas B-NP-GLU presented a very low bevacizumab loading (0.1 µg/mg). These results could be related to the inactivation of bevacizumab after reacting with glutaraldehyde. From B-NP, bevacizumab was released following an initial burst effect, proceeded by a continuous release of bevacizumab at a rate of 6 µg/h. Cytotoxicity studies in ARPE cells were carried out at a single dose up to 72 h and with repeated doses over a 5-day period. Neither bevacizumab nor B-NP altered cell viability even when repeated doses were used. Finally, B-NP were labeled with 99mTc and administered as eye drops in rats. 99mTc-B-NP remained in the eye for at least 4 h while 99mTc-HSA was rapidly drained from the administration point. In summary, HSA nanoparticles may be an appropriate candidate for ocular delivery of bevacizumab.

RP-HPLC method development for the simultaneous determination of timolol maleate and human serum albumin in albumin nanoparticles.

An isocratic high-performance liquid chromatographic method was developed and validated for the simultaneous determination of human serum albumin (HSA) and timolol in albumin nanoparticles. This method involved a reversed-phase-C18 column thermostated at 25 °C, UV detection at 276 nm, flow rate of 1.0 ml/min and a mobile phase compounded by 0.05% (v/v) trifluoroacetic acid in water/0.05% (v/v) trifluoroacetic acid in an acetonitrile (40:60, v/v) solution. The elution times for albumin and timolol were 1.84 ± 0.05 min and 2.67 ± 0.04 min, respectively. Calibration curves were linear from 0.2 to 100 mg/ml for HSA and 0.01 to 1 mg/ml for timolol. Limits of quantification were 0.2 mg/ml for HSA and 0.01 mg/ml for timolol. The values of accuracy and precision of intra- and inter-day variation studies were within acceptable limits, according to the US Food and Drug Administration Guidance for Industry. The described method has proved to be useful to give accurate measurements of human serum albumin and timolol from albumin nanoparticles to determine the percentage of encapsulation and the process yield.