Multi-functionalized systems of chitosan nanoparticles functionalized with methotrexate and incorporated into resistant starch/pectin microparticles as a strategy for colon-specific delivery of 5-fluorouracil for the treatment of colorectal cancer

Author(s)

Aline Martins dos Santos

• Document type: Doctoral Thesis
• Press: Araraquara. 2021-02-20.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Farmacêuticas. Araraquara
• Defense date: 2019-07-30
• Advisor: Maria Palmira Daflon Gremião; Miziara Barboza Ferreira Ferreira

Abstract

5-fluorouracil (5-FU) and methotrexate (MTX) has been widely used in the treatment of colorectal cancer (CRC), however, its clinical efficacy is limited due to its lack of specificity, leading to severe side effects. In this sense, chitosan (CS) nanoparticles (NPs) encapsulated with 5-FU and functionalized with MTX, as well as the incorporation of these NPs into resistant starch and pectin (RS/P) microparticles (MPs) for oral administration were designed to achieve targeted release, and to increase local drug concentration in the colon and/or tumor region. Ionotropic gelation method using tripolyphosphate (TPP) as a crosslinker was efficient in obtaining CS/TPP/5-FU NPs, with a mean diameter between 122.2 and 155.0 nm, with a polydispersity index (PDI) between 0.24 and 0.35, zeta potential value (above +21 mV) and spherical shape. 5-FU encapsulation efficiency (EE) in these NPs ranged from 12.24 to 23.58%, showing that the sample with a higher proportion of CS (4:1:1 CS/TPP/5-FU) which presented higher EE. CS was successfuly labelled to the MTX and MTX content obtained for CS-MTX-1; CS-MTX-2 and CS-MTX-3 samples were 16.92, 27.52 and 30.89%, respectively. NPs functionalized with MTX presented mean diameter between 376.4 and 407.8 nm, with PDI values between 0.38 and 0.41 and zeta potential between +31.6 and +26.3 mV, with a small reduction in the EE of 5-FU (15.71-18.23%). Mucosadhesion studies demonstrated that the CS/TPP NPs with and without 5-FU, presented higher mucoadhesive capacity compared to the NPs functionalized with MTX, which led to the reduction in the zeta potential values, indicating lower adsorption of mucin on the surface of these NPs. CS/TPP NPs with and without 5-FU were encapsulated into RS/P MPs using ionotropic gelation method by manual dripping and/or aerosolization, and MPs loaded with NPs had average diameter above 800 μm, and diameter of 10 μm, respectively. Spherical shape of the MPs and nanoparticle encapsulation efficiency into microparticles were confirmed in both methods. In vitro release studies demonstrated that the encapsulation of NPs into RS/P MPs promoted greater control of 5-FU release rates, with a significant reduction in acid media (53%). CS NPs were successfuly labelled using Cy5 fluorophore and were monitored using multispectral optical imaging in mouse. In vivo biodistribution studies, CS-Cy5 NPs showed a faster clearance in the distribution pattern along the gastrointestinal tract (GIT), i.e., a shorter transit time compared to CS NPs-loaded RS/P microparticles. In addition, CS-Cy5 NPs showed non-specific absorption into the blood-stream with associated kidney accumulation, while for the CS NPs-loaded RS/P microparticles no significant accumulation was observed in blood or major organs, indicating that the encapsulation of NPs into RS/P MPs resulted in higher protection of the NPs along the GIT after oral administration. Therefore, the set of results suggests that RS/P MPs are potential carriers for delivering drug-loaded nanoparticles to the colon and this work will contribute to the development of oral-systems for the treatment of CRC. (AU)

• FAPESP's process: 16/01464-9 - Multifunctionalized systems-based chitosan nanoparticles anchored with methotrexate and incorporated into resistant starch/pectin microparticles for colon-specific release of 5-fluourouracil
• Grantee: Aline Martins dos Santos
• Support Opportunities: Scholarships in Brazil - Doctorate