Description of Release Process of Doxorubicin from Modified Carbon Nanotubes

Abstract

The article discusses the release process of doxorubicin hydrochloride (DOX) from multi-wall carbon nanotubes (MWCNTs). The studies described a probable mechanism of release and actions between the surface of functionalized MWCNTs and anticancer drugs. The surface of carbon nanotubes (CNTs) has been modified via treatment in nitric acid to optimize the adsorption and release process. The modification efficiency and physicochemical properties of the MWCNTs+DOX system were analyzed by using SEM, TEM, EDS, FTIR, Raman Spectroscopy and UV-Vis methods. Based on computer simulations at pH 7.4 and the experiment at pH 5.4, the kinetics and the mechanism of DOX release from MWNT were discussed. It has been experimentally observed that the acidic pH (5.4) is appropriate for the efficient release of the drug from CNTs. It was noted that under acidic pH conditions, which is typical for the tumour microenvironment almost 90% of the drug was released in a relatively short time. The kinetics models based on different mathematical functions were used to describe the release mechanism of drugs from MWCNTs. Our studies indicated that the best fit of experimental kinetic curves of release has been observed for the Power-law model and the fitted parameters suggest that the drug release mechanism of DOX from MWCNTs is controlled by Fickian diffusion. Molecular dynamics simulations, on the other hand, have shown that in a neutral pH solution, which is close to the blood pH, the release process does not occur keeping the aggregation level constant. The presented studies have shown that MWCNTs are promising carriers of anticancer drugs that, depending on the surface modification, can exhibit different adsorption mechanisms and release.

Functionalized Carbon Nanotubes for Delivery of Ferulic Acid and Diosgenin Anticancer Natural Agents

“…For example, the release of methotrexate and cyclophosphamide fits the Higuchi and Korsmeyer–Peppas kinetic models, respectively, depending on pH and temperature. 51 Chudoba et al 52 reported that the best-fit release kinetics of doxorubicin from modified CNTs are due to Korsmeyer–Peppas/Ritger–Peppas kinetics (power-law model) and release controls by Fickian diffusion. Other studies have shown different kinetic models for releasing drugs from CNTs, such as the release of the natural agent silibinin from MWCNTs, which best fits pseudo-second-order kinetics.…”

Carbon Nanotube Hybrid Materials: Efficient and Pertinent Platforms for Antifungal Drug Delivery

“…[92] Additionally, several mathematical operations include zero, first and second-order kinetics, Higuchi, Hixson-Crowell, Ritger-Peppas/Korsmeyer-Peppas (power-law model), and Weibull can be applied to illustrate the release mechanism. [93,94] The zero-order model has a constant drug release rate across time, whereas in the first-order model, the release of the drug is directly proportional to the drug concentration. [94] The Higuchi model explains the release rate as a function of the square root of time, and its generalized model is termed the Korsmeyer-Peppas model.…”

Carboxyl Functionalization of N-MWCNTs with Stone–Wales Defects and Possibility of HIF-1α Wave-Diffusive Delivery

“…If the HIF-1α content is low, it suppresses the immune function, cartilaginous tissue formation, wound healing, etc. [ 13 , 14 , 15 , 16 ]. If the HIF-1α content is high, it points to oncological or cardiovascular diseases: hypoxia, strokes, heart attacks, pulmonary hypertension, etc.…”

“…Therefore, increasing or decreasing the HIF-1α content through pharmacological intervention can help to treat many types of diseases [ 12 , 13 , 14 , 15 ]. The concentration of a drug released from its carrier varies linearly or exponentially with time, which is normally described by the diffusion equation [ 16 , 17 ]. However, as has been found experimentally, wavelike kinetics of drug release are also possible [ 18 ].…”