An Inhalable Powder Formulation Based on Micro- and Nanoparticles Containing 5-Fluorouracil for the Treatment of Metastatic Melanoma

Abstract

Melanoma is the most aggressive and lethal type of skin cancer, with a poor prognosis because of the potential for metastatic spread. The aim was to develop innovative powder formulations for the treatment of metastatic melanoma based on micro- and nanocarriers containing 5-fluorouracil (5FU) for pulmonary administration, aiming at local and systemic action. Therefore, two innovative inhalable powder formulations were produced by spray-drying using chondroitin sulfate as a structuring polymer: (a) 5FU nanoparticles obtained by piezoelectric atomization (5FU-NS) and (b) 5FU microparticles of the mucoadhesive agent Methocel™ F4M for sustained release produced by conventional spray drying (5FU-MS). The physicochemical and aerodynamic were evaluated in vitro for both systems, proving to be attractive for pulmonary delivery. The theoretical aerodynamic diameters obtained were 0.322 ± 0.07 µm (5FU-NS) and 1.138 ± 0.54 µm (5FU-MS). The fraction of respirable particles (FR%) were 76.84 ± 0.07% (5FU-NS) and 55.01 ± 2.91% (5FU-MS). The in vitro mucoadhesive properties exhibited significant adhesion efficiency in the presence of Methocel™ F4M. 5FU-MS and 5FU-NS were tested for their cytotoxic action on melanoma cancer cells (A2058 and A375) and both showed a cytotoxic effect similar to 5FU pure at concentrations of 4.3 and 1.7-fold lower, respectively.

Keywords: 5-fluorouracil; biopolymers; cytotoxicity; metastatic melanoma; microparticles; nanoparticles; pulmonary delivery.

Figure 1

Particle size distribution obtained by laser diffraction (volume average analysis) for the 5FU nanoparticles obtained by piezoelectric atomization (5FU-NS) and 5FU microparticles of sustained release produced by conventional spray drying (5FU-MS) formulations, and drug 5FU pure (n = 3).

Figure 2

Scanning electron microscopy (SEM) images of dry powders: (a,b) 5FU-NS, obtained at 6500× and 16,000× magnifications, respectively; (c,d) 5FU-MS formulation, obtained at 6500× and 10,000× magnifications, respectively. Scale bars represent 2 µm (right) and 1 µm (left).

Figure 3

FTIR spectroscopy spectra of drug 5FU pure, chondroitin sulfate, and dry formulations, 5FU-MS and 5FU-NS.

Figure 4

Deposition Performance (% 5FU) by ACI: 5FU-NS and 5FU-MS formulations, and drug 5FU pure (mean ± SD; n = 3).

Figure 5

In vitro drug release profile: 5FU-NS and 5FU-MS formulations, and drug 5FU pure (mean ± SD; n = 3).

Figure 6

Mucoadhesive performance obtained for the 5FU-MS formulation, and MS-AM (5FU-MS formulation obtained in absence Methocel^TM F4M) and MS-AD (5FU-MS formulation obtained in absence of drug) powders, determined by the Force (mN) of the detachment from the mucin membrane versus Distance traveled (mm). The area under the curve represents the Mucoadhesion Work (W_MA—mN·mm⁻¹) (mean ± SD, n = 3; * No significant difference; † Significant difference of *).

Figure 7

Concentration of mucin adsorbed (%) by 5FU-MS formulation, and MS-AM and MS-AD powders. Values obtained from the mean ± SD; n = 2).

Figure 8

Washability profiles (0–300 min) of 5FU-MS formulation, MS-AM powder, and drug 5FU pure.

Figure 9

Cell viability (24, 48 and 72 h) of the 5FU-MS and 5FU-NS formulations at five concentrations. 5FU pure was used as a positive control. (A) A2058 cell viability; (B) A375 cell viability.