Optimizing gefitinib nanoliposomes by Box-Behnken design and coating with chitosan: A sequential approach for enhanced drug delivery

Abstract

Background and purpose: This study aimed to improve the stability and prolonged gefitinib release from the nanoliposomes.

Experimental approach: Nanoliposomes were prepared by reverse-phase evaporation and optimized using Box-Behnken design to investigate the influence of sonication time (X ₁), tween 80 / soya phosphatidylcholine ratio (X ₂), and cholesterol/soya phosphatidylcholine ratio (X ₃) on nanoliposomes.

Key results: Optimized nanoliposomes were quasi-spherical shaped, with a mean dimension of 93.2 nm and an encapsulation efficiency of 87.56±0.17 %. Surface decoration of the optimized batch was done using different concentrations of chitosan. The optimal chitosan concentration required to adorn the nanoliposome surface was 0.01 %. In comparison to unadorned nanoliposomes (82.16±0.65 %), adorned nanoliposomes (78.04±0.35 %) released the drug consistently over 24 h via Fickian diffusion. The IC₅₀ values for surface-adorned nanoliposomes in A549 and H1299 cells were 6.53±0.75 and 4.73±0.46 μM, respectively. Cytotoxicity of the surface-decorated nanoliposomes may be due to their higher zeta potential and prolonged drug release. At the end of the sixth month, the samples stored at 4 °C were more stable than those stored at 25 °C and 45 °C. The stability of plain nanoliposomes has increased after chitosan coating. Thus, by using different concentrations of chitosan solution as coating material, we can develop a suitable sustained drug-release surface-adorned nanoliposomal formulation.

Conclusion: The developed nanoliposomes may offer a new path for melanoma clinics.

Keywords: Liposomes; pulmonary cancer; response surface methodology.

Figure 1.

(I) Upshot plot of coefficients on encapsulation efficiency [A₁, A₂, and A₃ are coefficients of main effects (X₁, X₂, and X₃); A₄, A₅, and A₆ are coefficients of interaction terms (X₁X₂, X₂X₃, and X₁X₃); and A₇, A₈, and A₉ are coefficients of square terms (X₁², X₂², X₃²)]. (II) Upshot plot of particle size [(B₁, B₂, and B₃ are coefficients of main effects (X₁, X₂, and X₃); B₄, B₅, and B₆ are coefficients of interaction terms (X₁X₂, X₂X₃, and X₁X₃); and B₇, B₈, and B₉ are coefficients of square terms (X₁², X₂², X₃²)].

Figure 2.

Response surface plots and contour plots showing the influence of level of sonication time, Tween 80/soya lecithin ratio, and cholesterol/soya lecithin ratio on mean particle size (I, II) and encapsulation efficiency (III, IV).

Figure 3.

Overlay of DSC analysis of gefitinib, chitosan, cholesterol, soya lecithin, and uncoated nanoliposomal formulation (I), and chitosan-coated optimized nanoliposomes (formulation NG13) (II).

Figure 4.

Overlay of FTIR spectra of cholesterol (I), chitosan (II), soya lecithin (III), and (IV) gefitinib.

Figure 5.

Overlay of FTIR spectra of unadorned nanoliposomal formulation (I); coated nanoliposomal formulation (II).

Figure 6.

Transmission electron micrographs of unadorned nanoliposomes (I), surface adorned nanoliposomes (II).

Figure 7.

Comparison of in vitro release of drug from pure drug dispersion, optimized uncoated nanoliposomes and chitosan-coated nanoliposomes (I) in simulated gastrointestinal fluid, (II) in acetate buffer pH 4.0, and (III) in simulated intestinal fluid pH 6.8. Data presents mean ± SD, n = 3.

Figure 8.

IC₅₀ value of pure gefitinib, simple nanoliposomes (uncoated), and surface-adorned nanoliposomes.