Enhancement of Anti-Tumoral Properties of Paclitaxel Nano-Crystals by Conjugation of Folic Acid to Pluronic F127: Formulation Optimization, In Vitro and In Vivo Study

Abstract

A brand-new nano-crystal (NC) version of the hydrophobic drug Paclitaxel (PT) were formulated for cancer treatment. A stable NC formulation for the administration of PT was created using the triblock co-polymer Pluronic F127. To achieve maximum entrapment effectiveness and minimal particle size, the formulation was improved using the central composite design by considering agitation speed and vacuum pressure at five levels (coded as +1.414, +1, 0, -1, and -1.414). According to the Design Expert software's predictions, 13 runs were created and evaluated for the chosen responses. The formulation prepared with an agitation speed of 1260 RPM and a vacuum pressure of 77.53 mbar can meet the requirements of the ideal formulation in order to achieve 142.56 nm of PS and 75.18% EE, according to the level of desirability (D = 0.959). Folic acid was conjugated to Pluronic F127 to create folate receptor-targeted NC. The drug release profile of the nano-crystals in vitro demonstrated sustained release over an extended period. Folate receptor (FR)-targeted NC (O-PT-NC-Folate) has also been prepared by conjugating folic acid to Pluronic F127. MTT test is used to validate the targeting efficacy on the FR-positive human oral cancer cell line (KB). At pharmacologically relevant concentrations, the PT nano-crystal formulation did not cause hemolysis. Compared to non-targeted NC of PT, the O-PT-NC-Folate showed a comparable but more sustained anti-cancer effect, according to an in vivo anti-tumor investigation in NCI/ADR-RES cell lines. The remarkable anti-tumor effectiveness, minimal toxicity, and simplicity of scale-up manufacturing of the NC formulations indicate their potential for clinical development. Other hydrophobic medications that are formulated into nano-systems for improved therapy may benefit from the formulation approach.

Keywords: Paclitaxel; anti-cancer; central composite design; nano-crystals; optimization.

Figure 1

Schematic representation of conjugation of folic acid to Pluronic F127 nitrogen as the reagent.

Figure 2

FTIR Spectra of (a) PT and (b) physical mixture of PT and polymers.

Figure 2

FTIR Spectra of (a) PT and (b) physical mixture of PT and polymers.

Figure 3

Contour plots and three-dimensional response surface graphs for (a) EE and (b) PS.

Figure 4

Overlay plot of optimization result.

Figure 5

SEM image of O-PT-NC.

Figure 6

In vitro dissolution profile of optimized formulation of PT.

Figure 7

Viability of the human FR-positive oral cancer cell line in the presence of the targeted (O-PT-NC-Folate) and non-targeted (O-PT-NC) nano-crystals following a 48 h incubation period. The targeted nano-crystals comprised (a) varying levels of F127-folate with different PT concentrations and (b) diverse concentrations of F127-folate with 2 mM PT. Untreated cells were used as a control group, and their vitality was measured at 100%. The data were provided as the mean and standard deviation (n = 8). ** p < 0.01.

Figure 7

Viability of the human FR-positive oral cancer cell line in the presence of the targeted (O-PT-NC-Folate) and non-targeted (O-PT-NC) nano-crystals following a 48 h incubation period. The targeted nano-crystals comprised (a) varying levels of F127-folate with different PT concentrations and (b) diverse concentrations of F127-folate with 2 mM PT. Untreated cells were used as a control group, and their vitality was measured at 100%. The data were provided as the mean and standard deviation (n = 8). ** p < 0.01.

Figure 8

Hemolysis activity of the O-PT-NC-Folate and O-PT-NC-CEL. There was evidence of hemolytic activity in the erythrocyte suspensions collected from mouse blood (n = 3, mean SD).

Figure 9

Tumor growth inhibition effect of O-PT-NC and O-PT-NC-Folate in the NCI/ADR-RES xenograft model. (Solid arrows indicate the days of intravenous administration.)