Chondroitin Sulfate for Cartilage Regeneration, Administered Topically Using a Nanostructured Formulation

Abstract

In the pharmaceutical sector, solid lipid nanoparticles (SLN) are vital for drug delivery incorporating a lipid core. Chondroitin sulfate (CHON) is crucial for cartilage health. It is often used in osteoarthritis (OA) treatment. Due to conflicting results from clinical trials on CHON's efficacy in OA treatment, there has been a shift toward exploring effective topical systems utilizing nanotechnology. This study aimed to optimize a solid lipid nanoparticle formulation aiming to enhance CHON permeation for OA therapy. A 3 × 3 × 2 Design of these experiments determined the ideal parameters: a CHON concentration of 0.4 mg/mL, operating at 20,000 rpm speed, and processing for 10 min for SLN production. Transmission electron microscopy analysis confirmed the nanoparticles' spherical morphology, ensuring crucial uniformity for efficient drug delivery. Cell viability assessments showed no significant cytotoxicity within the tested parameters, indicating a safe profile for potential clinical application. The cell internalization assay indicates successful internalization at 1.5 h and 24 h post-treatment. Biopharmaceutical studies supported SLNs, indicating them to be effective CHON carriers through the skin, showcasing improved skin permeation and CHON retention compared to conventional methods. In summary, this study successfully optimized SLN formulation for efficient CHON transport through pig ear skin with no cellular toxicity, highlighting SLNs' potential as promising carriers to enhance CHON delivery in OA treatment and advance nanotechnology-based therapeutic strategies in pharmaceutical formulations.

Keywords: biopharmaceutical studies; cell viability; chondroitin sulfate; design of experiments; drug delivery; osteoarthritis; skin permeation; solid lipid nanoparticles.

Figure 1

Plots of the DOE premises evaluation. Graphs (A–C) are used to evaluate the normality of the residuals, linearity, independence, and homoscedasticity. Graphs (D–G) help to assess the normality of the data, with a value of p ≥ 0.05.

Figure 2

Pareto chart of main effects in DOE. % EE, Z potential and particle size, are represented in (A–C) respectively. Bars that cross the reference line are statistically significant at the 0.05 level with the current model terms. The main effects that are statistically significant (α = 0.05) are those values that exceed the intermittent vertical red line. The null hypothesis is that the coefficient of the term is equal to zero, which implies that there is no association between the term and the response.

Figure 3

Graph of the main effects, according to the factors and levels defined in DOE.

Figure 4

TEM images of SLN with CHON in aqueous medium as part of DOE study. (A) 0.4 mg/mL of CHON; (B) 0.7 mg/mL of CHON, and (C) 1.0 mg/mL of CHON. Scale bar  =  200 nm.

Figure 5

Effect of SLN on the viability of HaCaT cells (keratinocyte) at 24 h, 48 h, and 72 h. Data are expressed as mean ± SEM; * p < 0.05 and *** p < 0.001; the significant difference is compared to C: control cells without treatment.

Figure 6

Cellular uptake by confocal microscopy analysis in HaCaT cells. Cells were incubated for 1.5 h and 24 h with the indicated Nile red chondroitin sulfate nanoparticles. (a) Membrane staining with WGA; (b) nuclei staining with DAPI; (c) fluorescence of internalized chondroitin sulfate nanoparticles; (d) merged (b,c), and (e) merged (a–c). The figure scale bar corresponds to 10 μm.

Figure 6

Cellular uptake by confocal microscopy analysis in HaCaT cells. Cells were incubated for 1.5 h and 24 h with the indicated Nile red chondroitin sulfate nanoparticles. (a) Membrane staining with WGA; (b) nuclei staining with DAPI; (c) fluorescence of internalized chondroitin sulfate nanoparticles; (d) merged (b,c), and (e) merged (a–c). The figure scale bar corresponds to 10 μm.

Figure 7

Schematic representation of solid lipid nanoparticles with CHON, prepared by the hot microemulsification process. Source: own source.