Preparation and characterization of adapalene and clindamycin-loaded nanofiber for acne treatment

Adapalene (ADA) and clindamycin (CLN) are the drugs of choice for the treatment of moderate to severe acne. This study aimed to prepare ADA and CLN nanofibers using polyvinyl pyrrolidone (PVP) and ethyl cellulose (EC) polymers via electrospinning and to investigate their physicochemical properties. In this regard, nanofibers containing ADA, CLN, PVP, and EC were prepared with different polymer ratios. Their morphological features, functional groups, possible interactions, and material purity were evaluated using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The drug release rate was measured at 32 °C using a dialysis bag. The disk diffusion method and MTT assay were employed to assess the antibacterial and cytotoxic effects of the formulations. Finally, drug stability was evaluated at multiple time intervals. The optimized formulation (EC: PVP 40:60) produced uniform, bead-free nanofibers with an average diameter of 171.19 ± 59.02 nm. Drug incorporation led to complete amorphization, as confirmed by the disappearance of crystalline peaks in XRD and DSC. Hydrophobicity increased with ADA loading (contact angle: 90.63 ± 2.08° for ADA-CLN vs. 58.56 ± 3.47° for drug-free fibers). CLN exhibited rapid release (≈ 90% within 12 h), while ADA showed sustained release (≈ 80% over 160 h), fitting Weibull and Korsmeyer-Peppas models, respectively. CLN nanofibers showed the highest antibacterial activity against Staphylococcus aureus , but no synergistic effect was observed with ADA. Drug-free nanofibers enhanced cell proliferation (> 120% viability), while ADA exhibited concentration-dependent cytotoxicity (IC₅₀ ≈ 45 µg/mL). Drug loading efficiencies were 99.3% for CLN and 98.6% for ADA. Stability studies revealed that CLN degraded significantly at room temperature, whereas ADA remained stable for over one year. Collectively, these findings position the developed nanofiber system as a highly promising and effective platform for the dual delivery of antimicrobial and anti-inflammatory agents in dermal applications.