Dual-Drug Delivery via Zein In Situ Forming Implants Augmented with Titanium-Doped Bioactive Glass for Bone Regeneration: Preparation, In Vitro Characterization, and In Vivo Evaluation

In situ forming implants (IFIs) are non-surgical approach using biodegradable polymers to treat bone fractures. The study aimed at preparing dual-drug-loaded IFIs to deliver pitavastatin (osteogenic drug) and tedizolid (antibiotic) using zein as the implant matrix via solvent-induced phase inversion method. At first, several investigations were done on pitavastatin-loaded zein IFIs, where three concentrations of zein were used (10, 20, and 30% w/v). IFIs were evaluated for their solidification time, rheological properties, injectability, and in vitro release. IFIs containing bioactive glass nanoparticles were prepared by the addition of non-doped bioactive glass nanoparticles (BGT₀; 1, 3, 5, and 10% w/v) or titanium-doped bioactive glass nanoparticles (BGT₅; 1% w/v) to the selected concentration of zein (30% w/v) and then evaluated. The optimized dual-medicated implant (D-ZIFI 1) containing pitavastatin, tedizolid, sodium hyaluronate (3% w/v), and BGT₅ (1% w/v) was prepared and compared to IFI lacking both sodium hyaluronate and BGT₅ (D-ZIFI 2). D-ZIFI 1 and 2 sustained the release profiles of both drugs for 28 days. SEM images proved the interconnected porous structure of D-ZIFI 1 due to sodium hyaluronate. In vivo studies on surgically induced bone defects in Sprague–Dawley rats signified the proper accelerated bone healing ability of D-ZIFI 1 over D-ZIFI 2. Results presented D-ZIFI 1 as a promising, effective, non-surgical approach for bone healing.

Preparation and characterization of 58S bioactive glass based scaffold with Kaempferol-containing Zein coating for bone tissue engineering

The aim of this study was to prepare a porous scaffold out of 58S bioactive glass as the bare and coated with Zein to improve mechanical properties and acting as a carrier for Kaempferol controlled delivery. Porosity and morphology, mechanical properties, drug release behavior, bioactivity, cell attachment, and biodegradation of the scaffolds were evaluated accordingly. Obtained results indicated that the scaffolds coated by (7wt/v %) Zein solution, showed the highest mechanical strength (3.06 ± 0.4 MPa) and desirable porous morphology. These scaffolds could support bioactivity, cell attachment, and provide sustained drug release in the safe range of Kaempferol concentration confirmed via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide analysis. Overall, this study showed that the Zein-coated scaffold possesses superior properties rather than bare scaffold, and the scaffolds coated with 7wt/v % Zein solution could be considered as appropriate scaffolds for bone regeneration.

Zein/Bioactive Glass Coatings with Controlled Degradation of Magnesium under Physiological Conditions: Designed for Orthopedic Implants

Magnesium and its alloys are widely considered as temporary bio-implants owing to their mechanical properties and biocompatibility. However, the high corrosion rates and degradation in the physiological environment restrict the practical application of Mg as a biomedical device. Therefore, in this study, Zein/45S5 bioactive glass (BG) coatings were deposited via electrophoretic deposition (EPD) on pretreated pure magnesium (Mg) substrates, which controls the rapid degradation of magnesium. The set of EPD parameters was first optimized on stainless steel (SS) and then the optimum EPD parameters were applied to obtain zein/BG composite coatings on Mg substrates. The morphology of the obtained coatings was studied by scanning electron microscopy (SEM). SEM results showed that both zein and BG were successfully deposited on the surface of the Mg substrate. Electrochemical measurements consisting of open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization confirmed that the corrosion resistance of Mg improved after the deposition of zein/BG coatings. The in-vitro bioactivity study was carried out by immersing the zein/BG coatings in simulated body fluid for 3, 7, and 21 days. SEM, energy dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy results elucidated that the hydroxyapatite layer developed after 21 days of immersion in SBF, which confirmed the bone binding ability of the coatings.