Strontium-containing, carbohydrate-based polymer networks as tooth-adherent systems for the treatment of dentine hypersensitivity

Strontium nitrate-dopped zinc oxide-loaded alginate gels with gentamicin for improved wound healing

Wound dressing development is an area of active research. Traditional dressings lack antibacterial activity, biocompatibility, and tissue regeneration. Alginate is a heavily investigated polymer employed as wound dressings and can be combined with a wide range of additives. Herein, we report the preparation of alginate gel using the crosslinking technique as potential wound dressing, with insight investigation of the influence of employing single, two, or three cross-linkers: Strontium (Sr), zinc oxide (ZnO), and gentamicin sulfate. Rheology was used to confirm the gel's preparation, where the samples' viscosity curves show decreased viscosity with increased shear rate, indicating pseudoplastic flow. The linear viscoelastic region shows constant G' and G" within the sample structure. In this study, we used three gels with different mixtures of ingredients: Gels A, B, and C contain sodium alginate (1% w/v) and 0.5 mL of Sr nitrate (4% w/v). However, Gels B and C contain 0.25 mL of ZnO (0.5% w/v). Gel C also includes 0.1 mL of gentamicin (1% w/v). The study examined the effectiveness of Gel A, B, and C on wound healing, calculating the reduction of wound area after seven, 14, and 20 days of a single topical treatment. Gel A, B, and C significantly reduced wound area, while Gel B and C showed a significant reduction. The zone of inhibition was used to detect the gels' efficacy against microorganisms. The study found zinc deposition in the liver and bone, with Gel B and C showing higher levels. The study also found significant overexpression of MIP α and MIP β in tissues and downregulation of CCL2, IL8, and TGF β, explaining wound healing with minimal scar formation.

Drug release from hydroxypropylcellulose gels cannot be statistically predicted from their viscometric and initial viscoelastic properties

This study questioned whether rheological properties can predict drug (metronidazole) release from Hydroxypropylcellulose (HPC) platforms. Viscometric and viscoelastic properties of aqueous, alcohols/diols and mixed solvent HPC solutions and gels were determined using viscometry and oscillatory analysis. Drug release was conducted at pH 7.4 under sink conditions. Relationships between rheological parameters and drug release were modelled using multiple linear stepwise regression. Viscometry identified ethanol and water as good solvents for HPC. Diol solvents were predicted to exhibit greater interactions with HPC (COSMO modelling) but possessed lowest intrinsic viscosities. Pentanediol or ethylene glycol prepared gels exhibited greatest elasticity. No relationships were observed between dilute solution properties and initial gel viscoelasticity. Drug release from HPC gels occurred via gel erosion and diffusion. No relationships were observed between initial gel viscoelasticity and drug release and thus, for gel platforms that undergo erosion in aqueous media, drug release cannot be predicted from initial gel viscoelasticity.