The efficacy of sustained-release chitosan microspheres containing recombinant human parathyroid hormone on MRONJ

Abstract Treatment of patients with bisphosphonate usage is a significant concern for oral surgeons because it interferes with jaw bone turnover and regeneration. In case of adverse effects manifesting related to bisphosphonate use, oral surgeons are usually treating and keep the patient's symptoms under control. In this study, we aimed to investigate a new treatment protocol for medication-related osteonecrosis of the jaw (MRONJ). This treatment protocol consisted of administering human parathyroid hormone (hPTH) loaded chitosan microspheres which were prepared by ionotropic gelation method or/and the prepared microspheres were suspended in a poloxamer gel. After in-vitro optimization studies, the efficacy of the chosen formulations was evaluated in-vivo studies. Zoledronic acid was administered daily to forty-eight adult female Sprague-Dawley rats, divided into four experimental groups, at a daily concentration of 0.11 mg/kg over three weeks to induce the MRONJ model. At the end of this period, maxillary left molar teeth were extracted. In the first group, the subjects received no treatment. In the negative control group, poloxamer hydrogel containing empty microspheres were immediately applied to the soft tissues surrounding the extraction socket. The treatment group-1 was treated with local injections of poloxamer hydrogel containing hPTH. The treatment group-2 was treated with a single local injection of poloxamer hydrogel containing hPTH-loaded chitosan microspheres. Both treatment groups received a total of 7 µg of hPTH at the end of the treatment protocol. Our study demonstrates successful attenuation of MRONJ through a local drug delivery system combined with hPTH, as opposed to previously attempted treatment strategies.

Preparation, characterization and tableting of cilnidipine solid dispersions

Solid dispersion technique has been developed many years for improving solubility of water-insoluble drugs, aiming to achieve a better oral bioavailability. However, this technique exhibits many inconveniences when used for large-scale tableting procedures. The objective of current research work was to develop cilnidipine solid dispersions [SDs] to improve the dissolution behaviors of this water-insoluble drug. Moreover, an innovative granulation method was designed to simplify the traditional tableting technology used in solid dispersion technique. Three different kinds of polymers, polyethylene glycol [PEG], polyvinylpyrrolidone [PVP] and poloxamer, were used as carriers to prepare solid dispersions. The interactions in the solid state were characterized by differential scanning calorimetry [DSC], powder Xray diffraction [PXRD] and FT-IR spectroscopy. The designed granulation method was employed to prepare solid dispersion tablets and the formulation was optimized through investigating the dissolution behaviors. The results indicated PEG solid dispersion showed the best effect both on physical characterizations and dissolution studies. Furthermore, all type of solid dispersions significantly improved the dissolution rates when compared to pure drug and its corresponding physical mixture [PM]. The solid dispersion tablets prepared in simplified tableting method exhibited better operability, stability and dissolution behavior than the tablets prepared in traditional ways, which brought more opportunities to solid dispersion technique for industrial production