No abstract

No abstract

To improve the solubility and bioavailability of oridonin (ORI), glycerol monooleate lipid (GMO)- or phytantriol (PYT)-Poloxamer 407-propylene glycol-water systems were firstly used to develop cubosomes containing ORI for oral delivery. These cubosomes prepared through the fragmentation of bulk gels under homogenization conditions of 1200 bar and nine cycles had a mean particle size of around 200 nm with narrow size distribution, and ORI encapsulation efficiency over 85%. Powder X-ray diffraction and differential scanning calorimetry indicated that ORI was in an amorphous or molecular form in the cubosomes. The internal structures of GMO- and PYT-based cubosomes were revealed by small-angle X-ray scattering as a bi-continuous cubic liquid crystalline phase with Im3m and Pn3m geometry, respectively. About 80% of ORI was released in vitro from GMO- and PYT-based cubosomes at 24 h, showing a sustained release kinetics fitted with Higuchi's equation. The pharmacokinetic study in rats showed that the PYT-based cubosomes significantly enhanced the adsorption of ORI as compared to the GMO-based cubosomes and ORI suspension, with evidence of longer half-life and greater relative bioavailability (p < 0.01). Therefore, the PYT-based cubosomes containing ORI might be proposed as a promising candidate carrier for the efficient delivery of drug with therapeutic treatment.

Periodontitis is a chronic bacterial infection, and its effective treatment is dependent on the retention of antibiotics of effective concentrations at the periodontal pockets. In this study, a solution-gel based inverse lyotropic liquid crystalline (LLC) system was explored to deliver metronidazole to the periodontal pockets for local treatment of periodontitis. It was found that the metronidazole-loaded LLC precursor spontaneously transformed into gel in the presence of water in the oral cavity. The low viscosity of the precursor would allow its penetration to the rather difficult to reach infection sites, while the adhesiveness and crystalline nanostructures (inverse bicontinuous cubic Pn3m phase and inverse hexagonal phase) of the formed gel would permit its firm adhesion to the periodontal pockets. The LLC system provided sustained drug release over one week in vitro. Results from in vivo study using a rabbit periodontitis model showed that the LLC system was able to maintain the metronidazole concentrations in the periodontal pockets above the minimum inhibition concentration for over 10 days without detectable drug concentration in the blood. Owing to the spontaneous solution-gel transition in the periodontal pockets and unique liquid crystalline nanostructures, the LLC in situ gel provided effective treatment of periodontitis for a prolonged period of time with reduced systematic side effects, compared to metronidazole suspension which was effective for 24 h with detectable metronidazole concentrations in the blood after 6 h.

No abstract

Lyotropic liquid crystals (LLC) have received increasing attention as a drug delivery system. In this study, a novel intra-canal disinfectant based on the glycerol monooleate (GMO) LLC precursor incorporation with chlorhexidine (CHX) and silver nanoparticles (Ag-NPs) was designed and evaluated. The LLC precursor with excellent fluidity was able to penetrate deeply into the complex tiny collateral branch root canals. The transformation of cubic LLC in root canals upon coming into contact with water provided long-lasting disinfection against multidrug-resistant bacteria to avoid the endodontic reinfection and follow-up visits. The GMO-ethanol-water (48% : 12% : 40%, w/w) formulation containing 0.5% CHX and 0.02% Ag-NPs was selected for further studies. The low viscosity of the precursor presented excellent injectability and flowabilities. From the in vitro release test, the release behaviours were found to be influenced by CHX and Ag-NP contents, allowing the optimized precursor to obtain a 28-day release profile. The CHX-Ag-NP containing LLC precursor exhibited an excellent and sustained sterilization effect on Enterococcus faecalis for more than one month with a bacterial inactivation rate of ≥98.5%, which was far more than the minimum clinical requirement (7 days). Furthermore, no in vitro toxicity was observed in the cytotoxicity evaluation. The CHX-Ag-NP containing LLC precursor was proved to be a promising intra-canal disinfectant in our study.

No abstract

This study develops a HA combined lyotropic liquid crystal based spray dressing loaded with pirfenidone for wound healing and scar prophylaxis.