In vitro and in vivo evaluation of a ciprofloxacin delivery system based on poly(DLLA-co-GA-co-CL) for treatment of chronic osteomyelitis

Lactoferrin/pectin nanocomplex encapsulating ciprofloxacin and naringin as a lung targeting antibacterial nanoplatform with oxidative stress alleviating effect

Pseudomonas aeruginosa is an opportunistic Gram-negative bacterium with adaptive metabolic abilities. It can cause hospital-acquired infections with significant mortality rates, particularly in people with already existing medical conditions. Its ability to develop resistance to common antibiotics makes managing this type of infections very challenging. Furthermore, oxidative stress is a common consequence of bacterial infection and antibiotic therapy, due to formation of reactive oxygen species (ROS) during their mode of action. In this study we aimed to alleviate oxidative stress and enhance the antibacterial efficacy of ciprofloxacin (CPR) antibiotic by its co-encapsulation with naringin (NAR) within a polyelectrolyte complex (PEX). The PEX comprised of polycationic lactoferrin (LF) and polyanionic pectin (PEC). CPR/NAR-loaded PEX exhibited spherical shape with particle size of 237 ± 3.5 nm, negatively charged zeta potential (-23 ± 2.2 mV) and EE% of 61.2 ± 4.9 for CPR and 76.2 ± 3.4 % for NAR. The LF/PEC complex showed prolonged sequential release profile of CPR to limit bacterial expansion, followed by slow liberation of NAR, which mitigates excess ROS produced by CPR's mechanism of action without affecting its efficacy. Interestingly, this PEX demonstrated good hemocompatibility with no significant in vivo toxicity regarding hepatic and renal functions. In addition, infected mice administrated this nanoplatform intravenously exhibited significant CFU reduction in the lungs and kidneys, along with reduced immunoreactivity against myeloperoxidase. Moreover, this PEX was found to reduce the lungs´ oxidative stress via increasing both glutathione (GSH) and catalase (CAT) levels while lowering malondialdehyde (MDA). In conclusion, CPR/NAR-loaded PEX can offer a promising targeted lung delivery strategy while enhancing the therapeutic outcomes of CPR with reduced oxidative stress.

Formulation development, in vivo bioequivalence and pediatric PBPK modeling studies of taste-masked ciprofloxacin chewable tablets

A taste-masked chewable tablet of ciprofloxacin using ion exchange resin Kyron T-134 for enhancing compliance for the paediatric population was developed. The drug-to-resin ratio was optimized for maximum taste masking by studying the effects of soaking time (X1) and mixing time (X2) on complexation (%) using Central Composite Rotatable Design (CCRD). The resin complexes were characterized by bitterness score, DSC, FTIR, and PXRD. The complex was further formulated and optimized into chewable tablets through full factorial design, The optimized formulation was subjected to a bioequivalence study, and a virtual approach of PBPK modelling was adapted to predict the pharmacokinetics of the drug in the paediatric group. The drug resin ratio of 1:1.5 yielded an optimum drug loading of 99.05%. The optimized formulation shows minimum disintegration time with more than 99% drug release within 30 min. The formulation F-9 was found to be bioequivalent with a geometric mean ratio of Cmax, Tmax, AUC0-t, and AUC0-∞ within 90% CI. It was concluded that quality by design approach can successfully be applied to optimize the drug resin ratio and PBPK modeling is a successful predictive tool for estimating the pharmacokinetics of ciprofloxacin HCl in the paediatric population.

Current research progress of local drug delivery systems based on biodegradable polymers in treating chronic osteomyelitis

Chronic osteomyelitis is one of the most challenging diseases in orthopedic treatment. It is usually treated with intravenous antibiotics and debridement in clinical practice, which also brings systemic drug side effects and bone defects. The local drug delivery system of antibiotics has the characteristics of targeted slow release to the lesion site, replacing systemic antibiotics and reducing the toxic and side effects of drugs. It can also increase the local drug concentration, achieve sound bacteriostatic effects, and promote bone healing and formation. Currently, PMMA beads are used in treating chronic osteomyelitis at home and abroad, but the chain beads need to be removed after a second operation, inconveniences patients. Biodegradable materials have been extensively studied as optimal options for antibiotic encapsulation and delivery, bringing new hope for treating chronic osteomyelitis. This article reviews the research progress of local drug delivery systems based on biodegradable polymers, including natural and synthetic ones, in treating chronic osteomyelitis.

Individualized, Additively Manufactured Drug-Releasing External Ear Canal Implant for Prevention of Postoperative Restenosis: Development, In Vitro Testing, and Proof of Concept in an Individual Curative Trial

Postoperative restenosis in patients with external ear canal (EEC) atresia or stenosis is a common complication following canaloplasty. Our aim in this study was to explore the feasibility of using a three dimensionally (3D)-printed, patient-individualized, drug ((dexamethasone (DEX)), and ciprofloxacin (cipro))-releasing external ear canal implant (EECI) as a postoperative stent after canaloplasty. We designed and pre-clinically tested this novel implant for drug release (by high-performance liquid chromatography), biocompatibility (by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay), bio-efficacy (by the TNF-α (tumor necrosis factor-alpha)-reduction test (DEX) and inhibition zone test (for cipro)), and microbial contamination (formation of turbidity or sediments in culture medium). The EECI was implanted for the first time to one patient with a history of congenital EEC atresia and state after three canaloplasties due to EEC restenosis. The preclinical tests revealed no cytotoxic effect of the used materials; an antibacterial effect was verified against the bacteria Staphylococcus aureus and Pseudomonas aeruginosa, and the tested UV-irradiated EECI showed no microbiological contamination. Based on the test results, the combination of silicone with 1% DEX and 0.3% cipro was chosen to treat the patient. The EECI was implantable into the EEC; the postoperative follow-up visits revealed no otogenic symptoms or infections and the EECI was explanted three months postoperatively. Even at 12 months postoperatively, the EEC showed good epithelialization and patency. Here, we report the first ever clinical application of an individualized, drug-releasing, mechanically flexible implant and suggest that our novel EECI represents a safe and effective method for postoperatively stenting the reconstructed EEC.

Efficacy Evaluation of Ciprofloxacin-Loaded Poly (Trimethylene Carbonate) Implants in the Treatment of Chronic Osteomyelitis

In this study, poly (trimethylene carbonate) (PTMC) with excellent biocompatibility was synthesized via ring-opening of TMC to prepare the Ciprofloxacin-loaded PTMC implants, and antibacterial effects in vitro or in vivo of the resulting implants were investigated to evaluate the potential for treating chronic osteomyelitis. The in vitro results showed the Ciprofloxacin-loaded PTMC implants could sustain release ciprofloxacin at a release amount of about 90 μg/d for 28 days and possessed excellent antibacterial effect, as evidenced by the smaller size of the antibacterial ring of 32.6 ± 0.64 mm and the biofilm inhibition of 60% after 28 days of release. The in vivo results showed that after 28 days of treatment, the body weight and the white blood cell counts of chronic-osteomyelitis-model rats in the treatment group reached 381.6 ± 16.8 g and (7.86 ± 0.91) ×10⁹/L, respectively, returning to normal rapidly compared with the control and blank group, indicating the remarkable antibacterial effect of the Ciprofloxacin-loaded PTMC implants. X-ray images and HE staining results also confirmed that most of the proximal and middle parts of the tibia returned to typical structures and new and trabecular bone had been formed for the rats in the treatment group, and no inflammatory cells were found as compared to the control and blank groups, after 28 days of treatment. The significant lower number of colonies of (9.92 ± 1.56) × 10 CFU/g in the treatment group also suggests that the Ciprofloxacin-loaded PTMC implants achieve a practical antibacterial effect through a local application.

Recent Advances in the Evaluation of Antimicrobial Materials for Resolution of Orthopedic Implant-Associated Infections In Vivo

While orthopedic implant-associated infections are rare, revision surgeries resulting from infections incur considerable healthcare costs and represent a substantial research area clinically, in academia, and in industry. In recent years, there have been numerous advances in the development of antimicrobial strategies for the prevention and treatment of orthopedic implant-associated infections which offer promise to improve the limitations of existing delivery systems through local and controlled release of antimicrobial agents. Prior to translation to in vivo orthopedic implant-associated infection models, the properties (e.g., degradation, antimicrobial activity, biocompatibility) of the antimicrobial materials can be evaluated in subcutaneous implant in vivo models. The antimicrobial materials are then incorporated into in vivo implant models to evaluate the efficacy of using the material to prevent or treat implant-associated infections. Recent technological advances such as 3D-printing, bacterial genomic sequencing, and real-time in vivo imaging of infection and inflammation have contributed to the development of preclinical implant-associated infection models that more effectively recapitulate the clinical presentation of infections and improve the evaluation of antimicrobial materials. This Review highlights the advantages and limitations of antimicrobial materials used in conjunction with orthopedic implants for the prevention and treatment of orthopedic implant-associated infections and discusses how these materials are evaluated in preclinical in vivo models. This analysis serves as a resource for biomaterial researchers in the selection of an appropriate orthopedic implant-associated infection preclinical model to evaluate novel antimicrobial materials.