Development of a local antibiotic delivery system using fibrin glue

TEMPO-oxidized nanofibrillated cellulose as potential carrier for sustained antibacterial delivery

Designing a suitable, cost-effective nanocarrier with an ability to capture and deliver antibiotics for restricting microbial spread remains an unmet need. A simple two-stepped strategy involving citric acid-induced hydrolysis of cellulose pulp (NFC) followed by TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) mediated oxidation to obtain carboxylated nano fibrillated cellulose (TNFC-5) with high carboxyl content (1.12 mmol/g) has been explored. TNFC-5 so obtained was able to capture remarkable extent of antibiotics (drug loading (DL) > 40 % and entrapment efficiency (EE) >80 %) irrespective of their hydrophilicity as in, triclosan (hydrophobic) and ampicillin sodium (hydrophilic). In silico molecular docking study revealed the excess carboxyl content in nanocellulose imparted the strongest binding affinity to antibiotics via H-bonding. A slower and sustained release of triclosan was observed for TNFC-5 than that of NFC, reiterating the enhanced binding efficiency of the drugs with TNFC-5. Well-dispersed triclosan loaded TNFC-5 displayed sustained antibacterial activity against Escherichia coli and Staphylococcus aureus up to one week. Thus, TNFC-5 has been demonstrated as a green, cheap, and eco-friendly alternative to the other biodegradable nanocarriers for carrying antibiotics with high DL and EE, thereby reducing the wastage of expensive drugs while ensuring a sustained antibacterial effect. Our study established that the drug loaded nanofibers (TNFC-5) might act as a promising candidate to penetrate through biofilm for treating serious bacterial infections by retarding their growth and eventually eradicating bacterial colonies.

Vancomycin-Loaded Collagen/Hydroxyapatite Layers Electrospun on 3D Printed Titanium Implants Prevent Bone Destruction Associated with S. epidermidis Infection and Enhance Osseointegration

The aim of the study was to develop an orthopedic implant coating in the form of vancomycin-loaded collagen/hydroxyapatite layers (COLHA+V) that combine the ability to prevent bone infection with the ability to promote enhanced osseointegration. The ability to prevent bone infection was investigated employing a rat model that simulated the clinically relevant implant-related introduction of bacterial contamination to the bone during a surgical procedure using a clinical isolate of Staphylococcus epidermidis. The ability to enhance osseointegration was investigated employing a model of a minipig with terminated growth. Six weeks following implantation, the infected rat femurs treated with the implants without vancomycin (COLHA+S. epidermidis) exhibited the obvious destruction of cortical bone as evinced via a cortical bone porosity of up to 20% greater than that of the infected rat femurs treated with the implants containing vancomycin (COLHA+V+S. epidermidis) (3%) and the non-infected rat femurs (COLHA+V) (2%). The alteration of the bone structure of the infected COLHA+S. epidermidis group was further demonstrated by a 3% decrease in the average Ca/P molar ratio of the bone mineral. Finally, the determination of the concentration of vancomycin released into the blood stream indicated a negligible systemic load. Six months following implantation in the pigs, the quantified ratio of new bone indicated an improvement in osseointegration, with a two-fold bone ingrowth on the COLHA (47%) and COLHA+V (52%) compared to the control implants without a COLHA layer (27%). Therefore, it can be concluded that COLHA+V layers are able to significantly prevent the destruction of bone structure related to bacterial infection with a minimal systemic load and, simultaneously, enhance the rate of osseointegration.

In vitro evaluation of local antibiotic delivery via fibrin hydrogel

BACKGROUND/PURPOSE

Fibrin hydrogel is commonly used as hemostatic agent and scaffold but it is questionable for carrying antibiotics. Thus, this study aimed to investigate whether the fibrin hydrogel can be used to deliver the optimal concentration of ciprofloxacin against oral pathogen.

MATERIALS AND METHODS

The optimal concentration of ciprofloxacin was investigated from broth microdilution technique against three common oral bacteria. Ten times the bactericidal concentration of ciprofloxacin loaded to 0.4% fibrin hydrogel was observed by using a confocal laser scanning microscope and then was left in tris-buffer saline solution (TBS) for 0, 1, 12, 24, 72 and 168 h in parallel with the control group of ciprofloxacin loaded to 0.5% alginate hydrogel and ciprofloxacin solution. Spectrophotometer was used to analyze the accumulated drug release from the collected TBS, of which the measurement method was calibrated. The efficacy of the released ciprofloxacin was tested using an agar well diffusion assay. The inhibition zone of the released ciprofloxacin from fibrin hydrogel was statistically compared with 150 and 1500 μg/ml ciprofloxacin solution, while non-loaded fibrin hydrogel served as the control.

RESULTS

The results revealed that minimum inhibitory concentration was 1-2 μg/ml and minimum bactericidal concentration was 4-15 μg/ml. The fibrin hydrogel gradually released ciprofloxacin until 168 h while the alginate hydrogel immediately liberated all the loaded ciprofloxacin within an hour. The agar well diffusion significantly showed greater clear zone in fibrin hydrogel loaded ciprofloxacin compared to non-loaded fibrin hydrogel but not with ciprofloxacin in TBS.

CONCLUSION

The results suggested that fibrin hydrogel can be used for local ciprofloxacin delivery without interfering the efficacy of ciprofloxacin.

Percutaneous intratumoral injection of gemcitabine plus cisplatin mixed with fibrin glue for advanced pancreatic carcinoma: Case Report

RATIONALE

The aim of this study was to determine the effectiveness of intratumoral injection of chemotherapeutics in improving the quality of life and survival of patients with pancreatic carcinoma.

PATIENT CONCERNS

We present a case series of 5 patients with unresectable pancreatic adenocarcinoma.

DIAGNOSES

Patients diagnosed with unresectable poorly differentiated pancreatic ductal adenocarcinoma by intraoperative frozen biopsyor percutaneous biopsy.

INTERVENTIONS

Five patients with unresectable pancreatic adenocarcinoma received a computed tomography-guided percutaneous intratumoral injection of gemcitabine plus cisplatin mixed with fibrin glue.

OUTCOMES

Mean overall survival was 16.2 ± 3.7 months. Local control rates were 100% and 80% at postoperative 3 and 6 months, respectively. Mean Visual Analogue Scale pain score decreased from 7.2 ± .84 preoperatively to 2 ± 1.22 at postoperative 4 weeks. There were no complications associated with the procedure.

LESSONS

Percutaneous intratumoral injection of gemcitabine plus cisplatin mixed with fibrin glue for advanced pancreatic may be safe and effective.

Biomaterials approaches to treating implant-associated osteomyelitis

Orthopaedic devices are the most common surgical devices associated with implant-related infections and Staphylococcus aureus (S. aureus) is the most common causative pathogen in chronic bone infections (osteomyelitis). Treatment of these chronic bone infections often involves combinations of antibiotics given systemically and locally to the affected site via a biomaterial spacer. The gold standard biomaterial for local antibiotic delivery against osteomyelitis, poly(methyl methacrylate) (PMMA) bone cement, bears many limitations. Such shortcomings include limited antibiotic release, incompatibility with many antimicrobial agents, and the need for follow-up surgeries to remove the non-biodegradable cement before surgical reconstruction of the lost bone. Therefore, extensive research pursuits are targeting alternative, biodegradable materials to replace PMMA in osteomyelitis applications. Herein, we provide an overview of the primary clinical treatment strategies and emerging biodegradable materials that may be employed for management of implant-related osteomyelitis. We performed a systematic review of experimental biomaterials systems that have been evaluated for treating established S. aureus osteomyelitis in an animal model. Many experimental biomaterials were not decisively more efficacious for infection management than PMMA when delivering the same antibiotic. However, alternative biomaterials have reduced the number of follow-up surgeries, enhanced the antimicrobial efficacy by delivering agents that are incompatible with PMMA, and regenerated bone in an infected defect. Understanding the advantages, limitations, and potential for clinical translation of each biomaterial, along with the conditions under which it was evaluated (e.g. animal model), is critical for surgeons and researchers to navigate the plethora of options for local antibiotic delivery.

In vitro degradation and drug release of a biodegradable tissue adhesive based on functionalized 1,2-ethylene glycol bis(dilactic acid) and chitosan

Biodegradability and adhesive-associated local drug release are important aspects of research in tissue adhesive development. Therefore, this study focuses on investigating the in vitro degradation and drug release of a tissue adhesive consisting of hexamethylene diisocyanate functionalized 1,2-ethylene glycol bis(dilactic acid) and chitosan chloride. To prevent infections, ciprofloxacin hydrochloride (CPX·HCl) was incorporated into the adhesive. The influence of CPX·HCl on the adhesive reaction and adhesive strength was analyzed by FTIR-ATR-spectroscopy and tensile tests. The CPX·HCl release was investigated by HPLC. The degradation-induced changes at 37 °C were evaluated by gravimetric/morphological analyzes and micro-computer tomography. The antibiotic potential of the CPX·HCl loaded adhesive was determined by agar diffusion tests. The degradation tests revealed a mass loss of about 78 % after 52 weeks. The adhesive reaction velocity and tensile strength were not influenced by CPX·HCl. Using a 2 mg/g CPX·HCl loaded adhesive an inhibition of all tested bacteria was observed.

Injectable in situ forming drug delivery system for cancer chemotherapy using a novel tissue adhesive: Characterization and in vitro evaluation

Injectable polymers that are biocompatible and biodegradable are important biomaterials for drug delivery system (DDS) and tissue engineering. We have already developed novel tissue adhesives consisting of biomacromolecules and organic acid derivatives with active ester groups. The resulting tissue adhesive forms in situ as a gel and has high bonding strength for living tissue as well as it has good biocompatibility and biodegradability. Here, we report on the physicochemical properties and in vitro evaluation of this novel tissue adhesive consisting of human serum albumin (HSA) and tartaric acid derivative (TAD) containing doxorubicin hydrochloride (DOX). The results of the measurement of physicochemical characteristics indicate that the gelation time and gel strength of HSA-TAD gels can be controlled according to the material composition. The bonding strength of HSA-TAD adhesives was found to be sufficient to adhere at focus and to correspond with the cross-linking density of HSA-TAD gels. Furthermore, the release of DOX from HSA-TAD gels was sustained for approximately 100 h in an in vitro evaluation. The novel tissue adhesive, therefore, is expected to be applicable for use as an injectable in situ forming DDS.

Antitumor effect of an injectable in-situ forming drug delivery system composed of a novel tissue adhesive containing doxorubicin hydrochloride

Our group has developed a novel tissue adhesive composed of biomacromolecules and organic acid derivatives which have good biocompatibility and exhibit high bonding strength to living tissues. We propose to use this tissue adhesive for in-situ forming drug delivery system (DDS) for cancer chemotherapy. In a previous work, we had prepared a novel in-situ forming DDS composed of human serum albumin (HSA) and tartaric acid derivative (TAD) containing doxorubicin hydrochloride (DOX), and we had demonstrated an in vitro release profile of DOX from HSA-TAD gel for approximately up to 100h. Here, we report on antitumor effect of this injectable in-situ forming DDS. Local injection of DOX by the HSA-TAD was administered to human colon carcinoma (WiDr) implanted subcutaneously onto the immunodeficient mouse. The results of the in vivo experiments showed that the presence of DOX in blood of mice was detectable for up to 3days, and that the tumor volume was effectively minimized with injection of HSA-TAD containing DOX. The in-situ forming DDS with the novel tissue adhesive containing DOX, therefore, is a useful technique for cancer chemotherapy.

Drug delivery through the sclera: effects of thickness, hydration, and sustained release systems

The purpose of this study was to determine whether trans-scleral pressure affects scleral solute permeability by altering scleral thickness or hydration, and to investigate the sustained release delivery of dexamethasone. Scleral sections from donor human globes were mounted for in vitro flux studies. Scleral thickness and hydration were measured as functions of trans-scleral pressure. For the sustained release studies, 3H-dexamethasone in pluronic F-127 gel or in fibrin sealant was added to the episcleral side of the tissue and flux studies were performed. While scleral thickness showed a tendency to decrease with increasing pressure, a significant decrease in thickness was measured only at a trans-scleral pressure of 60 mmHg. No significant changes in scleral hydration were measured over the range of trans-scleral pressures studied. The apparent permeability constants (Ktrans) of human sclera for 3H-dexamethasone in BSS plus, fibrin sealant and F-127 gel were 11.5 x 10(-6), 7.3 x 10(-6), and 1.5 x 10(-6) cm sec(-1), respectively. Human scleral permeability to dexamethasone differed significantly among the three vehicles (p < 0.0001). Cumulative delivery of dexamethasone from BSS plus, F-127 gel, and fibrin sealant were 85.0, 29.3, and 67.9% at 20 hr, respectively. Scleral hydration was unaffected by trans-scleral pressures. Scleral thinning was only observed at 60 mmHg. Trans-scleral pressures below 60 mmHg would not be expected to significantly affect the permeability of the tissue to solutes in the size range of conventional drugs. F-127 gel and fibrin sealant provided a slow, relatively uniform sustained release through a 24 hr period. These systems might be employed to achieve sustained therapeutic levels of drugs to the posterior segment of eye.

Transscleral drug delivery for posterior segment disease

Exciting new treatments are being developed for retinal degenerations and posterior segment eye disease. The successful treatment of these visually devastating diseases will likely require delivering effective doses of pharmacologic agents to the posterior segment, possibly in conjunction with surgical or genetic interventions. Currently, the treatment of diseases affecting the posterior segment is limited by the difficulty in delivering effective doses of drugs to target tissues in the posterior vitreous, retina or choroid. This review summarizes recent laboratory and clinical studies that indicate that transscleral delivery of therapeutic solutes might be an effective means of achieving therapeutic concentrations of these agents in the posterior eye.

Fibrin encapsulated liposomes as protein delivery system. Studies on the in vitro release behavior

The efficacy of biologically active proteins in medical therapy depends on the development of suitable drug delivery systems. These delivery systems need to overcome the severe problems connected with the use of proteins such as their usually short half lives in body fluids and their susceptibility to proteolysis and denaturation. Our delivery system combines two widespread devices by encapsulating liposomes containing the model protein horseradish peroxidase (HRP) inside the biopolymer fibrin. The liposomes enable the protein to remain in its preferred aqueous environment and protect it during the polymerization process. Further encapsulation of the liposomes inside fibrin was carried out in order to achieve a depot system with sustained protein release. In vitro experiments showed that the protein filled liposomes were absolutely stable within the fibrin network. In contrast to 'free' HRP, enzyme entrapped in liposomes was completely retained by the fibrin network and wasn't released from the device unless the fibrin was degraded by plasmin.