Dual effect biodegradable ciprofloxacin loaded implantable matrices for osteomyelitis: controlled release and osteointegration

Biodegradable Bone Implants as a New Hope to Reduce Device-Associated Infections-A Systematic Review

Bone fractures often require fixation devices that frequently need to be surgically removed. These temporary implants and procedures leave the patient more prone to developing medical device-associated infections, and osteomyelitis associated with trauma is a challenging complication for orthopedists. In recent years, biodegradable materials have gained great importance as temporary medical implant devices, avoiding removal surgery. The purpose of this systematic review was to revise the literature regarding the use of biodegradable bone implants in fracture healing and its impact on the reduction of implant-associated infections. The systematic review followed the PRISMA guidelines and was conducted by searching published studies regarding the in vivo use of biodegradable bone fixation implants and its antibacterial activity. From a total of 667 references, 23 studies were included based on inclusion and exclusion criteria. Biodegradable orthopedic implants of Mg-Cu, Mg-Zn, and Zn-Ag have shown antibacterial activity, especially in reducing infection burden by MRSA strains in vivo osteomyelitis models. Their ability to prevent and tackle implant-associated infections and to gradually degrade inside the body reduces the need for a second surgery for implant removal, with expectable gains regarding patients’ comfort. Further in vivo studies are mandatory to evaluate the efficiency of these antibacterial biodegradable materials.

Polymeric implants with drug-releasing capabilities: a mapping review of laboratory research

PURPOSE

To provide a systematic map of the nature and extent of preclinical research concerning drug-releasing polymeric implants.

SIGNIFICANCE

By summarizing available data, this mapping review can guide the development of new drug-delivery devices.

METHODS

In-vitro studies assessing drug-delivery implants were reviewed. A study protocol was registered at Open Science Framework. The association of polymers with prominent drugs, manufacturing processes, geometries, treatments, and anatomical locations was assessed using the VOSviewer software. The release periods were also evaluated.

RESULTS

A total of 423 articles, published between 1975 and 2020, were included and grouped into a framework with nine main categories. More than half of studies were published between 2010 and 2020. Among 201 individual polymers or combinations, the most investigated were PLGA, PCL, PLA, Silicone (SIL), EVA, and PU. Similarly, from 232 individual drugs or combinations, the most prominent were dexamethasone (DEX; anti-inflammatory), paclitaxel (PTX; anticancer), fluoruracil (anticancer), ciprofloxacin (CFX) hydrochloride (antibiotic), and gentamicin (GS; antibiotic). A total of 51 manufacturing processes were encountered, of which the most reported were solvent evaporation, compression molding (CM), extrusion (EX), electrospinning (ELS), and melt molding (MM). Among 38 implant geometries, cylinder (CIL) was the most prominent, followed by disk, square film, circular film (FCIR), and undefined film. Release times varied greatly, although the majority of articles ranged between 5 and 300 d.

CONCLUSIONS

Drug-delivery implants were highly heterogeneous due to its applicability for multiple health conditions. Most implants were made of PLGA and most drugs assessed presented anti-inflammatory, antibiotic, or anticancer effects. Solvent evaporation and CIL were the most prominent manufacturing process and geometry, respectively.

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

Chronic osteomyelitis causes serious injury to patients. Antibiotic delivery systems based on poly(lactide-co-glycolide) (PLGA) have great potential for treatment of chronic osteomyelitis. However, PLGA has a glass-transition temperature that is higher than physiological temperatures, resulting in a lack of flexibility for implantation into the bone marrow cavity. As an alternative, poly(d, l-lactide-co-glycolide-co-ε-caprolactone) (PLGC) presents good flexibility due to the introduction of poly(ε-caprolactone) segments. To develop a new strategy for treatment of chronic osteomyelitis, a ciprofloxacin delivery system was prepared using PLGC as carriers, the antibacterial effects of which were evaluated both in vivo and in vitro. The in vitro release behavior showed that the average release reached 268.5 μg/days on day 33, with a cumulative release rate of 56.01%. A bacteriostatic ring, with a diameter of 26.83 ± 0.83 mm, was produced by ciprofloxacin against Staphylococcus aureus after 30 days of release via our ciprofloxacin-PLGC system. After 4 weeks of treatment in vivo, chronic-osteomyelitis-model rats had a bodyweight of 385.83 ± 17.23 g and a normal white-blood-cell count, as well as a lower number of bacterial colonies per gram of bone tissue of (10.6 ± 3.0) × 10¹ CFU/g. Furthermore, no inflammatory cells were observed via hematoxylin-and-eosin staining, and normal bone structure was observed via X-ray. Taken together, our findings indicate that our novel ciprofloxacin-PLGC system yielded noteworthy antibacterial effects both in vitro and in vivo, suggesting that it may be useful for treating patients with chronic osteomyelitis.

Osteogenic Properties of Novel Methylsulfonylmethane-Coated Hydroxyapatite Scaffold

Despite numerous advantages of using porous hydroxyapatite (HAp) scaffolds in bone regeneration, the material is limited in terms of osteoinduction. In this study, the porous scaffold made from nanosized HAp was coated with different concentrations of osteoinductive aqueous methylsulfonylmethane (MSM) solution (2.5, 5, 10, and 20%) and the corresponding MH scaffolds were referred to as MH2.5, MH5, MH10, and MH20, respectively. The results showed that all MH scaffolds resulted in burst release of MSM for up to 7 d. Cellular experiments were conducted using MC3T3-E1 preosteoblast cells, which showed no significant difference between the MH2.5 scaffold and the control with respect to the rate of cell proliferation (p > 0.05). There was no significant difference between each group at day 4 for alkaline phosphatase (ALP) activity, though the MH2.5 group showed higher level of activity than other groups at day 10. Calcium deposition, using alizarin red staining, showed that cell mineralization was significantly higher in the MH2.5 scaffold than that in the HAp scaffold (p < 0.0001). This study indicated that the MH2.5 scaffold has potential for both osteoinduction and osteoconduction in bone regeneration.

Biopolymers as bone substitutes: a review

Human bones have unique structures and characteristics, and replacing a natural bone in the case of bone fracture or bone diseases is a very complicated problem. The main goal of this paper was to summarize the recent research on polymer materials as bone substitutes and for bone repair. Bone treatment methods, bone substitute materials as well as their advantages and drawbacks, and manufacturing methods were reviewed. Biopolymers are the most promising materials in the field of artificial bones and using biopolymers with the shape memory effect can improve the integration of an artificial bone into the human body by better mimicking the structure and properties of natural bones, decreasing the invasiveness of surgical procedures by producing deployable implants. It has been shown that the application of the rapid prototyping technology for artificial bones allows the customization of bone substitutes for a patient and the creation of artificial bones with a complex structure.

Effect of Polyethylene Glycol Content and Molar Mass on Injection Molding of Hydroxypropyl Methylcellulose Acetate Succinate-Based Gastroresistant Capsular Devices for Oral Drug Delivery

Capsular devices for oral drug delivery were recently proposed and manufactured by injection molding (IM) as an evolution of traditional reservoir systems comprising a core and a functional coating. IM allowed the fabrication of capsule shells with release-controlling features based on the employed materials and the design characteristics. These features are independent of the drug, with significant savings in development time and costs. In previous work, IM was used to produce enteric-soluble capsules from blends of hydroxypropyl methylcellulose acetate succinate, with polyethylene glycol (PEG) as the plasticizer. In this work, the range of plasticizer concentrations and molar mass was broadened to evaluate in-depth how those parameters affect material processability and capsule performance over time. As expected, increasing the amount of the low molar mass plasticizer decreased the viscosity and modulus of the material. This simplified the molding process and enhanced the mechanical resistance of the shell, as observed during assembly. However, some samples turned out translucent, depending on several factors including storage conditions. This was attributed to plasticizer migration issues. Such results indicate that higher molar mass PEGs, while not significantly impacting on processability, lead to capsular devices with consistent performance in the investigated time lapse.