Natural rubber dressing loaded with silver sulfadiazine for the treatment of burn wounds infected with Candida spp.

Millions of people are burned worldwide every year and 265,000 of the cases are fatal. The development of burn treatment cannot consist only of the administration of a single drug. Due to the infection risk, antibiotics are used in conjunction with gels and damp bandages. In this work, an inexpensive curative based on silver sulfadiazine (SS) and natural rubber latex (NRL) was developed to treat burn wounds. It was produced by the casting method. The infrared spectrum presented no interaction between drug and biopolymer. At the same time, electronic micrographs showed that the SS crystals are inserted on the polymeric dressing surface. Mechanical properties after the drug incorporation were considered suitable for dermal application. About 32.4% of loaded SS was released in 192 h by the dressings that also inhibited the growth of Candida albicans and Candida parapsilosis at 75.0 and 37.5 µg·mL-1, respectively. The curative proved to be biocompatible when applied to fibroblast cells, in addition to enhancing cellular proliferation and, in the hemocompatibility test, no hemolytic effects were observed. The good results in mechanical, antifungal and biological assays, combined with the average bandage cost of $0.10, represent an exciting alternative for treating burn wounds.

Ibuprofen-loaded biocompatible latex membrane for drug release: Characterization and molecular modeling.

The incorporation of drugs and bioactive compounds in the natural rubber latex (NRL) matrix has been an alternative for the development of transdermal release membranes. Ibuprofen (IBF) is known to be used to treat inflammatory diseases, but when administered orally, high concentrations can cause some adverse problems. In this work, the incorporation of IBF in the NRL membranes was evaluated by physical-chemical, in vitro permeation, hemocompatibility and molecular modeling assays. In addition, the in vitro release profile of IBF in acid and basic media was analyzed during 96 h. The IBF-NRL membrane exhibited the absence of intermolecular bonding that could hinder drug release and presented compatible mechanical properties for applications as a cutaneous adhesive (0.58 and 1.12 MPa to Young's modulus and rupture tension, respectively). The IBF-NRL system did not present a significant hemolysis degree (1.67%) within 24 h. The release test indicated that in the first hours of the study, 48.5% IBF was released at basic pH and 22.5% at acidic pH, which is characteristic of a burst effect. Then, a stable release profile was observed until the end of the assay, with total IBF release of 60% in alkaline medium and 50% in acidic medium. The drug permeation results indicated that the IBF-NRL membranes can be used for the local skin treatment with permeation of 3.11% of IBF. Dynamic Molecular simulations indicated a pronounced electric dipole in the ionized form of IBF, which suggests a more effective interaction with water, explaining the efficient drug release in alkaline solutions. In general, the results demonstrate that the IBF-NRL membrane has great potential for a new adhesive that can be used for the treatment of inflammatory processes and injuries.

Gentamicin encapsulated within a biopolymer for the treatment of Staphylococcus aureus and Escherichia coli infected skin ulcers.

Skin wound infection requires carefully long-term treatment with an immense financial burden to healthcare systems worldwide. Various strategies such as drug delivery systems using polymer matrix from natural source have been used to enhance wound healing. Natural rubber latex (NRL) from Hevea brasiliensis has shown angiogenic and tissue repair properties. Gentamicin sulfate (GS) is a broad-spectrum antibiotic which inhibits the growth of a wide variety of microorganisms and, because of this, it has also been applied topically for treatment of local infections. The aim of this study was to develop a GS release system using NRL as matrix for Staphylococcus aureus and Escherichia coli infected skin ulcers treatment, without changing drug antibiotic properties. The matrix did not change the GS antimicrobial activity against S. aureus and E. coli strains. Moreover, the NRL-GS biomembrane did not exhibit hemolytic activity, being non-toxic to red blood cells. The eluates of NRL-GS biomembranes and GS solutions did not significantly reduce the survival of Caenorhabditis elegans worms for 24 h at any of the tested concentrations. Thus, these results emphasize that the NRL-GS biomembrane proved to be a promising biomaterial for future studies on the development of dressings for topical uses, inexpensive and practicable, keeping drug antibiotic properties against pathogens and to reduce the side effects.

Novel polymeric dressing to the treatment of infected chronic wound.

Natural rubber latex (NRL) is a natural polymer which has arisen large interest in the biomedical field, mostly, due to its ability to facilitate angiogenesis and therefore, tissue repair. Moxifloxacin (MXF) is a broad-spectrum antibiotic orally administrated. Considering the biological properties of the NRL and its ability to deliver a wide range of compounds, the present study aimed to develop a novel device for infected chronic wound treatment. MXF-loaded NRL was obtained by a casting method. The results demonstrated that the incorporation of MXF in NRL did not promote any molecular interaction, preserving the integrity of the compounds. The mechanical properties of the biomaterial did not show any significant change, indicating enough elasticity for dermal application. The microbiological assays confirmed the ability of the polymer to deliver the drug without influencing its pharmacological properties. Moreover, it has expressed activity against major bacterial strains presented in wound infections. Finally, the biomaterial shown biocompatibility from the in vitro study. Thus, the present work has shown that MXF-loaded NRL membrane is a promising biomaterial to infected wound treatment.