Influence of the antiseptic agents polyhexanide and octenidine on FL cells and on healing of experimental superficial aseptic wounds in piglets. A double-blind, randomised, stratified, controlled, parallel-group study

Sterilized Polyhexanide-Releasing Chitosan Membranes with Potential for Use in Antimicrobial Wound Dressings

Wound infection is a common complication of chronic wounds. It can impair healing, which may not occur without external help. Antimicrobial dressings (AMDs) are a type of external help to infected chronic wounds. In this study, highly porous membranes made of only chitosan and containing the antiseptic polyhexanide (poly(hexamethylene biguanide); PHMB) were prepared by cryogelation, aiming to be used in AMDs. These membranes exhibited a water swelling capacity of 748%, a water drop penetration time of 11 s in a dry membrane and a water vapor transmission rate of 34,400 g H2O/m2/24 h when in contact with water. The best drug loading method involved simultaneous loading by soaking in a PHMB solution and sterilization by autoclaving, resulting in sterilized, drug-loaded membranes. When these membranes and a commercial PHMB-releasing AMD were assayed under the same conditions, albeit far from the in vivo conditions, their drug release kinetics were comparable, releasing PHMB for ca. 6 and 4 h, respectively. These membranes exhibited high antibacterial activity against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa, which are bacterial species commonly found in infected wounds and blood clotting activity. The obtained results suggest that these membranes may have potential for use in the development of AMDs.

A prospective study to analyse the concentration of octenidine in hand wounds after disinfection by LC-MS/MS

Toxic reactions can appear after pressurised flushing of soft tissue with octenidine (OCT) containing disinfectants. Their use for surgical disinfection could complicate the diagnosis of possible contamination. In patients with open lacerations of their hand's subcutaneous tissue samples were taken before and after surgical disinfection with Octenisept® and analysed by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). In 16 out of 20 tissue samples, OCT was detected after disinfection (lower limit of quantification (LLOQ)=10 pg/mL/mg). The concentration of OCT was below the LLOQ, estimation of mean of 0.6 pg/mL/mg (0.22-0.98 pg/mL/mg, 95%-CI) before disinfection and mean of 179.4 pg/mL/mg (13.35-432.0 pg/mL/mg, 95%-CI) after disinfection. This study shows that the disinfection of open wounds with Octenisept® leads to a quantifiable concentration of OCT in open wounds. In cases of suspected OCT-mediated toxic reaction, the use of antiseptics containing OCT should be avoided.

Prophylaxis of Ocular Infection in the Setting of Intraocular Surgery: Implications for Clinical Practice and Risk Management

In this review we discuss the role of intraocular surgery preoperative prophylaxis. The correct choice of antimicrobial drug is variable in each surgical setting, according to the available strengths of evidence, the anatomical district involved, and the type of procedure. In the ophthalmic surgical field, there has been a progressive shift from antibiotic formulations, which are known to cause antibiotic resistance, to a new class of antiseptic compounds, which proved to be effective not only against bacteria, but also against fungi, protozoa, and viruses. Among these, povidone-iodine (PVI) is a water-soluble polymer that can form a complex with iodine, and the perioperative application of PVI 5-10% eye drop for 3 min is the gold standard for infection prophylaxis. A new formulation of 0.6% PVI eye drop is a new option for infection prophylaxis in the days before surgery. Chlorhexidine is a biguanide compound, which is a valid alternative with a good safety and efficacy profile and is the antiseptic of choice in patients with iodine allergy. New compounds that are currently being studied include polyhexamethylene biguanide (PHMB), picloxydine, ozone, hypochlorous acid (HOCl), and Biosecur. PHMB is a biguanide polymer that was found to be more effective than PVI in in vitro studies for reducing microorganisms and extending the duration of antisepsis, but to date, there are no formulations available on the market for preoperative ocular surgery in which it is present as main ingredient. Ozone is a molecule with oxidizing effect, which showed interesting preliminary results but is not effective against virus, Staphylococcus aureus and Candida albicans. HOCl has a natural bactericidal propriety but its applicability to prophylaxis of ocular infection in the setting of ocular surgery is not established. Biosecur is a non-toxic organic alcohol-free compound that exhibited bactericidal and fungicidal effect versus all common microorganisms and is currently available as an ocular spray.

Povidone-Iodine Adverse Effects and Alternatives for Ocular Procedures

Purpose: Povidone-iodine (PVI), also known as Betadine, is a widely used antiseptic agent used in several fields of medicine. In ophthalmology, it is applied as a preoperative antiseptic to prevent infectious complications that can result from surgical procedures. PVI's safety and efficacy have been extensively studied and represented in the literature; however, the incidence of adverse effects has been reported in conjunction. The aim of this paper is to compile information regarding PVIs use, safety profile, adverse effects, and possible alternatives through a review of the existing literature. Methods: Literature was compiled utilizing the database PubMed and Google Scholar using specified keywords with a total of 86 reviewed articles, after excluding search results that did not meet the inclusion criteria. Results: While the allergic potential to PVI is a highly contested topic, there are several nonallergic adverse effects of PVI that should not be overlooked. These effects include chemical burn, cytotoxic effects, and general patient discomfort. In light of these adverse effects, alternatives to PVI may be considered. However, there has been little research identifying feasible alternatives in preoperative intraocular procedures. Alternatives including chlorhexidine, polyhexamethylene biguanide (polyhexanide), and octenidine were identified as potential substitutes for PVI. Conclusions: Further study is needed to provide robust evidence regarding the efficacy profiles of these alternatives in comparison with PVI and to demonstrate comparable tolerance to PVI in intraocular procedures.

Fabrication of collagen with polyhexamethylene biguanide: A potential scaffold for infected wounds

Bacterial infection remains a great challenge in wound healing, especially in chronic wounds. Multidrug-resistant organisms are increasing in acute and chronic wound infections, which compromise the chance of therapeutics. Resistance to conventional antibiotics has created an urge to study new approach/system that can effectively control wound infection and enhance healing. Wound cover/dressing must exhibit biocompatibility and effectiveness in reducing bioburden at the wound site. Collagen, a natural biopolymer, possesses advantages over synthetic and other natural materials due to its unique biological properties. It can act as an excellent wound dressing and controlled drug delivery system. Currently, antiseptic agents such as silver, iodine, and polyhexamethylene biguanide (PHMB)-incorporated scaffolds have become widely accepted in chronic wound healing. In this study, PHMB-incorporated collagen scaffold has been prepared and characterized using Fourier transform infrared spectroscopy (FTIR), circular dichroism (CD), and differential scanning calorimetry (DSC), which showed retention of collagen nativity and integration of PHMB. The scanning electron microscopy (SEM) analysis revealed the porous structures of scaffolds. The cytotoxicity analysis showed PHMB is nontoxic at the concentration of 0.01% (wt/wt). The agar diffusion test and bacterial adhesion study demonstrated the effectiveness of PHMB-incorporated collagen scaffold against both gram positive and negative strains. This study concludes that PHMB-incorporated collagen scaffold could have the potential for infected wound healing.

In Vitro Efficacy of Bacterial Cellulose Dressings Chemisorbed with Antiseptics against Biofilm Formed by Pathogens Isolated from Chronic Wounds

Local administration of antiseptics is required to prevent and fight against biofilm-based infections of chronic wounds. One of the methods used for delivering antiseptics to infected wounds is the application of dressings chemisorbed with antimicrobials. Dressings made of bacterial cellulose (BC) display several features, making them suitable for such a purpose. This work aimed to compare the activity of commonly used antiseptic molecules: octenidine, polyhexanide, povidone-iodine, chlorhexidine, ethacridine lactate, and hypochlorous solutions and to evaluate their usefulness as active substances of BC dressings against 48 bacterial strains (8 species) and 6 yeast strains (1 species). A silver dressing was applied as a control material of proven antimicrobial activity. The methodology applied included the assessment of minimal inhibitory concentrations (MIC) and minimal biofilm eradication concentration (MBEC), the modified disc-diffusion method, and the modified antibiofilm dressing activity measurement (A.D.A.M.) method. While in 96-well plate-based methods (MIC and MBEC assessment), the highest antimicrobial activity was recorded for chlorhexidine, in the modified disc-diffusion method and in the modified A.D.A.M test, povidone-iodine performed the best. In an in vitro setting simulating chronic wound conditions, BC dressings chemisorbed with polyhexanide, octenidine, or povidone-iodine displayed a similar or even higher antibiofilm activity than the control dressing containing silver molecules. If translated into clinical conditions, the obtained results suggest high applicability of BC dressings chemisorbed with antiseptics to eradicate biofilm from chronic wounds.

In Vitro Evaluation of Polihexanide, Octenidine and NaClO/HClO-Based Antiseptics against Biofilm Formed by Wound Pathogens

Chronic wounds complicated with biofilm formed by pathogens remain one of the most significant challenges of contemporary medicine. The application of topical antiseptic solutions against wound biofilm has been gaining increasing interest among clinical practitioners and scientific researchers. This paper compares the activity of polyhexanide-, octenidine- and hypochlorite/hypochlorous acid-based antiseptics against biofilm formed by clinical strains of Candida albicans, Staphylococcus aureus and Pseudomonas aeruginosa. The analyses included both standard techniques utilizing polystyrene plates and self-designed biocellulose-based models in which a biofilm formed by pathogens was formed on an elastic, fibrinous surface covered with a fibroblast layer. The obtained results show high antibiofilm activity of polihexanide- and octenidine-based antiseptics and lack or weak antibiofilm activity of hypochlorite-based antiseptic of total chlorine content equal to 80 parts per million. The data presented in this paper indicate that polihexanide- or octenidine-based antiseptics are highly useful in the treatment of biofilm, while hypochlorite-based antiseptics with low chlorine content may be applied for wound rinsing but not when specific antibiofilm activity is required.

Reduction of Postoperative Wound Infections by Antiseptica (RECIPE)?: A Randomized Controlled Trial

OBJECTIVE

To evaluate whether intraoperative subcutaneous wound irrigation with 0.04% polyhexanide can reduce surgical site infection (SSI) in elective laparotomies compared to saline.

BACKGROUND

SSI is a common complication after gastrointestinal surgery. To date, there is a lack of evidence whether subcutaneous wound irrigation is beneficial in terms of reduction of SSI.

METHODS

The RECIPE trial was an investigator initiated single-center, single-blind prospective, randomized controlled trial with 2 parallel treatment groups, comparing wound irrigation with 0.9% saline to antiseptic 0.04% polyhexanide solution in elective laparotomies. Primary endpoint was the rate of SSI within 30 days postoperatively according to Centers for Disease Control and Prevention criteria.

RESULTS

Between February 02, 2015, and May 23, 2018, 456 patients were randomly assigned to saline (n = 228) or polyhexanide (n = 228). Final cohort for analysis comprised 393 patients (202 in the saline and 191 in the polyhexanide group). Overall rate of SSI was 28.2%, n = 111. Simple analysis with cross tabulation revealed that significantly fewer SSIs occurred in the polyhexanide group: n = 70 (34.7%) versus n = 41 (21.5%); P = 0.004. In a multiple logistic regression model the factor wound irrigation with polyhexanide [odds ratio (OR) 0.44; 95% confidence interval (CI) 0.27-0.72; P = 0.001) was associated with risk reduction of SSI. Preoperative anemia (OR 2.08; 95% CI 1.27-3.40; P = 0.004) and more than 5 prior abdominal operations compared to none (OR 8.51; 95% CI 2.57-28.21; P < 0.001) were associated with SSI.

CONCLUSIONS

Intraoperative subcutaneous wound irrigation with antiseptic 0.04% polyhexanide solution is effective in reducing SSI after elective laparotomies.

Bacterial skin recolonization in the operating room: comparison between various antisepsis protocols

BACKGROUND

Surgical site infection (SSI) largely implicates the patient's endogenous skin microbiota. Perioperative disinfection protocols do not follow a general agreement.

AIM

To compare antisepsis and skin protection protocols on quantitative analysis of recolonization in the operating room at regular time-steps. The study hypothesis was that one protocol would be more effective than others.

METHODS

A single-centre prospective interventional study was conducted between January and June 2019. Healthy volunteers were randomized between protocols and served as their own controls. The protocols began ahead of scheduled orthopaedic surgery with a preoperative shower, mechanical cleansing, application of major antiseptics (alcoholic Bétadine™ 5% or alcoholic chlorhexidine 0.5%), sterile draping, then adhesive draping (3M™ Steri-Drape™ or iodine-impregnated 3M™ Ioban2™). Sampling was by swabbing in the operating room at 30 min intervals up to 90 min after draping. Cultures were performed under aerobic and anaerobic conditions. Qualitative and quantitative (cfu/mL) bacteriology was performed in the laboratory by direct reading on the blood agar plates.

FINDINGS

Thirty subjects were included; none was lost to follow-up or excluded from analysis. Bacterial load before manipulation (T0) was significantly higher in males (P < 0.0001) despite a significantly shorter shower-to-sampling interval (P = 0.03). Smoking (P = 0.85), body mass index (P = 0.38), and depilation (P = 0.50) did not significantly affect preoperative load. Mean load increased significantly under all protocols up to T90 min, without significant superiority for any one protocol. Associated Bétadine™/Ioban™ showed the lowest T90 load, and chlorhexidine alone the highest, but without significant difference. Isolates at T0 were predominantly healthy skin commensals: coagulase-negative staphylococci, micrococci, and coryneforms.

CONCLUSION

No one protocol demonstrated superiority, whether in immediate bactericidal action or in preventing skin recolonization in the operating room. Further studies are needed to define generally agreed protocols for SSI risk management.

Porous Poly(Hexamethylene Biguanide) Hydrochloride Loaded Silk Fibroin Sponges with Antibacterial Function

In order to endue silk fibroin (SF) sponges with antibacterial function, positively charged poly(hexamethylene biguanide) hydrochloride (PHMB) was incorporated in SF through electrostatic interaction and by freeze-drying technique. The influence of PHMB on the structure and antibacterial activities of SF sponges was investigated. The zeta potential of SF was increased significantly when PHMB was incorporated in SF. The pores with size from 80 to 300 µm and the microscale holes in the pore walls within PHMB-loaded SF sponges provided the channels of PHMB release. The PHMB loaded in the porous sponges showed continuous and slow release for up to 20 days. Effective growth inhibition of both Escherichia coli and Staphylococcus aureus was achieved when the mass ratio of PHMB/SF was higher than 2/100. These results suggest that the porous PHMB/SF sponges have the potential to be used as a novel wound dressing for open skin wounds.

Re-evaluation of polihexanide use in wound antisepsis in order to clarify ambiguities of two animal studies

OBJECTIVE

Due to classification of the agent polihexanide (PHMB) in category 2 'may cause cancer' by the Committee for Risk Assessment of the European Chemicals Agency in 2011, the users of wound antiseptics may be highly confused. In 2017, this statement was updated, defining PHMB up to 0.1% as a preservative safe in all cosmetic products. In the interest of patient safety, a scientific clarification of the potential carcinogenicity of PHMB is necessary.

METHODS

A multidisciplinary team (MDT) of microbiologists, surgeons, dermatologists and biochemists conducted a benefit-risk assessment to clarify the hazard of antiseptic use of PHMB.

RESULTS

In two animal studies, from which the assessment of a carcinogenic risk was derived, PHMB was administered orally over two years in extremely high concentrations far above the NO(A)EL (no-observed-(adverse-) effect level) in rats and mice. Feeding in the NO(A)EL range resulted in no abnormal effects. In one male in the highest dose group of 4000ppm PHMB, an adenocarcinoma was found, which the author attributed to chronic inflammation of the colon with systemic atypical exposure. The increasing incidence of hemangiosarcomas highly probably resulted from increased endothelial proliferation, triggered by the exceedingly high dosage fed, because PHMB is not genotoxic and there is no evidence for epigenetic effects.

DISCUSSION

It is well known that PHMB is not absorbed when applied topically. Considering the absence of genotoxicity and epigenetic effects together with the interpretation of the animal studies, it is the consensus of the multidisciplinary experts that a carcinogenic risk from PHMB-use for wound antisepsis can be ruled out.

CONCLUSION

On this basis and considering their effectiveness, tolerability and clinical evidence, the indications for PHMB based wound antiseptics are justified.

In vitro evaluation of the decontamination effect of cold atmospheric argon plasma on selected bacteria frequently encountered in small animal bite injuries

Beneficial effects of cold atmospheric argon plasma (CAAP) on wound healing and its capacity for bacterial decontamination has recently been documented. First, in vivo studies in small animals did not prove any decontamination effect in canine bite wounds. The present study evaluated the overall decontamination effect of CAAP for different bacteria frequently encountered in canine bite wounds with respect to growth phase, initial bacteria concentration and treatment duration. Standard strains of Escherichia (E.) coli, Staphylococcus (S.) pseudintermedius, S. aureus, Streptococcus (S.) canis, Pseudomonas (P.) aeruginosa and Pasteurella multocida were investigated. To evaluate the influence of the bacterial growth phase, each bacterium was incubated for three and eight hours, before CAAP treatment. Three different bacterial concentrations were created per bacterium and growth phase, and were exposed to CAAP for 30 s, 1 min and 2 min. CAAP treatment resulted in acceptable decontamination rates (range 98.9-99.9%) in all bacteria species in vitro; however, differences in susceptibility were detected. Decontamination rate was mainly influenced by initial bacterial concentration and treatment time. Growth phase only influenced decontamination in S. pseudintermedius. Treatment time significantly (P < .05) correlated with the decontamination rate in E. coli, S. canis and S. aureus, with an exposure time of 2 min being most effective. Initial bacterial concentration significantly (P < .05) influenced decontamination in Pasteurella multocida and P. aeruginosa, in which treatment time was not as important. CAAP exerts effective antibacterial activity against the tested bacteria strains in vitro, with species specific effects of treatment time, growth phase and concentration.

Three-dimensional human skin model infected with Staphylococcus aureus as a tool for evaluation of bioactivity and biocompatibility of antiseptics

In the light of pandemic spreads of multi-drug-resistant micro-organisms, alternative antimicrobial strategies to the use of antibiotics are the focus of research attention. As a prerequisite for medical application, the aim of this study was to develop a three-dimensional full skin infection model to evaluate the bioactivity and biocompatibility of antiseptics in application-relevant concentrations. A three-dimensional (3D) full skin model consisting of collagen-embedded fibroblasts as dermis and a fully differentiated epidermis built from keratinocytes was infected with Staphylococcus aureus. Infected skin models were treated for 24 h with the antiseptics polihexanide, octenidine dihydrochloride, chlorhexidine digluconate and povidone-iodine. Infection resulted in detrimental effects, a strong immune response with increased secretion of lactate dehydrogenase and pro-inflammatory cytokines, and increased gene expression of pro-inflammatory cytokines and antimicrobial peptides after 24 h. Application of antiseptics protected the skin models from damage due to S. aureus infection while demonstrating good biocompatibility. The best ratio of bioactivity to biocompatibility was observed for polihexanide. Polihexanide also enhanced the innate immune response by increasing the gene expression levels of antimicrobial peptides such as human β-defensin 2, human β-defensin 3, psoriasin and ribonuclease 7. The developed model provides an excellent tool to investigate the response of human cells to microbial infections in a complex 3D structure. Furthermore, the infection model is appropriate for evaluation of bioactivity and biocompatibility of antiseptics. As such, the model presented in this study is a promising approach to evaluate the mechanisms and effectiveness of new antimicrobial strategies.

Polyhexamethylene Biguanide:Polyurethane Blend Nanofibrous Membranes for Wound Infection Control

Polyhexamethylene biguanide (PHMB) is a broad-spectrum antiseptic which avoids many efficacy and toxicity problems associated with antimicrobials, in particular, it has a low risk of loss of susceptibility due to acquired antimicrobial resistance. Despite such advantages, PHMB is not widely used in wound care, suggesting more research is required to take full advantage of PHMB’s properties. We hypothesised that a nanofibre morphology would provide a gradual release of PHMB, prolonging the antimicrobial effects within the therapeutic window. PHMB:polyurethane (PU) electrospun nanofibre membranes were prepared with increasing PHMB concentrations, and the effects on antimicrobial activities, mechanical properties and host cell toxicity were compared. Overall, PHMB:PU membranes displayed a burst release of PHMB during the first hour following PBS immersion (50.5–95.9% of total released), followed by a gradual release over 120 h (≤25 wt % PHMB). The membranes were hydrophilic (83.7–53.3°), gradually gaining hydrophobicity as PHMB was released. They displayed superior antimicrobial activity, which extended past the initial release period, retained PU hyperelasticity regardless of PHMB concentration (collective tensile modulus of 5–35% PHMB:PU membranes, 3.56 ± 0.97 MPa; ultimate strain, >200%) and displayed minimal human cell toxicity (<25 wt % PHMB). With further development, PHMB:PU electrospun membranes may provide improved wound dressings.

The Antiseptic Octenidine Inhibits Langerhans Cell Activation and Modulates Cytokine Expression upon Superficial Wounding with Tape Stripping

Ideal agents for the topical treatment of skin wounds should have antimicrobial efficacy without negative influence on wound healing. Octenidine (OCT) has become a widely used antiseptic in professional wound care, but its influence on several components of the wound healing process remains unclear. In the present study, we have used a superficial wound model using tape stripping on human full-thickness skin ex vivo to investigate the influence of OCT on epidermal Langerhans cells (LCs) and cytokine secretion pattern of skin cells during wound healing in a model without disruption of the normal skin structure. Histological and immunofluorescence studies showed that OCT neither altered human skin architecture nor the viability of skin cells upon 48 hours of culture in unwounded or wounded skin. The epidermis of explants and LCs remained morphologically intact throughout the whole culture period upon OCT treatment. OCT inhibited the upregulation of the maturation marker CD83 on LCs and prevented their emigration in wounded skin. Furthermore, OCT reduced both pro- and anti-inflammatory mediators (IL-8, IL-33, and IL-10), while angiogenesis and growth factor mediators (VEGF and TGF-β1) remained unchanged in skin explant cultures. Our data provide novel insights into the host response to OCT in the biologically relevant environment of viable human (wounded) skin.

Betulin wound gel accelerated healing of superficial partial thickness burns: Results of a randomized, intra-individually controlled, phase III trial with 12-months follow-up

OBJECTIVE

Acceleration of wound healing promises advantages for patients and caregivers in reducing the burden of disease, avoiding complications such as wound infections, and improving the long-term outcome. However, medicines that can accelerate wound healing are lacking. The objective of this open, blindly evaluated, randomized, multicenter phase III study was to compare intra-individually the efficacy and tolerability of Oleogel-S10 with fatty gauze dressing versus Octenilin^® wound gel with fatty gauze dressing in accelerating the healing of superficial partial thickness burn wounds.

METHODS

Acute superficial partial thickness burn wounds in adults caused by fire, heat burn or scalding were divided into 2 halves and randomly assigned to treatment with Oleogel-S10 or Octenilin^® wound gel. Photos for observer-blinded analysis of wound healing were taken at each wound dressing change. Percentages of reepithelialization were assessed at defined intervals. Efficacy and tolerability were evaluated based on a 5-point Likert scale.

RESULTS

Of 61 patients that were enrolled, 57 received the allocated intervention and 48 completed treatment. The percentage of patients with earlier wound healing was significantly higher for Oleogel-S10 (85.7%, n=30) compared to Octenilin^® wound gel (14.3%, n=5, p<0.0001). The mean intra-individual difference in time to wound closure was -1.0 day in favour of Oleogel-S10 (-1.4, -0.6; 95% CI, p<0.0001). Most investigators (87.0%) and patients (84.8%) evaluated the efficacy of Oleogel-S10 to be 'better' or 'much better' than that of Octenilin^® wound gel. Long-term outcome 3 months and 12 months post injury was improved in some patients.

CONCLUSIONS

Oleogel-S10 (Episalvan) significantly accelerated the healing of superficial partial thickness burn wounds. It was safe and well tolerated.

Irritative potency of selected wound antiseptics in the hen's egg test on chorioallantoic membrane to predict their compatibility to wounds

Antiseptics are being used for prevention of infections in acute wounds and for treatment of infections in acute and chronic wounds. However, some antiseptics' high tissue toxicity might delay the healing process. The aim of this study was to investigate the tissue toxicity of preferentially used wound antiseptics and the influence of antiphlogistic additives via the hen's egg test on the chorioallantoic membrane (HET-CAM). The HET-CAM is a semi-in-vivo method testing the tissue tolerability of wound antiseptics by evaluating the blood vessel reaction of the chorioallantoic membrane in terms of hemorrhage, vessel lysis, and coagulation. For each test day, selected test substances were applied on the membranes of two to three eggs according to the test protocol. The overall irritation was then evaluated by referring to a calculated score. Normal distribution of the resulting scores was confirmed by D'Agostino-Pearson omnibus K2 test. Significant differences between the antiseptics were calculated by Tukey's multiple comparisons test. Severe CAM reactions were observed after short-term application of octenidine based wound gel (0.05%) and chlorhexidine digluconate (0.5% solution), moderate reactions for octenidine (0.05%) in aqueous solution combined with dexpanthenol (1.34%) and allantoin (0.2%) or for hydrogen peroxide (1.5% and 0.5%) in aqueous solution, slight reactions were observed for hydrogen peroxide (1.5%) in aqueous solution in combination with sodium thiocyanate (0.698%) and for the combination of NaOCl/HOCl (each 0.004%). Polyhexanide (0.04%) in Ringer solution and polyhexanide (0.05%) in Lipofundin, the hemoglobin spray (10%), dexpanthenol, and allantoin showed no irritation. The HET-CAM qualifies as a primary screening test for tissue tolerance of wound antiseptics. Regarding local tolerability, polyhexanide and hypochlorite are superior to other antiseptics.

Consensus on Wound Antisepsis: Update 2018

Wound antisepsis has undergone a renaissance due to the introduction of highly effective wound-compatible antimicrobial agents and the spread of multidrug-resistant organisms (MDROs). However, a strict indication must be set for the application of these agents. An infected or critically colonized wound must be treated antiseptically. In addition, systemic antibiotic therapy is required in case the infection spreads. If applied preventively, the Wounds-at-Risk Score allows an assessment of the risk for infection and thus appropriateness of the indication. The content of this updated consensus recommendation still largely consists of discussing properties of octenidine dihydrochloride (OCT), polihexanide, and iodophores. The evaluations of hypochlorite, taurolidine, and silver ions have been updated. For critically colonized and infected chronic wounds as well as for burns, polihexanide is classified as the active agent of choice. The combination 0.1% OCT/phenoxyethanol (PE) solution is suitable for acute, contaminated, and traumatic wounds, including MRSA-colonized wounds due to its deep action. For chronic wounds, preparations with 0.05% OCT are preferable. For bite, stab/puncture, and gunshot wounds, polyvinylpyrrolidone (PVP)-iodine is the first choice, while polihexanide and hypochlorite are superior to PVP-iodine for the treatment of contaminated acute and chronic wounds. For the decolonization of wounds colonized or infected with MDROs, the combination of OCT/PE is preferred. For peritoneal rinsing or rinsing of other cavities with a lack of drainage potential as well as the risk of central nervous system exposure, hypochlorite is the superior active agent. Silver-sulfadiazine is classified as dispensable, while dyes, organic mercury compounds, and hydrogen peroxide alone are classified as obsolete. As promising prospects, acetic acid, the combination of negative pressure wound therapy with the instillation of antiseptics (NPWTi), and cold atmospheric plasma are also subjects of this assessment.

Effect of antiseptic irrigation on infection rates of traumatic soft tissue wounds: a longitudinal cohort study

OBJECTIVE

Acute traumatic wounds are contaminated with bacteria and therefore an infection risk. Antiseptic wound irrigation before surgical intervention is routinely performed for contaminated wounds. However, a broad variety of different irrigation solutions are in use. The aim of this retrospective, non-randomised, controlled longitudinal cohort study was to assess the preventive effect of four different irrigation solutions before surgical treatment, on wound infection in traumatic soft tissue wounds.

METHOD

Over a period of three decades, the prophylactic application of wound irrigation was studied in patients with contaminated traumatic wounds requiring surgical treatment, with or without primary wound closure. The main outcome measure was development of wound infection. From 1974-1983, either 0.04 % polihexanide (PHMB), 1 % povidone-iodine (PVP-I), 4 % hydrogen peroxide, or undiluted Ringer's solution were concurrently in use. From 1984-1996, only 0.04 % PHMB or 1 % PVP-I were applied. From 1997, 0.04 % PHMB was used until the end of the study period in 2005.

RESULTS

The combined rate for superficial and deep wound infection was 1.7 % in the 0.04 % PHMB group (n=3264), 4.8 % in the 1 % PVP-I group (n=2552), 5.9 % in the Ringer's group (n=645), and 11.7 % in the 4 % hydrogen peroxide group (n=643). Compared with all other treatment arms, PHMB showed the highest efficacy in preventing infection in traumatic soft tissue wounds (p<0.001). However, compared with PVP-I, the difference was only significant for superficial infections.

CONCLUSION

The large patient numbers in this study demonstrated a robust superiority of 0.04 % PHMB to prevent infection in traumatic soft tissue wounds. These retrospective results may further provide important information as the basis for power calculations for the urgently needed prospective clinical trials in the evolving field of wound antisepsis.

Antibacterial activity of polihexanide formulations in a co-culture of HaCaT keratinocytes and Staphylococcus aureus and at different pH levels

Complex stalled wounds feature an alkaline milieu that favors tissue destruction and microbial growth. The presence of bacteria in turn perpetuates the inflammatory response. However, only limited knowledge exists of pH dependency on the antibacterial efficacy of polyhexamethylene biguanide (PHMB) or the influence of surfactants or delivery vehicle used in antiseptic formulations. So far, PHMB alone has been shown to protect the keratinocytes from bacterial damage in such a co-culture system as well as exhibiting increased antimicrobial activity at higher pH values. Here, the interaction of PHMB with the surfactants macrogolum and undecylenamidopropyl betaine that are most commonly used as additives in antiseptics and rinsing solutions such as Lavasept and Prontosan has been explored in addition to the PHMB-containing biocellulose dressing Suprasorb X + PHMB. Undecylenamidopropyl betaine was found to lower the antimicrobial activity of polihexanide in the co-culture system, while macrogolum and the biocellulose increased polihexanide efficiency to reduce Staphylococcus aureus especially in the presence of serum. The increasing antibacterial efficacy of PHMB with rising pH was not altered by undecylenamidopropyl betaine, macrogolum, or the biocellulose. The results suggest that application of PHMB with macrogolum or by delivery through a biocellulose dressing might be advantageous for management of wound infections.

Effectiveness of a polyhexanide irrigation solution on methicillin-resistant Staphylococcus aureus biofilms in a porcine wound model

Irrigation and removal of necrotic debris can be beneficial for proper healing. It is becoming increasingly evident that wounds colonized with biofilm forming bacteria, such as Staphylococcus aureus (SA), can be more difficult to eradicate. Here we report our findings of the effects of an irrigation solution containing propyl-betaine and polyhexanide (PHMB) on methicillin-resistant Staphylococcus aureus (MRSA) biofilms in a porcine wound model. Thirty-nine deep partial thickness wounds were created with six wounds assigned to one of six treatment groups: (i) PHMB, (ii) Ringer's solution, (iii) hypochlorous acid/sodium hypochlorite, (iv) sterile water, (v) octenidine dihydrochloride, and (vi) octenilin. Wounds were inoculated with MRSA and covered with a polyurethane dressing for 24 hours to allow biofilm formation. The dressings were then removed and the wounds were irrigated twice daily for 3 days with the appropriate solution. MRSA from four wounds were recovered from each treatment group at 3 days and 6 days hours after initial treatment. Irrigation of wounds with the PHMB solution resulted in 97·85% and 99·64% reductions of MRSA at the respective 3 days and 6 days assessment times when compared to the untreated group. Both of these reductions were statistically significant compared to all other treatment groups (P values <0·05).

Toxicological assessment of polyhexamethylene biguanide for water treatment

Polyhexamethylene biguanide (PHMB) is an antiseptic with antiviral and antibacterial properties used in a variety of products including wound care dressings, contact lens cleaning solutions, perioperative cleansing products, and swimming pool cleaners. There are regulatory concerns with regard to its safety in humans for water treatment. We decided to assess the safety of this chemical in Sprague-Dawley rats. PHMB was administered in a single dose by gavage via a stomach tube as per the manufacturer's instruction within a dose range of 2 mg/kg to 40 mg/kg. Subchronic toxicity studies were also conducted at doses of 2 mg/kg, 8 mg/kg and 32 mg/kg body weight and hematological, biochemical and histopathological findings of the major organs were assessed. Administration of a dose of 25.6 mg/kg, i.e. 1.6 mL of 0.4% PHMB solution (equivalent to 6.4x10(3) mg/L of 0.1% solution) resulted in 50% mortality. Histopathological analysis in the acute toxicity studies showed that no histopathological lesions were observed in the heart and kidney samples but 30% of the animals had mild hydropic changes in zone 1 of their liver samples, while at a dosage of 32 mg/kg in the subchronic toxicity studies, 50% of the animals showed either mild hepatocyte cytolysis with or without lymphocyte infiltration and feathery degeneration. Lymphocyte infiltration was, for the first time, observed in one heart sample, whereas one kidney sample showed mild tubular damage. The acute studies showed that the median lethal dose (LD50) is 25.6 mg/kg (LC50 of 1.6 mL of 0.4% PHMB. Subchronic toxicological studies also revealed few deleterious effects on the internal organs examined, as seen from the results of the biochemical parameters evaluated. These results have implications for the use of PHMB to make water potable.

Pulp tissue dissolution capacity of QMix 2in1 irrigation solution

OBJECTIVE

The aim of this study was to evaluate the tissue dissolution efficacy of four root canal irrigation solutions (sodium hypochlorite [NaOCl], chlorhexidine gluconate [CHX], Octenidine [OCT], and QMix 2in1) on bovine pulp tissue.

MATERIALS AND METHODS

Fifty bovine pulp tissue samples, each weighing 6.55 mg, were prepared and randomly divided into four experimental groups and one control group (n = 10) according to the dissolution irrigants used: (1) 5.25% NaOCl group; (2) 2% CHX group; (3) OCT group; (4) QMix 2in1 group; and (5) control group (saline solution). These samples were then placed into special bovine dentin reservoir models and immersed for 1 h with each test solution (0.1 mL of each) at room temperature. The pulp samples were then blotted dry and weighed again. The percentage of weight loss was calculated. Statistically analyzed with one-way analysis of variance and post-hoc Tukey tests (P = 0.05).

RESULTS

Saline solution did not dissolve the bovine pulp tissue. All groups, except OCT, dissolved pulp samples more effectively than the control group (P < 0.05). The highest tissue dissolution was observed in 5.25% NaOCl group (P < 0.05). No statistically significant difference was found between the tissue-dissolving effect between QMix 2in1 and those of 2% CHX.

CONCLUSIONS

Within the limitations of this in vitro study, NaOCl exhibited the best tissue-dissolving effect out of all solutions tested. CHX and QMix 2in1 were able to dissolve pulp tissue but less than NaOCl. OCT and saline solutions could not exhibit significantly tissue-dissolving effectiveness. This study shown that QMix 2in1 has little capacity to dissolve pulp tissue therefore used alone is not sufficient for this purpose.

Antimicrobial functionalization of bacterial nanocellulose by loading with polihexanide and povidone-iodine

Bacterial nanocellulose (BNC) is chemically identical with plant cellulose but free of byproducts like lignin, pectin, and hemicelluloses, featuring a unique reticulate network of fine fibers. BNC sheets are mostly obtained by static cultivation. Now, a Horizontal Lift Reactor may provide a cost efficient method for mass production. This is of particular interest as BNC features several properties of an ideal wound dressing although it exhibits no bactericidal activity. Therefore, BNC was functionalized with the antiseptics povidone-iodine (PI) and polihexanide (PHMB). Drug loading and release, mechanical characteristics, biocompatibility, and antimicrobial efficacy were investigated. Antiseptics release was based on diffusion and swelling according to Ritger-Peppas equation. PI-loaded BNC demonstrated a delayed release compared to PHMB due to a high molar drug mass and structural changes induced by PI insertion into BNC that also increased the compressive strength of BNC samples. Biological assays demonstrated high biocompatibility of PI-loaded BNC in human keratinocytes but a distinctly lower antimicrobial activity against Staphylococcus aureus compared to PHMB-loaded BNC. Overall, BNC loaded with PHMB demonstrated a better therapeutic window. Moreover, compressive and tensile strength were not changed by incorporation of PHMB into BNC, and solidity during loading and release could be confirmed.

[Severe complications after non-intended usage of octenidine dihydrochloride. A case series with four dogs]

OBJECTIVE

Case series of four dogs in which extensive bite wounds had been treated using octenidine dihydrochloride (Octenivet® or Octenisept®) flushing. The dogs subsequently developed severe local complications.

MATERIAL AND METHODS

Retrospective evaluation of clinical symptoms, diagnostics, therapy and course of the disease.

RESULTS

In four dogs, severe necrosis and persistent edematous changes of the treated area developed after the application of octenidine dihydrochloride. The clinical course was comparable to complications described previously in human medicine. Therapy was protracted and complicated by secondary wound infection.

CONCLUSION AND CLINICAL RELEVANCE

Irrigation of deep wounds, particularly bite wounds, using octenidine dihydrochloride without drainage may lead to persistent edematous changes, inflammatory reactions and necrosis. The inappropriate application of octenidine dihydrochloride for wound irrigation should be avoided in veterinary medicine.

Cell growth and migration under octenidine-antiseptic treatment

OBJECTIVE

The toxicity of octenidine antiseptics in cultured cells contrasts their good tolerability in tissue. This phenomenon prompted us to examine which cell culture conditions allow survival and proliferation and to investigate a possible modulation of toxicity by the extracellular matrix proteoglycan chondroitin sulfate.

METHOD

We tested fibroblasts and MCF7 cells for growth using the MTT test, and assessed wound healing potency with a laceration assay. Expression levels of the genes involved in controlling wound healing were assessed with RT-PCR.

RESULTS

A 24 hour exposure to the octenidine-based solution was found incompatible with cell growth. When octenidine solution (0.5-0.5mg/l) was coated on dishes, growth was profoundly reduced after 24 hours, however there was no cytotoxic effect at 0.012 mg/l. Interestingly, when dishes were first coated with chondroitin sulfate the cytotoxicity of octenidine-based solution was modulated. Cell migration was not inhibited by octenidine-based solution treatment (2 minutes; 15 mg/l). No significant changes in gene expression levels in response to the octenidine-based solution treatment were detected.

CONCLUSION

In cell culture conditions application of the octenidine-based solution without toxicity can be observed, comparable to the minimal application required to give full bactericidal effect. Alteration of toxicity by interaction with chondroitin sulfate in cell culture suggests a similar function for extraceullar matrix in intact tissue.

Clinical use of cold atmospheric pressure argon plasma in chronic leg ulcers: A pilot study

OBJECTIVE

In the age of multiresistant microbes and the increasing lack of efficient antibiotics, conventional antiseptics play a critical role in the prevention and therapy of wound infections. Recent studies have demonstrated the antiseptic effects of cold atmospheric pressure plasma (APP). In this pilot, study we investigate the overall suitability of one of the first APP sources for wound treatment focusing on its potential antimicrobial effects.

METHOD

The wound closure rate and the bacterial colonisation of the wounds were investigated. Patients suffering from chronic leg ulcers were treated in a clinical controlled monocentric trial with either APP or octenidine (OCT). In patients who presented with more than one ulceration in different locations, one was treated with APP and the other one with OCT. Each group was treated three times a week over a period of two weeks. The antimicrobial efficacy was evaluated immediately after and following two weeks of treatment.

RESULTS

Wounds treated with OCT showed a significantly higher microbial reduction (64%) compared to wounds treated with APP (47%) immediately after the treatment. Over two weeks of antiseptic treatment the bacterial density was reduced within the OCT group (-35%) compared to a slight increase in bacterial density in the APP-treated group (+12%). Clinically, there were no signs of delayed wound healing observed in either group and both treatments were well tolerated.

CONCLUSION

The immediate antimicrobial effects of the APP prototype source were almost comparable to OCT without any signs of cytotoxicity. This pilot study is limited by current configurations of the plasma source, where the narrow plasma beam made it difficult to cover larger wound surface areas and in order to avoid untreated areas of the wound bed, smaller wounds were assigned to the APP-treatment group. This limits the significance of AAP-related effects on the wound healing dynamics, as smaller wounds tend to heal faster than larger wounds. However, clinical wound healing studies on a larger scale now seem justifiable. A more advanced plasma source prototype allowing the treatment of larger wounds will address APP's influence on healing dynamics, synergetic treatment with current antiseptics and effects on multiresistant bacteria.

Evaluation of angiogenesis, epithelialisation and microcirculation after application of polyhexanide, chitosan and sodium chloride in rodents

The purpose of this study was to investigate the effect of polyhexanide and a new developed chitin-based wound dressing on skin microcirculation, epithelialisation and angiogenesis. A full-thickness dermal layer extending to the underlying cartilage was excised on the dorsal side of hairless mice (n = 27; 2·3 ± 0·3 mm² ). A polyhexanide ointment, a chitosan solution and a sodium chloride group as control were analysed using intravital fluorescence microscopy. Angiogenesis, epithelialisation and microcirculatory standard parameters were measured over a time period of 20 days. The non-perfused area is regarded as a parameter for angiogenesis and showed the following results: on days 12, 16 and 20, the sodium chloride group was significantly superior to chitosan solution (P < 0·05) and, on days 8, 12, 16 and 20, the polyhexanide group was superior to chitosan solution (P < 0·05). The epithelialisation was measured significantly faster in the polyhexanide and control group on day 8 versus chitosan solution. Whereas polyhexanide and sodium chloride were nearly completely epithelialised, treatment with chitosan solution showed still an open wound of 11% of the initial wound size. Altogether, we could demonstrate the advantageous effects of a polyhexanide ointment on microcirculation, angiogenesis and epithelialisation. Chitosan solution appears to inhibit angiogenesis and delays epithelialisation. Further studies in different models would be worthwhile to confirm these results.

Antimicrobial and antiseptic strategies in wound management

Wounds, especially chronic wounds, represent a global problem costing millions of dollars per year in developed countries and are characterised by microbial complications including local or overt infection, delayed healing and spread of multiresistant germs. Therefore, antimicrobial wound management is a major challenge that continues to require new solutions against microbes and their biofilms. As systemic antibiotics can barely penetrate into wound biofilms and topically applied ones can easily lead to sensitisation, antisepsis is the method of choice to treat germs in wounds. This brief review discusses the role of antiseptics in reducing bioburden in chronic wounds. Balancing antimicrobial potency and tolerability of antiseptic procedures is critical in wound therapy. However, antiseptics alone may not be able to achieve wound healing without addressing other factors regarding the patient's general health or the wound's physical environment. Although the precise role of bioburden in chronic wounds remains to be evaluated, planktonic as well as biofilm-bound microbes are indications for antiseptic intervention. Octenidine dihydrochloride and polyhexanide are the most effective, as well as best tolerated, antiseptics in wound management today, and new strategies to reduce bacterial wound burden and support the body's immune response are being developed.

Polyhexanide-containing solution reduces ciliary beat frequency of human nasal epithelial cells in vitro

In ENT, polyhexanide-containing solutions are used to treat nasal infections caused by multiresistant bacteria like methicillin-resistant Staphylococcus aureus. Many forms of commercial nasal solutions containing polyhexanide exist, such as gels or solutions for topical use. Data regarding the influence of polyhexanide on ciliary beat frequency (CBF) are lacking to date. We tested the CBF of nasal ciliated epithelial cells under the influence of a commercially available polyhexanide-containing solution (Lavasept(®) Concentrate) in a therapeutic concentration (0.04, 0.02%). In addition, we tested the concentrations of 0.1 and 0.01%. Cells were visualized with a phase contrast microscope, and the CBF was measured with the SAVA system's region of interest method. Ringer's solution and macrogol served as negative controls. A therapeutic concentration of Lavasept significantly reduced CBF in a time- and concentration-dependent manner. After 1 min, the CBF was reduced from 8.90 ± 1.64 to 5.00 ± 3.72 Hz with a concentration of 0.04% (p value = 0.001). After 10 min, all cilia stopped beating. After 5 min, a 0.02% solution of Lavasept concentrate decreased CBF significantly from 8.64 ± 1.71 to 3.30 ± 3.27 Hz (p value < 0.001). In conclusion, CBF of human nasal epithelia is significantly reduced with the use of the polyhexanide-containing solution Lavasept in some therapeutic concentrations. Due to our findings in this study, Lavasept should be used on ciliated mucosa only with caution and in a concentration of 0.02%.

In-vitro activity of polyhexanide alone and in combination with antibiotics against Staphylococcus aureus

BACKGROUND

The resistance of Staphylococcus aureus is increasing, not only to antibiotics but also to antiseptics.

AIM

To investigate the activity of the antiseptic polyhexanide and several antibiotics against clinical isolates of meticillin-susceptible and meticillin-resistant Staphylococcus aureus (MSSA and MRSA, respectively). Polyhexanide was tested alone and in combination with oxacillin, penicillin G, ampicillin, cefazolin, cefuroxime, imipenem, gentamicin, erythromycin, doxycycline, levoflocaxin, linezolid and vancomycin.

METHODS

Fifty MSSA and 50 MRSA strains, including one vancomycin-intermediate (VISA) strain, were tested. All strains were typed by pulsed-field gel electrophoresis (PFGE) to exclude testing of clonal isolates. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined using the serial broth microdilution technique according to DIN 58940. Combinations of polyhexanide and different antibiotics were investigated using the checkerboard technique.

FINDINGS

Polyhexanide MICs and MBCs in the range of 0.5-2mg/L were found for both MSSA and MRSA, and the VISA strain had MIC and MBC values of 2mg/L. All isolates were regarded as susceptible to polyhexanide, and no antagonism was observed between polyhexanide and the tested antibiotics. Synergism between polyhexanide and some bacteriostatic antibiotics (erythromycin, doxycycline and linezolid) was found for some strains.

CONCLUSIONS

Polyhexanide appears to be suitable for the topical treatment of S. aureus alone and in combination with antibiotics.

Simultaneous irrigation and negative pressure wound therapy enhances wound healing and reduces wound bioburden in a porcine model

Infected foot wounds are one of the most common reasons for hospitalization and amputation among persons with diabetes. The objective of the study was to investigate a new wound therapy system that employs negative pressure wound therapy (NPWT) with simultaneous irrigation therapy. For this study, we used a porcine model with full-thickness excisional wounds, inoculated with Pseudomonas aeruginosa. Wounds were treated for 21 days of therapy with either NPWT, NPWT with simultaneous irrigation therapy using normal saline or polyhexanide biguanide (PHMB) at low or high flow rates, or control. Data show that NPWT with either irrigation condition improved wound healing rates over control-treated wounds, yet did not differ from NPWT alone. NPWT improved bioburden over control-treated wounds. NPWT with simultaneous irrigation further reduced bioburden over control and NPWT-treated wounds; however, flow rate did not affect these outcomes. Together, these data show that NPWT with simultaneous irrigation therapy with either normal saline or PHMB has a positive effect on bioburden in a porcine model, which may translate clinically to improved wound healing outcomes.

Poly(ethyleneimines) in dermal applications: biocompatibility and antimicrobial effects

Cationic polyamines, such as poly(ethyleneimines) (PEIs), may recommend themselves for antimicrobial applications as they can interact with microbial membranes resulting in their disruption. The purpose of the study was the assessment of biocompatibility and antibacterial activity of PEIs with different architectures (branched (b) and linear (l)) and molar masses (0.8-750 kDa). lPEI and bPEI exhibited a strong antibacterial activity against Staphylococcus aureus and Escherichia coli with a more pronounced effect on the Gram-positive bacteria. lPEIs further demonstrated a higher antibacterial efficacy compared to bPEIs but no significant differences between 5 and 25 kDa were observed. In accordance, antibacterial activity of bPEI did not specifically depend on molar mass. Only slightly lower minimal inhibitory concentrations (MIC) were observed at 5 kDa (S. aureus) and 25 kDa (E. coli) in the tests. As PEIs are compelling candidates for use in antimicrobial treatment, two basic aspects have to be investigated: treatment effectiveness and safety. PEIs clearly induced molecular weight dependent cytotoxic effects in vitro. PEIs with low molecular weight (0.8 and 5 kDa) exhibited higher biocompatibility. Nonetheless, the results confirmed a low genotoxic potential of lPEI and bPEIs. In conclusion, 2.5 kDa-lPEI and 0.8 kDa-bPEI can be recommended for use as antimicrobial polymers in dermal applications due to their high biocompatibility with concomitant antibacterial efficacy.

In vitro comparison of the effectiveness of polihexanide and chlorhexidine against canine isolates of Staphylococcus pseudintermedius, Pseudomonas aeruginosa and Malassezia pachydermatis

BACKGROUND

Polihexanide (polyhexamethylene biguanide) is an antiseptic substance that plays a prominent role in the treatment of critically colonized or infected acute and chronic wounds in humans.

HYPOTHESIS/OBJECTIVES

The aim of this study was to assess the in vitro antimicrobial efficacy of polihexanide against canine isolates of Staphylococcus pseudintermedius, Pseudomonas aeruginosa and Malassezia pachydermatis and compare it with 4.5% chlorhexidine digluconate for two different contact times.

METHODS

Ten isolates of each organism were incubated at 37°C for 3 and 5 min, respectively, with each antiseptic diluted 1:2 to 1:4096 in phosphate-buffered saline.

RESULTS

Both products showed excellent antimicrobial activity against all isolates tested. No significant differences in antimicrobial efficacy between antiseptics for all isolates were found. With the exception of one isolate of M. pachydermatis at 3 min exposure time, all isolates were completely killed by a dilution of 1:32 of polihexanide as well as chlorhexidine at both exposure times. Although the mean values of break-point concentrations for both antiseptics increased with the longer exposure time of 5 min, there were no significant differences between the two exposure times. The P. aeruginosa isolates were more susceptible than S. pseudintermedius for both antiseptics, and break-point dilutions were significantly higher compared with break-point dilutions obtained by all other treatments.

CONCLUSIONS AND CLINICAL IMPORTANCE

The results indicate that polihexanide has comparable in vitro antimicrobial efficacy to chlorhexidine and presents a potential alternative agent for skin and wound antisepsis in veterinary medicine.

Rapid, simple and stability-indicating determination of polyhexamethylene biguanide in liquid and gel-like dosage forms by liquid chromatography with diode-array detection

A rapid and simple method for the determination of polyhexamethylene biguanide (polyhexanide, PHMB) in liquid and gel-like pharmaceutical formulations by means of high performance liquid chromatography coupled to diode-array detection (HPLC–DAD) was developed. Best separation was achieved using a cyanopropyl bonded phase (Agilent Zorbax Eclipse XDB-CN column 4.6 mm×75 mm with particle size of 3.5 μm) as well as gradient elution consisting of acetonitrile/deionized water at a flow rate of 1.0 mL/min. The optimized and applied chromatographic conditions permitted separation of polyhexanide from interacting matrix with subsequent detection at a wavelength of 235 nm with good sensitivity. The method validation was carried out with regard to the guidelines for analytical procedures demanded by the International Conference on Harmonisation (ICH). Mean recoveries of 102% and 101% for gel-like as well as liquid preparations were obtained. Suitable repeatability as well as intermediate precision could be achieved with limits of detection ≤0.004 mg/mL for both formulations, equivalent to ≤0.004% PHMB concerning sample preparation. Determination of PHMB was accomplished without tedious sample preparation. Interacting matrix could be eliminated by the chromatographic procedure with excellent performance of system suitability. All analytical requirements were fulfilled permitting a reliable and precise determination of PHMB in pharmaceuticals. Furthermore, the developed method was applied to stability testing of pharmaceutical preparations containing PHMB.

Interaction of polyhexamethylene biguanide hydrochloride (PHMB) with phosphatidylcholine containing o/w emulsion and consequences for microbicidal efficacy and cytotoxicity

Oil-in-water (o/w) emulsions containing egg yolk phosphatidylcholine (EPC) were combined with aqueous polyhexamethylene biguanide hydrochloride (PHMB). The PHMB concentration in the aqueous phase was estimated by filtration centrifugation experiments. In parallel, PHMB concentration was assessed utilizing cytotoxicity assays (neutral red) on cultured murine fibroblasts (L929 cells) and tests of bactericidal efficacy on either Pseudomonas aeruginosa or Staphylococcus aureus. Biological tests were performed in cell culture medium. Filtration centrifugation experiments demonstrated much higher aqueous PHMB concentrations than did the assays for biologically effective PHMB. Therefore, biological test systems should preferably be used to verify effective PHMB concentrations. Tests of microbicidal efficacy in which the same 0.05% PHMB o/w emulsion was re-used 8 times revealed a drug delivery system activated by the presence of test bacteria.

Evaluation of the antiseptic efficacy and local tolerability of a polihexanide-based antiseptic on resident skin flora

OBJECTIVE

The primary objective of this study was to compare the antimicrobial efficacy of polihexanide 0.02% and 0.04% with chlorhexidine 0.05% after 30 minutes of topical treatment on healthy intact skin.

DESIGN

This study was performed as a double-blind, randomized, comparator-controlled, 3-arm, crossover study.

SETTING

: A phase I dermatological study unit.

PARTICIPANTS

Twenty healthy volunteers with intact skin.

INTERVENTIONS

: Test areas of 5 cm on the subjects' arms were treated with the investigational products using a polyurethane swab. Skin swabs were taken before and after treatment for quantitative microbial evaluation.

MAIN OUTCOME MEASURES

The main outcome measure was the log reduction factor of colony-forming units on the skin after 30 minutes of treatment.

MAIN RESULTS

No statistically significant difference was seen between both of the polihexanide test products (mean lgRF polihexanide 0.02%, 1.2251 [SD, 0.9399]; mean lgRF polihexanide 0.04%, 1.8991 [SD, 0.88]) and the comparator, chlorhexidine 0.05% (P > .1).

CONCLUSION

The results of this study indicate that polihexanide is a suitable alternative to chlorhexidine for skin and wound antisepsis.