Development of a topical mupirocin spray for antibacterial and wound-healing applications

Formulation and Antimycotic Evaluation of Colloidal Itraconazole-Loaded Metered Dose Sprays for Treating Superficial Mycoses

Commercial topical formulations containing itraconazole (poorly water soluble), for mycotic infections, have poor penetration to infection sites beneath the nails and skin thereby necessitating oral administration. To improve penetration, colloidal solutions of itraconazole (G1-G4) containing Poloxamer 188, tween 80, ethanol, and propylene glycol were prepared and incorporated into HFA-134-containing sprays. Formulations were characterized using particle size, drug content, and Fourier-transform infrared spectroscopy (FTIR). In vitro permeation studies were performed using Franz diffusion cells for 8 h. Antimycotic activity on Candida albicans and Trichophyton rubrum was performed using broth micro-dilution and flow cytometry, while cytotoxicity was tested on HaCaT cell lines. Particle size ranged from 39.35-116.80 nm. FTIR and drug content revealed that G1 was the most stable formulation (optimized formulation). In vitro release over 2 h was 45% for G1 and 34% for the cream. There was a twofold increase in skin permeation, fivefold intradermal retention, and a sevenfold increase in nail penetration of G1 over the cream. Minimum fungicidal concentrations (MFC) against C. albicans were 0.156 and 0.313 µg/mL for G1 and cream, respectively. The formulations showed optimum killing kinetics after 48 h. MFC values against T. rubrum were 0.312 and 0.625 µg/mL for the G1 and cream, respectively. Transmission electron microscopy revealed organelle destruction and cell leakage for G1 in both organisms and penetration of keratin layers to destroy T. rubrum. Cytotoxicity evaluation of G1 showed relative safety for skin cells. The G1 formulation showed superior skin permeation, nail penetration, and fungicidal activity compared with the cream formulation.

Fabrication and in vitro characterization of curcumin film-forming topical spray: An integrated approach for enhanced patient comfort and efficacy

Background

Curcumin, known for its anti-inflammatory properties, was selected for the developing consumer friendly film forming spray that offers precise delivery of curcumin and and improves patient adherence.

Methods

An optimized film-forming solution was prepared by dissolving curcumin (1%), Eudragit RLPO (5%), propylene glycol (1%), and camphor (0.5%) in ethanol: acetone (20:80) as the solvent. The solution was filled in a spray container which contained 70% solutions and 30% petroleum gas. In-vitro characterization was performed.

Results

Potential anti-inflammatory phytoconstituents were extracted from the PubChem database and prepared as ligands, along with receptor molecules (nsp10-nsp16), for molecular docking using Autodock Vina. The docking study showed the lowest binding energy of -8.2 kcal/mol indicates better binding affinities. The optimized formulation consisted of ethanol:acetone (20:80) as the solvent, Eudragit RLPO (5%) as the polymer, propylene glycol (1%) as the plasticizer, and camphor oil (0.5%) as the penetration enhancer. The optimized formulation exhibited pH of 5.8 ± 0.01, low viscosity, low film formation time (19.54 ± 0.78 sec), high drug content (8.243 ± 0.43 mg/mL), and extended ex vivo drug permeation (85.08 ± 0.09%) for nine hours. Consequently, the formulation was incorporated into a container using 30% liquefied petroleum gas, delivering 0.293 ± 0.08 mL per actuation, containing 1.53 ± 0.07 mg of the drug. The film-forming spray exhibited higher cumulative drug permeation (83.94 ± 0.34%) than the marketed cream formulation and pure drug solution after 9 h, with an enhancement ratio of 14. Notably, the film-forming spray exhibited no skin irritation and remained stable for over three months.

Conclusions

The developed curcumin film-forming system is promising as a carrier for wound management because of its convenient administration and transport attributes. Further in vivo studies are required to validate its efficacy in wound management.

Design of High-Payload Ascorbyl Palmitate Nanosuspensions for Enhanced Skin Delivery

A high-payload ascorbyl palmitate (AP) nanosuspension (NS) was designed to improve skin delivery following topical application. The AP-loaded NS systems were prepared using the bead-milling technique, and softly thickened into NS-loaded gel (NS-G) using hydrophilic polymers. The optimized NS-G system consisted of up to 75 mg/mL of AP, 0.5% w/v of polyoxyl-40 hydrogenated castor oil (Kolliphor® RH40) as the suspending agent, and 1.0% w/v of sodium carboxymethyl cellulose (Na.CMC 700 K) as the thickening agent, in citrate buffer (pH 4.5). The NS-G system was embodied as follows: long and flaky nanocrystals, 493.2 nm in size, -48.7 mV in zeta potential, and 2.3 cP of viscosity with a shear rate of 100 s-1. Both NS and NS-G provided rapid dissolution of the poorly water-soluble antioxidant, which was comparable to that of the microemulsion gel (ME-G) containing AP in solubilized form. In an ex vivo skin absorption study using the Franz diffusion cell mounted on porcine skin, NS-G exhibited faster absorption in skin, providing approximately 4, 3, and 1.4 times larger accumulation than that of ME-G at 3, 6, and 12 h, respectively. Therefore, the high-payload NS makes it a promising platform for skin delivery of the lipid derivative of ascorbic acid.

Chitosan and α-cellulose-based mupirocin topical film-forming spray: Optimization, in vitro characterization, antimicrobial studies and wound healing activity

The study aimed to develop a biopolymer-based mupirocin film-forming spray (MUP-FFS) for wound healing using chitosan and α-cellulose. MUP-FFS formulation was optimized by box-Behnken design, wherein the amount of chitosan, glycerol, and microfluidizer cycles showed a significant effect on the drying time and sprayability, but drug release remained unaffected. The optimized MUP-FFS formulation prepared by 13 microfluidizer cycles containing chitosan (0.125 %), glycerol (2.76 %) was quickly sprayable with 235 s drying time. The viscosity, spray uniformity and occlusive potential were found optimum for MUP-FFS. MUP-FFS released 98.066 % of MUP, 2-fold and 4-fold greater than the marketed ointment and MUP-API. The transmission electron microscopy displayed a homogeneous fibrous network, and scanning electron microphotographs showed uniform drug distribution on the MUP-film surface. The antimicrobial study revealed the efficacy of MUP-FFS against S.aureus and E.coli, wherein the former was more susceptible to formulation than the later. MUP-FFS indicated better wound contraction and healing than other groups on 7th and 14th day in rats. On Day-21, MUP-FFS could regress TGF-β1 to a normal level similar to the marketed formulation, which was also reflected in histopathological observations. Therefore, MUP-FFS can be a treatment option for chronic wounds, applied without touch and with minimal mechanical pressure.

Plant-based Natural Products as inhibitors for Efflux Pumps to Reverse Multidrug Resistance in Staphylococcus aureus: A Mini Review

Wounds provide a favourable site for microbial infection. Wound infection makes the healing more complex and does not proceed in an orchestrated manner leading to the chronic wound. Clinically infected wounds require proper antimicrobial therapy. Broad-spectrum antibiotics are usually prescribed first before going to targeted therapy. The current conventional mode of therapy mainly depends on the use of antibiotics topically or systemically. Repeated and prolonged use of antibiotics, however, leads to multidrug resistance. Staphylococcus aureus is the most common multidrugresistant microorganism found in wounds. It effectively colonizes the wound and produces many toxins, thereby reducing the host immune response and causing recurrent infection, thus making the wound more complex. The overexpression of efflux pumps is one of the major reasons for the emergence of multidrug resistance. Inhibition of efflux pumps is, therefore, a potential strategy to reverse this resistance. The effective therapy to overcome this antibiotic resistance is to use combination therapy, namely the combination of an inhibitor, and a non-antibiotic compound with an antibiotic for their dual function. Many synthetic efflux pump inhibitors to treat wound infections are still under clinical trials. In this connection, several investigations have been carried out on plant-based natural products as multidrug resistance-modifying agents as they are believed to be safe, inexpensive and suitable for chronic wound infections.

Sprayable ciprofloxacin-loaded poloxamer hydrogels for wound infection treatment

Topical antimicrobial treatments for severe burns and chronic wounds provide effective treatment against infections, but cause pain and discomfort with application. This study aimed to develop an antimicrobial topical formulation comprising thermoreversible poloxamers (Pluronic F127 and F68) and a broad-spectrum antimicrobial agent (ciprofloxacin hydrochloride, CH), that could be sprayed to eliminate application pain while maintaining antimicrobial activity. Formulations were characterized to determine their sprayability under cold conditions, gelation temperature, final storage modulus at skin temperature, drug release profile, ex vivo permeation through impaired porcine skin, and inhibition against common bacterial pathogens that colonize wounds. All cold formulations were sprayable from simple hand-held, pump-action sprayers due to their low viscosity. Upon heating, 17 and 20% Pluronic F127 formulations produced hydrogels eight to ten degrees below skin temperature, independent of ciprofloxacin loading. Increasing concentrations of Pluronic F127 increased the final storage modulus and viscosity of the gels, while inclusion of Pluronic F68 reduced these properties, showing that hydrogel rheological properties at skin temperature can be tuned via choice of formulation. Drug release was directly correlated to the rheological properties, with stiffer gels resulting in a decrease in drug release rate. Overall, gels released about 65-90% of their load within 12 hours. Ex vivo skin permeation demonstrated that drug was well retained in impaired porcine skin, which is desired to continuously treat bacteria localized to the wound. A well-diffusion assay indicated that the hydrogels had greater bacterial inhibition against Pseudomonas aeruginosa, Escherichia coli, and two strains of Staphylococcus aureus when compared to commercial controls. Overall, the results show the potential of CH-loaded poloxamer formulations as suitable sprayable topical dressings to deliver antimicrobials directly to wounds.

Novel Synergistic Approach: Tazarotene-Calcipotriol-Loaded-PVA/PVP-Nanofibers Incorporated in Hydrogel Film for Management and Treatment of Psoriasis

Psoriasis is an autoimmune skin disease that generally affects 1%-3% of the total population globally. Effective treatment of psoriasis is limited because of numerous factors, such as ineffective drug delivery and efficacy following conventional pharmaceutical treatments. Nanofibers are widely being used as nanocarriers for effective treatment because of their multifunctional and distinctive properties, including a greater surface area, higher volume ratio, increased elasticity and improved stiffness and resistance to traction, favorable biodegradability, high permeability, and sufficient oxygen supply, which help maintain the moisture content of the skin and improve the bioavailability of the drugs. Similar to the extracellular matrix, nanofibers have a regeneration capacity, promoting cell growth, adhesion, and proliferation, and also have a more controlled release pattern compared with that of other conventional therapies at the psoriatic site. To ensure improved drug targeting and better antipsoriatic efficacy, this study formulated and evaluated a tazarotene (TZT)-calcipotriol (CPT)-loaded nanofiber and carbopol-based hydrogel film. The nanofiber was prepared using electrospinning with a polyvinyl alcohol/polyvinylpyrrolidone (PVA/PVP) K-90 polymeric blend that was later incorporated into a carbopol base to form hydrogel films. The prepared nanofibers were biochemically evaluated and in vitro and in vivo characterized. The mean diameters of the optimized formulation, i.e., TZT-loaded polyvinyl alcohol/polyvinylpyrrolidone nanofiber (TZT-PVA/PVP-NF) and TZT-CPT-loaded polyvinyl alcohol/polyvinylpyrrolidone nanofiber (TZT-CPT-PVA/PVP-NF) were 244.67 ± 58.11 and 252.31 ± 35.50 nm, respectively, as determined by scanning electron microscopy, and their tensile strength ranged from 14.02 ± 0.54 to 22.50 ± 0.03 MPa. X-ray diffraction revealed an increase in the amorphous nature of the nanofibers. The biodegradability studies of prepared nanofiber formulations, irrespective of their composition, showed that these completely biodegraded within 2 weeks of their application. The TZT-CPT-PVA/PVP-NF nanofibers exhibited 95.68% ± 0.03% drug release at the end of 72 h, indicating a controlled release pattern and following Higuchi release kinetics as a best-fit model. MTT assay, antioxidant and lipid profile tests, splenomegaly assessment, and weight fluctuation were all performed in the in vitro as well as in vivo studies. We found that the TZT-CPT-PVA/PVP-NF-based hydrogel film has high potential for antipsoriatic activity in imiquimod-induced Wistar rats in comparison with that of TT-PVA/PVP-NF nanofibers.

Spray Film-Forming systems as promising topical in situ Systems: A review

Spray film-forming systems (SFFSs) provide great potential for the treatment of various types of wounds. Such systems afford to prolong the action of active substances, to prevent cross-contamination, and to ensure accelerated wound healing. Spray films are known since the mid-20th century, and nowadays they are widely used to treat minor skin injuries, but numerous clinical cases describe their successful use in the treatment of burns, wounds, bedsores, etc. The current level of polymer development and composite synthesis has greatly expanded the possibilities of creating compositions of spray film-forming systems. Scattered information and lack of standardization of such delivery systems creates difficulties for pharmaceutical development. This review highlights most of the existing requirements and suggestions from studies to standardize the characteristics of SFFSs and classify them based on scientific sources and regulatory documentation, as well as the position of such systems in the pharmaceutical market. The search and evaluation of known characterization methods and their modifications, as well as the approval of their list (separately for development and for standardization) can potentially increase the research interest in the problem of spray film-forming systems development and contribute to the registration of new drugs and medical devices in this promising dosage form, including with its own pharmacological effect.

Effect of Polymeric Nanoparticles with Entrapped Fish Oil or Mupirocin on Skin Wound Healing Using a Porcine Model

The utilization of poly(lactic-co-glycolic) acid (PLGA) nanoparticles (NPs) with entrapped fish oil (FO) loaded in collagen-based scaffolds for cutaneous wound healing using a porcine model is unique for the present study. Full-depth cutaneous excisions (5 × 5 cm) on the pig dorsa were treated with pure collagen scaffold (control, C), empty PLGA NPs (NP), FO, mupirocin (MUP), PLGA NPs with entrapped FO (NP/FO) and PLGA NPs with entrapped MUP (NP/MUP). The following markers were evaluated on days 0, 3, 7, 14 and 21 post-excision: collagen, hydroxyproline (HP), angiogenesis and expressions of the COX2, EGF, COL1A1, COL1A3, TGFB1, VEGFA, CCL5 and CCR5 genes. The hypothesis that NP/FO treatment is superior to FO alone and that it is comparable to NP/MUP was tested. NP/FO treatment increased HP in comparison with both FO alone and NP/MUP (day 14) but decreased (p < 0.05) angiogenesis in comparison with FO alone (day 3). NP/FO increased (p < 0.05) the expression of the CCR5 gene (day 3) and tended (p > 0.05) to increase the expressions of the EGF (day 7, day 14), TGFB1 (day 21) and CCL5 (day 7, day 21) genes as compared with NP/MUP. NP/FO can be suggested as a suitable alternative to NP/MUP in cutaneous wound treatment.

Optimization, Characterization and In Vivo Evaluation of Mupirocin Nanocrystals for Topical Administration

Treatment of infectious skin conditions resulting from wounds and burns with topical antibiotics is challenging, particularly those caused by methicillin-resistant Staphylococcus aureus bacteria (MRSA). This is due to the formation of bacterial biofilms characterized by antimicrobial resistance. Mupirocin (MP), a widely used topical antibiotic, is active against gram-positive bacteria including MRSA. However, MP suffers from sub-optimal therapeutic efficacy due to its poor water-solubility and the significant rise in MP-resistant S. aureus. In this study, the physico-chemical characteristics of MP were modified through nanocrystallization to improve its therapeutic efficacy for the treatment of skin infections. Mupirocin-nanocrystals (MP-NC) were prepared using a nanoprecipitation technique and optimized using a D-optimal response surface design. The optimization of MP-NC produced ultra-small monodisperse spherical particles with a mean diameter of 70 nm and a polydispersity index of 0.2. The design resulted in two optimal MP-NC formulations that were evaluated by performing series of in vitro, ex vivo, microbiological, and in vivo studies. In-vitro results showed a 10-fold increase in the saturation solubility and a 9-fold increase in the dissolution rate of MP-NC. Ex vivo permeation studies, using pig ears skin, showed a 2-fold increase in the dermal deposition of MP-NC with the highest drug deposition occurring at 500-µm skin depth. Moreover, the optimal MP-NC formulations were lyophilized and incorporated into a 2% w/w cream. Microbiological studies revealed a 16-fold decrease in the minimum inhibitory concentration and the minimum bactericidal concentration of MP-NC. In vivo studies, using a rat excision burn wound model, demonstrated rapid and complete healing of infected burn wounds in rats treated with MP-NC cream in comparison to marketed Avoban ointment. Our results suggest that nanocrystallization of MP may provide an avenue through which higher levels of a topically applied MP can be permeated into the skin to reach relevant infectious areas and exert potential local antibacterial effects.

One-Pot and Green Preparation of Phyllanthus emblica Extract/Silver Nanoparticles/Polyvinylpyrrolidone Spray-On Dressing

A spray-on wound dressing has many benefits, including easy and quick administration to broad and uneven wounds, better interface with the wound site, adhesion without additional dressing, and multiple applications in a portable package. By limiting direct contact with the wound site, such a design can prevent wound damage during treatment. This study revealed a simple, one-pot synthesis of spray-on wound dressing relying on polyvinylpyrrolidone solution incorporating silver nanoparticles as a broad-spectrum antibacterial agent and wound-healing antioxidant Phyllanthus emblica extract. Silver nanoparticles were synthesized in situ using Phyllanthus emblica extract as a biogenic reducing agent. Polyvinylpyrrolidone was employed as a film-forming agent to create an adhesive hydrogel-based dressing matrix to provide moisture and establish a shielding barrier for the wound bed as well as to regulate the release of fruit extract. In vitro tests revealed that the produced dressing film had a controlled release of the fruit extract, high antioxidant activity, and a good antibacterial action against S. aureus, P. aeruginosa, E. coli, and MRSA. Additionally, a biocompatibility study has shown that both human fibroblasts and keratinocytes are unaffected by the dressing film. Based on established findings, the current spray-on solution might be a potential option for antibacterial wound dressing.

Topical Film-Forming Chlorhexidine Gluconate Sprays for Antiseptic Application

Topical film-forming sprays of chlorhexidine gluconate (CHG-FFS) were developed for antiseptic application. Various polymers and solvents were studied for their potential as film-forming polymers and solvent systems, respectively. To produce CHG-FFS, the optimal polymer and solvent were selected, and their physicochemical properties were evaluated. The in vivo evaluation of CHG-FFS was investigated for the satisfaction of the dosage forms, time required for the film formation, film appearance, and adhesion on the skin. Antibacterial activity was also studied in vitro and in vivo. The optimized formulation was assessed for the in vitro cell line evaluations of the cytotoxicity and wound healing. The results demonstrate that Eudragit® S100, Eudragit® L100, and polyvinyl alcohol (PVA) have the ability to be used as film-forming polymers in an ethanolic solution. A clear and flexible film was obtained from transparent homogenous solutions of CHG-FFS after actuation. They generated the fast thin film formation on the skin with the satisfaction of the dosage forms. Furthermore, the formulations inhibited the growth of Staphylococcus aureus in vitro and provided antiseptic activity in vivo. However, PVA was found to be an optimal film-forming polymer for promoting CHG adhesion on the skin. The CHG-FFS obtained from the PVA also provided a CHG film, which was non-toxic to human skin cells and did not interfere with the wound healing process. Therefore, the developed CHG-FFS could be a promising candidate for topical antiseptic application.

Spray with Nitric Oxide Donor Accelerates Wound Healing: Potential Off-the-Shelf Solution for Therapy?

Background

Ditrosyl iron complexes (DNIC) are endogenous donors of nitric oxide. The possibility of their application to stimulate regeneration has been studied for more than 15 years. However, the most effective dose and form of delivery have not yet been determined.

Purpose

The aim of this research was to develop a spray form of DNIC that accelerates wound healing.

Methods

We prepared a series of DNIC sprays with spray dosages of 10, 50 and 100 μg. We modelled full-thickness skin wounds in 24 Wistar rats and treated them with distilled water (n = 6), 10 (n = 6), 50 (n = 6) and 100 μg (n = 6) for three post-operative days. On the fourth day, the excised wound tissues were studied by morphological, immunohistochemical and morphometric methods.

Results

We demonstrated that 50 μg of DNIC spray had the most beneficial effect on wound healing: the thickness of the granulation tissue layer was 140% higher, vimentin positive fibroblasts predominated and the intensity of inflammation was significantly lower than in the control. There was a dose-dependent decrease in the functional activity of mast cells in the experimental groups compared to the control.

Conclusion

DNIC spray is a potential effective dosage form for the treatment of large-area skin lesions.

Synthesis And Evaluation of Polyethylene Glycol-4000-Co-Poly (AMPS) Based Hydrogel Membranes for Controlled Release of Mupirocin for Efficient Wound Healing

BACKGROUND

Chronic wound healing is a major challenge for health care system around the globe. Current study was conducted to develop and characterize chemically cross-linked polyethylene glycol-co-poly (AMPS) hydrogel membranes to enhanced the wound healing efficiency of antibiotic mupirocin (MP).

METHODS

Free radical polymerization technique was used for the development of hydrogel membranes. In aqueous medium, polymer PEG-4000 cross-linked with the monomer 2-acrylamido-2-methylpropane sulfonic acid (AMPS) in the presence of initiators ammonium peroxide sulfate (APS) and sodium hydrogen sulfite (SHS). N, N-Methylenebisacrylamide (MBA) was used as cross-linker in the preparation of hydrogel membranes. Developed membranes were spherical, transparent, and elastic. FTIR, TGA/DSC, and SEM were used to characterize the polymeric system. Swelling behavior, drug loading, and its release pattern at pH of 5.5 and 7.4, irritation study, ex vivo drug permeation, and deposition study was also evaluated.

RESULTS

Formed membranes were spherical, transparent and elastic. The formation of a stable polymeric network was confirmed by structural and thermal analysis. Permeation of the drug its deposition in the skin showed good permeation and retention. No irritancy to the skin was observed.

CONCLUSION

On the basis of results obtained, the present study concluded that it may be an ideal network for the delivery of mupirocin in skin infections.

Chitosan-bovine serum albumin-Carbopol 940 nanogels for mupirocin dermal delivery: ex-vivo permeation and evaluation of cellular binding capacity via radiolabeling

The goal of this study was to develop and examine the nanogel-based topical delivery system of mupirocin. Nanogels were prepared with chitosan and bovine serum albumin by ionic gelation and Carbopol 940 was added to improve the gelling/adhesive properties. Detailed characterization studies were performed and the cellular binding capacity of radiolabeled nanogels was investigated on CCD-1070Sk cell lines. Results indicate the successful formation of nanogels with particle size and zeta potential ranged between 341.920-603.320 nm and 13.120-24.300 mV, respectively. The mechanical and rheological studies proved pseudoplastic and strong elastic gel behavior (G' > G''). Mupirocin was successfully entrapped into nanogels with a ratio of more than 95% and the loaded drug was slowly released up to 93.89 ± 3.07% within 24 h. The ex vivo penetration and permeation percentages of mupirocin were very low (1.172 ± 0.202% and 0.161 ± 0.136%) indicating the suitability of nanogels for dermal use against superficial skin infections. The microbiological studies pointed out the effectiveness of nanogels against Staphylococcus aureus strains. Nanogels did not show toxicity signs and the cell binding capacity of radiolabeled formulations was found to be higher than [^99mTc]NaTcO₄ to CCD-1070Sk cell line. Overall, mupirocin nanogels might be considered as a potential and safe topical treatment option for bacterial skin infections.

Comparison of Antibacterial Activity and Wound Healing in a Superficial Abrasion Mouse Model of Staphylococcus aureus Skin Infection Using Photodynamic Therapy Based on Methylene Blue or Mupirocin or Both

Background: Antibiotic resistance and impaired wound healing are major concerns in S. aureus superficial skin infections, and new therapies are needed. Antimicrobial photodynamic therapy (aPDT) is a new therapeutic approach for infections, but it also improves healing in many wound models. Objective: To compare the antimicrobial activity and the effects on wound healing of aPDT based on Methylene Blue (MB-aPDT) with mupirocin treatment, either alone or in combination, in superficial skin wounds of S. aureus-infected mice. Additionally, to evaluate the clinical, microbiological, and cosmetic effects on wound healing. Materials and Methods: A superficial skin infection model of S. aureus was established in SKH-1 mice. Infected wounds were treated with MB-aPDT, MB-aPDT with a daily topical mupirocin or only with mupirocin. No treatment was carried out in control animals. Daily clinical and microbiological examinations were performed until complete clinical wound healing. Histopathological studies and statistical analysis were performed at the end of the study. Results: MB-aPDT treatment induced the best wound healing compared to mupirocin alone or to mupirocin plus MB-aPDT. Superficial contraction at 24 h and a greater reduction in size at 48 h, quicker detachment of the crust, less scaling, and absence of scars were observed. Histopathological studies correlated with clinical and gross findings. By contrast, mupirocin showed the highest logaritmic reduction of S. aureus. Conclusions: MB-aPDT and mupirocin treatments are effective in a murine superficial skin infection model of S. aureus. One session of MB-aPDT was the best option for clinical wound healing and cosmetic results. The addition of mupirocin to MB-aPDT treatment improved antimicrobial activity; however, it did not enhance wound healing. No synergistic antibacterial effects were detected.

Nanocomposite Sprayed Films with Photo-Thermal Properties for Remote Bacteria Eradication

Currently there is a strong demand for novel protective materials with efficient antibacterial properties. Nanocomposite materials loaded with photo-thermally active nanoparticles can offer promising opportunities due to the local increase of temperature upon near-infrared (NIR) light exposure capable of eradicating bacteria. In this work, we fabricated antibacterial films obtained by spraying on glass slides aqueous solutions of polymers, containing highly photo-thermally active gold nanostars (GNS) or Prussian Blue (PB) nanoparticles. Under NIR light irradiation with low intensities (0.35 W/cm²) these films demonstrated a pronounced photo-thermal effect: ΔT_max up to 26.4 °C for the GNS-containing films and ΔT_max up to 45.8 °C for the PB-containing films. In the latter case, such a local temperature increase demonstrated a remarkable effect on a Gram-negative strain (P. aeruginosa) killing (84% of dead bacteria), and a promising effect on a Gram-positive strain (S. aureus) eradication (69% of dead bacteria). The fabricated films are promising prototypes for further development of lightweight surfaces with efficient antibacterial action that can be remotely activated on demand.

Laser-induced vapor nanobubbles improve diffusion in biofilms of antimicrobial agents for wound care

Being responsible for delayed wound healing, the presence of biofilms in infected wounds leads to chronic, and difficult to treat infections. One of the reasons why antimicrobial treatment often fails to cure biofilm infections is the reduced penetration rate of antibiotics through dense biofilms. Strategies that have the ability to somehow interfere with the integrity of biofilms and allowing a better penetration of drugs are highly sought after. A promising new approach is the use of laser-induced vapor nanobubbles (VNB), of which it was recently demonstrated that it can substantially enhance the penetration of antibiotics into biofilms, resulting in a marked improvement of the killing efficiency. In this study, we examined if treatment of biofilms with laser-induced vapor nanobubbles (VNB) can enhance the potency of antimicrobials which are commonly used to treat wound infections, including povidone-iodine, chlorhexidine, benzalkonium chloride, cetrimonium bromide and mupirocin. Our investigations were performed on Pseudomonas aeruginosa and Staphylococcus aureus biofilms, which are often implicated in chronic wound infections. Pre-treatment of biofilms with laser-induced VNB did enhance the killing efficiency of those antimicrobials which experience a diffusion barrier in the biofilms, while this was not the case for those compounds for which there is no diffusion barrier. The magnitude of the enhanced potency was in most cases similar to the enhancement that was obtained when the biofilms were completely disrupted by vortexing and sonication. These results show that laser-induced VNB are indeed a very efficient way to enhance drug penetration deep into biofilms, and pave the way towards clinical translation of this novel approach for treatment of wound infections.

Medicated Foams and Film Forming Dosage Forms as Tools to Improve the Thermodynamic Activity of Drugs to be Administered Through the Skin

Medicated foams and film forming systems are dosage forms formulated to undergo a con-trolled metamorphosis when applied on the skin. Indeed, due to the presence of propellant or a particular air-spray foam pump, a liquid can generate foam when applied on the stratum corneum, or a liquid or conventional dosage form can form on the skin a continuous film as a consequence of the solvent evapora-tion. Thanks to these controlled modifications, the drug thermodynamic activity increases favoring the skin penetration and, therefore, the bioavailability with respect to conventional semi-solid and liquid dosage forms. Furthermore, the available clinical data also evidence that these dosage forms improve the patient’s compliance. The main formulative aspects of medicated foams and film forming systems are reviewed with the aim to underline the possible advantages in terms of biopharmaceutical performances and pa-tient’s adherence.