Antibacterial efficacy of silver nanoparticles, sodium hypochlorite, chlorhexidine, and hypochlorous acid on dentinal surfaces infected with Enterococcus faecalis.

The purpose of this study was to evaluate the antibacterial effect of silver nanoparticles (AgNPs) against Enterococcus faecalis and compare it with different irrigation solutions. This study was performed using 64 dentin blocks. E. faecalis suspension was dispensed to each sample and incubated under anaerobic conditions at 37°C throughout 21 days. After the inoculation period, the following solutions were added to each group and kept for 5 min: Group 1, 5.25% sodium hypochlorite (NaOCl); Group 2, 2.5% NaOCl; Group 3, 1% NaOCl; Group 4, 2% chlorhexidine (CHX); Group 5, 200 ppm hypochlorous acid (HOCl); and Group 6, AgNPs. The samples of positive control were treated with sterile saline. Biofilm viability assay was performed using the LIVE/DEAD BacLight Bacterial Viability Kit. Samples were examined using confocal laser scanning microscopy, respectively. There was no significant difference between the 5.25% NaOCl, 2.5% NaOCl, and 1%NaOCl groups (p > .05). However, these groups showed statistically higher antibacterial activity than the 2% CHX, 200 ppm HOCl, and AgNP groups. Also, 2% CHX showed greater percentage of dead cells compared with the AgNP and HOCl groups. While AgNPs group showed lower dead cell rate than all NaOCl groups and 2% CHX, it caused higher dead cells than 200 ppm HOCl group. The 200 ppm HOCl group showed the lowest percentage of dead cells (p < .05) Although the antibacterial effect of AgNPs is not as high as NaOCl and CHX, it has considerable bactericidal activity against E. faecalis and can be improved by further studies. RESEARCH HIGHLIGHTS: New antimicrobial approaches for root canal irrigation. Antimicrobial effect of silver nanoparticles against E. faecalis. Elimination of the biofilm layer for the success of endodontic treatment.

Bacterial Membrane Vesicles as Smart Drug Delivery and Carrier Systems: A New Nanosystems Tool for Current Anticancer and Antimicrobial Therapy.

Bacterial membrane vesicles (BMVs) are known to be critical communication tools in several pathophysiological processes between bacteria and host cells. Given this situation, BMVs for transporting and delivering exogenous therapeutic cargoes have been inspiring as promising platforms for developing smart drug delivery systems (SDDSs). In the first section of this review paper, starting with an introduction to pharmaceutical technology and nanotechnology, we delve into the design and classification of SDDSs. We discuss the characteristics of BMVs including their size, shape, charge, effective production and purification techniques, and the different methods used for cargo loading and drug encapsulation. We also shed light on the drug release mechanism, the design of BMVs as smart carriers, and recent remarkable findings on the potential of BMVs for anticancer and antimicrobial therapy. Furthermore, this review covers the safety of BMVs and the challenges that need to be overcome for clinical use. Finally, we discuss the recent advancements and prospects for BMVs as SDDSs and highlight their potential in revolutionizing the fields of nanomedicine and drug delivery. In conclusion, this review paper aims to provide a comprehensive overview of the state-of-the-art field of BMVs as SDDSs, encompassing their design, composition, fabrication, purification, and characterization, as well as the various strategies used for targeted delivery. Considering this information, the aim of this review is to provide researchers in the field with a comprehensive understanding of the current state of BMVs as SDDSs, enabling them to identify critical gaps and formulate new hypotheses to accelerate the progress of the field.

Development and quality assessment of glutathione tripeptide loaded niosome containing carbopol emulgels as nanocosmeceutical formulations.

This study focuses on the preparation, physicopharmaceutical and mechanical characterization of reduced glutathione tripeptide loaded niosome containing emulgels as a novel nanocosmeceutical product. Prepared emulgel formulations were mainly composed of oily phase containing different lipids such as glycerine dibehenate, cetyl alcohol, cetearyl alcohol, etc., and aqueous phase containing Carbopol934® as gelling agent. Niosomal lipidic vesicles prepared from Span 60 and cholesterol were subsequently incorporated into optimum emulgel formulations. The pH, viscosity, and textural/mechanical properties of emulgels were examined before and after the incorporation of niosomes. The viscoelasticity and morphological characterization were performed on the final formulation before the packed formulation's microbiological stability test. The hardness and compressibility results ensured easy removal of the emulgel from the container. Due to the carboxyl groups of Carbopol934®, moderate adhesiveness with good cohesiveness was achieved. The rheological characteristics of the emulgels were estimated by oscillatory testing and the data fitted with the Herschel-Bulkley model. Thus, the viscoelastic properties and shear-thinning flow of emulgels were demonstrated. The final formulation was microbiologically stable, and pathogens or skin-irritating allergens were not detected. An anti-aging cosmeceutical preparation containing glutathione tripeptide loaded lipid-based niosome dispersion, suitable for topical use due to its textural and viscosity properties, was successfully produced.

Effects of chitosan-containing silver nanoparticles or chlorhexidine as the final irrigant on the bond strength of resin-based root canal sealers.

Background. This study evaluated the combined effects of silver nanoparticles (AgNPs) and chitosan on the dentin bond strength of resin-based root canal sealers using the push-out test and scanning electron microscopy (SEM). Methods. This in vitro study was conducted on 72 extracted mandibular premolar teeth. All the teeth were decoronated perpendicular to the long axis to leave a 13-mm root length. The root canals were prepared, and the samples were randomly divided into seven experimental groups and one control group based on final irrigation solutions. All the final irrigation procedures were performed for one minute. The root canals were dried using paper points and filled with a resin-based sealer and gutta-percha points using a lateral condensation technique. Sections measuring 2 mm in thickness were taken from the apical, middle, and coronal thirds of each root using a cutting machine. The push-out test was performed using a universal testing machine. Results. The solution of AgNPs combined with 0.4% chitosan showed higher bond strength in the coronal region than a combination with 0.2% chitosan. Samples treated with 0.4% chitosan solution exhibited a higher bond strength than the 0.2% chitosan group. There were no significant differences between chlorhexidine (CHX) solution alone and in combination with 0.2% or 0.4% chitosan solution. Conclusion. The combination of chitosan and AgNPs was as effective as CHX in improving the bond strength of resin-based sealers.

Comparative evaluation of the antifungal efficacy of sodium hypochlorite, chlorhexidine, and silver nanoparticles against Candida albicans.

Candida albicans is a microorganism that causes root canal infections. However, it cannot be eliminated with conventional irrigation solutions. Recently, silver nanoparticles (AgNPs) have become popular for their superior antimicrobial effects. The purpose of this study was to evaluate the antifungal effect of AgNPs to C. albicans comparing with 5.25% sodium hypochlorite (NaOCl) and 2% chlorhexidine (CHX). Silver nanoparticles were synthesized by chemical reduction method. Minimum inhibitory concentration and minimum fungicidal concentration of AgNPs against C. albicans strain were determined according to microdilution method reported by Clinical Laboratory Standards Institute. C. albicans biofilm layer was formed on the dentin blocks for 10 days. The biofilm structure was observed by scanning electron microscopy. Statistical analysis was performed with one way analysis of variance analysis and group comparisons were performed with Tukey test. AgNPs showed the highest antifungal effect among the groups. 5.25% NaOCl showed the lowest antifungal effect among the groups. While the 2% CHX solution had a statistically lower antifungal effect than AgNPs, it was found to have a higher effect than NaOCl (p < .016). Nanoparticles present a wide research field as an alternative irrigation solution in root canal treatment. The antifungal effect of AgNPs against C. albicans was confirmed in this study. Further in vivo studies should evaluate the conditions of use and long-term prognosis of AgNPs.

Development of salting-out extraction methodology for the determination of piroxicam from polymeric based nanocarriers and biological samples.

The aim of the present study is to develop the polymeric nanoparticulate drug delivery systems of piroxicam and to evaluate the in-vitro characteristics such as entrapment efficiency, surface morphology, in-vitro drug release performance, etc. For this reason, a novel HPLC methodology was developed for the determination of piroxicam from its bulk form, pharmaceutical preparation, and nanoparticulate delivery systems. Furthermore, the developed formulation was applied to the rats and the biological samples (plasma, liver, heart, spleen, kidney, and lung homogenates) were analyzed by the developed HPLC method following a salting-out assisted liquid-liquid extraction strategy for the first time in the literature. A Kinetex C18 analytical column (150 mm × 4.6 mm i.d., 5 µm) was used as a stationary phase with a 0.8 mL/min flow rate of acetonitrile: phosphate buffer (40:60, v/v), the column oven was adjusted to 40 °C and detection wavelength is set to 360 nm. Developed method were validated as per selectivity, linearity, LOD, LOQ, precision, and accuracy specified in the International Council for Harmonisation guidelines. As a result of the present study, it has been shown that the analysis of piroxicam from the bulk form, pharmaceutical preparation, developed polymeric-based drug delivery system, and biological samples can be successfully performed and no interferences were observed in any matrix. The developed method was also successfully utilized to study the tissue distribution of piroxicam in rats.

Silver nanoparticles in endodontics: recent developments and applications.

The elimination of endodontic biofilms and the maintenance of a leak-proof canal filling are key aspects of successful root canal treatment. Several materials have been introduced to treat endodontic disease, although treatment success is limited by the features of the biomaterials used. Silver nanoparticles (AgNPs) have been increasingly considered in dental applications, especially endodontics, due to their high antimicrobial activity. For the present study, an electronic search was conducted using MEDLINE (PubMed), the Cochrane Central Register of Controlled Trials (CENTRAL), Google Scholar, and EMBASE. This review provides insights into the unique characteristics of AgNPs, including their chemical, physical, and antimicrobial properties; limitations; and potential uses. Various studies involving different application methods of AgNPs were carefully examined. Based on previous clinical studies, the synthesis, means of obtaining, usage conditions, and potential cytotoxicity of AgNPs were evaluated. The findings indicate that AgNPs are effective antimicrobial agents for the elimination of endodontic biofilms.

A study to enhance the oral bioavailability of s-adenosyl-l-methionine (SAMe): SLN and SLN nanocomposite particles.

The endogenous molecule, S-adenosyl-l-methionine (SAMe) is a key factor due to its role in the methylation cycle and modulation of monoaminergic neurotransmission. Since many mental disorders have linked to the monoaminergic system, the level of SAMe in blood and cerebrospinal fluid is important in the treatment of major depression. In this study, solid lipid nanoparticles (SLN) were prepared in order to increase the limited oral bioavailability of SAMe, and SLN based nanocomposite particles (SAMe-SLN-NC) were further developed using an enteric polymer for passive targeting of intestinal lymphatic system. In this manner, it was also aimed to protect SAMe loaded SLN from harsh gastric environment as well as hepatic first-pass metabolism. Dynamic light scattering (DLS) analysis of SLN was performed, drug content was measured, SAMe release patterns were examined and the permeation ability of SAMe was investigated by the Parallel Artificial Membrane Permeability Assay (PAMPA) to characterize SAMe loaded SLN formulation. According to the PAMPA results, SAMe-SLN with the average particle size of 242 nm showed enhanced SAMe permeability in comparison to pure drug. Delayed drug release obtained by SLN nanocomposite particles indicated the protection of drug-loaded SLN in the acidic gastric medium and their intact presence in the intestine. SAMe solution or particle suspensions were prepared using 0.45 (w/v) hydroxypropyl methylcellulose aqueous solution to be applied to groups of animals for pharmacokinetic studies. In vivo pharmacokinetic parameters revealed enhancement in relative bioavailability of SAMe upon oral administration of SLN based formulations. This was attributed to intact absorption of lipid matrix through lymphatic path. A statistically significant increase in SAMe plasma levels was obtained at 15th and 30th minutes with SAMe-SLN and at 2nd and 4th hours with SAMe-SLN-NC. Overall results suggest that SLN is a promising carrier to passive lymphatic targeting of SAMe and novel SLN nanocomposite particles which presented efficient oral bioavailability is a potential way for oral delivery of SAMe and treatment of major depression.

Layer by layer assembly of core-corona structured solid lipid nanoparticles with ß-cyclodextrin polymers.

This study aims to design and characterize the layer-by-layer assembly of core-corona nanoarchitecture for novel surface-modified solid lipid nanoparticles. Oppositely charged ß-cyclodextrin polymers were used to build corona structure onto lipid core, and the particle size, polydispersity index, and zeta potential of SLN with polymer layers were evaluated. Morphology of surface-modified SLN was identified using TEM. The effect of polymer coating on drug release pattern was investigated by in-vitro release studies. The biocompatibility of the novel SLN systems was assessed on various healty cell lines using in vitro cytotoxicity assay. The presence of the oppositely charged polymer layers was found to be effective on alteration of zeta potential from negative to positive values and an increased surface charge density was achieved in comparison to core SLN. The results also revealed that the drug release is mainly controlled by diffusion and ß-cyclodextrin polymers could enhance the slow/controlled release of drug. Cytotoxicity assay results suggested that the novel, hierarchical core-corona structured SLNs don't have cytotoxic effects on healthy cells and can be safely used as drug carriers. Overall, the layer-by-layer assembly of ß-cyclodextrin polymers is promising for designing surface-modified nanoarchitectures of lipid nanoparticles that may be applied via many administration routes.

Development and Statistical Optimization of Solid Lipid Nanoparticle Formulations of Fluticasone Propionate.

OBJECTIVES: The aim of this study was to develop fluticasone propionate (FP)-loaded solid lipid nanoparticle (SLN) formulations by using factorial design approach. MATERIALS AND METHODS: Tristearin percentages (X1) (1%, 2%, and 4%) and homogenization cycles (X2) (2, 4, and 8 cycles) were selected as independent variables in the factorial design. SLN formulations were optimized by multiple linear regression (MLR) to evaluate the influence of the selected process and formulation independent variables on SLNs' characteristics, namely as encapsulation efficiency (Q1) and particle size (Q2). The polydispersity index and surface charge of the SLNs were also evaluated in this research. Moreover, transmission electron microscopy, differential scanning calorimetry, and in vitro drug release studies were carried out on the optimum SLN formulation. RESULTS: The MLR analysis indicated that as the homogenization cycle (X2) increased in the production process, the mean particle size decreased. CONCLUSION: This research showed that FP-encapsulated SLNs with desired characteristics can be produced by varying the production and content variables of the formulations.

SLN enriched hydrogels for dermal application: Full factorial design study to estimate the relationship between composition and mechanical properties.

When considering dermal administration of cosmeceuticals and/or drugs, the stratum corneum layer of the skin, has a barrier function that limits the penetration of active substances to the targeted skin tissues. Solid lipid nanoparticles/SLNs are colloidal carrier systems, which show superiority in dermal administration of cosmeceuticals/drugs. This superiority results from the ability of the SLNs to penetrate the skin layers easily. However, the main problem in dermal administration of colloidal drug systems is the need for a suitable semisolid vehicle for application as well as patient compliance. The main purpose of this study is to investigate the relationship between hydrogels and SLNs by using 32 full factorial design which simplifies the process by establishing the relationship between variables. Two different types of gel forming agent, hydroxypropyl methylcellulose or Carbopol 934 P, in three different polymer concentration used for preparation of SLN-enriched hydrogels. Formulations evaluated for their hardness and cohesiveness by using 32 full factorial design and the optimum formulations obtained for both gelling agents. As a result, mechanical properties of hydrogels consisting either hydroxypropyl methylcellulose or Carbopol 934 P revealed promotive results for dermal application of SLNs. The type and concentration of the gel-forming agent which is selected as a semisolid carrier for lipid nanoparticles are basic parameters affecting the dermal behavior of the system.

QbD guided early pharmaceutical development study: Production of lipid nanoparticles by high pressure homogenization for skin cancer treatment.

This research attempts to bring together the positive aspects of lipid nanoparticles and Quality by Design (QbD) approach for developing a novel drug delivery system for skin cancers and aktinic keratosis. Lipid nanoparticles which is one of the most efficacious options for topical treatment of skin diseases were prepared due to their ability to overcome the complex structure of skin barrier and to enhance the skin penetration. Since the formulation development contains complex variables of active ingredients, raw materials or production method; all the variables of the product should be elaborated. QbD approach which refers to design and develop formulations and manufacturing processes to maintain the prescribed product quality was also successfully adopted to achieve a time- and cost-saving process ensuring a high-quality product. 5-Fluorouracil (5-FU) loaded lipid nanoparticles, both solid lipid nanoparticles and nanostructured lipid carriers, were developed and characterized by following QbD steps. Optimal lipid nanoparticle formulation with guaranteed quality which was within the design space has been reached through the artificial neural networks. The optimal lipid nanoparticle formulation which is a NLC formulation with a mean particle size of 205,8 ±â€¯9,34 nm, narrow size distribution (0.279 ±â€¯0.01) and negative zeta potantial -30,20 ±â€¯0,92 was produced by high pressure homogenization method. Cytotoxicity profiles of the optimal NLC was determined by cell culture studies on epidermoid carcinoma cells and human keratinocyte cells. Optimal NLC showed significantly higher anticancer effect on epidermoid carcinoma cells than free 5-FU and also less cytotoxicity towards human keratinocyte cells. Optimal NLC was formulated in hydrogel formulation for ease of application which has suitable occlusive and mechanical properties, viscocity and pH for patient complience. The cumulative amount of 5-FU in dermal tissues of rat skin was found 20.11 ±â€¯2.14 µg/cm2 and 9.73 ±â€¯0.87 µg/cm2 after application of NLC enriched hydrogel and 5-FU hydrogel respectively. In conclusion, this study showed that a time and cost saving process ensuring a high-quality product can be obtained by QbD guided formulation development study with the help of artificial neural networks. A novel semisolid dosage form enriched by NLC which is promising for topical treatment of skin cancers was developed.

Development of a HILIC method for the determination of 5-fluorouracil from nano drug delivery systems and rat skin extracts.

This is the first report in literature using hydrophilic interaction liquid chromatography (HILIC) in combination with diode array detector (DAD) for stability indicating determination of 5-Fluorouracil (5-FU) from its bulk form, pharmaceutical preparations, developed solid lipid nanoparticle (SLN) and nano structured lipid carrier (NLC) drug delivery systems as well as the rat skin extracts. The separation was performed at 45 °C, on Sequant Zic HILIC (250 mm × 4.60 mm ID, 5 µm, 200 Ao), peek HPLC column. Mobile phase is consisting of a mixture of acetonitrile: buffer containing 5 mM ammonium acetate (95:5; v/v). The pH of the mobile phase was adjusted to 7.0 using 1 M NaOH. The analysis was carried out at 0.75 mL min-1 flow rate with a detection wavelength of 265 nm and the injection volume was arranged as 10 µL. The developed method was fully validated in accordance with the International Council on Harmonization (ICH) Guidelines. Specificity of this method was demonstrated by forced degradation studies. As a result of calibration studies, the calibration curve was found linear in the concentration range of 1-250 µg mL-1 (R2 = 0.999). The precision of this technique calculated within the frame of intra-day and inter-day based on a percentage of relative standard deviation (RSD%) values (<2%). The limits of detection and quantification were 11 and 37 ng mL-1 respectively. On the other hand, 5-FU loaded SLN and NLC formulations with average particle size of 370 nm were also developed and compared in order to increase the permeation of drug into the rat skin. Ex-vivo Penetration/Permeation Studies indicated that higher dermal accumulation of 5-FU was obtained with NLC formulation. As a conclusion, the present work expressed the optimization and the validation of a selective, simple, precise and accurate fully validated HILIC method with sufficient sensitivity for the estimation of 5-FU in raw materials, marketed formulation and rat skin extract after applying both of the commercial product and newly developed nanoparticulate drug delivery systems on to the rat skins with high percentage recoveries.

Novel Drug Delivery System for Dermal Uptake of Etofenamate: Semisolid SLN Dispersion.

BACKGROUND: Semisolid SLNs are novel strategy for dermal drug administration instead of incorporating the SLN dispersions into conventional semisolids. Etofenamate loaded semisolid SLNs were successfully prepared and in vitro characterization of formulations were performed in our previous study. The present study is an attempt to evaluate the dermal behavior of the semisolid SLNs selected on the basis of previous research and investigate the properties in terms of the convenience for topical applications. OBJECTIVE: The objective of this study is to evaluate the skin penetration characteristics of semisolid SLN formulations. The occlusive and mechanical properties of semisolid SLNs were also evaluated because of their impression on the dermal behavior of the formulations. METHOD: The occlusive properties were investigated by in vitro occlusion test. Texture analysis was performed to define the hardness, compressibility, adhesiveness, cohesiveness and elasticity of the formulations. Rat skin was chosen to evaluate the ex vivo penetration of etofenamate loaded semisolid SLNs and commercial gel product. Coumarin-6 was used to visualize the dermal distribution of the semisolid SLN formulations. For monitorizing the penetration of coumarin-6 into the skin samples Confocal Laser Scanning Microscopy was employed. RESULTS: The occlusive and mechanical properties of C1 coded semisolid SLN formulation were found more favorable in comparison with P1. The cumulative etofenamate amount in skin samples was found to be 39.88 ± 1.50 µg/cm2 for C1 and 30.56 ± 2.10 µg/cm2 for P1 coded formulations. According to CLSM images, greater fluorescence intensities and deeper skin penetrations were obtained with both of the semisolid SLNs in comparison to plain Carbopol gel. CONCLUSION: It can be concluded that the semisolid SLNs are promising alternative dermal drug delivery systems to the conventional dosage forms.

Quality by design case study 1: Design of 5-fluorouracil loaded lipid nanoparticles by the W/O/W double emulsion - Solvent evaporation method.

With Quality by Design (QbD), a systematic approach involving design and development of all production processes to achieve the final product with a predetermined quality, you work within a design space that determines the critical formulation and process parameters. Verification of the quality of the final product is no longer necessary. In the current study, the QbD approach was used in the preparation of lipid nanoparticle formulations to improve skin penetration of 5-Fluorouracil, a widely-used compound for treating non-melanoma skin cancer. 5-Fluorouracil-loaded lipid nanoparticles were prepared by the W/O/W double emulsion - solvent evaporation method. Artificial neural network software was used to evaluate the data obtained from the lipid nanoparticle formulations, to establish the design space, and to optimize the formulations. Two different artificial neural network models were developed. The limit values of the design space of the inputs and outputs obtained by both models were found to be within the knowledge space. The optimal formulations recommended by the models were prepared and the critical quality attributes belonging to those formulations were assigned. The experimental results remained within the design space limit values. Consequently, optimal formulations with the critical quality attributes determined to achieve the Quality Target Product Profile were successfully obtained within the design space by following the QbD steps.

Skin Localization of Lipid Nanoparticles (SLN/NLC): Focusing the Influence of Formulation Parameters.

BACKGROUND: In this study, fluorescein labeled SLN and NLC formulations were prepared for improving the dermal distribution of the hydrophilic active ingredients and for enhancing the skin penetration. METHODS: To determine skin distribution of the lipid nanoparticles ex-vivo penetration/ permeation experiments were performed using full thickness rat skin by means of Franz diffusion cells. Studies on the localization of fluorescence labeled nanoparticles were performed by confocal laser scanning microscopy (CLSM). Cellular uptake studies were performed on human keratinocyte cell line (HaCaT) and visualized by fluorescence microscope. Both tissue and cell uptake were also quantitatively determined by means of fluorimetric method in the skin extract or cell extract. RESULTS: Both imaging and quantification studies suggest that the dermal localization of the lipid nanoparticles depends on their dimensions and particle size distribution. The CLSM images clearly show that the Tripalmitin based lipid nanoparticles have higher accumulation in the skin. It is possible to overcome the stratum corneum barrier function with T-NLC05 coded lipid nanoparticle formulation. Additionally cellular uptake of this NLC formulation is time dependent. Conclusion: It can be concluded that this formulation is promising for treating local skin disorders without systemic side effects. On the other hand obtained results suggest that optimum formulation (T-NLC05) might be an interesting option even for novel cosmetic products.