Short- and long term antibacterial effects of a single rinse with different mouthwashes: A randomized clinical trial.

Objectives: Reducing the microbial level in the aerosol created during dental procedures is essential to avoiding infections. The aim of this study was to examine the change in Streptococcus mutans (S. mutans) and the total bacterial load in human saliva in vivo after a single rinse with different mouthwashes. Material and methods: One mL of unstimulated saliva was collected from volunteers with poor oral hygiene at baseline and 5 min after a 1-min rinsing with diluted Solumium Oral® (hyper-pure 0.0015% chlorine dioxide; ClO2), Listerine Total Care®, Corsodyl® (0.2% chlorhexidine-digluconate; CHX), or BioGate Si*CLEAN for bacterial investigation. In a second study, volunteers rinsed with 0.003% ClO2 or CHX for 1 min, and saliva was collected at baseline, after 5 min, and after 90 min. After plating, the total plate and S. mutans colony numbers were determined. Results: In the first study, ClO2 and CHX similarly reduced both total germ and S. mutans numbers, while Listerine Total Care® decreased only the S. mutans counts. BioGate Si*Clean had no effect on either the total germ or S. mutans numbers. In the second study, an increasing tendency toward bacterial regrowth was observed with CHX after 90 min compared to the 5-min value, while no change was measured after ClO2 rinsing. Conclusion: Hyper-pure ClO2 rinsing may be a new promising preventive and therapeutic adjuvant in dental practice, as it is similar in effectiveness to the gold standard CHX-containing mouthwashes, especially in patients concerned with taste or tooth discoloration during oral health therapy.

Formulation of Levocetirizine-Loaded Core-Shell Type Nanofibrous Orally Dissolving Webs as a Potential Alternative for Immediate Release Dosage Forms.

Several applications of nanofiber-based systems are based on their corresponding functionality-related properties, which often cannot be satisfied by a fiber web with a monolithic structure because of the various physicochemical properties and amounts of embedded compounds. Therefore, one of the main directions in the development of fiber systems is creating core-shell type complex fiber structures that can provide application-specific properties to the fiber matrix. The present study aimed to formulate levocetirizine-loaded core-shell type hydrophilic polymer-based fibrous systems. The core phase contained the antihistamine levocetirizine, while the permeation enhancer (Na-taurocholate), the local pH regulator (citric acid), and the cyclodextrin used as a taste masking agent were included in the shell phase of the fibrous formulation. Scanning electron microscopy images indicated that a randomly oriented homogeneous fibrous structure was obtained, while the Raman mapping and chemometric analysis confirmed the partially formed core-shell structure. A fast release rate of the antihistamine drug from the complex structural fibrous system was obtained (within 1 min complete dissolution can be observed) due to its increased surface area to volume ratio and its more favorable wettability properties, which consequently allows for more erosion. The masking properties against the unpleasant bitter taste of API of the formulated complex nanostructure were confirmed by the results of the electronic tongue. The formulated complex nanostructure enabled fast and complete release of the API, providing a potential enhancement in the rate and extent of absorption while masking the unpleasant taste of levocetirizine, which has a high impact on the patient adherence. All in all, the results show that the developed orally dissolving fibrous web formulation can be a potential alternative to the commercially available orally disintegrating tablets.

Formulation of Chlorine-Dioxide-Releasing Nanofibers for Disinfection in Humid and CO2-Rich Environment.

Background: Preventing infectious diseases has become particularly relevant in the past few years. Therefore, antiseptics that are harmless and insusceptible to microbial resistance mechanisms are desired in medicine and public health. In our recent work, a poly(ethylene oxide)-based nanofibrous mat loaded with sodium chlorite was formulated. Methods: We tested the chlorine dioxide production and bacterial inactivation of the fibers in a medium, modeling the parameters of human exhaled air (ca. 5% (v/v) CO2, T = 37 °C, RH > 95%). The morphology and microstructure of the fibers were investigated via scanning electron microscopy and infrared spectroscopy. Results: Smooth-surfaced, nanoscale fibers were produced. The ClO2-producing ability of the fibers decreased from 65.8 ppm/mg to 4.8 ppm/mg with the increase of the sample weight from 1 to 30 mg. The effect of CO2 concentration and exposure time was also evaluated. The antibacterial activity of the fibers was tested in a 24 h experiment. The sodium-chlorite-loaded fibers showed substantial antibacterial activity. Conclusions: Chlorine dioxide was liberated into the gas phase in the presence of CO2 and water vapor, eliminating the bacteria. Sodium-chlorite-loaded nanofibers can be sources of prolonged chlorine dioxide production and subsequent pathogen inactivation in a CO2-rich and humid environment. Based on the results, further evaluation of the possible application of the formulation in face-mask filters as medical devices is encouraged.

Formulation of acyclovir (core)-dexpanthenol (sheath) nanofibrous patches for the treatment of herpes labialis.

Topically applied antiviral creams and patches are the commercially available options for the treatment of herpes labialis. The nanofibrous patches could be a new direction in the formulation. The project aimed to formulate core-shell type nanofibrous scaffolds loaded with dexpanthenol (shell) and acyclovir (core). To achieve the fast dissolution of the antiviral agent, hydroxypropyl-beta-cyclodextrin was used as a complexation agent. The further aim was to study the prepared electrospun scaffolds' morphological- and physicochemical properties and antiviral activity. The fibrous samples were prepared by electrospinning using polyvinylpyrrolidone (PVP) as a shell, hypromellose (HPMC), and poly(ethylene oxide)(PEO) composite or poly(vinyl alcohol) (PVA) as a core polymer. The morphology of the prepared sample was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. The SEM photos showed that fibrous structures were obtained. In the case of the PVA/PVP composition, the desired structure was obtained. While when HPMC-PEO was used as a core, the core-shell structure could not be observed. The Raman measurements revealed the mixed fibre structure of this sample. All of the fibrous samples released about 100% of acyclovir and also the dexpanthenol within 20 min. Coaxially electrospun fibres of different compositions were successfully prepared with various structural homogeneities, furthermore, a better antiviral activity could be achieved compared to the commercially available Zovirax cream.

Chlorine dioxide-loaded poly(acrylic acid) gels for prolonged antimicrobial effect.

Chlorine dioxide, the so-called "ideal biocide", can be successfully applied as an antiseptic agent based on its rapid and safe antimicrobial property. One of the significant limitations of its topical or oral use is that the chlorine dioxide residence time in aqueous solution is very short due to the volatility of the gas. Therefore, the primary purpose of the present study was to increase the duration of chlorine dioxide effect by creating a system capable of loading the gas for a prolonged time and gradually releasing it at the site of action. Poly(acrylic acid) gels of various chlorine dioxide and polymer concentrations were formulated to achieve this goal. A two-factor, three-level face-centred central composite design was applied for the formulation. The microstructure of the gels was tracked by positron annihilation lifetime spectroscopy based on the ortho-positronium (o-Ps) lifetime distributions with the residual chlorine concentrations, determined by iodometric titration and their antibacterial effects. The results indicate that the polymer possesses two functions. On the one hand, as a diffusion barrier inhibits the fugacity of the gaseous chlorine dioxide but on the other side, the polymer chains form an arranged supramolecular structure with the hydrated forms of chlorine dioxide thus resulting in its sustained fugacity. The latter showed optimum as a function of the polymer concentration in the investigated range (0.1-0.3% w/w). The o-Ps lifetime distributions confirmed the microstructural changes of the formulations and were in good agreement with the analytical and microbiological evaluation. The application of chlorine dioxide-loaded bioadhesive gels could be a promising alternative for the effective and safe treatment of topical infections.

Different types, applications and limits of enabling excipients of pharmaceutical dosage forms.

Along with the development of novel drug delivery systems the material science is also advancing. Conventional and novel synthetic or natural excipients provide opportunities to design dosage forms of the required features including their bioavailability. Emerging trends in the design and development of drug products indicate an increasing need for the functionality-related characterization of excipients. The purpose of this review is to provide an overview of different types of excipients in relation to their application possibilities in various dosage forms with special focus on the enabling excipients. The study also summarizes the applied excipient systems of research formulations and dosage forms available on the market.