CE detection of N-(3-dimethylaminopropyl)-N-carbodiimide/N-hydroxysuccinimide-coupled proteins after homo- and hetero-crosslinking reactions

Protein-protein conjugates formed by carbodiimide crosslinking reactions have been analyzed for the first time using CE. Lysozyme and BSA were chosen as model proteins to study the efficacy of N-(3-dimethylaminopropyl)-N-ethylcarbodiimide and N-hydroxysuccinimide as crosslinkers. Detection of the molecular mass increase was checked by SDS-PAGE. Commercially available, PVA-coated capillaries showed appropriate selection, while phospho-deactivated and dynamic PVA-coated capillaries did not give suitable resolution. CE was found to be an efficient tool to characterize homo- (lysozyme-lysozyme) and hetero- (lysozyme-BSA) protein coupling by suitable variations of electrophoretic mobilities.

Effect of ionic and non-ionic polymer on the pH of lidocaine hydrochloride preparation assessed below and over human skin surface temperature

Lidocaine is widely accepted local anesthetic, which is applied in the form of freely soluble hydrochloride salt. In this study we evaluated the pH of respective solutions of lidocaine hydrochloride with ionic polymer--polyacrylic acid or non-ionic polymer--methylcellulose, and compared to physiological skin conditions in the range between 22 degrees C and 41 degrees C. In microscopic observation of lidocaine hydrochloride preparations with polyacrylic acid the micro-sedimentation was revealed, however obtained mixture was opalescent, and homogenously dispersed in aqueous environment. The pH was maintained on the level not higher then 4,0 in the period of 12 hours for polyacrylic acid formulation, whereas in the case of preparation with methylcellulose, the pH increased from acceptable pH of ca. 4,5 to the level of above 6,0. The polyacrylic acid derivatives should be further studied as vehicles forming preparations with stable pH value during application on the skin, with more specific methods including pH microelectrodes, sufficient for assessments in small quantities of liquids of skin surface.

The influence of increased cross-linker chain length in thermosensitive microspheres on potential sun-protection activity

The sun protection should involve substances with protecting activity against both UVB and UVA radiation. In this research the evaluation of thermosensitive microspheres as potential molecules for sunscreen formulations was approached, using modified Boots star rating system. The microspheres, thermosensitive N-isopropylacrylamide derivatives, have potential protecting activity against UV radiation. The MX and DX microspheres, with ethylene glycol dimethacrylate and diethylene glycol dimethacrylate crosslinker respectively, due to theirs thermosensitivity exhibit increase in protecting activity against UV radiation when heated to 45 degrees C. The MX microspheres have higher increase in terms of UV absorbance, comparing to DX microspheres, when heated in the 25 degrees C to 45 degrees C range. Studied microspheres have high potential for application as components of sun-screens used in elevated temperatures.

The influence of anionic and non-ionic polymer on adjustment of pH of chlorhexidine preparation including respective solubility aspect

The solubility of chlorhexidine is highly dependent on the salt present in solution. The aim of present research was evaluation of the effect of two polymers: polyacrylic acid and methylcellulose on the pH of resulting preparation, containing chlorhexidine. Also the solubility aspect was considered in the discussion, as an helpful issue in development in drug form technology. Preparations of chlorhexidine with methylcellulose are characterized by high pH in the range between 9,70-9,98 depending on the temperature of measurements. For preparations of chlorhexidine and polyacrylic acid pH of 5,31-5,72 was evaluated, which was near the physiological values of skin pH. The polyacrylic acid acts as a buffer and enables maintaining of pH near to physiological values. As the connection between polyacrylic acid and chlorhexidine seems to be strong, respective assessments of antimicrobial activity should be performed, to evaluate the applicative value of the preparations.

Evaluation of thermosensitive microspheres as potential components for sun-protectors

In this study thermosensitive polymeric microspheres obtained in former research were evaluated in vitro for their photoprotective activity. The UVA/UVB ratio was assessed at so called shelf temperature, i.e., at 25 degrees C, and at elevated temperature of 45 degrees C. The evaluated polymers absorb higher levels of UV radiation, when heated from 25 degrees C to 45 degrees C. The MS1 polymer may be defined as polymer with high efficiency in the terms of gaining protection against UVA radiation, when heated. The MS2 absorbs both UVA and UVB radiation, and may be considered, as most protective, when heated to 45 degrees C. The equalized and less strong activity has the polymer MS3 when heated, with lipophilic radical implemented during synthesis.

Industrial production of enzyme-modified wool fibers for machine-washable bed coverings

Enzyme technology is explored on wool fibers to prevent shrinkage and consolidation behavior during washing of woolen bed coverings using normal household machine conditions. Enzyme modification of wool fibers after two different pretreatments has been realized on industrial scale. Enlarged proteolytic enzyme by chemical modification was applied successfully to prevent substantial fiber strength loss. Felt-ball analysis of the fibers as obtained from this industrial process showed substantial improvement in felting resistance. Further processing of these enzyme-modified fibers and finally integration in bed covering quilts have been executed successfully on industrial production lines. The observed fiber losses during processing were in the range of 4.5-6% which is comparable with that of nonmodified fibers. The machine-washability of these produced bed covering quilts was tested in a household washing machine using both wool and normal wash programs applied at different temperatures. It appeared that, contrary to the good washing results in terms of shrinkage and consolidation resistance using the wool program at moderate temperatures, this resistance is marginal when washed with the normal washing program with higher mechanical agitation level or with the wool program at elevated temperature. This result was different from that obtained with woolen fabrics and explained by the less-structured organisation of fibers within a fleece.

The conductivity measurements applied for the evaluation of controlled release of chlorhexidine from thermosensitive N-isopropylacrylamide derivative microgels

The aim of the work was the evaluation of the conductivity changes in aqueous environment, consisting of chlorhexidine, and N-isopropylacrylamide derivative microgel, during increasing the temperature between 25 degrees C and 42 degrees C, as a prerequisite to develop the this microgel for controlled release of chlorhexidine, when alterations in temperature are involved. Conductivity of studied systems underwent specific alterations, when temperature increased. For the system with polymer PNM I the values of conductivity were in the range 104,47 microS/cm - 134,70 microS/ cm, for temperature range 25 degrees C and 42 degrees C. In the case of PNM II - CX system, respective values reached 91,75 microS/cm - 135,95 microS/cm. The lowest conductivity values were observed when PNM III - CX mixture was studied: 96,90 microS/cm and 117,37 microS/cm. When a complex of derivatives of N-isopropylacrylamide with chlorhexidine undergoes thermal alteration, there is a potential to obtain controlled release of chlorhexidine from the polymeric bead in the range between 25 degrees C and 42 degrees C. The affinity of chlorhexidine to the polymer may be assessed in this systems applying the conductivity measurements. The solubility of chlorhexidine in the polymeric systems should be in future evaluated, to determine role of this factor in the conductivity alterations.

The pH changes of diluted dispersions of poly(N-isopropylacrylamide) below and over the LCST in the presence of chlorhexidine

The pH of diluted aqueous dispersions of modified poly(N-isopropylacrylamide) with chlorhexidine was evaluated, at normalized skin surface temperature, as well below and over the lower critical solution temperature value. Three different poly-N-isopropylacrylamides were synthesized by surfactant free emulsion polymerization. They were evaluated in the terms of pH in the aqueous dispersions in the presence of chlorhexidine. The tendency was similar in all investigated systems at increasing temperature between 25 degrees C and 45 degrees C. The pH value decreased from the range between 9.87-9.94 down to the range 9.38-9.46. The course of pH decrease between the temperature of 32 degrees C and 45 degrees C was more radical, comparing to 25 degrees C and 32 degrees C, however in general the decrease was monotonic. The systems with chlorhexidine tend to change the pH with temperature increase more radically, in the comparison to the chlorhexidine alone. The formulations applied on the skin surface or in the oral cavity should be evaluated in proper temperature spectrum.

The application of conductivity measurements for preliminary assessments of chlorhexidine and lidocaine hydrochloride release from methylcellulose gel at various temperatures

For the evaluation of conductivity measurements in the control and monitoring of release process, high number of conductivity measurements was performed. The measurements were done for the compositions of chlorhexidine with methylcellulose, and lidocaine hydrochloride with methylcellulose. Chlorhexidine, a very slightly soluble substance is released from the methylcellulose bead in the amounts ca. 30%-70%, and it depends of temperature of the release process. The lidocaine hydrochloride at the same time is released from methylcellulose formulation in 70-100%. The conductivity in the donor compartment at the start point, and in the acceptor compartment at the termination point, reflect the released amounts of the drug. This study confirms the possibility of application of conductivity measurements for the preliminary assessments of the kinetics of release of soluble and practically insoluble substances from the nonionic polymeric matrix.

The influence of lidocaine hydrochloride on environmental pH changes of diluted dispersions of poly(N-isopropylacrylamide) below and over the LCST

In this study we assessed the influence of lidocaine hydrochloride on the pH of diluted aqueous dispersions of modified poly(N-isopropylacrylamide), at temperature assigned as normalized skin surface temperature, and below and over the lower critical solution temperature value. Three different N-isopropylacrylamide polymer derivatives were synthesized by surfactant free emulsion polymerization, and assessed in the terms of pH in the aqueous dispersions in the presence and absence oflidocaine hydrochloride. The tendency in observed system was similar at three different temperatures, when lidocaine was applied. The pH value increased from the range between 5,39 - 5,90 up to the range 6,22 - 6,55. However, the step of pH between the temperature of 25 degrees C and 32 degrees C was more radical, comparing to 32 degrees C and 45 degrees C. The lidocaine hydrochloride influences the pH patterns observed at various temperature in polymeric systems: measurements of preparations applied on the skin or mucosa should be evaluated in respective temperature range.

The use of conductometric assessments for development of pulsed release of lidocaine hydrochloride from thermosensitive N-isopropylacrylamide microgels

The aim of present work was preliminary assessment of the conductivity changes in aqueous compartment, consisting oflidocaine hydrochloride, and N-isopropylacrylamide derivative microgel, during increasing the temperature between 25 degrees and 42 degrees C, as a prerequisite to demonstrate the possibility of applying this microgel for pulsed release of lidocaine hydrochloride, when increased temperature is applied. Conductivity of respective systems composed of polymer and lidocaine hydrochloride were assigned as PNM I-LD, PNM II-LD, and PNM III-LD: obtained values were in the ranges: 39,91 microS/cm - 53,30 microS/cm in the 25 degrees C temperature, 46,14 microS/cm - 56,16 microS/cm in the temperature of 32 degrees C, and 53,30 microS/cm - 118,42 microS/cm at 42 degrees C. During heating or cooling of the microgels derivatives of N-isopropylacrylamide, there is possibility to obtain pulsed release of lidocaine hydrochloride from the polymeric bead in the range between 25 degrees C and 42 degrees C, according to the conductivity measurements.

The preliminary assessment of chlorhexidine and lidocaine release from preparations of anionic polymer, evaluated by the conductivity measurements

The aim of this work was the evaluation of conductivity assessments for the monitoring and controlling the release study process of chlorhexidine and lidocaine hydrochloride from the ionic polyacrylic gel, applying different temperatures. According to performed measurements of release, the chlorhexidine, characterized by very low water solubility, is observed in the acceptor compartment in the amount of 2.0-3.0% and its level depends of the temperature. The amount of well soluble lidocaine hydrochloride released in parallel conditions was between 60 and 70%. Beyond, the assessments confirm the presence of a specific bond between the chlorhexidine imine groups and polyacrylic acid carboxylic groups. Presented method may be applied in the prediction of release rates, before actual release analysis, and may assure better evaluation of the systems.

Enzymatic reduction of azo and indigoid compounds

A customer- and environment-friendly method for the decolorization azo dyes was developed. Azoreductases could be used both to bleach hair dyed with azo dyes and to reduce dyes in vat dyeing of textiles. A new reduced nicotinamide adenine dinucleotide-dependent azoreductase of Bacillus cereus, which showed high potential for reduction of these dyes, was purified using a combination of ammonium sulfate precipitation and chromatography and had a molecular mass of 21.5 kDa. The optimum pH of the azoreductase depended on the substrate and was within the range of pH 6 to 7, while the maximum temperature was reached at 40 degrees C. Oxygen was shown to be an alternative electron acceptor to azo compounds and must therefore be excluded during enzymatic dye reduction. Biotransformation of the azo dyes Flame Orange and Ruby Red was studied in more detail using UV-visible spectroscopy, high-performance liquid chromatography, and mass spectrometry (MS). Reduction of the azo bonds leads to cleavage of the dyes resulting in the cleavage product 2-amino-1,3 dimethylimidazolium and N approximately 1 approximately ,N approximately 1 approximately -dimethyl-1,4-benzenediamine for Ruby Red, while only the first was detected for Flame Orange because of MS instability of the expected 1,4-benzenediamine. The azoreductase was also found to reduce vat dyes like Indigo Carmine (C.I. Acid Blue 74). Hydrogen peroxide (H(2)O(2)) as an oxidizing agent was used to reoxidize the dye into the initial form. The reduction and oxidation mechanism of Indigo Carmine was studied using UV-visible spectroscopy.

Enzymatic coating of lignocellulosic surfaces with polyphenols

Upgrading of the surface characteristics could enhance the bulk properties of naturally abundant fiber-forming materials for better performance or create new value-added products. Laccase can induce cross-linkage and covalent coupling of low molecular weight compounds onto lignocellulosic surfaces. For this purpose the 38-kDa laccase from Trametes hirsuta was purified and characterized. The best conditions for laccase-induced coating of flax fibers were determined. This evaluation was based on the obtained coloration and color depth. A screening was carried out with different phenols for their potential as monomers for enzyme-catalyzed polymerization resulting in a coating with antibacterial performance. While all the methoxyphenols showed different coloration with weak fastness properties, bacterial growth of Bacillus subtilis and Staphylococcus aureus was reduced significantly using ferulic acid and hydroquinone. Using laccase-induced coupling and polymerization, multi-functionality of the lignocellulosic surface, such as coloration and antimicrobial performance, was achieved, which depended on the nature of the applied phenolic monomer.

A new cuticle scale hydrolysing protease from Beauveria brongniartii

From a screening for the production of new proteases specific for cuticle scales, Beauveria brongniartii was selected producing an alkaline Ca(++) dependent protease. The purified had a molecular weight of 27 kDa and a pI value of 8.0. Substrate specificities of model substrates (wool with partially removed cuticles treated with SDS) were analyzed by protein release, dissolved organic carbon (DOC) and nitrogen analysis. The C/N ratio of released material turned out to be a good parameter to determine the site of action of proteases on fibres. Compared to other enzymes, the fungal protease preferentially hydrolyzed cuticle scales and has thus a potential for anti-shrinking pre-treatment of wool fabrics.