Bioactive compounds, such as antimicrobial peptides (AMPs), have increasingly been used recently to counteract the rapidly increasing incidence of bacterial resistance to usual antibiotics and chemotherapeutics. In humans, endogenous AMPs are part of the immune system and act against pathogens. Defensins compose a class of AMPs that have activity against gram-positive and-negative bacteria, viruses, and fungi. For some, antitumour activity has also been reported. Such characteristics indicate that they represent a potential new class of therapeutic agents against microorganisms, including multidrug resistant pathogens. However, pH and enzymatic degradation and variable tissue distribution of these compounds limit their clinical application. New technologies and different methods have been developed to overcome these limitations and increase their half-life, such as cyclization, lipidation, design of peptidomimetics, synthesis of hybrid peptides, and use of nanocarriers. The objective of this review was to analyse current applications of defensins as antimicrobial agents and their mechanism of action. Moreover, new technologies and methods for stabilizing defensins are discussed.
Present study describes a high-performance liquid chromatography method for the determination of the potent kinetic stabilizer—Tafamidis in human plasma. It was approved for medical use in European Union in 2011. Ultra violet (UV) detection mode and isocratic elution of the mobile phase were set and made the analytical procedure fast and widely applicable. Chromatographic determination was performed on a Purospher® RP-18 column. The mobile phase consisted of 0.1% trifluoroacetic acid in water and acetonitrile in the ratio 42:58 v/v and the flow rate was 1.0 ml/min. All analyses were carried at a room temperature and the detector was set at 280 nm. Calibration curve over a range of 1.00–10.00 μM was constructed for the purposes of linearity method validation. The specificity and effectiveness of the developed method made it suitable for observation of patients’ plasma Tafamidis concentration with time and drug therapy monitoring.
Lavender (L. angustifolia Mill.) is an important essential oil-bearing and medicinal plant with high commercial value. Lavender scent components can be derived not only as an essential oil but also as lavender concrete or absolute. The development of reliable analytical methods for origin assessment and quality assurance is of significant fundamental importance and high practical interest. Therefore, a comprehensive chemical profiling of seven industrial samples of Bulgarian lavender absolute (L. angustifolia Mill.) was performed by means of gas chromatography–mass spectrometry (GC/MS) and gas chromatography with flame ionization detection (GC-FID). As a result, 111 individual compounds were identified by GC/MS, and their quantitative content was simultaneously determined by GC-FID, representing 94.28–97.43% of the total contents of the lavender absolute. According to our results, the main constituents of lavender absolute (LA) are representatives of the terpene compounds (with the dominating presence of oxygenated monoterpenes, 52.83–80.55%), followed by sesquiterpenes (7.80–15.21%) and triterpenoids (as minor components). Coumarins in various amounts (1.79–14.73%) and aliphatic compounds (hydrocarbons, ketones, esters, etc.) are found, as well. The acyclic monoterpene linalool is the main terpene alcohol and, together with its ester linalyl acetate, are the two main constituents in the LAs. Linalool was found in concentrations of 27.33–38.24% in the LA1-LA6 samples and 20.74% in the LA7 samples. The amount of linalyl acetate was in the range of 26.58 to 37.39% in the LA1–LA6 samples, while, surprisingly, it was not observed in LA7. This study shows that the chemical profile of the studied LAs is close to the lavender essential oil (LO), fulfilling most of the requirements of the International Standard ISO 3515:2002.
Objective: A high performance liquid chromatographic method with ultra violet detection for simultaneous analysis of three sartans (Valsartan, Irbesartan and Telmisartan) has been developed for quality control. Method and Results: Isocratic elution on a LiChrospher C18 column (250 × 4 mm, particle size 5 µm) at the temperature 30ºC with a mobile phase consisting of 10mM phosphate buffer: acetonitrile (65:35 v/v) at a flow rate 1.0 ml/min has been done. The column eluent was monitored with a UV detector at 225 nm. This allowed a rapid detection and identification as well as quantitation of the eluting peaks. Method Validation: Calibration curves for all drugs were in the range of 5-40 µg/ml and the linear regression coefficients were more than 0.995. Recovery rates for the sartans were in the range 96.5% to 103.1%. The limits of detection were calculated between 0.04-0.06 µg/ ml. Also, the limits of quantification were 0.12-0.16 µg/ml. Within-day and between-day coefficient of variation for all sartans at all concentrations in the range of 0.83 -3.79% was calculated. Conclusion: The procedure can provide a simple, sensitive and fast method for the quality control of the three sartans in bulk and tablets.
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