Analysis of vitamin K1 and major K2 variants in rat/human serum and lipoprotein fractions by a rapid, simple, and sensitive UHPLC-MS/MS method.

Determination of the various forms of vitamin K, which are involved in coagulation and other physiological processes in humans, is challenging and no standardized method is yet available. Therefore, a reliable and practical method was developed to quantify vitamin K levels in serum and additionally in lipoprotein fractions to clarify its distribution. The LC-MS/MS method for the determination of vitamin K1 and the three main isoforms of vitamin K2 (MK-4, MK-7, MK-9) was combined with a gradient ultracentrifugation technique to allow the separation of lipoprotein fractions. The chromatographic separation was carried out on a Kinetex™ C18 column using a mobile phase consisting mainly of methanol. The target analytes were detected by electrospray ionization mass spectrometry. The separation of all four substances was achieved after a simple sample preparation technique based on miniaturized liquid-liquid extraction. Our method of only 8.5 min revealed the levels of the major forms of vitamin K in 59 human and 12 rat sera and confirmed our hypothesis that vitamin K is primarily (about 50 %) found in the high-density lipoprotein fraction. The median concentrations of vitamin K1, MK-4, MK-7, and MK-9 were found to be 1.19, 2.98, 0.43, and < 0.71 nmol/L in human serum and 1.74, 6.75, less than 0.2, and less than 0.5 nmol/L in rat serum, respectively.

Comparison of the liquisolid technique and co-milling for loading of a poorly soluble drug in inorganic porous excipients.

Drug loading into mesoporous carriers may help to improve the dissolution of poorly aqueous-soluble drugs. However, both preparation method and carrier properties influence loading efficiency and drug release. Accordingly, this study aimed to compare two preparation methods: formulation into liquisolid systems (LSS) and co-milling for their efficiency in loading the poorly soluble model drug cyclosporine A (CyA) into mesoporous magnesium aluminometasilicate Neusilin® US2 (NEU) or functionalized calcium carbonate (FCC). Scanning electron microscopy was used to visualize the morphology of the samples and evaluate the changes that occurred during the drug loading process. The solid-state characteristics and physical stability of the formulations, prepared at different drug concentrations, were determined using X-ray powder diffraction. In vitro release of the drug was evaluated in biorelevant media simulating intestinal fluid. The obtained results revealed improved drug release profiles of the formulations when compared to the milled (amorphous) CyA alone. The dissolution of CyA from LSS was faster in comparison to the co-milled formulations. Higher drug release was achieved from NEU than FCC formulations presumably due to the higher pore volume and larger surface area of NEU.

Analysis of terbinafine in PLGA-based drug delivery systems by a fast and sensitive UHPLC-DAD method.

A novel ultra-high performance chromatography method with multichannel detection that allows fast, sensitive, and robust analysis of an antifungal drug terbinafine and its three main impurities ß-terbinafine, (Z)-terbinafine, and 4-methylterbinafine in just 5.0 min has been developed. Analysis of terbinafine is important in pharmaceutical analysis since it enables the detection of its impurities at very low concentrations. In this study, we focused on the development, optimization, and validation of the UHPLC method as well as its subsequent application in the evaluation of terbinafine and its three main impurities in the dissolution medium to reveal the incorporation of terbinafine in two poly(lactic-co-glycolic acid) (PLGA) carriers and testing of the drug release at pH 5.5. PLGA based drug delivery systems such as solid dispersions, thin films, microparticles, and nanoparticles are new favorable ways of terbinafine administration. PLGA features excellent tissue compatibility, biodegradation, and adjustable drug release profile. Our pre-formulation study indicates that poly(acrylic acid) branched PLGA polyester has more suitable properties than tripentaerythritol branched PLGA polyester. Therefore, the former is likely to enable design of a new drug delivery system for topically applied terbinafine that could facilitate its administration and increase patient compliance.

Vitamin K - sources, physiological role, kinetics, deficiency, detection, therapeutic use, and toxicity.

Vitamin K is traditionally connected with blood coagulation, since it is needed for the posttranslational modification of 7 proteins involved in this cascade. However, it is also involved in the maturation of another 11 or 12 proteins that play different roles, encompassing in particular the modulation of the calcification of connective tissues. Since this process is physiologically needed in bones, but is pathological in arteries, a great deal of research has been devoted to finding a possible link between vitamin K and the prevention of osteoporosis and cardiovascular diseases. Unfortunately, the current knowledge does not allow us to make a decisive conclusion about such a link. One possible explanation for this is the diversity of the biological activity of vitamin K, which is not a single compound but a general term covering natural plant and animal forms of vitamin K (K1 and K2) as well as their synthetic congeners (K3 and K4). Vitamin K1 (phylloquinone) is found in several vegetables. Menaquinones (MK4-MK13, a series of compounds known as vitamin K2) are mostly of a bacterial origin and are introduced into the human diet mainly through fermented cheeses. Current knowledge about the kinetics of different forms of vitamin K, their detection, and their toxicity are discussed in this review.