In this study, a solid-phase extraction (SPE)–high performance liquid chromatography (HPLC)–ultra violet (UV) method was developed for the determination of rivaroxaban (RIV), an oral anticoagulant drug, in human plasma samples. The concentration of RIV in plasma samples was increased 7.5 times and the interference coming from matrix components was avoided by using SPE. The extracted samples of RIV were analyzed by using an HPLC–UV method. RIV was approved in 2008 and many studies have been published in recent years in order to investigate its pharmacokinetic profile in various groups. In light of this information, it is clear that the RIV pharmacokinetic profile should be investigated in further studies; the HPLC–UV method presented in this study might be an easy method to apply, as it is a cheap and rapid alternative to HPLC–MS-MS for this purpose. A Phenomenex Luna 5-µm C18 100 Å LC column (250 × 4.6 mm) was used for the separation of RIV and prednisolone (internal standard). The total analysis time was <6 min. The method was validated according to the FDA guidelines and can be proposed for pharmacokinetic studies of RIV.

The aim of this study was to determine the acid dissociation constant (pKa) of piroxicam using high performance liquid chromatography (HPLC) and ultraviolet-visible (UV-Vis) spectrophotometry, and to determine the partition coefficient (Log P), distribution coefficient (Log D), and “Log kw” values of piroxicam using HPLC. The HPLC studies were performed on a reversed-phase ACE C18 (150x4.6 mm ID, 5 μm) column at a flow rate of 1.0 mL min-1. The detector was set to 360 nm. Log D at different pH values (3.0-6.5) was examined with a phosphate buffer (20 mM) and acetonitrile (30:70 v/v) mixture as the mobile phase. For pKa determination, HPLC studies were performed with a mixture of phosphate buffer (20 mM) and methanol within the pH range of 3.50-6.00. Log kw measurements were performed with phosphate buffer (20 mM) and MeOH (from 20:80 v/v to 10:90 v/v) mixtures within the pH range of 3.50-6.00. UV-Vis spectrophotometric pKa measurements were performed at 285 nm wavelength. The pKa value of piroxicam was found to be 5.3 by HPLC and 5.7 by UV-Vis spectrophotometry. Log P of piroxicam was determined as 1.58 in our experimental conditions. Log D values were 1.57, 1.57, 1.44, 1.13, and 0.46 for pH values of 3.17, 3.79, 4.44, 5.42, and 6.56, respectively. In the literature, different Log P (3.1, 2.2, and 0.6) and pKa (6.3 and 4.8) values were reported for piroxicam. The Log P (1.58) and pKa (5.3 and 5.7) values obtained for piroxicam in our study were within the range of the literature values. All these results indicate that different experimental approaches used for the determination of physicochemical properties could provide different values. Although UV spectrophotometry is easy to apply, HPLC is a unique technique for simultaneous determination of pKa, Log D, and Log P values of compounds.

Background/aim: Metabolomics has the potential to provide putative biomarkers and insights into the pathophysiology and diagnosis of pediatric multiple sclerosis (pMS), which is an inflammatory demyelinating disorder of the central nervous system with a broad spectrum of clinical manifestations. In this study, we aimed to investigate serum metabolomics in pMS to help elucidate the pathophysiology of MS. Materials and methods: An untargeted approach was applied using the quadrupole time-of-flight liquid chromatography/mass spectrometry (Q-TOF LC/MS) method to study plasma metabolites in patients with pMS (n = 33), patients with unclassified central nervous system demyelinating diseases (n = 6), and age-matched healthy control subjects (n = 40). The patient and control groups were compared for metabolites and the normalized peak areas differed statistically (p < 0.05), showing at least a 1.25-fold change between groups. Bioinformatic tools combined with a clinical perspective were employed for the identification of the putative metabolites. In addition to the untargeted metabolomics approach, targeted LC-MS/MS metabolite analysis was employed to compare the pMS group with the control group. Results: Significant differences between the patient and control groups were noted for tyramine, 4-hydroxyphenylacetaldehyde, sphingosine/3-dehydrosphinganine, prostaglandins/thromboxane A2, 20-hydroxy-leukotriene E4, 3∝,7∝,12∝-trihydroxy-5ß-cholestan26-al/calcitriol, pantetheine, ketoleucine/3-methyl-2-oxovaleric acid, L-arginine/D-arginine, coproporphyrinogen III, (S)-reticuline, carnosine, cytidine, and phosphoribosyl pyrophosphate. Additional tests for sphingosine 1-phosphate, sphingophosphocholines, ceramides, oxysterols, and calcitriol levels yielded significant metabolomic differences for the pMS group compared to the control group. The metabolomic data of 3/6 patients with unclassified demyelinating disorders matched the pMS group; their follow-up verified the diagnosis of pMS. Conclusion: In general, plasma metabolites related to sphingolipid metabolism, myelin products, inflammatory pathways, mitochondrial dysfunction, and oxidative stress were found to be altered in cases of pMS. The method applied in this study, combining untargeted analysis with a targeted approach, can be applied to larger series of cases of pMS and other demyelinating disorders for further validation.

Background: Ankaferd Blood Stopper® is a commercially available herbal extract with potent blood-stopping property and is clinically used to treat immediate dental, dermal, external and internal bleeding. Its possible anti-neoplastic effect or whether it ingenerates drug resistance in cells has not been previously scrutinized. Objective: In the present study HEPG2 hepatocellular carcinoma cell line was exposed to clinically used dose (8 μL/mL) of the blood stopper for 24 h and the behavioral changes were investigated on both proteomic and genomic levels. Method: Cell culture experiments were performed by using Ankaferd® application in HepG2 cell line. Cytotoxic activity experiments with MTT, oncoproteomic studies with 2d gel electrophoresis, genomic studies were performed with RT-PCR. Results: It was seen that the agent did not significantly inhibit cell viability subsequent to 24 h of the treatment meanwhile, it clearly deducted cell viability after 72 h. Although reduction of HEPG2 cell proliferation was not witnessed as a response to 24 h of treatment with Ankaferd®, genomic and oncoproteomic analysis demonstrated diversification. Conclusion: It was established that protein processing networks in endoplasmic reticulum which regulate protein folding, relocation and degradation were effected. Additionally, it was proved that along with the elongation of the exposure period, mitochondrial apoptotic pathway may be activated due to hnRNP F-p53 interaction. Given to the fact that the agent did not cause P-glycoprotein-dependent drug resistance unlike many clinically used chemotherapeutic agents, it can also be considered for combination treatment. Overall, these findings suggest that Ankaferd® offers a novel promising approach against hepatocellular carcinoma which needs further investigation.