Photodegradation of a Broad-Spectrum Antibiotic Azithromycin Using H2O2 under Ultraviolet Irradiation.

The photodegradation of azithromycin present was carried out in water using H2O2 under UV irradiation. The reaction variables considered in this study were the amount of H2O2 solution and the initial concentration of azithromycin to evaluate the performance of the photodegradation process. The azithromycin degradation was not observed in the dark during stirring for 20 min. The study showed an efficient photodegradation of azithromycin using H2O2 as an oxidant in the presence of UV irradiation. The azithromycin degradation was altered significantly by the pH of the irradiated solution. The degradation was low at an acidic pH and showed an increasing trend as the pH changed to basic. The azithromycin degradation increased with a higher amount (higher concentration) of H2O2. The degradation of azithromycin decreased with a higher concentration of azithromycin in the reacting solution. The highest degradation of AZT was achieved in 1 h using a 1.0 ppm AZT solution containing 3 mL of H2O2. The experimental data obtained were well-fitted to zero-order reaction kinetics. The results of this study were found quite excellent. They showed 100% degradation in 1 h when compared with those reported in the literature, both with photocatalysis using nanomaterials and photolysis using light irradiation and/or H2O2. The UV/H2O2 system was found to be quite efficient for the photodegradation of azithromycin, and this system can be applied to degrade other organic pollutants present in industrial wastewater.

Sample pretreatment and HPLC determination of antiplatelet drug ticagrelor in blood plasma from patients with acute coronary syndromes.

A simple HPLC method was developed for the determination of antiplatelet drug ticagrelor (TCG) in blood. Sample preparation and extraction conditions were investigated and optimized. The preparation of blood plasma was investigated by protein precipitation using perchloric acid, methanol, acetonitrile (ACN), and trifluoroacetic acid. Protein precipitation using ACN was found to be the most suitable. Chromatographic separation of TCG was performed on a C18 column with a mobile phase consisting of ACN and 15 mM ammonium acetate buffered at pH 8.0. The method was applied to determine TCG in blood plasma of patients who had a heart attack. Blood samples were collected 1.5 h after the administration of the initial loading dose of the antiplatelet drug. The average concentration of TCG was found to be 0.97 ± 0.53 µg/ml. The developed method proved to be very selective, without interferences from other endogenous substances and the influences of possible coadministered drugs. The limits of detection and quantification estimated by the signal-to-noise ratio in real samples were 0.24 and 0.4 µg/ml, respectively. The developed method is simple and can be easily applied in clinics and emergency cardiac situations after the initial loading dose of TCG in the first few hours of a heart attack.

Comparison of three electromembrane-based extraction systems for NSAIDs analysis in human urine samples.

A comparative study on the extraction efficiency of five non-steroidal anti-inflammatories was carried out using three different electromembrane extraction (EME) devices with different geometries. The employed setups were (a) a hollow fiber configuration (HF-EME), (b) a microfluidic device that allows working in semi-dynamic mode (µF-EME), and (c) a static miniaturized flat membrane device (FM-EME). Each system was applied to the extraction of salicylic acid (SAC), ketoprofen (KTP), naproxen (NAX), diclofenac (DIC), and ibuprofen (IBU) and subsequent determination by high-performance liquid chromatography with UV and fluorescence detection (HPLC/UV-DAD-FLD). Voltage, pH composition, and extraction time were optimized for all devices. Additionally, volume ratio was investigated for HF-EME and FM-EME and flow rate for the microfluidic device. HF-EME provides the best result in terms of sensitivity with a limit of detection (LOD) between 0.1 and 1.5 ng mL-1 for SAC and KTP, respectively, while LODs for µF-EME were between 100 ng mL-1 and 400 ng mL-1 for SAC and DIC, respectively; however, a lower amount of sample was required. Finally, the obtained results, in terms of enrichment factors and extraction recoveries, were discussed to establish the advantages and disadvantages of each device. The proposed EME methods were successfully applied to the determination of the target analytes in fortified human urine samples. Graphical abstract.

Investigation of Anti-Fatigue Effect and Simultaneous Determination of Eight Nucleosides in Different Parts of Velvet Antler in Red Deer and Sika Deer.

Velvet antler (VA) is crucial and precious nourishment in China and some countries in Southeast Asia and has excellent anti-fatigue effect. The incidence of fatigue syndrome has increased gradually. VA can be a potential source of anti-fatigue products. Therefore, we investigated the anti-fatigue activity of different sections (upper, middle, and basal section) of VA from different species (red deer and sika deer) via loading swimming test in mice. Furthermore, nucleosides are one kind of active components in VA which could considerably reduce fatigue in mice. In order to explore whether the nucleosides are correlated with anti-fatigue effect, the contents of eight nucleosides (uracil, cytidine, hypoxanthine, xanthine, thymine, inosine, guanosine, and adenosine) were determined simultaneously using high-performance liquid chromatography. The results indicated that the swimming time in mice was increased from basal to upper section, which was consistent with the change trend of the total contents of eight nucleosides of VA. Therefore, we speculated that the contents of nucleosides in VA may affect its anti-fatigue effect. Furthermore, the contents of nucleosides were also used as a reference for evaluating the quality of different parts of VA obtained from red and sika deer.

Measurement of α-dicarbonyl compounds in human saliva by pre-column derivatization HPLC.

Background α-Dicarbonyl compounds (α-DCs) have been detected in body fluids including plasma and urine and elevation of this sort of compounds in vivo has been associated with the development of many kinds of chronic diseases. However whether α-DCs are present in human saliva, and if their presence/absence can be related with various chronic diseases is yet to be determined. Methods In this study, a pre-column derivatization HPLC-UV method was developed to measure 3-deoxyglucosone (3-DG), glyoxal (GO), methylglyoxal (MGO), diacetyl (DA), and pentane-2,3-dione (PD) in human saliva employing 4-(2,3-dimethyl-6-quinoxalinyl)-1,2-benzenediamine (DQB) as a derivatizing reagent. The derivatization of the α-DCs is fast and the conditions are facile. The method was evaluated and the results show that it is suitable for the quantification of α-DCs in human saliva. Results In the measurements of these α-DCs in the saliva of 15 healthy subjects and 23 type 2 diabetes mellitus (T2DM) patients, we found that the concentrations of GO and MGO in the saliva of the diabetic patients were significantly higher than those in healthy subjects. As far as we know, this is the first time that salivary α-DC concentrations have been determined and associated with T2DM. Conclusions The developed method would be useful for the measurement of the salivary α-DC levels and the data acquired could be informative in the early screening for diabetes.

Antimicrobial, Antioxidant Activities, and HPLC Determination of the Major Components of Verbena carolina (Verbenaceae).

Verbena carolina L. (Verbenaceae) is used as a decoction in Mexican folk medicine with applications against digestive problems and for dermatological infections. The present work firstly reported HPLC analysis, as well as the free radical scavenging capacity of the extracts and isolated compounds. Antimicrobial analyses of these substances against the bacteria Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Salmonella typhi and the fungi Candida albicans, Trichophyton mentagrophytes and T. rubrum were also tested, as well as the acute oral toxicity in mice of aqueous extracts. Major secondary metabolites in V. carolina extracts were isolated by conventional phytochemical methods which consisted of three terpenoids ((1), (3) and (4)) and four phenolic compounds ((2), (4)-(6)). Their contents were determined by HPLC in six different samples from different locations. The results indicated that ursolic acid (1), hispidulin (2), verbenaline (3), hastatoside (4), verbascoside (5), hispidulin 7-O-ß-d-glucuronopyranoside (6) and pectolinaringenin-7-O-α-d-glucuronopyranoside (7) were the main constituents and ranged from 0.17 to 3.37 mg/g of dried plant, with verbascoside being the most abundant and with a significant antioxidant activity in reactive oxygen species (ROS). Hispidulin was the only active compound against T. mentagrophytes and T. rubrum. The aqueous extract showed no significant toxicity (LD50: > 5000 mg/mL). To our knowledge, this is the first comprehensive report of the chemical characterization of V. carolina and also of the activity of its constituents towards reactive oxygen species and dermatophytes, and its safety for consumption.

Investigation of Permeation of Theophylline through Skin Using Selected Piperazine-2,5-Diones.

Transdermal administration of drugs that penetrate, in this case directly into the blood circulation, has many advantages and is promising for many drugs thanks to its easy application and good patient compliance. (S)-8-Methyl-6,9-diazaspiro[4.5]decan-7,10-dione (alaptide), has been studied as a potential chemical permeation enhancer. Based on its structure, four selected piperazine-2,5-diones were synthesized by means of multi-step synthetic pathways. All the compounds were investigated on their ability to enhance the permeation of the model drug theophylline from the hydrophilic medium propylene glycol:water (1:1). In vitro experiments were performed using vertical Franz diffusion cells at constant temperature 34 ± 0.5 °C and using full-thickness pig (Sus scrofa f. domestica) ear skin. Withdrawn samples were analyzed by RP-HPLC for determination of the permeated amount of theophylline. All the compounds were applied in ratio 1:10 (w/w) relative to the amount of theophylline. One hour after application, the permeated amount of theophylline from formulations with alaptide and (3S,6S)-3,6-dimethylpiperazine-2,5-dione, was ca. 15- and 12-fold higher, respectively, than from the formulation without the tested compounds. Despite the enhancement ratio of both enhancers in a steady state was ca. 2.3, the pseudo-enhancement ratio in the time range from 1 to 3 h was 4.4. These enhancement ratios indicate that the compounds are able to enhance the permeation of agents through the skin; however, the short-term application of both compound formulations seems to be more advantageous. In addition, the screening of the cytotoxicity of all the prepared compounds was performed using three cell lines, and the compounds did not show any significant toxic effect.

A Novel Two-Step Liquid-Liquid Extraction Procedure Combined with Stationary Phase Immobilized Human Serum Albumin for the Chiral Separation of Cetirizine Enantiomers along with M and P Parabens.

The research into the separation of drug enantiomers is closely related to the safety and efficiency of the drugs. The aim of this study was to develop a simple and validated HPLC method to analyze cetirizine enantiomers. In the case of liquid dosage forms, besides the active substance in large amounts there are usually also inactive ingredients such as methyl- and propylparaben. Unfortunately, these compounds can interfere with the analyte, inter alia during chiral separation of the analyte enantiomers. The proposed innovative two-step liquid-liquid extraction procedure allowed for the determination of cetirizine enantiomers (along with M and P parabens) also in liquid dosage forms. The main focus of this study was the chromatographic activity of cetirizine dihydrochloride on the proteinate-based chiral stationary phase. The chromatographic separation of cetirizine enantiomers was performed on an immobilized human serum albumin (HSA) column for the first time. Measurements were performed at a wavelength of 227 nm. Under optimal conditions, baseline separation of two enantiomers was obtained with 1.43 enantioseparation factor (α) and 1.82 resolution (Rs). Finally, the proposed method was successfully applied to the selected pharmaceutical formulations.

Improved protein deproteinization method for the determination of meloxicam in human plasma and application in pharmacokinetic study.

A simple, rapid, specific and reliable high-performance liquid chromatographic assay of meloxicam in human plasma has been developed using a C18 reversed-phase analytical column. Reversed-phase chromatography was conducted using a mobile phase of 0.02 potassium dihydrogen phosphate (adjusted to pH 2.7 with phosphoric acid)-acetonitrile-triethylamine (35:65:0.05, v/v) with UV detection at 354 nm. The drug in human plasma was deproteinized using a combination of methanol and chloroform. This method is simple, rapid and consistent with a high recovery of meloxicam in human plasma ranging from 93.29 to 111.09%. Regression analysis for the calibration plot for plasma standards obtained for the drug concentrations between (25-4000) ng/mL indicated excellent linearity (r ≥ 0.9997). The proposed method was applied to study the bioequivalence between Mobic (original) and Melocam (generic) products. The study was conducted on using two tablets (4 × 7.5 mg) of each of the commercial product and the reference standard in a two-way open randomized crossover design involving 20 volunteers. Area under the concentration-time curve, peak concentration (C(max)) and time to reach C(max) were 72,868.61 ng h/mL, 2133.93 ng/mL and 4.06 h for Mobic, and 78,352.52 ng h/mL, 2525.18 ng/mL and 3.61 h for Melocam. Two C(max) were discovered in the pharmacokinetic profiles which confirm enterohepatic recirculation.

Determination of α-Dicarbonyl compounds in traditional Chinese herbal medicines.

α-DCs (α-dicarbonyls) have been proven to be closely related to aging and the onset and development of many chronic diseases. The wide presence of this kind of components in various foods and beverages has been unambiguously determined, but their occurrence in various phytomedicines remains in obscurity. In this study, we established and evaluated an HPLC-UV method and used it to measure the contents of four α-DCs including 3-deoxyglucosone (3-DG), glyoxal (GO), methylglyoxal (MGO), and diacetyl (DA) in 35 Chinese herbs after they have been derivatized with 4-nitro-1,2-phenylenediamine. The results uncover that 3-DG is the major component among the α-DCs, being detectable in all the selected herbs in concentrations ranging from 22.80 µg/g in the seeds of Alpinia katsumadai to 7032.75 µg/g in the fruit of Siraitia grosuenorii. The contents of the other three compounds are much lower than those of 3-DG, with GO being up to 22.65 µg/g, MGO being up to 55.50 µg/g, and DA to 18.75 µg/g, respectively. The data show as well the contents of the total four α-DCs in the herbs are generally in a comparable level to those in various foods, implying that herb medicines may have potential risks on human heath in view of the α-DCs.

HPLC determination of massoia lactone in fermented Cordyceps sinensis mycelium Cs-4 and its anticancer activity in vitro.

The fermentation product of Cordyceps sinensis mycelium Cs-4 was commonly used as alternative substitutes of natural C. sinensis. Massoia lactone is the dominant component in the volatile oil of Cs-4 mycelium. In this research, we present a high performance liquid chromatography (HPLC) method for the quantitation of massoia lactone in Cs-4 mycelium. The high and stable contents of massoia lactone with values of 2.98-3.77 mg/g, indicated that massoia lactone could be considered as a marker for the quality assessment of this product. The results of MTT and CCK-8 assay showed that Cs-4 mycelium volatiles exhibited cytotoxicity against eight malignant tumor cells (IC50  = 6.0-49.8 µg/ml) in comparison to the anticancer drug 5-fluorouracil (IC50  = 17.0-425.3 µg/ml), and massoia lactone might be the chemical basis for the anticancer effects of Cs-4 mycelium. Compared to the commercial drugs paclitaxel and docetaxel (IC50  = 253-1973 µg/ml), the Cs-4 mycelium volatiles and massoia lactone were discovered to possess inhibitory to taxol-resistant cell lines (IC50  = 1.5-8.6 µg/ml). PRACTICAL APPLICATIONS: Considering that there is still a lack of marker components distinctive to Cs-4 mycelium, the HPLC method represents a useful tool for the quality evaluation of Cs-4 mycelium. Moreover, the volatile oil of Cs-4 mycelium and massoia lactone have prominent anticancer property in vitro. It gives a clue that Cs-4 mycelium, the volatile oil and massoia lactone could be potentially employed in the food and medical industries for its anticancer applications.

Antioxidant Activity and Total Phenolic and Flavonoid Contents of Hieracium pilosella L. Extracts.

The antioxidant activity of water, ethanol and methanol Hieracium pilosella L. extracts is reported. The antioxidative activity was tested by spectrophotometrically measuring their ability to scavenge a stable DPPH(•) free radical and a reactive hydroxyl radical trapped by DMPO during the Fenton reaction, using the ESR spectroscopy. Total phenolic content and total flavonoid content were evaluated according to the Folin-Ciocalteu procedure, and a colorimetric method, respectively. A HPLC method was used for identification of some phenolic compounds (chlorogenic acid, apigenin-7-O-glucoside and umbelliferone). The antioxidant activity of the investigated extracts slightly differs depending on the solvent used. The concentration of 0.30 mg/mL of water, ethanol and methanol extract is less effective in scavenging hydroxyl radicals (56.35, 58.73 and 54.35%, respectively) in comparison with the DPPH(•) radical scavenging activity (around 95% for all extracts). The high contents of total phenolic compounds (239.59-244.16 mg GAE/g of dry extract) and total flavonoids (79.13-82.18 mg RE/g of dry extract) indicated that these compounds contribute to the antioxidative activity.

HPLC method development for determination of doxycycline in human seminal fluid.

The present paper reports the development and validation of an analytical method for doxycycline quantification in human seminal fluid by HPLC with UV detection. The separation of doxycycline was achieved at 40°C on a reversed-phase C18 column using isocratic elution. The mobile phase consisted of acetonitrile (A) and water buffered at pH 2.5 with a concentrated orthophosphoric acid (B) in the volume ratio of 20:80 (v/v), respectively. The detection was performed at 350nm. As an internal standard (IS), tetracycline was used. The proposed method involves the extraction of doxycycline from seminal fluid based on acidic precipitation of the proteins using perchloric acid. The method showed good intra- and inter-day precisions (RSD<7.0%), good accuracy (recovery for doxycycline>80%), and high correlation coefficient (r=0.998) for standards subjected to the entire procedure. The detection and quantification limits were 0.087µg/ml and 0.264µg/ml. The developed method was used to analyze doxycycline in the seminal fluids obtained from male subjects who were treated with doxycycline-hyclate. The mean doxycycline concentrations of 0.89±0.07µg/ml and 0.45±0.26µg/ml were detected in seminal fluid after 6h and 12h, respectively. This is the first study reporting extraction and HPLC determination of doxycycline in this complex sample and can be very useful in support of clinical and pharmacokinetic studies on this antibiotic.

Determination of Patulin and Ochratoxin A using HPLC in apple juice samples in Saudi Arabia.

Although, Patulin and Ochratoxin are produced by the same genera of molds, however, Patulin was the most extensively studied mycotoxins in apple juice and no reports have explored the presence of Ochratoxin A in the apple juice. Therefore, the objective of this study was to explore the presence of Patulin and Ochratoxin A in apple juice in Saudi Arabian market of Jeddah. Potato dextrose agar(PDA) was used to detect fungal contamination. Patulin was determined using HPLC equipped with a UV detector set at 276 nm. Also, HPLC with fluorescence detector was set at 333 and 420 nm as excitation and emission wavelength, respectively,was used for Ochratoxin A separation. All samples of apple juice were free from fungi and yeasts. The Patulin (PAT) was detected in only one type out of 17 types (5.88%) with a concentration of 152.5 ppb, (305%) increased compared with the maximum permitted level (50 ppb). However the occurrence of Ochratoxin A (OTA) in apple juice samples was discovered in 5 types out of 17 types (29.41%). The concentration of OTA ranged from 100 to 200 ppb reaching 5-10-folds compared with the permissible limits (20 ppb).