A Stability-Indicating HPLC Method for the Determination of Fingolimod in Pharmaceutical Dosage Forms

Fingolimod is an immunosuppressive agent which is used for the prophylaxis of organ transplantation rejection or multiple sclerosis treatment. In this study, systematic forced degradation studies on fingolimod bulk powder were performed to develop a stability-indicating HPLC method. Separation of fingolimod and its degradation products was achieved on a Nova-Pak C8 column. The mobile phase was a mixture of potassium dihydrogenphosphate 50 mM (pH 3.0) and acetonitrile (45:55, v/v) at a flow rate of 1 ml/min. The proposed method was linear in the range of 0.125-20 μg mL(-1). The within-day and between-day coefficients of variation were in the range of 0.6-1.2%. The developed method was successfully applied for the determination of the fingolimod amount in pharmaceutical dosage forms.

Characterization and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in urban atmospheric Particulate of Tehran, Iran

In this study, atmospheric concentrations of particulate-bound polycyclic aromatic hydrocarbons (PAHs) in Tehran megacity were determined to investigate the concentration, distribution, and sources of PAHs in PM10. The health risk from exposure to airborne BaPeq through inhalation pathway was also assessed. Toxic equivalency factors (TEFs) approach was used for quantitative risk estimate, and incremental lifetime cancer risk (ILCR) was calculated. PM10 samples were collected at ten sampling locations during the summer 2013 and winter 2014 by using two independent methods of field sampling. The PM10 concentration in winter (89.55 ± 15.56 μg m(-3)) was 1.19 times higher than that in summer (75.42 ± 14.93 μg m(-3)). Sixteen PAHs were measured with the total average concentrations of PAHs ranged from 56.98 ± 15.91 to 110.35 ± 57.31 ng m(-3) in summer and from 125.87 ± 79.02 to 171.25 ± 73.94 ng m(-3) in winter which were much higher than concentrations measured in most similar studies conducted around the world. Molecular diagnostic ratios were used to identify PAH emission sources. The results indicated that gasoline-driven vehicles are the major sources of PAHs in the study area. Risk analysis showed that the mean and 90 % probability estimated inhalation ILCRs were 7.85 × 10(-6) and 16.78 × 10(-6), respectively. Results of a sensitivity analysis indicated that BaP concentration and cancer slope factor (CSF) contributed most to effect on ILCR mean.

A margin of exposure approach to assessment of non-cancerous risk of diethyl phthalate based on human exposure from bottled water consumption

Phthalates may be present in food due to their widespread presence as environmental contaminants or due to migration from food contact materials. Exposure to phthalates is considered to be potentially harmful to human health as well. Therefore, determining the main source of exposure is an important issue. So, the purpose of this study was (1) to measure the release of diethyl phthalate (DEP) in bottled water consumed in common storage conditions specially low temperature and freezing conditions; (2) to evaluate the intake of DEP from polyethylene terephthalate (PET) bottled water and health risk assessment; and (3) to assess the contribution of the bottled water to the DEP intake against the tolerable daily intake (TDI) values. DEP migration was investigated in six brands of PET-bottled water under different storage conditions room temperature, refrigerator temperature, freezing conditions (40 °C ,0 °C and -18 °C) and outdoor] at various time intervals by magnetic solid extraction (MSPE) using gas chromatography-mass spectroscopy (GC-MS). Eventually, a health risk assessment was conducted and the margin of exposure (MOE) was calculated. The results indicate that contact time with packaging and storage temperatures caused DEP to be released into water from PET bottles. But, when comprising the DEP concentration with initial level, the results demonstrated that the release of phthalates were not substantial in all storage conditions especially at low temperatures (<25 °C) and freezing conditions. The daily intake of DEP from bottled water was much lower than the reference value. However, the lowest MOE was estimated for high water consumers (preschooler > children > lactating women > teenagers > adults > pregnant women), but in all target groups, the MOE was much higher than 1000, thus, low risk is implied. Consequently, PET-bottled water is not a major source of human exposure to DEP and from this perspective is safe for consumption.

Distribution of estrogenic steroids in municipal wastewater treatment plants in Tehran, Iran

Background

Estrogenic steroids such as estrone (E1), 17β–estradiol (E2), estriol (E3), and 17α–ethinylestradiol (EE2) are among the most potent endocrine disrupting compounds (EDCs). Compared with North America, Europe and Japan there is no reliable information on the concentration of steroid hormones in wastewater treatment plants (WWTPs) influents and effluents in Iran. The aim of the present study was to determine the amounts of E1, E2, E3, and EE2 influents and effluents of 7 municipal WWTPs across Tehran, the capital city of Iran, in two seasons, summer and autumn, through solid-phase extraction (SPE) gas chromatography–mass spectrometry (GC–MS).

Results

The results showed that the concentrations of E1, E2, and EE2 in influents ranged from 6.54–18.76 ng/L, 1.02–8 ng/L and 4.18–11.76 ng/L, respectively. Also, the concentrations of E1, E2, and EE2 in effluents ranged from 1.04–4.99 ng/L, 0.5–2.20 ng/L and 0.5–2.58 ng/L, respectively. The levels of E3 were below the detection limit (0.5 ng/L). The percentage removal rate of E1, E2 and EE2 ranged between 61.76–87.25%, 50.98–82.63%, and 66.3–90.25%, respectively. Results indicated no significant correlation between hormone concentrations and seasons.

Conclusions

The study showed that WWTP number 7 had significant differences in influent hormone concentrations compared with others. Results only showed a significant relationship between hormones and TSS removal rate, but there was no significant relationship between hormones and COD removal rate. The removal rate of hormone in WWTP number 4 and 7 were significantly different from the others. There was no significant correlation between hormone concentrations and seasons.

A stability indicating HPLC method for the determination of clobazam and its basic degradation product characterization

Background

Clobazam is used for the treatment of different types of seizure and epilepsy. The present research is undertaken to study the systematic forced degradation of clobazam and to identify its main degradation product under basic conditions.

Methods

The degradation of clobazam was studied under different conditions. Clobazam and its degradation products were separated using a Nova-Pak C18 column and a mixture of KH₂PO₄ 50 mM (pH 8.5) and acetonitrile (50:50, v/v) as the mobile phase with UV detection at 230 nm.

Results

The within-day and between-day precision values in the calibration range of 0.1-20 μg/ml were within 0.5-1.5%. Clobazam was relatively stable in solid from under exposure to visible and UV light and also heat. The clobazam aqueous solution of clobazam was more labile under exposure to visible and UV light. The bulk drug was significantly degraded under exposure to 2 M HCl, 0.1 M NaOH or 3% H₂O₂. Using the tablet powder, higher degradation rates were observed under different stress conditions. The main degradation product of clobazam under basic condition was subsequently characterized.

Conclusion

The developed method could be used for the determination of clobazam in the presence of its degradation products with acceptable precision and accuracy. The applicability of the proposed method was evaluated in commercial dosage forms analysis.

Association of urinary bisphenol a concentration with type-2 diabetes mellitus

BACKGROUND

Bisphenol A as an endocrine-disrupting chemical is widely used chemical in the manufacture of polycarbonate plastics and epoxy resin and has become ubiquitous environmental contaminants. Human exposure to Bisphenol A is widespread and recent studies have been shown to be associated with a higher risk for self-reported adverse health outcomes that may lead to insulin resistance and the development of type-2 diabetes mellitus. In this context, we sought to confirm the association between Bisphenol A and diabetes in a community-based analysis of Bisphenol A urinary concentrations investigation in adult population of Iran.

METHODS

Regression models were adjusted for age, sex, Body Mass Index, serum triglyceride level and serum cholesterol level and serum creatinine concentration. Main outcomes were reported diagnoses of diabetes that defined according the latest American Diabetes Association guidelines.

RESULTS

The median age of the 239 participants was 51.65 years and 119 people had type-2 diabetes mellitus. Urinary Bisphenol A was categorized into two groups based on the median for Bisphenol A (≤0. 85 to >0.85 μg/L). The results of statistical analysis revealed a clear association between hypertension, and type 2 diabetes (P < 0.05). The multi variable-adjusted odds ratio for type-2 diabetes mellitus associated with the group 1 (referent), of urinary Bisphenol A was 57.6 (95% confidence interval: 21.10-157.05; P-value < 0.001). A positive correlation between HbA1c and urinary BPA concentration was observed (r = 0.63, P = 0.001).

CONCLUSIONS

Urinary Bisphenol A levels are found to be associated with diabetes independent of traditional diabetes risk factors. Higher Bisphenol A exposure, reflected in higher urinary concentrations of Bisphenol A, is consistently associated with diabetes in the general adult population of the Iran. Studies to clarify the mechanisms of these associations are urgently needed.

Effect of frozen storage on the anthocyanins and phenolic components of pomegranate juice

Pomegranate juice's valuable nutritional components may be reduced during its processing or storage. This work examined the effect of frozen storage at -25 °C on some chemical characteristics of pomegranate juice. Total anthocyanin content of pomegranate juice, which was measured using the pH differential method, decreased by 11% after 20 days of frozen storage. Phenolic components, measured using a Folin and Ciocalteu assay by means of a UV-vis spectrophotometer, decreased by 29% after 20 days of frozen storage. Antioxidant activity, measured based on the radical scavenging properties of the juice using the 2,2-diphenyl-1-picrylhydrazyl method, decreased by 50% after 20 days of frozen storage. Pomegranate juice has 5 major anthocyanins, including Cyanidin 3-glucoside, Cyanidin 3,5-diglucoside, Delphinidin 3-glucoside, Pelargonidin 3-glucoside and Pelargonidin 3,5-diglucoside are 5 major anthocyanins of pomegranate juice. They were measured using the LC-MS method and results showed that Pelargonidin 3,5- diglucoside had the greatest decrease. Also, the LC-MS method showed that ellagic acid decreased by 15%.

Polycyclic Aromatic Hydrocarbons in drinking water of Tehran, Iran

Distribution and seasonal variation of sixteen priority polycyclic aromatic hydrocarbons (PAHs) were investigated in the drinking water of Tehran, the capital of Iran. Detected single and total PAHs concentrations were in the range of 2.01-38.96 and 32.45-733.10 ng/L, respectively, which were quite high compared to the values recorded in other areas of the world. The average occurrence of PAHs with high molecular weights was 79.55%; for example, chrysene occurred in 60.6% of the samples, with a maximum concentration of 438.96 ng/L. In addition, mean carcinogen to non-carcinogen PAHs ratio was 63.84. Although the concentration of benzo[a]pyrene, as an indicator of water pollution to PAHs, was lower than the guideline value proposed by World Health Organization (WHO) as well as that of Iranian National Drinking Water Standards for all of the samples, the obtained results indicated that carcinogen PAHs present in the drinking water of Tehran can cause threats to human health.

Levels of organophosphorus pesticides in medicinal plants commonly consumed in Iran

The frequent occurrence of pesticide residues in herbal materials was indicated by previous studies. In this study, the concentration of some of the organophosphorus pesticides including parathion, malathion, diazinon and pirimiphos methyl in different kinds of medicinal plants were determined. The samples were collected randomly from ten local markets of different areas of Iran. At the detection limit of 0.5 ng g^-1, parathion and pirimiphos methyl were not detected in any of the samples_. Some amounts of malathion and diazinon were found in Zataria, Matricaria chamomile, Spearmint and Cumin Seed samples while, the concentrations of target organophosphorus pesticides in Borage samples were below the detection limits of the methods which could be a result of intensive transformation of organophosphorus pesticides by Borage. In addition the organophosphorus pesticides were detected in all of the samples below the maximum residue levels (MRLs) proposed by the international organizations.

Structural characterization and surface activities of biogenic rhamnolipid surfactants from Pseudomonas aeruginosa isolate MN1 and synergistic effects against methicillin-resistant Staphylococcus aureus

The aim of present work was to study chemical structures and biological activities of rhamnolipid biosurfactants produced by Pseudomonas aeruginosa MN1 isolated from oil-contaminated soil. The results of liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis revealed that total rhamnolipids (RLs) contained 16 rhamnolipid homologues. Di-lipid RLs containing C(10)-C(10) moieties were by far the most predominant congeners among mono-rhamnose (53.29 %) and di-rhamnose (23.52 %) homologues. Mono-rhamnolipids form 68.35 % of the total congeners in the RLs. Two major fractions were revealed in the thin layer chromatogram of produced RLs which were then purified by column chromatography. The retardation factors (R (f)) of the two rhamnolipid purple spots were 0.71 for RL1 and 0.46 for RL2. LC-MS/MS analysis proved that RL1 was composed of mono-RLs and RL2 consisted of di-RLs. RL1 was more surface-active with the critical micelle concentration (CMC) value of 15 mg/L and the surface tension of 25 mN/m at CMC. The results of biological assay showed that RL1 is a more potent antibacterial agent than RL2. All methicillin-resistant Staphylococcus aureus (MRSA) strains were inhibited by RLs that were independent of their antibiotic susceptibility patterns. RLs remarkably enhanced the activity of oxacillin against MRSA strains and lowered the minimum inhibitory concentrations of oxacillin to the range of 3.12-6.25 μg/mL.

Simultaneous determination of parathion, malathion, diazinon, and pirimiphos methyl in dried medicinal plants using solid-phase microextraction fibre coated with single-walled carbon nanotubes

A reliable and sensitive headspace solid-phase microextraction gas chromatography-mass spectrometry method for simultaneous determination of different organophosphorus pesticides in dried medicinal plant samples is described. The analytes were extracted by single-walled carbon nanotubes as a new solid-phase microextraction adsorbent. The developed method showed good performance. For diazinon and pirimiphos methyl calibration, curves were linear (r² ≥ 0.993) over the concentration ranges from 1.5 to 300 ng g⁻¹, and the limit of detection at signal-to-noise ratio of 3 was 0.3 ng g⁻¹. For parathion and malathion, the linear range and limit of detection were 2.5–300 (r² ≥ 0.991) and 0.5 ng g⁻¹, respectively. In addition, a comparative study between the single-walled carbon nanotubes and a commercial polydimethylsiloxane fibre for the determination of target analytes was carried out. Single-walled carbon nanotubes fibre showed higher extraction capacity, better thermal stability (over 350°C), and longer lifespan (over 250 times) than the commercial polydimethylsiloxane fibre. The developed method was successfully applied to determine target organophosphorus pesticides in real samples.

Butyltin compounds in fish commonly sold in north of Iran

Levels of tributyltin (TBT) and its degradation products, mono (MBT) and dibutyltin (DBT), were monitored in fish commonly consumed in Iran. Samples were purchased from fish markets at seasonal intervals in 2010 along the North coast of Iran. Concentration of MBT, DBT and TBT in the muscle of these fish were in the range of n.d. -1.01 ± 0.84, n.d. -0.33 ± 0.26 and n.d. -4.31 ± 0.95 ngg(-1) (wet weight), respectively. Residue levels of butyltins were found lower than the tolerable average residue level of 100 ngg(-1) (wet weight).

A rapid, simple, liquid chromatographic-electrospray ionization, ion trap mass spectrometry method for the determination of finasteride in human plasma and its application to pharmacokinetic study

A fast, accurate, sensitive, selective and reliable method using reversed-phase high performance liquid chromatography coupled to electrospray ionization ion trap mass spectrometry was developed and validated for the determination of finasteride in human plasma. After protein precipitation with perchloric acid, satisfactory separation was achieved on a Zorbax Eclipse(®) C8 analytical column using a mobile phase consisted of acetonitrile, 2 mM ammonium formate buffer (58:42, pH adjusted at 2.5 using formic acid); the flow rate was 0.25 mLmin(-1) and the column oven was set to 50°C. Tamoxifen citrate was used as internal standard. This method involved the use of [M +H](+) ions of finasteride and IS at m/z 373 and 372 respectively with the selected ion monitoring (SIM) mode. The calibration curve was linear over the range of 0.1-60 ng mL(-1). The limit of quantification for finasteride in plasma was 0.1 ng mL(-1). The intra-day and inter-day repeatability (precision) were 2.68-13.87% and 2.14-14.69% respectively. Intra-day and inter-day accuracy were 98-101.57% and 99.7-110%. The assay method has been successfully used to estimate the pharmacokinetics of finasteride after oral administration of a 5 mg tablet of finasteride in 12 healthy volunteers.

Assessment of endogenous androgen levels in meat, liver and testis of Iranian native cross-breed male sheep and bull by gas chromatography-mass spectrometry

Androgenic steroids always exist in different animal tissues at trace level, with significant numbers of interfering compounds, which makes their determination difficult. To solve some of the problems in quantification of the natural steroids in those tissues, a new GC-MS method was developed in this study. By using a surrogate analyte approach, which was developed in the authors' previous studies, and extensive sample preparation procedure, which successfully eliminates many of the interfering compounds and resulting in a cleaner extract, accuracy, precision, sensitivity and selectivity of the method for the determination of steroids in complex matrices such as meat, liver and testis were improved. By aid of this method, the levels of androgens in different tissues of Iranian native cross-breed bulls and male sheep were determined. According to the results obtained in the present study, although the androgenic profile (contents and ratios of precursors and metabolites to the main hormones) is similar between the same tissues of both animals, the total androgenic content of each tissue is higher in the bull than the same tissue in male sheep. In addition, in both animals higher amount of androgens were found in liver in comparison with meat and testis.

Prodigiosin, the red pigment of Serratia marcescens, shows cytotoxic effects and apoptosis induction in HT-29 and T47D cancer cell lines

In this study, a red pigment of Serratia marcescens PTCC 1111 was purified and identified for antiproliferative activities in HT-29 and T47D cancer cell lines. (1)H-NMR spectroscopy and LC/MS analysis confirmed prodigiosin structure. The antiproliferative effects of prodigiosin were determined by employing the MTT assay. The changes in cell cycle pattern were studied with 4',6-diamidino-2-phenylindole (DAPI) reagent using flow cytometry assay, and Annexin V-PI method was used for apoptotic analysis. Results of MTT assay showed that HT-29 cells were more sensitive to prodigiosin than T47D cells. Prodigiosin-treated HT-29 cells showed increase in S phase and decrease in G2/M, but treated T47D cells showed cell cycle pattern relatively similar to Roswell Park Memorial Institute medium (RPMI). Apoptotic effect of prodigiosin was higher than doxorubicin in HT-29 cells. The data reported here indicate that prodigiosin is a promising antineoplastic agent that triggers apoptosis in different cancer cell lines.

Exposure assessment to trichloroethylene and perchloroethylene for workers in the dry cleaning industry

Perchloroethylene and trichloroethylene are two particular organochloro compounds, are often used for dry-cleaning. In the present study the excretion of urinary Perchloroethylene and trichloroethylene were evaluated as biomarkers of exposure to these compounds. The mean value of Perchloroethylene in breathing zone and the total Perchloroethylene uptake during the work shift of the three groups of dry-cleaning workers according to the capacity of the dry-cleaning machine (8, 12 and 18 kg) were 31.04, 50.87 and 120.99 mg m(-3) and 11.46, 22.6 and 41.6 μg L(-1), respectively, which were significantly greater than the occupationally nonexposed groups. A good correlation (r = 0.907) between the mean values of Perchloroethylene in breathing zone and the urinary concentrations was observed.