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  • Author: Mircea Dumitru Croitoru x
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Oxidative stress is an imbalance between free radicals or other reactive species and the antioxidant activity of the organism. Oxidative stress can induce several illnesses such as cardiovascular disease, neurodegenerative disorders, diabetes, cancer, Alzheimer and Parkinson. The biomarkers of oxidative stress are used to test oxidative injury of biomolecules. The indicators of lipid peroxidation (malondialdehyde, 4-hydroxy- 2-nonenal, 2-propenal, isoprostanes), of protein oxidation (carbonylated proteins, tyrosine derivatives), of oxidative damage of DNA, and other biomarkers (glutathione level, metallothioneins, myeloperoxidase activity) are the most used oxidative stress markers. Diseases caused by oxidative stress can be prevented with antioxidants. In human body are several enzymes with antioxidant capacity (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase) and spin traps. Antioxidants are synthetized in the organism (glutathione) or arrive in the body by nutrition (ascorbic acid, vitamin E, carotenoids, flavonoids, resveratrol, xanthones). Different therapeutic strategies to reduce oxidative stress with the use of synthetic molecules such as nitrone-based antioxidants (phenyl-α-tert-butyl-nitrone (PBN), 2,4-disulphophenyl- N-tert-butylnitrone (NXY-059), stilbazulenyl nitrone (STAZN), which scavenge a wide variety of free radical species, increase endogenous antioxidant levels and inhibits free radical generation are also tested in animal models.


Objective: The aim of this study was to evaluate how the membrane transport of diclofenac on presence of different types of food is modified.

Methods: The interaction of diclofenac, as a pure substance and solid dispersions of the active ingredient, with different types of foods was investigated in vitro condition using a modified Franz diffusion cell.

Results: The amount of diclofenac transported through a lipophilic membrane was reduced by the presence of foodstuffs in artificial gastric juice and intestinal juice also, both in the case of the pure substance and solid dispersions also. The only exception was the case of milk in artificial gastric juice, when the amount of diclofenac in the receiving compartment increased about 2-fold compared to the fasted conditions simulating media. In the case of the solid dispersions of diclofenac the membrane transport increased in all cases compared to the pure substance, but was also reduced by the foods.

Conclusions: It was concluded that, the presence of different foodstuffs can influence the membrane transport of diclofenac – by inhibiting its solubility – and these differences observed in vitro can lead to modifications in the in vivo pharmacokinetic parameters. The lowest difference in diclofenac membrane transport was observed in the case of diclofenac:PEG 6000 solid dispersion prepared in 1:5 mass ratio.


Introduction: Camellia sinensis, a widely used plant, optimally grows in a low pH soil that in most cases contains high amounts of aluminum. Objectives: The aluminum content of the tea obtained from Camellia sinensis and other plants was compared. The influence of pH on the aluminum content of the tea was also measured. Materials and methods: The aluminum content of 48 samples was measured using a colorimetric method. The method is based on the ability of aluminum to form a stable complex with xylenol orange at low pH; this complex has an absorption maximum of 555 nm. Results: The method was validated for tea obtained with water and for tea obtained with water containing citric acid. The method proved linear over the rage of 0.7 – 7 ug/ml, coefficient of variation ranged between 2.6 – 7.68% (was dependent on the pH of the solution used to obtain the tea), accuracy was suitable for quantitative measurement (92.39-102.92%) and the complex proved to be stable for at least 1 hour. The following concentrations were measured: green tea (1.59 - 7.70 µg/ml), black tea (1.39 - 5.60 µg/ml), fruit tea (1.01 - 5.63 µg/ml) and herbal tea (1.03 - 5.24 µg/ml). Conclusion: The method proved useful and easily applicable for screening aluminum content of plants used for tea brewing. Camellia sinensis both green and black types had significantly higher aluminum contents than other type of teas. Adding citric acid, as would result from use of lemon juice, significantly increased the aluminum extraction from the plants used for tea brewing.


A method of measuring in vivo nitric oxide (NO) levels is required to detect pathological conditions in which endogenous production is decreased or to identify agents able to release this biomolecule. Unfortunately, nitric oxide has a very short biological half-life and is very difficult to measure. Assay of the oxidative products’ of NO levels, nitrite (NO2 -) and nitrate (NO3 -), measured as total amount, after the reduction of nitrate to nitrite, determined after conversion in an azo dye, is usually the used method, named NOx test. The NOx test is frequently used as a NO biomarker in human studies and also in animal experiments. The aim of this work is to evaluate the suitability of the NOx test for the detection of an instant release of nitric oxide.

Rabbits were used as experimental animals, a validated HPLC-UV/VIS method was used for speciation of nitrite and nitrate. The following substances were administered: blank; “negative blank”: phenyl-N-tert-butylnitrone (PBN); “positive blank” (nitroglycerin); nitrite.

PBN administration significantly increased nitrate and decreased nitrite levels, nitrite administration excessively increased nitrate levels, while nitroglycerin (1 mg/kg) significantly increased both nitrate and nitrite levels.

Results show that NOx test cannot be considered accurate in acute nitric oxide status testing. Nitrite alone should be used as an in vivo released nitric oxide marker.


Objective: One of the most important sources of nitrite and nitrate anions, besides vegetables and meat products, is the drinking water. Presence of nitrite and nitrate in the water in higher concentrations than those set by EFSA (0.5 mg/l nitrite, 50 mg/l nitrate), may have toxicological significance. A quantitative determination of these ions in samples collected from several pleases from Mureș County was made.

Methods: Ninety-seven well water samples were tested from 12 different places from Mureș County. We used a simple HPLC-UV ion pair method for the determination of nitrite and nitrate concentrations. Sensitivity of the method enables the quantification for concentrations far below the MCL value.

Results: The highest amounts of nitrate and nitrite were measured in Sangeorgiu de Mureș and Cristești. Concentrations of nitrite and nitrate were exceeded in 4.12% and respectively 44.32% of the samples.

Conclusions: The high amounts of nitrites and nitrates existing in well water go beyond the expected extent. This pollution can become a health risk since this water is used in human nutrition especially in child nourishment.


Oxidative stress appears when the amount of free radicals that are formed in a living organism exceed its spin-trapping ability. One of the most dangerous free radicals that are formed in the human body is the hydroxyl radical. It can alter several biomolecules, including the unsaturated fatty acids; this process is known as lipid peroxidation and can lead to cell necrosis and generation of several harmful byproducts including malondialdehyde, which serves also as a biomarker of oxidative stress. A new HPLC method with visible detection was developed for the detection of malondialdehyde in human serum and saliva samples. The method was verified in terms of specificity, linearity, limits of detection (0.35 ng/ml), limit of quantification (1.19 ng/ml), recovery (90.13±10.25 – 107.29±14.33) and precision (3.84±1.49% – 6.66±1.76%). An analysis time of only 1 minute was obtained and no interferences from the matrices were observed. Statistical analysis (Pearson correlation test) showed a moderate correlation (R = 0.5061, p = 0.0099) between serum and saliva concentrations (N = 25). The possibility of measuring salivary concentrations of malondialdehyde extents the applications of oxidative stress/lipid peroxidation estimations to categories of population unreachable before (pregnant women, small children, etc); repeated sample studies are also easier to make.


Mefenamic acid (MA) is a widely used non-steroidal antiinflammatory (NSAID) drug. The adverse effects typical of NSAIDs are also present in the case of MA, partly due to its low water solubility. The aim of this study was to increase the water solubility of MA in order to influence its absorption and bioavailability. Solid dispersions of MA were prepared by the melting method using polyethylene glycol 6000 and different types (laurate, D-1216; palmitate, P-1670; stearate, S-1670) and amounts of sucrose esters as carriers. The X-ray diffraction results show that MA crystals were not present in the products. Dissolution tests carried out in artificial intestinal juice showed that the product containing 10 % D-1216 increased water solubility about 3 times. The apparent permeability coefficient of MA across human Caco-2 intestinal epithelial cell layers was high and, despite the difference in solubility, there was no further increase in drug penetration in the presence of the applied additives.


Objective: Analgesic medicines containing combinations of nonsteroidal anti-inflammatory drugs and codeine are available without prescription. Codeine, in these combinations can not be used recreationally due to the high toxicity profile of the nonsteroidal anti-inflammatory drugs. However, methods for extracting codeine from these types of medication are available on the internet. The purpose of this work is to evaluate if codeine can be extracted from codeine containing analgesics sold without prescription.

Methods: High Performance Liquid Chromatography (HPLC) with UV detection was used to measure the amounts of codeine and nonsteroidal anti-inflammatory drugs recovered after applying an extraction method described on the internet.

Results: The results show that codeine can be very easily separated from NSAID as aspirin, acetaminophen, ibuprofen using the cold water extraction method. However, very large differences (20 to 90%) were recorded for the recovery of codeine depending on the OTC product that was used. That large difference increases the risk of potentially lethal overdoses when the user switches between “similar” products.

Conclusions: Our work shows that analgesic medication with codeine content can be recreationally used after the extraction of codeine. In order to prevent this, the sell of this type of products should be regulated or products that do not allow the extraction of codeine should be developed.


Objective: the number of alkaloids like morphine and codeine found in poppy seeds used in food industry are monitored by a directive given by European Food Safety Authority. Based on this regulation the aim of the study was to determine the quantity of morphine and codeine from several brands of poppy seeds. Methods: an HPLC-UV method (205 nm) was developed to measure the quantity of morphine and codeine. Sample preparation was made using recipes posted on Drugs Forum by some users. Limits of detection were not determined because the lowest concentration from the reference (0.1 μg/ml) detected morphine concentrations that are far lower than a limit of toxicological concern. Results: The concentrations, which were found, ranged between Below the Level of Toxicological Concern (BLTC) - 243.26 mg/kg for morphine and BLTC - 88.58 mg/kg for codeine using several methods of preparation. Conclusions: one can observe that there are some brands of poppy seeds which do not respect the regulation about the amount of morphine and codeine. The high amount of morphine in some samples suggests that there are different varieties of poppy seeds, which can be used for an illicit purpose and can lead to addiction or even overdose in some cases.


A reverse-phase HPLC (RP-HPLC) method was developed for strontium ranelate using a full factorial, screening experimental design. The analytical procedure was validated according to international guidelines for linearity, selectivity, sensitivity, accuracy and precision. A separate experimental design was used to demonstrate the robustness of the method. Strontium ranelate was eluted at 4.4 minutes and showed no interference with the excipients used in the formulation, at 321 nm. The method is linear in the range of 20–320 μg mL−1 (R2 = 0.99998). Recovery, tested in the range of 40–120 μg mL−1, was found to be 96.1–102.1 %. Intra-day and intermediate precision RSDs ranged from 1.0–1.4 and 1.2–1.4 %, resp. The limit of detection and limit of quantitation were 0.06 and 0.20 μg mL−1, resp. The proposed technique is fast, cost-effective, reliable and reproducible, and is proposed for the routine analysis of strontium ranelate.