Liquid chromatographic-mass spectrometric method for determination of drug content uniformity of two commonly used dermatology medications in a split-tablet dosage form

Purpose: To develop and validate a simple, efficient and reliable Liquid chromatographic-mass spectrometric (LC-MS/MS) method for the quantitative determination of two dermatological drugs, Lamisil® (terbinafine) and Proscar® (finasteride), in split tablet dosage form. Methods: Thirty tablets each of the 2 studied medications were randomly selected. Tablets were weighed and divided into 3 groups. Ten tablets of each drug were kept intact, another group of 10 tablets were manually split into halves using a tablet cutter and weighed with an analytical balance; a third group were split into quarters and weighed. All intact and split tablets were individually dissolved in a water: methanol mixture (4:1), sonicated, filtered and further diluted with mobile phase. Optimal chromatographic separation and mass spectrometric detection were achieved using an Agilent 1200 HPLC system coupled with an Agilent 6410 triple quadrupole mass spectrometer. Analytes were eluted through an Agilent eclipse plus C8 analytical column (150 mm × 4.6 mm, 5 μm) with a mobile phase composed of solvent A (water) containing 0.1% formic acid and 5mM ammonium formate pH 7.5, and solvent B (acetonitrile mixed with water in a ratio A:B 55:45) at a flow rate of 0.8 mL min-1 with a total run time of 12 min. Mass spectrometric detection was carried out using positive ionization mode with analyte quantitation monitored by multiple reaction monitoring (MRM) mode. Results: The proposed analytical method proved to be specific, robust and adequately sensitive. The results showed a good linear fit over the concentration range of 20 - 100 ng mL-1 for both analytes, with a correlation coefficient (r2) ≥ 0.999 and 0.998 for finasteride and terbinafine, respectively. Following tablet splitting, the drug content of the split tablets fell outside of the proxy USP specification for at least 14 halves (70 %) and 34 quarters (85 %) of FIN, as well as 16 halves (80 %) and 37 quarters (92.5 %) of TBN. Mean weight loss, after splitting, was 0.58 and 2.22 % for FIN half- and quarter tablets, respectively, and 3.96 and 4.09 % for TBN half- and quarter tablets,respectively. Conclusion: The proposed LC-MS/MS method has successfully been used to provide precise drug content uniformity of split tablets of FIN and TBN. Unequal distribution of the drug on the split tablets is indicated by the high standard deviation beyond the accepted value. Hence, it is recommended not to split non-scored tablets especially, for those medications with significant toxicity

Impact of HydroPolymers on the soil biological components in mediterranean drylands

Soil degradation affects more than 52 million ha of land in counties of the European Union. This problem is particularly serious in Mediterranean areas, where the effects of anthropogenic activities (tillage on slopes, deforestation, and pasture production) add to problems caused by prolonged periods of drought and intense and irregular rainfall. Soil microbiota can be used as an indicator of the soil healthy in degraded areas. This is because soil microbiota participates in the cycle elements and in the organic matter decomposition. All this helps to the young plants establishment and in long term protect the soils against the erosion. During dry periods in the Mediterranean areas, the lack of water entering the soil matrix leads to a loss of soil microbiological activity and it turns into a lower soil production capabilities. Under these conditions, the aim of this study was to evaluate the positive effect on soil biological components produced by an hydro absorbent polymer (Terracottem). The aim of the experiment was to evaluate the impact assessment of an hydropolymer (Terracottem) on the soil biological components. An experimental flowerpot layout was established in June 2015 and 12 variants with different amount of Terracottem were applied as follow: i) 3.0 kg.m3 ; ii) 1.5 kg.m3 and; iii) 0 kg.m3. In all the variants were tested the further additives: a) 1% of glucose, b) 50 kg N.ha-1 of Mineral nitrogen, c) 1% of Glucose + 50 kg N.ha-1 of Mineral nitrogen d) control (no additive). According to natural conditions, humidity have been kept at 15% in all the variants. During four weeks, mineral nitrogen leaching and soil respiration have been measured in each flowerplot. Respiration has been quantified four times every time while moistening containers and alkaline soda lime has been used as a sorbent. The amount of CO 2 increase has been measured with the sorbent. Leaching of mineral nitrogen has been quantified by ion exchange resins (IER). IER pouches have been placed on the bottom of each container, and after completion of the experiment mineral nitrogen leaching has been evaluated by distillation and titration method. Results from respiration have shown statistically significant differences between the variants. According to control, soil with polymers have shown significant difference when comparing respiration with independence of the additive used. CO 2 production in the first week has exceeded the sum of the outputs of the following weeks. Mineral nitrogen leaching measurement has shown statistically significant differences. The lowest leaching has been occurred in control variant, while the highest in variant containing only the addition of mineral nitrogen. Research results may conclude that the biological part of the test soil is not limited by a lack of components, the only thing that suppresses its activity is the lack of moisture. After moistening it leads to a rapid growth of soil activity, without causing the nutrients loss. Besides, Terracottem has affected soil activity neither positively nor negatively, but it considers being a suitable tool for reducing the drought impact in arid and semi-arid areas.

Stress-testing centralised model stores

One of the current challenges in model-driven engineering is enabling effective collaborative modelling. Two common approaches are either storing the models in a central repository, or keeping them under a traditional file-based version control system and build a centralized index for model-wide queries. Either way, special attention must be paid to the nature of these repositories and indexes as networked services: they should remain responsive even with an increasing number of concurrent clients. This paper presents an empirical study on the impact of certain key decisions on the scalability of concurrent model queries, using an Eclipse Connected Data Objects model repository and a Hawk model index. The study evaluates the impact of the network protocol, the API design and the internal caching mechanisms and analyzes the reasons for their varying performance.