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Open access

Othman A. Al Hanbali, Haji Muhammad Shoaib Khan, Muhammad Sarfraz, Mosab Arafat, Shakeel Ijaz and Abdul Hameed

Abstract

Use of transdermal patches can evade many issues associated with oral drug delivery, such as first-pass hepatic metabolism, enzymatic digestion attack, drug hydrolysis and degradation in acidic media, drug fluctuations, and gastrointestinal irritation. This article reviews various transdermal patches available in the market, types, structural components, polymer role, and the required assessment tools. Although transdermal patches have medical applications for smoking cessation, pain relief, osteoporosis, contraception, motion sickness, angina pectoris, and cardiac disorders, advances in formulation development are ongoing to make transdermal patches capable of delivering more challenging drugs. Transdermal patches can be tailored and developed according to the physicochemical properties of active and inactive components, and applicability for long-term use. Therefore, a number of chemical approaches and physical techniques for transdermal patch development are under investigation.

Open access

Mohammed Albratty, Karam Ahmed El-Sharkawy and Hassan Ahmed Alhazmi

Abstract

In an attempt to produce heterocyclic compounds based on 1,3,4-oxadiazole derivatives with potential antiviral activity, synthesis of compound 1 [2-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)acetonitrile] was performed through the reaction of cyanoacetic acid hydrazide with carbon disulfide in alcoholic potassium hydroxide. Compound 1 has an activating methylene group, so it was directed toward some specific reactions. Thus, aryldiazonium chlorides reacted with compound 1 affording hydrazono derivatives 2a-c. Also, aromatic aldehydes reacted with compound 1 to produce compounds 3a,b. Furthermore, cyclic ketones were subjected to the synthesis of fused thiophene derivatives 4a,b via reaction with compound 1 in the presence of elemental sulfur. In addition, 1,3,4-oxadiazole derivative 1, when reacted with isothiocyanates, salicylaldehyde or 1,3-dicarbonyl compounds, formed thiazole derivatives 5a,b, coumarin derivative 6 and alkenyl derivatives 7a,b resp. Compound 7b underwent cyclization to afford pyridine derivative 8. Arylhydrazono derivatives 9a,b were produced through the reaction of compound 7a with aryldiazonium chlorides. Products 9a,b underwent cyclization to produce pyridazine derivatives 10a,b. Finally, 1,3,4-oxadiazole derivative 1 was directed toward reaction with hydrazine derivatives, bromoacetophenone and ethylchloroacetate affording compounds 11a,b, 12 and 13, resp. Fused thiophene derivatives 14a,b were produced via reaction of compounds 4a,b with a mixture of malononitrile and ethylorthoformate. Antiviral activity of the synthesized products showed that 5-(4-amino-3-ethyl-2-thioxo-2,3-dihydrothiazol-5-yl)-1,3,4-oxadiazole-2(3H)-thione (5a) and 5-(4-amino-3-phenyl-2-thioxo-2,3-dihydrothiazol-5-yl)-1,3,4-oxadiazole-2(3H)-thione (5b) acted as the most active agents against Feline herpes virus, Feline corona virus, Herpes simplex virus-1 and Herpes simplex virus-2, whereas compound 2-(5-(2-phenylhydrazono)-4,5-dihydro-1,3,4-oxadiazol-2-yl)acetonitrile (11b) was the most effective against Vaccinia virus, Herpes simplex virus (TK-KOS-ACVr), Coxsackie virus B4 and Vesicular stomatitis virus.

Open access

Maja Beus, Diana Fontinha, Jana Held, Zrinka Rajić, Miguel Prudêncio and Branka Zorc

Abstract

The paper is focused on the synthesis and screening of the antiplasmodial activity of novel fumardiamides 5–10 with the mefloquine pharmacophore and a Michael acceptor motif. Multi-step reactions leading to the title compounds included two amide bond formations. The first amide bond was achieved by the reaction of (E)-ethyl 4-chloro-4-oxobut-2-enoate (1) and N 1-(2,8-bis(trifluoromethyl)quinolin-4-yl) butane-1,4-diamine (2). The obtained ester 3 was hydrolyzed and gave acid 4, which then reacted with the selected halogenanilines in the presence of HATU/DIEA and formed products 5–10. Title compounds showed marked, dose dependent activity in vitro against hepatic stages of Plasmodium berghei. IC 50 values of the most active compounds 5, 7 and 9 bearing 3-fluoro, 3-chloro and 3-trifluoromethyl substituents were 3.04–4.16 µmol L−1, respectively. On the other hand, the compounds exerted only weak activity against the erythrocytic stages of two P. falciparum strains (Pf3D7 and PfDd2) in vitro, with the exception of compound 5 (IC 50 = 2.9 µmol L−1).

Open access

Amir Ali, Muhammad Makshoof Athar, Mahmood Ahmed, Kashif Nadeem, Ghulam Murtaza, Umar Farooq and Muhammad Salman

Abstract

With the increased number of multi-drug formulations, there is a need to develop new methods for simultaneous determinations of drugs. A precise, accurate and reliable liquid chromatographic method was developed for simultaneous determination of paracetamol, thiamine, and pyridoxal phosphate in pharmaceutical formulations. Separation of analytes was carried out with an Agilent Poroshell C18 column. A mixture of ammonium phosphate buffer (pH = 3.0), acetonitrile and methanol in the ratio of 86:7:7 (V/V/V) was used as the mobile phase pumped at a flow rate of 1.8 mL min−1. Detection of all three components, impurities and degradation products was performed at the selected wavelength of 270 nm. The developed method was validated in terms of linearity, specificity, precision, accuracy, LOD and LOQ as per ICH guidelines. Linearity of the developed method was found in the range 17.5–30 µg mL−1 for thiamine, 35–60 µg mL−1 for pyridoxal phosphate and 87.5–150 µg mL−1 for paracetamol. The coefficient of determination was ≥ 0.9981 for all three analytes. The proposed HPLC method was found to be simple and reliable for the routine simultaneous analysis of paracetamol, thiamine and pyridoxal phosphate in tablet formulations. Complete separation of analytes in the presence of degradation products indicated selectivity of the method.

Open access

Andrej Martinčič, Tone Wraber and Igor Dakskobler

Abstract

In the alpine belt of the Julian Alps (glacial cirque Na Jezerih under Mt. Veliki Rokav, Jarečica, the Mangart Saddle and Prodi under Mt. Mangart as well as Mt. Plešivec in the rock wall of Loška Stena) we studied the phytosociology and ecology of snow-bed vegetation with dominating flowering plants Salix herbacea, Luzula alpinopilosa, Gnaphalium supinum, Soldanella pusilla and Salix retusa, and numerous moss species. Based on the comparison with similar snow-bed communities in the Central, Eastern and Southern Alps we described a new association Salicetum retuso-herbaceae and classified it into the alliance Salicion herbaceae and class Salicetea herbaceae. We determined several successional stages of snow-bed vegetation on mixed calcareous-silicate bedrock that we treat as variants, in two relevés also the initial association Polytrichetum sexangularis.

Open access

Nathalia Yeremenko

Abstract

The present paper studies the ruderal vegetation of the class of Robinietea in Kryvyi Rih. We present the spontaneous woody vegetation of parks and other artificial plantations. Urban landscapes remain unstudied phytosociologically despite the highly diverse habitat niches. We have carried out the comparisons of communities from other regions of Ukraine and adjacent territories. In total, four associations and one derivate community, belonging to three alliances, were identified and categorized as follows: Chelidonio-Acerion negundi (synanthropic tree communities with Acer negundo), Chelidonio majoris-Robinion pseudoacaciae (artificial and spontaneous plantations of Robinia pseudoacacia), Geo-Acerion platanoidis (artificial plantations of broad-leaved tree species). The ordination analysis indicates ecological differentiation of syntaxa investigated in Kryvyi Rih. The most important of them are soil aeration (Ae), the cryo-climate (Cr) and nitrogen content in soil (Nt). Critical revision of the class Robinietea syntaxonomy demands further current research.

Open access

Bahman Jabbarian Amiri, Junfeng Gao, Nicola Fohrer and Jan Adamowski

Abstract

There is an emerging challenge within water resources on how, and to what extent, borrowing concepts from landscape ecology might help re-define traditional concepts in hydrology in a more tangible manner.

A stepwise regression model was adopted in this study to assess whether the time of concentration of catchments could be explained by five landscape structure-representing metrics for land use/land cover, soil and geological patches, using spatial data from 39 catchments.

The models suggested that the times of concentration of the catchments could be predicted using the measures of four landscape structure-representing metrics, which include contiguity index (r 2 = 0.46, p ≤0.05), fractal dimension index (r 2 = 0.51, p ≤0.05), related circumscribing circle (r 2 = 0.52, p ≤0.05), and shape index (r 2 = 0.47, p ≤0.05).

The models indicated that the regularity or irregularity in land use/land cover patch shape played a key role in affecting catchment hydrological response. Our findings revealed that regularity and irregularity in the shape of a given patch (e.g., urban and semi-urban, rangeland and agricultural patches) can affect patch functions in retarding and/or increasing flow accumulation at the catchment scale, which can, in turn, decrease or increase the times of concentration in the catchments.

Open access

Ahmed Mostafa and Heba Shaaban

Abstract

The study presents the application of multivariate curve resolution alternating least squares (MCR-ALS) with a correlation constraint for simultaneous resolution and quantification of ketoprofen, naproxen, paracetamol and caffeine as target analytes and triclosan as an interfering component in different water samples using UV-Vis spectrophotometric data. A multivariate regression model using the partial least squares regression (PLSR) algorithm was developed and calculated. The MCR-ALS results were compared with the PLSR obtained results. Both models were validated on external sample sets and were applied to the analysis of real water samples. Both models showed comparable and satisfactory results with the relative error of prediction of real water samples in the range of 1.70–9.75 % and 1.64–9.43 % for MCR-ALS and PLSR, resp. The obtained results show the potential of MCR-ALS with correlation constraint to be applied for the determination of different pharmaceuticals in complex environmental matrices.

Open access

Fahimed Koohdar, Masoud Sheidai and Seyed Mehdi Talebi

Abstract

Lallemantia royleana (Benth.) Benth. (Family Lamiaceae), is one of the most popular medicinal plants in Iran. It is an herbaceous pant that is commonly known as “Lady mantle”. The vernacular name of Lallemantia royleana’s seed is Balangu or Balangu Shirazi that is used as a source of medicine. Medicinal plants are very important from economic point of view in Iran and several large industries are focused on medicinal plants cultivation, extraction and export. Therefore, providing data on the biology of these plants is important for the country. Lallemantia royleana grows in different parts of Iran and forms several local populations. Genetic, morphological and biochemical divergence of geographical populations are well known in plant species. We have no report on population genetic structure, genetic fragmentation, local adaptation and gen flow of Lallemantia royleana populations in the country. Therefore, the present population genetics investigation was programmed to produce data on above said questions. Randomly collected plants of 7 geographical regions were studied by ISSR molecular markers. This information can be used in hybridization and gene conservation of this medicinal plant in Iran.

Open access

Elena Benito, Eufemia Varela and María Rodríguez-Alleres

Abstract

The primary purpose of this work was to assess the persistence of water repellency in the surface horizon of coarse-textured soils under natural Quercus robur ecosystems, and Pinus pinaster and Eucalyptus globulus plantations, in the northwest of the Iberian Peninsula. Water repellency was determined by applying the water drop penetration test (WDPT) to soil samples collected from variable depths (0–40 cm). Measurements were made on field-moist samples obtained at the end of the dry period and on samples dried at 25ºC in the air. All soils exhibited very high (severe to extreme) water repellency in the topmost soil layer (0–5 cm) but no significant differences among the three plant species studied. Extreme persistence was observed down to 20 cm in the soils under eucalyptus and down to 10 cm in those under pine. The soils under oak were those exhibiting the highest variability in water repellency and the greatest decrease in it with increasing depth (especially in relation to soils under eucalyptus).

Water repellency exhibited significant positive correlation with the C content and C/N ratio of the soils. Soil water repellency was similar in the air-dried samples and field-moist samples.