PREPARATION AND EVALUATION OF METRONIDAZOLE SUSTAINED RELEASE FLOATING TABLETS

Objective: The objective of the present study is the preparation of metronidazole (MZ) floating tablets that are designed to retain in the stomach for a long time for better eradication of Helicobacter Pylori (H. pylori), a main cause of peptic ulcer disease. Methods: Synthetic and natural polymers were studied for their floating potential in the presence of sodium bicarbonate, namely: hydroxypropyl methylcellulose (HPMC), carbopol 974P, sodium alginate{low and medium viscosity (LV & MV) grades}, locust gum and guar gum. Hardness, floating ability, release profiles and kinetics as well as DSC / FT-IR were studied. Results: Results of both DSC and FT-IR spectroscopy revealed that there was no interaction between the drug and any of the proposed polymers. Carbopol 974P based tablets showed an unacceptable floating lag time (2 h) and did not maintain good tablet integrity. All other formulas were able to float after few seconds and showed buoyancy for more than 24 h. Meanwhile, sustained profiles of MZ release were obtained. After 6 h the amount of MZ released were: 75.11 %, 61.26 %, 54.56 %, 54.25 % and 43.42 % from sodium alginate-LV, HPMC-K4M, guar gum, locust gum and sodium alginate-MV based tablets, respectively. Kinetically, among the 5 assessed models, the release pattern of MZ from the tablets fitted best to Zero order and Hixson & Crowell Cube-Root models. Conclusion: These stomach targeted dosage forms could maintain the minimum inhibitory concentration for sufficient time to allow for local eradication and thereby achieve better efficiency of therapy with improved patient compliance, reduced costs and minimized side effects caused by immediate release dosage forms

IN-VITRO DISSOLUTION STUDY OF MELOXICAM IMMEDIATE RELEASE PRODUCTS USING FLOW THROUGH CELL (USP APPARATUS 4) UNDER DIFFERENT OPERATIONAL CONDITIONS

Objective: To evaluate and compare the in-vitro dissolution profiles of five generic immediate release (IR) products of Meloxicam (MX) available in Egyptian market with the innovator reference product (Mobic®, R) using different operational conditions of the flow through dissolution cell (FTC, USP Apparatus 4), in phosphate buffer (pH=7.5). Methods: The comparative in-vitro dissolution studies were performed under different FTC operational conditions such as cell size, tablet position within the cell, open and closed loops setup and type of flow (laminar and turbulent) on MX dissolution rate from different IR products. Results: The study showed that two generic products, out of five, gave similar dissolution profiles with R using a specified well controlled condition of FTC. A selected generic product (Mobitil, G1) was tested versus R under different operational conditions of the FTC such as cell size, type of flow, tablet position and open & closed loops setup. The dissolution profile of MX from R was highly affected by changing the tablet position, slightly affected by the open & closed loops setup and not affected by cell size and type of flow. On the other hand, the dissolution profile of MX from G1 was affected by all the previous operational conditions. Comparing ƒ2 values between G1 against R among the different operational conditions proposed, only one in-vitro dissolution test showed similar dissolution profile of G1 with respect to R. Conclusion: Three generic products of MX might not be interchangeable with the innovator product (Mobic®)

IN VITRO EVALUATION OF IBUPROFEN HOT-MELT EXTRUDED PELLETS EMPLOYING DIFFERENT DESIGNS OF THE FLOW THROUGH CELL

Objective: Hot-melt extrusion technique (HME) was used to prepare a sustained release (SR) multiparticulate oral dosage form (pellets) containing Ibuprofen (IBU). Prepared IBU-HME pellets were in vitro evaluated by flow-through cell dissolution tester (FTC, USP Apparatus #4) using different flow conditions and FTC designs. Methods: In this study, Sucroester®WE15 was used as the polymeric carrier to prepare two different IBU loadings (60 % and 30 % w/w). In order to optimize the FTC conditions, different cell sizes, pellets loading and hydrodynamic conditions of FTC on IBU release rate from pellets were proposed. Results: The results showed that the IBU release rate was increased in the larger cell than the small cell. In addition, laminar flow showed more reproducible results than turbulent flow. It was found that the large cell with laminar flow rate and homogeneous mixing of the pellets with glass beads was the optimum conditions for in vitro evaluation of these preparations. Conclusion: Improper methods of sample loading as well as cell size may result in confusing or erroneous data if not analyzed carefully. Therefore, it might be critical to choose a specific cell design of the FTC for in vitro evaluation of pellets to obtain reliable and discriminative results reflecting the major as well as minor formulation variables

Systematic Review of Potential Health Risks Posed by Pharmaceutical, Occupational and Consumer Exposures to Metallic and Nanoscale Aluminum, Aluminum Oxides, Aluminum Hydroxide and Its Soluble Salts

Aluminum (Al) is a ubiquitous substance encountered both naturally (as the third most abundant element) and intentionally (used in water, foods, pharmaceuticals, and vaccines); it is also present in ambient and occupational airborne particulates. Existing data underscore the importance of Al physical and chemical forms in relation to its uptake, accumulation, and systemic bioavailability. The present review represents a systematic examination of the peer-reviewed literature on the adverse health effects of Al materials published since a previous critical evaluation compiled by Krewski et al. (2007). Challenges encountered in carrying out the present review reflected the experimental use of different physical and chemical Al forms, different routes of administration, and different target organs in relation to the magnitude, frequency, and duration of exposure. Wide variations in diet can result in Al intakes that are often higher than the World Health Organization provisional tolerable weekly intake (PTWI), which is based on studies with Al citrate. Comparing daily dietary Al exposures on the basis of “total Al”assumes that gastrointestinal bioavailability for all dietary Al forms is equivalent to that for Al citrate, an approach that requires validation. Current occupational exposure limits (OELs) for identical Al substances vary as much as 15-fold. The toxicity of different Al forms depends in large measure on their physical behavior and relative solubility in water. The toxicity of soluble Al forms depends upon the delivered dose of Al+ 3 to target tissues. Trivalent Al reacts with water to produce bidentate superoxide coordination spheres [Al(O2)(H2O4)+ 2 and Al(H2O)6 + 3] that after complexation with O2•−, generate Al superoxides [Al(O2•)](H2O5)]+ 2. Semireduced AlO2• radicals deplete mitochondrial Fe and promote generation of H2O2, O2 • − and OH•. Thus, it is the Al+ 3-induced formation of oxygen radicals that accounts for the oxidative damage that leads to intrinsic apoptosis. In contrast, the toxicity of the insoluble Al oxides depends primarily on their behavior as particulates. Aluminum has been held responsible for human morbidity and mortality, but there is no consistent and convincing evidence to associate the Al found in food and drinking water at the doses and chemical forms presently consumed by people living in North America and Western Europe with increased risk for Alzheimer\u27s disease (AD). Neither is there clear evidence to show use of Al-containing underarm antiperspirants or cosmetics increases the risk of AD or breast cancer. Metallic Al, its oxides, and common Al salts have not been shown to be either genotoxic or carcinogenic. Aluminum exposures during neonatal and pediatric parenteral nutrition (PN) can impair bone mineralization and delay neurological development. Adverse effects to vaccines with Al adjuvants have occurred; however, recent controlled trials found that the immunologic response to certain vaccines with Al adjuvants was no greater, and in some cases less than, that after identical vaccination without Al adjuvants. The scientific literature on the adverse health effects of Al is extensive. Health risk assessments for Al must take into account individual co-factors (e.g., age, renal function, diet, gastric pH). Conclusions from the current review point to the need for refinement of the PTWI, reduction of Al contamination in PN solutions, justification for routine addition of Al to vaccines, and harmonization of OELs for Al substances

Anomalous Fluctuation of Halogens in Relation to the Pollution Status along Lake Mariout, Egypt

This paper aimed to study the anomalous fluctuation of halogens with respect to the pollution status in surface water (w), pore water (p), and sediments (s) of Lake Mariout. It provided a framework for understanding the distribution of dissolved and precipitated halogen salts related to the pollution status of the lake. The study cleared out that bromide was only the most abundant halogen in the three studied partitions. On contrast, sediment’s partition contained the lowest chloride content. Fluoride minerals, especially, fluorapatites and carbonate-fluorapatite (FAP and CFAP), had high Saturation Index (SI) values in surface water (42.77–51.95 and 16.04–60.89, respectively) and in pore water (51.26–54.60 and 17.52–78.33, respectively). Bromide and chloride were mainly found in the soluble forms in the surface water and pore waters. Iodide salts, (Ca(IO3)2 and Ca(IO3)2.6H2O), were moderately precipitated in surface and pore waters. Thus, SI content reflected that halogens, especially fluoride and iodide, played a vital role in reducing lake pollution. Fluorite (CaF2) and sellaïte (MgF2) could only be formed in pore water, while calcite and aragonite could be deposited from surface water. In addition, Cl was mainly found in the forms of NaCl, CaCl2, MgCl2, and KCl in surface and pore waters. The multivariate analysis revealed that fluoride precipitate may serve in decreasing the dissolved salt pollution. Multivariate analysis showed that in the long run, the fluoride precipitation in FAP and CFAP can significantly adsorb and absorb various pollutants and can protect the lake from pollution. The ecological risk assessment conducted by calculating the enrichment factor (EF) showed that the lake was still unpolluted. Regarding human health risks, at appropriate levels of human health and safety, the hazard quotient (HQ) and hazard index (HI) of halogens found to be lower than these reported levels. Hence, ingestion and dermal absorption routes of halogens by surface water and sediments did not pose any adverse effects to population reflecting uncontaminated status of Lake Mariout

Stability and bioavailability of diltiazem/polyethylene oxide matrix tablets

<p>The aim of this study was to prepare and evaluate <i>in vitro</i> and <i>in vivo</i>; Diltiazem-Hydrochloride (DTZ) in sustained-release matrix tablets. Stability of DTZ tablets prepared with polyethylene oxide (MWs 900 000, 4 000 000, and 8 000 000) with or without addition of electrolytes was carried-out for 1-month, under short-term storage at 40 °C/75% RH. Stability was evaluated by DTZ content, DSC and drug release using the Flow-Through Cell (USP # IV). The majority of stored tablets were stable for 1-month under short-term storage with respect to DTZ content and drug release. DSC curves of stored samples showed appearance of new exothermic peak after 1-month storage at 40 °C/75% RH, which was not observed after 5 years storage at room temperature. A selected formula was tested <i>in vivo</i> against reference product on eight healthy human volunteers. DTZ-plasma profiles were different between the two formulae. However, no statistically significant differences were detected between <i>C</i>_max, AUC_0–48 and AUC_0–∞. The two products were therapeutically in-equivalent, as 90% confidence intervals “T/R” were 88.82–205.76, 91.40–139.94, and 93.73–134.97 for <i>C</i>_max, AUC_0–48 and AUC_0–∞, respectively. This study highlighted possible differences observed between the two regimes frequently applied for stability testing.</p

An electrochemical, and surface studies of synthesized Gemini ionic liquid as corrosion inhibitor for carbon steel in petroleum field

Abstract In this work, we study the efficiency of N 1, N 3-dibenzyl-N 1, N1, N 3, N 3-tetramethylpropane-1,3-diaminium chloride, as anticorrosion. This compound exhibits potential as a prospective remedy to stop the deterioration of carbon steel caused by corrosion in 1.0 M HCl. The synthesis of this compound is described in a comprehensive manner, and its composition is supported by a range of precise analytical approaches such as elemental analysis, and mass spectroscopy. Based on the findings of the investigation, the synthesized Gemini ionic liquid demonstrates a robust capacity to slow down the rate at which the metal corrodes. The Prepared compound was evaluation by electrochemical and morphology study. Our results revealed that elevating the inhibitor concentration led to an augmentation in inhibition effectiveness, reaching up to 94.8% at 200 ppm of the synthesized compound at 298 K. It is crucial to emphasize that the recently prepared Gemini ionic liquid is consistent with the Langmuir adsorption model and function as a mixed inhibitor, participating in the physio-chemisorption process of adsorption

Gamma radiation-induced grafting of C₅ aliphatic petroleum resin onto ethylene-co-vinyl acetate copolymer for improving crude oil flowability

At present, ethylene-co-vinyl acetate (EVA) copolymers are the predominant choice among pour point depressants (PPDS) for enhancing the flowability of waxy crude oil. Still, they have shortcomings. Thus, this work aims to investigate the irradiation modification of a commercial EVA copolymer using C5 aliphatic petroleum resin (C5 PR) and its potential for utilization as a flow improver for crude oil. Results conclusively demonstrate the successful grafting of (C5 PR) onto EVA copolymer through gamma radiation, confirmed via grafting parameter characterization, FTIR, and 1H NMR spectroscopy. This modification significantly improved pour point results (ΔPPD = 24, 21, and 24 °C) for (EVA)0kGy, (EVA)50kGy, and (1EVA:1C5 PR)50kGy when treated with 3000 ppm of additives. Notably, the grafted EVA copolymers with C5 PR (1EVA:1C5 PR)50kGy outperformed non-modified EVA at a lower dosage of 1000 ppm. Also, irradiating EVA copolymer without insertion C5 PR resulted in EVA copolymer crosslinking, leading to a decrease in efficiency that could attributed to its accumulation. Furthermore, the crude oil’s rheological properties were substantially enhanced, evidenced by viscosity reductions of 60.8%, 51.3%, and 64.1% at 25 °C, and 55.2%, 18.7%, and 59.4% at 12 °C with the addition of 1000 ppm. Increasing the dosage to 3000 ppm led to even more remarkable viscosity decreases: 76.2%, 67.7%, and 78.2% at 25 °C, and 83.2%, 74.9%, and 84.7% at 12 °C for (EVA)0kGy, (EVA)50kGy, and (1EVA:1C5 PR)50kGy, respectively.</p

Synthesis and Characterization of New Dihydronaphthalene Candidates as Potent Cytotoxic Agents against MCF-7 Human Cancer Cells

In the present work, a new series of dihydronaphthalene derivatives were synthesized starting with 6-methoxy-1-tetralone 1, and the corresponding hydrazine derivative 2. Reaction of compound 2 with aryl isothiocyanates produced thiosemicarbazides 3a-d, which were reacted with ethyl chloroacetate to give thiazolidinone derivatives 4a-d. Pyrano thiazolecarbonitrile derivatives 5a-f were prepared by heating a mixture of compounds 4a or 4c, aryl aldehydes, and malononitrile utilizing distilled water in the presence of catalytic amount of potassium hydrogen phthalate. Also, treatment of 4a with DMF-DMA under solvent-free conditions gave enaminone derivative 6, which condensed with ethyl acetoacetate or acetylacetone or malononitrile or cyanothioacetamide to give compounds 7-10, respectively. Finally, reaction of the enaminone 6 with 2-aminoimidazol or 2-aminothiazol in the presence of glacial acetic acid produced derivatives 11 and 12, respectively. Cytotoxic evaluation of eleven compounds, against MCF-7 (human breast adenocarcinoma) cell lines, was estimated. Results revealed that five of the examined compounds 5a, 5d, 5e, 10, and 3d showed potent cytotoxic activities recording, IC50 values; 0.93±0.02, 1.76±0.04, 2.36±0.06, 2.83±0.07, and 3.73±0.09 μM, respectively, which were more potent than the reference used (Saturosporin, IC506.08±0.15 μM). The new products were also examined towards normal epithelial breast cells (MCF10A). All of them showed very good safety profile with different degrees and were safer than the reference drug used. Compound 5a was the most effective against MCF-7 cells and was less toxic than Saturosporin by about 18.45-folds towards MCF01A normal cells. All the new compounds were fully characterized by the different spectral and analytical tools. Herein, detailed syntheses, spectroscopic, and biological data are reported