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Evaluation of Carbopol 71G for development of extended release dextromethorpahn tablets
No full textMastersThere is an increasing interest in Carbopol polymers as gel matrix formers for extended release of drugs. Thus, it was the objective of this dissertation to evaluate the Carbopol 71G as extended release excipient in development of extended release matrix tablets of dextromethorphan hydrobromide using direct compression technique. The evaluation of Carbopol was carried out in comparison with the non-ionic polymer, hydroxypropyl methylcellulose (HPMC K15 M and HPMC 15) and the ionic polymer, methacrylic acid co-polymer (Eudragit L100-55) individually and in combination at different drug to polymer ratios. The effect of polymer concentration, polymers combination, compression force and storage conditions on the tablet physical properties, and drug release profile were evaluated on the manufactured tablets. The extended release formulations were compared to a marketed capsule product by applying the FDA dissolution recommended model independent f2 similarity test. Additionally, the mechanism of drug release from the extended release formulations were evaluated by applying different mathematical kinetic models on drug release profiles.
It was found that the Carbopol polymer boost the tablet physical properties as investigated by crushing strength and friability test, indicating the good compressibility and binding characters of the investigated Carbopol polymer. A minimum concentration of 20% polymer was necessary to achieve a coherent matrix, able to extend the release of dextromethorphan. Increasing the concentration of Carbopol in the formulation leads to more retardation of drug release. A combination of Carbopol with other matrix forming excipients could modulate the release pattern of the drug, providing the formulator the great flexibility in achieving the desired drug release profiles. Drug release followed square root of time dependent kinetics, thus indicating a diffusion-controlled release mechanism. It was found that variation in compression force showed no significant change in release profile. This finding is considered a significant advantage for Carbopol formulations. On the other hand the Carbopol formulations showed reproducibility in the tablet physical properties and drug release profile. Therefore, a robust delivery system was attained using Carbopol polymer. A significant change in tablet physical properties was observed during stability test under accelerated storage conditions (40 ± 2 oC / 75 ± 5% RH) but no significant change in release profile up to 6 months. On the other hand, tablets stored under long term storage conditions (25 ± 2 oC / 60 ± 5% RH) showed no significant change in both tablet physical properties and release profile up to 12 months.
It was concluded that Carbopol 71G is a good matrix forming excipient for the production of extended release matrix tablets. The combination of Carbopol and HPMC showed synergistic effect on the release of dextromethorphan thus, with this blend, it is possible to reduce the total amount of polymers in matrix and minimize the size and weight of the tablet
Risk assessment of heavy metal contamination in soil and wild libyan jird, Meriones libycus in Riyadh, Saudi Arabia
No full textThis study was undertaken to document the impact of heavy metal pollution on the libyan jird, Meriones libycusand to contribute to an environmental impact statement for the rapidly growing City of Riyadh. All metal concentrations in surface soil of a polluted site (within Riyadh City) were higher than those from a reference site (outside the city). Although Pb declined versus earlier reports on Riyadh soil, Cd (0.97 Ag g-1) and Hg (0.28 Ag g-1) were above some of the most stringent quality guidelines (0.07- 0.62 Ag g-1 for Cd and 0.14- 0.18 Ag g-1 for Hg). Metal distribution in M. libycus proved site-related and organ-specific, recognizing a higher affinity of most tested metals towards the kidneys, liver and brain than the lung and heart. The comparatively lower sitespecific accumulation of Pb in soft tissues was attributed primarily to its major hypothetical accumulation in bones, whereas, the transition rate of Hg from the liver was suggested to be lower to the brain than to the kidneys. Although a non hazardous status was assumed for Cu (11.27-13.16 Ag g-1) and Hg (up to 0.207 Ag g-1) in tissues of M. libycus, a potential risk was imposed by mean tissue concentrations of Cd (up to 3.29 Ag g-1), Ni (up to 1.48 Ag g-1) and Pb (up to 1.94 Ag g-1). On the grounds of the significantly higher metal levels in polluted soft tissues versus reference subjects, libyan jirds possess high exposure potential and can be useful biomonitors of environmental metal contamination.Journal of Environmental Biolog
Therapeutic Efficacy and in vivo Giardia lamblia Morphological Alterations Induced by Some Natural Medicinals
No full textGiardia lamblia, the causative agent of giardiasis, is a protozoan intestinal flagellate that infects humans, specially children, allover the world. The current therapeutic agents have considerable adverse effects or be contraindicated in certain clinical situations or show failure due to drug resistance. Using a mouse model, the intent of the present study was to evaluate the in vivo therapeutic efficacy of garlic plant, wheat germ agglutinin "WGA" and selenium in comparison with meteronidazole, and to declare their impact on ultrastructure of luminal trophozoites. The patent period, intensity of infection, cyst shedding and cure rate in groups treated by the natural therapeutics revealed a highly significant difference in comparison with the non-treated control and insignificant difference in comparison with metronidazole, a finding that might be beneficial at least in clinical situations where current chemotherapy is contraindicated. All of the tested therapeutics proved to be injurious to the parasite with evident morphological changes. While garlic appeared to induce changes that interfere with the
progress of trophozoite motility, selenium and WGA seemed to be evidently lethal to the parasite.The Deanship of Scientific Research at king Saud Universit
Expression of p53 during apoptosis induced by D-galactosamine and the protective role of PGE1 in cultured rat hepatocytes
No full textThe controlled cell death (apoptosis) is involved in the normal regulation of organ size as well as the underlying mechanism of liver disease. Hepatic injury induced by D-galactoseamine (D-GalN) in rats is suitable experimental model to study human liver failure. Many transcription factors are involved in cellular responses, among of them are NF-kβ, TNF-α, AP-1 family; Jun, Fos and p53. Prostaglandin E1 (PGE1) reduces liver injury induced experimentally.
P53 is a critical player in the prevention of tumor development. It can contribute directly to DNA repair and inhibition of angiogenesis and to the induction of apoptosis. The regulation of p53 expression is mediated by NF-kβ. This includes regulation of p53 protein stability, control of its subcellular localization and conformational changes that allow activation of the DNA binding activity of p53.
Methods: Rat hepatocytes were isolated from male Wistar rats following collagenase perfusion of liver. We examined the change in the expression level of p53 in hepatocytes as a response of treatment with D-GalN (5 and 40 mM) in the presence or absence of PGE1 (1 mM) with or without the proteosome inhibitor (PSI) in protection against apoptosis. The expression of p53 is determined by separating the protein in denatured SDS-PAGE followed by western blotting and detecting the protein using polyclonal antibodies specific for p53.
Results: The addition of prostaglandin to control and D-GalN treated hepatocytes increased p53 expression in the cytoplasm during 24 h. While the addition of PSI in the absence of prostaglandin decreased p53 expression at 5 mM D-GalN. This inhibition is reversed in the presence of PGE1 at 5 and 40 mM D-GalN
Anthropometric Measurement and Ventilatory Function in Obese and Non-Obese Female College Students.
No full textObesity is global risk factor for many health problems. The aims of this study were to assess the relationship between the anthropometric measurements [Body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR), and abdominal circumference (AC)] and ventilatory function parameters [Forced vital capacity (FVC), forced expiratory volume (FEV1), maximum ventilatory ventilation (MVV)] and to investigate the impact and association of cut-off values of BMI, WC and WHR with ventilatory function in obese and non-obese young females. This cross-sectional study was conducted on 69 Saudi female students aged between 18-26 years. All participants were subjected to anthropometric and ventilatory function measurements. The results revealed variable relationships between the anthropometric measurements and parameters of ventilatory function. In obese group BMI was negatively associated with FEV1/FVC (β=-0.497, P=0.026), on average one kg/m2 increase in BMI resulted in 1.80% reduction in FEV1/FVC ratio. The WC ≥ 88 cm was negatively associated with VC (β=-0.538, P=0.031), FVC (β=-0.624, P=0.010) and FEV1 (β=-0.609, P=0.012). On average, one cm increase in WC was associated with 3.8 mL reduction in VC, 4.41 mL reduction in FVC and 4.3 mL reduction in FEV1.The WHR ≥80% was negatively associated with VC (β=-0.710, P=0.021), on average one % increase was associated with 2.492 mL reduction in VC. Trunk obesity as measured by WC, WHR and AC is more significant predictor to ventilatory function than overall obesity measure, BMI
ENHANCEMENT OF DISSOLUTION AND THE ANTI-INFLAMMATORY EFFECT OF NIMESULIDE, USING LIQUISOLID COMPACT FOR ORAL APPLICATION
No full textNimesulide is a poorly soluble drug, the rate of its oral absorption is often controlled by the dissolution rate in the gastrointestinal tract. There are several techniques to enhance the dissolution of poorly soluble drugs. Among them the technique of liquisolid compacts which is a promising one. The liquisolid compacts were prepared using 20 mg nimesulide, Avicel PH102 as a carrier, and Aerosil 200 as a coating material in a ratio of 20:1, as well as AC-DI-SOL as a disintegrant in a concentration of 5% from the total weight of the compact. The liquids used include PEG400, PG, and a mixture of these solvents with Tween 80. From the results obtained it is concluded that the suitable loading factor (Lf) is 0.2 which gave good flowability and compressibility. Friability, hardness, disintegration time and the dissolution rate were carried out. All the liquisolid compacts showed higher dissolution rate than the conventional tablets. The liquisolid compacts containing the PEG400 showed the highest dissolution rate than the other preparations. The effect of different concentrations of drug on the dissolution rate was studied, and it was observed that 20% of drug gave the maximum dissolution rate, and no significant increase of the dissolution rate with increasing the drug concentration. Conventional tablets and liquisolid compacts containing PG and PEG400 were tested for their anti-inflammatory effects using paw oedema test. liquisolid compacts exhibited a pronounced inhibition of swelling than that of conventional tablets. In conclusion liquisolid compact of nimesulide can be used as a technique to improve the dissolution rate and the anti-inflammatory effect of nimesulide.King Saud Universit
Synthesis,antiplatelet aggregation activity, and molecular modeling study of novel substituted-piperazine analogues.
No full textNew carbamoylpyridine and carbamoylpiperidine analogues containing nipecotic acid scaffold were designed, synthesized, and evaluated for their platelet aggregation inhibitory activity. Molecular modeling investigation was performed and the impact of lipophilicity on activity was also discussed. Structure activity relationship among this series was obtained. N1-[1-(4-bromobenzyl)-3-piperidinocarbonyl]-N4-(2-chlorophenyl)-piperazine hydrobromide (20), and 1,4-bis-[3-[N4-(2-chlorophenyl)-N1 (piperazinocarbonyl)]-piperidin-1-yl-methyl]-benzene dibromide (30) are the most active antiplatelet aggregating compounds in this study, both aconcentration of 0.06 lM.The financial support of King Abdulaziz City for Science and Technology
تحقيب دراسات ما قبل التاريخ في شبه الجزيرة العربية
No full textملخص: قَسَّم الباحث في هذه الدراسة تاريخ الدراسات الأثارية لعصور ما قبل التاريخ في شبه الجزيرة العربية إلى ثلاث مراحل تاريخية: المرحلة الأولى تبدأ بتسجيل أولى الأدوات الحجرية منذ زهاء الربع الثاني من القرن العشرين، عن طريق الجيولوجيين الهواة العاملين في الشركات النفطية، في الغالب، وتنتهي بتأسيس إدارات الآثار المحلية في النصف الأول من خمسينيات القرن العشرين، إلى جانب ظهور البعثة الدانيماركية في شرقي شبه الجزيرة عام 1953م. ويُعدُّ ظهور البعثة المذكورة، وتأسيس إدارات الآثار المحلية من العلامات المميزة لدخول المرحلية الثانية في الوقت نفسه، والتي انتهت بظهور برامج المسح والتنقيب الطويلة المدى، بدءاً بعام 1976م، مع الشراكة المحلية في هذه البرامج. بينما تبدأ المرحلة الثالثة بظهور البرامج المذكورة، وهي مستمرة إلى اليوم. كما قسَّم الباحث المرحلة الأولى إلى فترتين، بينما قسم كل من المرحلتين الثانية، والثالثة، إلى ثلاث فترات
ادارة الجودة الشاملة كمنهج ادارى حديث فى الجامعات العربية
No full textان اعتماد ادارة الجودة الشاملة من قبل مؤسسات التعليم في الوطن العربي سيؤثر بشكل ايجابي على اداء هذه المؤسسات وسيعمل على تطوير بنيتها الادارية وبالتالي الرفع من كفاءة الاداء الاكاديمي. على الرغم من هذه الحقيقة، فان ثقافة ادارة الجودة الشاملة في مؤسسات التعليم العالي العربية تكاد تكون غائبة، ولا تحظى بالاحترام المطلوب في العقلية الادارية المسؤولة عن تنظيم هذه المؤسسات. ان عدم تبني نظام ادارة الجودة الشاملة في مؤسسات التعليم العالي ادى الى ضعف مخرجات التعليم العالي، وادى الى عدم قدرة هذه المؤسسات على مواكبة التطورات المتسارعة في انظمة التعليم العالي حول العالم
اللساني واللاوعي
No full textيتمثل جوهر الكتاب في مراجعة العلاقة التي تنشأ بين الكلام واللاوعي، وهي علاقة أساسية جداً في منظور المحلل النفسي الفرنسي جاك لاكان- وفي صحيح القول بديهية كل البداهة- حتى إنه من المفترض أن تصبح معروفة على أوسع نطاق ممكن.
وعندما يعلم المرء أن الأعمدة الأساسية التي قام عليها هذا الصرح اللغوي الفكري الضخم هي أعمال: فرويد، وسوسير، ولاكان، وداموريت وبيشون، وبنفينيست، وستاروبنسكي، وهلمسليف، وأنغلر، وجاكبسون، وهاجيج، وسيرج لوكلير، وجورج مونان وغيرهم من علماء نفس ومحللين نفسيين ولغويين، ويرى مقدار ما تُرجم من أعمال هؤلاء الكتَّاب إلى العربية فإنه يدرك مدى أهمية الكتا