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71.
Muhammad Harris Shoaib Saniah Al Sabah Siddiqi Rabia Ismail Yousuf Kamran Zaheer Muhammad Hanif Saeed Rehana Sabahat Jabeen 《AAPS PharmSciTech》2010,11(2):708-718
The objective of the present study was to develop a once-daily sustained-release (SR) matrix tablet of famotidine. Nine different
formulations (F1–F9) were prepared by direct compression method using Avicel PH101 as filler/binder in the range of 41–27%
in F1–F3, 18–22% in F4–F7, and 16–18% in F8–F9 and hydroxypropyl methylcellulose (4,000 cps) as hydrophilic matrix was used
in F1–F3 from 19% to 30%, around 40% in F4–F7, and 42–45% in F8–F9. Talc and Aerosil were added in the ratio of 0.7–1.2%.
The tablets were subjected to various physical parameters including weight variation test, hardness, thickness, diameter,
friability, and in vitro release studies. Assay was also performed according to the USP 30 NF 25 procedure. The results of the physical parameters
and assay were found to be within the acceptable range. In vitro dissolution results indicated that formulation F4–F7, having around 40% of rate control polymer, produced a SR pattern throughout
24 h. F1–F3 showed drug release at a faster rate, while F8–F9 released much slower, i.e., <80% in 24 h. Model-dependent and
model-independent methods were used for data analysis and the best results were observed for F4 in zero order (r
2 = 0.984) and F6 in Korsmeyer and Higuchi (r
2 = 0.992 and 0.988). The parameter n indicated anomalous diffusion, while β in Weibull showed a parabolic curve with higher initial slope. The f
2 similarity test was performed taking F4 as a reference formulation. Only the F5–F7 formulations were similar to the reference
formulation F4. The mean dissolution time was around 10 h for the successful formulation. 相似文献
72.
Drug resistance in Mycobacterium tuberculosis 总被引:3,自引:0,他引:3
73.
Summary and Conclusions Decreasing the dose frequency of cefpodoxime proxetil increases patient compliance; patients prefer to take the drug once
daily. It also improves the rate of bacterial killing and hastens the cure from the indications, and therefore increases compliance.
The hydrophilic matrix of HPMC controlled the cefpodoxime proxetil release effectively for 24 hours; hence, the formulation
can be considered as a once-daily sustained-release tablet of cefpodoxime proxetil. The formulation showed acceptable pharmacotechnical
properties and assay requirements. In vitro dissolution studies indicated a sustained-release pattern throughout 24 hours
of the study that was comparable to the theoretical release profile. Drug release kinetics indicated that drug release was
best explained by Higuchi’s equation, as these plots showed the highest linearity (r
2=0.9734), but a close relationship was also noted with zero-order kinetics (r
2=0.9708). Korsmeyer’s plots indicated ann value of 0.57, which was indicative of an anomalous diffusion mechanism or diffusion coupled with erosion; hence, the drug
release was controlled by more than one process. Hixson-Crowell plots indicated a change in surface area and diameter of the
tablets with the progressive dissolution of the matrix as a function of time.
Published: September 22, 2006 相似文献
74.
Farooq Latif Muhammad Asgher Rabia Saleem Ahmed Akrem R. L. Legge 《World journal of microbiology & biotechnology》2006,22(1):45-50
Summary Xylanase was produced by growing Chaetomium thermophile NIBGE in a submerged liquid culture using wheat straw and urea as carbon and nitrogen sources respectively. The xylanase
was purified to electrophoretic homogeneity after ammonium sulphate precipitation, anion exchange chromatography by FPLC and
gel filtration. The molecular mass of this xylanase BII was 50 kDa. The pH and temperature optima were 6.5 and 70 °C respectively.
The xylanase BII showed reasonable stability at high pH and 65 °C temperature. Some metal ions and EDTA caused little inhibition
at low concentrations but complete inhibition was observed at concentrations higher than 2 mM. The Km and Vmax values with oat spelt xylan as the substrate were found to be 12.5 mg/ml and 83.3 IU/mg protein, respectively. Liberation
of reducing sugars from commercial paper pulp samples suggest the feasibility of a biopulping process using this xylanase. 相似文献
75.
Hüttemann M Helling S Sanderson TH Sinkler C Samavati L Mahapatra G Varughese A Lu G Liu J Ramzan R Vogt S Grossman LI Doan JW Marcus K Lee I 《Biochimica et biophysica acta》2012,1817(4):598-609
Cytochrome c (Cytc) and cytochrome c oxidase (COX) catalyze the terminal reaction of the mitochondrial electron transport chain (ETC), the reduction of oxygen to water. This irreversible step is highly regulated, as indicated by the presence of tissue-specific and developmentally expressed isoforms, allosteric regulation, and reversible phosphorylations, which are found in both Cytc and COX. The crucial role of the ETC in health and disease is obvious since it, together with ATP synthase, provides the vast majority of cellular energy, which drives all cellular processes. However, under conditions of stress, the ETC generates reactive oxygen species (ROS), which cause cell damage and trigger death processes. We here discuss current knowledge of the regulation of Cytc and COX with a focus on cell signaling pathways, including cAMP/protein kinase A and tyrosine kinase signaling. Based on the crystal structures we highlight all identified phosphorylation sites on Cytc and COX, and we present a new phosphorylation site, Ser126 on COX subunit II. We conclude with a model that links cell signaling with the phosphorylation state of Cytc and COX. This in turn regulates their enzymatic activities, the mitochondrial membrane potential, and the production of ATP and ROS. Our model is discussed through two distinct human pathologies, acute inflammation as seen in sepsis, where phosphorylation leads to strong COX inhibition followed by energy depletion, and ischemia/reperfusion injury, where hyperactive ETC complexes generate pathologically high mitochondrial membrane potentials, leading to excessive ROS production. Although operating at opposite poles of the ETC activity spectrum, both conditions can lead to cell death through energy deprivation or ROS-triggered apoptosis. 相似文献
76.
Abdellah Benachour Rabia Ladjouzi André Le Jeune Laurent Hébert Simon Thorpe Pascal Courtin Marie-Pierre Chapot-Chartier Tomasz K. Prajsnar Simon J. Foster Stéphane Mesnage 《Journal of bacteriology》2012,194(22):6066-6073
Lysozyme is a key component of the innate immune response in humans that provides a first line of defense against microbes. The bactericidal effect of lysozyme relies both on the cell wall lytic activity of this enzyme and on a cationic antimicrobial peptide activity that leads to membrane permeabilization. Among Gram-positive bacteria, the opportunistic pathogen Enterococcus faecalis has been shown to be extremely resistant to lysozyme. This unusual resistance is explained partly by peptidoglycan O-acetylation, which inhibits the enzymatic activity of lysozyme, and partly by d-alanylation of teichoic acids, which is likely to inhibit binding of lysozyme to the bacterial cell wall. Surprisingly, combined mutations abolishing both peptidoglycan O-acetylation and teichoic acid alanylation are not sufficient to confer lysozyme susceptibility. In this work, we identify another mechanism involved in E. faecalis lysozyme resistance. We show that exposure to lysozyme triggers the expression of EF1843, a protein that is not detected under normal growth conditions. Analysis of peptidoglycan structure from strains with EF1843 loss- and gain-of-function mutations, together with in vitro assays using recombinant protein, showed that EF1843 is a peptidoglycan N-acetylglucosamine deacetylase. EF1843-mediated peptidoglycan deacetylation was shown to contribute to lysozyme resistance by inhibiting both lysozyme enzymatic activity and, to a lesser extent, lysozyme cationic antimicrobial activity. Finally, EF1843 mutation was shown to reduce the ability of E. faecalis to cause lethality in the Galleria mellonella infection model. Taken together, our results reveal that peptidoglycan deacetylation is a component of the arsenal that enables E. faecalis to thrive inside mammalian hosts, as both a commensal and a pathogen. 相似文献
77.
Hussain Muhammad Zhaid Mahjabeen Ishrat Khan Muhammad Shahid Mumtaz Naila Maqsood Syed Uzair Ikram Farooq Ahmed Syed Nazir Kalim Qurrat-ul-Ain Abbas Rabia Cheema Ahmed Ammar 《Molecular biology reports》2021,48(6):5171-5180
Molecular Biology Reports - Rheumatoid arthritis (RA) is one of the most common autoimmune diseases globally, and is an important public health concern, associating with early death and systemic... 相似文献
78.
Diabetic retinopathy in the Eastern Morocco: Different stage frequencies and associated risk factors
Jamila Hammoudi Nour El Houda Bouanani El Habri Chelqi Yassamine Bentata Hamid Nouayti Abdelkhaleq Legssyer Abderrahim Ziyyat 《Saudi Journal of Biological Sciences》2021,28(1):775-784
Diabetes is a major cause of morbidity and mortality worldwide. It can affect many organs and, over time, leads to serious complications. Diabetic retinopathy (DR), a specific ocular complication of diabetes, remains the leading cause of vision loss and vision impairment in adults. This work is the first in Eastern Morocco aimed at identifying the different stages of DR and to determine their frequencies and associated risk factors. It is a case-control study conducted from December 2018 to July 2019 at the ophthalmology department of Al-Irfane Clinic (Oujda). Data were obtained from a specific questionnaire involving 244 diabetic patients (122 cases with retinopathy vs 122 controls without retinopathy). All results were analyzed by the EPI-Info software. This study shows a predominance of proliferative diabetic retinopathy (PDR) with 57.4% of cases (uncomplicated proliferative diabetic retinopathy (UPDR): 23.8%; complicated proliferative diabetic retinopathy (CPDR): 33.6%). The non-proliferative diabetic retinopathy (NPDR) represents 42.6% (minimal NPDR: 8.2%; moderate NPDR: 26.2%; severe NPDR: 8.2%). The determinants of DR were insulin therapy, high blood pressure, poor glycemic control and duration of diabetes. Regarding the chronological evolution, retinopathy precedes nephropathy. Diabetic nephropathy (DN) was present in 10.6% of cases especially in patients with PDR. In summary, the frequency of PDR was higher than that of NPDR. DR appears before DN with a high frequency of DN in patients with PDR. Good glycemic control and blood pressure control, as well as early diagnosis are the major preventive measures against DR. 相似文献
79.
Mohamed A. Al-Griw Rabia O. Alghazeer Naser M. Salama Bashir A. Lwaleed Areej A. Eskandrani Wafa S. Alansari Afnan M. Alnajeebi Nouf A. Babteen Ghalia Shamlan Abdul Hakim Elnfati 《Saudi Journal of Biological Sciences》2021,28(1):948
Bisphenol A (BPA), an endocrine and metabolic disruptor, is widely used to manufacture polycarbonate plastics and epoxy resins. Accumulating evidence suggests that paternal BPA exposure adversely affects male germlines and results in atypical reproductive phenotypes that might persist for generations to come. Our study investigated this exposure on testicular architecture and sperm quality in mouse offspring, and characterised underlying molecular mechanism(s). A total of 18 immature male Swiss albino mice (3.5 weeks old) were randomly divided into three groups and treated as follows: Group I, no treatment (sham control); Group II, sterile corn oil only (vehicle control); Group III, BPA (400 μg/kg) in sterile corn oil. At 9.5 weeks old, F0 males were mated with unexposed females. F0 offspring (F1 generation) were monitored for postnatal development for 10 weeks. At 11.5 weeks old, the animals were sacrificed to examine testicular architecture, sperm parameters, including DNA integrity, and oxidative stress biomarkers. Results showed that BPA significantly induced changes in the body and testis weights of the F0 and F1 generation BPA lineages compared to F0 and F1 generation control lineages. A decrease in sperm count and motility with further, increased sperm abnormalities, no or few sperm DNA alterations and elevated levels of MDA, PC and NO were recorded. Similar effects were found in BPA exposed F0 males, but were more pronounced in the F0 offspring. In addition, BPA caused alterations in the testicular architecture. These pathological changes extended transgenerationally to F1 generation males’ mice, but the pathological changes were more pronounced in the F1 generation. Our findings demonstrate that the biological and health BPA impacts do not end in paternal adults, but are passed on to offspring generations. Hence, linking observed testis and sperm abnormalities in the F1 generation to BPA exposure of their parental line was evident in this work. The findings also illustrate that oxidative stress appears to be a molecular component of the testis and sperm pathologies. 相似文献
80.
Dennis O’Shea Rabia Ahmad Erik Årstad Michelle Avory Wai-Fung Chau Clare Durrant Ella Hirani Paul A. Jones Imtiaz Khan Sajinder K. Luthra Dimitrios Mantzilas Véronique Morisson-Iveson Joanna Passmore Edward G. Robins Bo Shan Harry Wadsworth Sarah Walton Yongjun Zhao William Trigg 《Bioorganic & medicinal chemistry letters》2013,23(8):2368-2372
A series of novel TSPO ligands based on the tetracyclic class of translocator protein (TSPO) ligands first described by Okubo et al. was synthesised and evaluated as potential positron emitting tomography (PET) ligands for imaging TPSO in vivo. Fluorine-18 labelling of the molecules was achieved using direct radiolabelling or synthon based labelling approaches. Several of the ligands prepared have promising profiles as potential TSPO PET imaging ligands. 相似文献