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Mohammed SW, El-Megrab NA, Hasan AA, Gomaa E. A remodeled ivermectin polycaprolactone-based nanoparticles for inhalation as a promising treatment of pulmonary inflammatory diseases. Eur J Pharm Sci 2024; 195:106714. [PMID: 38301972 DOI: 10.1016/j.ejps.2024.106714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 01/09/2024] [Accepted: 01/29/2024] [Indexed: 02/03/2024]
Abstract
In recent years, ivermectin (IVM), an antiparasitic drug of low water solubility and poor oral bioavailability, has shown a profound effect on inflammatory mediators involved in diseases, such as acute lung injury, lung fibrosis, and COVID-19. In order to maximize drug bioavailability, polymeric nanoparticles can be delivered through nebulizers for pulmonary administration. The aim of this study was to prepare IVM-loaded polycaprolactone (PCL) nanoparticles (NPs) by solvent evaporation method. Box-Benkhen design (BBD) was used to optimize entrapment efficiency (Y1), percent drug release after 6 h (Y2), particle size (Y3), and zeta potential (Y4). A study was conducted examining the effects of three independent variables: PCL-IVM ratio (A), polyvinyl alcohol (PVA) concentration (B), and sonication time (C). The optimized formula was also compared to the oral IVM dispersion for lung deposition, in-vivo behavior, and pharmacokinetic parameters. The optimized IVM-PCL-NPs formulation was spherical in shape with entrapment efficiency (% EE) of 93.99 ± 0.96 %, about 62.71 ± 0.53 % released after 6 h, particle size of 100.07 ± 0.73 nm and zeta potential of -3.30 ± 0.23 mV. Comparing the optimized formulation to IVM-dispersion, the optimized formulation demonstrated greater bioavailability with greater area under the curve AUC0-t of 710.91 ± 15.22 μg .ml-1.h for lung and 637.97 ± 15.43 μg .ml-1.h for plasma. Based on the results, the optimized NPs accumulated better in lung tissues, exhibiting a twofold longer residence time (MRT 4.78 ± 0.55 h) than the IVM-dispersion (MRT 2.64 ± 0.64 h). The optimized nanoparticle formulation also achieved higher cmax (194.90 ± 5.01 μg/ml), and lower kel (0.21 ± 0.04 h-1) in lungs. Additionally, the level of inflammatory mediators was markedly reduced. To conclude, inhalable IVM-PCL-NPs formulation was suitable for the pulmonary delivery and may be one of the most promising approaches to increase IVM bioavailability for the successful treatment of a variety of lung diseases.
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Affiliation(s)
- Sabaa Wafiq Mohammed
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt.
| | - Nagia Ahmed El-Megrab
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Azza A Hasan
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Eman Gomaa
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
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Albadawy R, Hasanin AH, Agwa SHA, Hamady S, Mohamed RH, Gomaa E, Othman M, Yahia YA, Ghani AMA, Matboli M. Prospective insight into the role of benzyl propylene glycoside as a modulator of the cGAS-STING signaling pathway in the management of nonalcoholic fatty pancreas animal model. Biol Res 2023; 56:11. [PMID: 36915161 PMCID: PMC10010022 DOI: 10.1186/s40659-023-00423-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 03/06/2023] [Indexed: 03/14/2023] Open
Abstract
BACKGROUND Nonalcoholic fatty pancreatitis (NAFP) is one of the metabolic syndrome manifestations that need further studies to determine its molecular determinants and find effective medications. We aimed to investigate the potential effect of benzyl propylene glycoside on NAFP management via targeting the pancreatic cGAS-STING pathway-related genes (DDX58, NFκB1 & CHUK) and their upstream regulator miRNA (miR-1976) that were retrieved from bioinformatics analysis. METHODS The rats were fed either normal chow or a high-fat high-sucrose diet (HFHS), as a nutritional model for NAFP. After 8 weeks, the HFHS-fed rats were subdivided randomly into 4 groups; untreated HFHS group (NAFP model group) and three treated groups which received 3 doses of benzyl propylene glycoside (10, 20, and 30 mg/kg) daily for 4 weeks, parallel with HFHS feeding. RESULTS The molecular analysis revealed that benzyl propylene glycoside could modulate the expression of the pancreatic cGAS-STING pathway-related through the downregulation of the expression of DDX58, NFκB1, and CHUK mRNAs and upregulation of miR-1976 expression. Moreover, the applied treatment reversed insulin resistance, inflammation, and fibrosis observed in the untreated NAFP group, as evidenced by improved lipid panel, decreased body weight and the serum level of lipase and amylase, reduced protein levels of NFκB1 and caspase-3 with a significant reduction in area % of collagen fibers in the pancreatic sections of treated animals. CONCLUSION benzyl propylene glycoside showed a potential ability to attenuate NAFP development, inhibit pancreatic inflammation and fibrosis and reduce the pathological and metabolic disturbances monitored in the applied NAFP animal model. The detected effect was correlated with modulation of the expression of pancreatic (DDX58, NFκB1, and CHUK mRNAs and miR-1976) panel.
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Affiliation(s)
- Reda Albadawy
- grid.411660.40000 0004 0621 2741Department of Gastroenterology, Hepatology & Infectious Disease, Faculty of Medicine, Benha University, Benha, 13518 Egypt
| | - Amany Helmy Hasanin
- grid.7269.a0000 0004 0621 1570Clinical Pharmacology Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Sara H. A. Agwa
- grid.7269.a0000 0004 0621 1570Clinical Pathology and Molecular Genomics Unit, Medical Ain Shams Research Institute (MASRI), Faculty of Medicine, Ain Shams University, Cairo, 11382 Egypt
| | - Shaimaa Hamady
- grid.7269.a0000 0004 0621 1570Department of Biochemistry, Faculty of Science, Ain Shams University, Cairo, 11566 Egypt
| | - Reham Hussein Mohamed
- grid.7269.a0000 0004 0621 1570Clinical Pharmacology Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Eman Gomaa
- grid.7269.a0000 0004 0621 1570Histology and Cell Biology Department, Faculty of Medicine, Ain Shams University, Giza, Egypt
| | - Mohamed Othman
- grid.39382.330000 0001 2160 926XGastroenterology and Hepatology Section, Baylor College of Medicine, Houston, TX 77030 USA
| | - Yahia A. Yahia
- grid.252119.c0000 0004 0513 1456Chemistry Department, School of Science and Engineering, American University in Cairo, New Cairo, 11835 Egypt
- grid.440875.a0000 0004 1765 2064Biochemistry Department, Faculty of Pharmaceutical Sciences and Drug Manufacturing, Misr University for Science and Technology, Giza, Egypt
| | - Amani Mohamed Abdel Ghani
- grid.7269.a0000 0004 0621 1570Clinical Pathology, Faculty of Medicine, Ain Shams University, Cairo, 11566 Egypt
| | - Marwa Matboli
- grid.7269.a0000 0004 0621 1570Medical Biochemistry and Molecular Biology Department, Faculty of Medicine, Ain Shams University, Cairo, 11566 Egypt
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Gomaa E, Eissa NG, Ibrahim TM, El-Bassossy HM, El-Nahas HM, Ayoub MM. Development of depot PLGA-based in-situ implant of Linagliptin: Sustained release and glycemic control. Saudi Pharm J 2023; 31:499-509. [PMID: 37063437 PMCID: PMC10102447 DOI: 10.1016/j.jsps.2023.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 02/07/2023] [Indexed: 02/16/2023] Open
Abstract
High percentage of diabetic people are diagnosed as type 2 who require daily dosing of an antidiabetic drug such as Linagliptin (Lina) to manage their blood glucose levels. This study aimed to develop injectable Lina-loaded biodegradable poly (lactic-co-glycolic acid) (PLGA) in-situ implants (ISIs) to deliver a desired burst effect of Lina followed by a sustained release over several days for controlling the blood glucose levels over prolonged time periods. The morphological, pharmacokinetic, and pharmacodynamic assessments of the Lina-loaded ISIs were performed. Scanning electron microscopy (SEM) study revealed the rapid exchange between the water miscible solvent (N-methyl-2-pyrrolidone; NMP) and water during the ISI preparation, hence enhancing the initial burst Lina release. While, triacetin of lower water affinity could lead to formation of more compact and dense ISI structure with slower drug release. By comparing various ISI formulations containing different solvents and different PLGA concentrations, the ISI containing 40 % PLGA and triacetin was selected for its sustained release of Lina (93.06 ± 1.50 %) after 21 days. The pharmacokinetic results showed prolonged half life (t1/2) and higher area under the curve (AUC) values of the selected Lina-loaded ISI when compared to those of oral Lina preparation. The single Lina-ISI injection produced a hypoglycemic control in the diabetic rats very similar to the daily oral administration of Lina after 7 and 14 days. In conclusion, PLGA-based ISIs confirmed their suitability for prolonging Lina release in patients receiving long-term antidiabetic therapy, thereby achieving more enhanced patient compliance and reduced dosing frequency.
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Affiliation(s)
- Eman Gomaa
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
| | - Noura G. Eissa
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
| | - Tarek M. Ibrahim
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
- Corresponding author.
| | - Hany M. El-Bassossy
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
| | - Hanan M. El-Nahas
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
| | - Margrit M. Ayoub
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
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Abdulla NA, Balata GF, El-ghamry HA, Gomaa E. Intranasal delivery of Clozapine using nanoemulsion-based in-situ gels: An approach for bioavailability enhancement. Saudi Pharm J 2022; 29:1466-1485. [PMID: 35002385 PMCID: PMC8720818 DOI: 10.1016/j.jsps.2021.11.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 11/10/2021] [Indexed: 12/18/2022] Open
Abstract
Limited solubility and hepatic first-pass metabolism are the main causes of low bioavailability of anti-schizophrenic drug, Clozapine (CZP). The objective of the study was to develop and validate nanoemulsion (NE) based in-situ gel of CZP for intranasal administration as an approach for bioavailability enhancement. Solubility of CZP was initially investigated in different oils, surfactants and co-surfactants, then pseudoternary phase diagrams were constructed to select the optimized ratio of oil, surfactant and co-surfactant. Clear and transparent NE formulations were characterized in terms of droplet size, viscosity, solubilization capacity, transmission electron microscopy, in-vitro drug release and compatibility studies. Selected NEs were incorporated into different in-situ gel bases using combination of two thermosensitive polymers; Pluronic® F-127 (PF127) and F-68 (PF68). NE-based gels (NG) were investigated for gelation temperature, viscosity, gel strength, spreadability and stability. Moreover, selected NGs were evaluated for ex-vivo permeation, mucoadhesive strength and nasal ciliotoxicity. Peppermint oil, tween 80 and transcutol P were chosen for NE preparation owing to their maximum CZP solubilization. Clear NE points extrapolated from tween 80:transcutol P (1:1) phase diagram and passed dispersibility and stability tests, demonstrated globule size of 67.99 to 354.96 nm and zeta potential of −12.4 to −3.11 mV with enhanced in-vitro CZP release (>90% in some formulations). After incorporation of the selected N3 and N9 formulations of oil:Smix of 1:7 and 2:7, respectively to a mixture of PF127 and PF68 (20:2% w/w), the resultant NG formulations exhibited optimum gelation temperature and viscosity with enhanced CZP permeation and retention through sheep nasal mucosa. Ciliotoxicity examinations of the optimum NGs displayed no inflammation or damage of the lining epithelium and the underlying cells of the nasal mucosa. In conclusion, NE-based gels may be a promising dosage form of CZP for schizophrenia treatment.
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Affiliation(s)
- Nourhan A. Abdulla
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
- Corresponding author.
| | - Gehan F. Balata
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
- Department of Pharmacy Practice, Faculty of Pharmacy, Heliopolis University, Cairo, Egypt
| | - Hanaa A. El-ghamry
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Eman Gomaa
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
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Gomaa E, Attia MS, Ghazy FES, Hassan AE, Hasan AA. Pump-free electrospraying: A novel approach for fabricating Soluplus®-based solid dispersion nanoparticles. J Drug Deliv Sci Technol 2022. [DOI: 10.1016/j.jddst.2021.103027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Gomaa E, Ayoub MM. Vardenafil oral jellies as a potential approach for management of pediatric irritable bowel syndrome. Saudi Pharm J 2021; 29:955-962. [PMID: 34588841 PMCID: PMC8463432 DOI: 10.1016/j.jsps.2021.07.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 07/17/2021] [Indexed: 02/08/2023] Open
Abstract
Irritable bowel syndrome (IBS); a widespread disorder in gastrointestinal tract especially in children, burdens their healthcare systems and upsets families. Great attention was paid to understand the pathophysiological cause of disorder. However, developing a convenient treatment especially for children remains a challenge. Phosphodiesterase inhibitors were recently introduced for IBS management. Vardenafil (VDF), a phosphodiesterase-5 inhibitor, exhibiting limited bioavailability when taken orally due to extensive first-pass effect, was the choice for study. This study aimed to formulate VDF jellies as a buccal dosage form to improve pediatric compliance and achieve maximum drug efficacy. VDF oral jellies were prepared by heat and congeal method, and were evaluated for their pH, content uniformity, physical stability, general appearance, and in-vitro drug release. VDF jellies (F1), with satisfactory organoleptic properties and highest percent of drug released compared to other formulations was selected as a master formula for further study to ensure in-vivo efficacy. cyclic Guanosine Mono Phosphate (cGMP), used as indicator of VDF concentration in blood, was highly increased after administration of VDF jellies (F1), compared to oral VDF suspension. Increased defecation with improved fecal consistency strongly favored oral jellies as a potential alternative route for VDF for IBS management with high pediatric acceptance.
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Affiliation(s)
- Eman Gomaa
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
| | - Margrit M Ayoub
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
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Gomaa E, Fathi HA, Eissa NG, Elsabahy M. Methods for preparation of nanostructured lipid carriers. Methods 2021; 199:3-8. [PMID: 33992771 DOI: 10.1016/j.ymeth.2021.05.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/06/2021] [Accepted: 05/11/2021] [Indexed: 12/14/2022] Open
Abstract
Construction of nanocarriers of different structures and properties have shown great promise as delivery systems for a wide range of drugs to improve therapeutic effects and reduce side effects. Nanostructured lipid carriers (NLCs) have been introduced as a new generation of solid lipid nanoparticles (SLNs) to overcome several of the limitations associated with the SLNs. NLCs consist of a blend of solid and liquid lipids which result in a partially crystallized lipid system that enables higher drug loading efficiency compared to SLNs. Owing to their biocompatibility, low toxicity, ease of preparation and scaling-up, and high stability, NLCs have been exploited in numerous pharmaceutical applications. Different methods for fabrication of NLCs have been described in the literature. In this article, procedures involved in emulsification-solvent evaporation method, one of the commonly utilized methods for preparation of NLCs, are described in detail. Critical aspects that should be considered throughout preparation process are also highlighted to allow for consistent and reproducible construction of NLCs.
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Affiliation(s)
- Eman Gomaa
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
| | - Heba A Fathi
- Assiut International Center of Nanomedicine, Al-Rajhy Liver Hospital, Assiut University, Assiut 71515, Egypt
| | - Noura G Eissa
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt; Science Academy, Badr University in Cairo (BUC), Badr City, Cairo 11829, Egypt
| | - Mahmoud Elsabahy
- Science Academy, Badr University in Cairo (BUC), Badr City, Cairo 11829, Egypt; Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut 71515, Egypt; Misr University for Science and Technology, 6(th) of October City, 12566, Egypt.
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Ibrahim M, Gomaa E. Efficacy of midazolam addition to local anesthetic in peribulbar block. Anaesthesist 2019; 68:143-151. [DOI: 10.1007/s00101-018-0525-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 11/21/2018] [Accepted: 11/24/2018] [Indexed: 10/27/2022]
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Gomaa E, Mostafa N, Aly EH. Positron annihilation study of nanoholes and compatibility of EPDM/NBR blends. Journal of Taibah University for Science 2018. [DOI: 10.1016/s1658-3655(12)60025-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- E. Gomaa
- Physics Department, Faculty of Science, Ain Shams University, Abbassia, 11566, Cairo, Egypt
| | - N. Mostafa
- Physics Department, Faculty of Science, King Abdul-Aziz University, Jeddah, KSA
| | - E. H. Aly
- Physics Department, Faculty of Science, Ain Shams University, Abbassia, 11566, Cairo, Egypt
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Abbas A, H. AEW, Abd El-Hameid N, S. AEG, Gomaa E. Susceptibility of Some Legume Plants to Some Leaf Miners. Egyptian Academic Journal of Biological Sciences A, Entomology 2017. [DOI: 10.21608/eajbsa.2017.12689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Abd El-Lahot M, Abd El-Razek A, Massoud M, Gomaa E. Utilization of Glycyrrhizin and Licorice Extract as Natural Sweetener in Some Food Products and Biological Impacts. Journal of Food and Dairy Sciences 2017; 8:127-136. [DOI: 10.21608/jfds.2017.37143] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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Gomaa E, N. Asaad J. Effect of adding feldspar on free volume properties of crosslinked polyester studied by positron annihilation lifetime spectroscopy. J Appl Polym Sci 2012. [DOI: 10.1002/app.35492] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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EL-Nashar DE, Gomaa E, Abd-El-Messieh SL. Study of electrical, mechanical, and nanoscale free-volume properties of NBR and EPDM rubber reinforced by bentonite or kaolin. ACTA ACUST UNITED AC 2009. [DOI: 10.1002/polb.21765] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Mazroua A, Gomaa E. Effects of some solvents on the thermal and free-volume properties of poly(4-vinylpyridine) complexes. J Appl Polym Sci 2008. [DOI: 10.1002/app.28416] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Gomaa E, Mazzroua A, Mohamed M. Comparison between the effects of alcohols and diols on polymethyl-methacrylate and polyacrylamide with positron annihilation lifetime and electric conductivity measurements. J Appl Polym Sci 2003. [DOI: 10.1002/app.11955] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Mazzroua A, Mostafa N, Gomaa E, Mohsen M. The use of positron annihilation lifetime technique to study the effect of doping metal salts on polyhydroxamic acid polymers. J Appl Polym Sci 2001. [DOI: 10.1002/app.1644] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
Abstract
Measuring the thermal properties of rocks and rock-fluid systems is difficult and time consuming and the results from such measurements are of limited value unless complete descriptions of the rock and fluids are given. A need exists for a method of predicting thermal behavior from other more easily measurable properties. Presented here are correlations developed for predicting the thermal conductivity of consolidated sandstones from a knowledge of density, porosity, permeability, and formation resistivity factor. Values for all these properties are available from well logs or core properties are available from well logs or core analysis data. Also obtained were correlations for estimating the thermal conductivity of liquid-saturated sandstones from a knowledge of the conductivities of dry sandstone. The thermal conductivity of most rocks decreases with increasing temperature and a method of estimating this effect is presented. The effect of pressure on conductivities is generally small, but may be predicted from a knowledge of the bulk predicted from a knowledge of the bulk compressibility of the rock.
Introduction
Although thermal recovery processes have been applied in the petroleum industry for many years, there is still a lack of basic thermal data with which predict the performance of these processes. Much of the thermal conductivity work reported in the literature lacks a complete description of the physical properties of the rocks used, and in physical properties of the rocks used, and in addition, most of the thermal conductivity measurements have been made at room temperature and at atmospheric pressure. The work reported in this paper deals with the thermal conductivity of typical porous rocks at simulated subsurface conditions of temperature, pressure, and saturation. Because thermal conductivity is difficult to measure, emphasis has been placed here on methods of predicting thermal conductivity from other more easily measured properties as well as on methods of predicting the effects of temperature, pressure, and liquid saturation on thermal properties. pressure, and liquid saturation on thermal properties. RELATIONSHIP OF THERMAL CONDUCTIVITY TO OTHER PHYSICAL PROPERTIES
The thermal conductivities of dry rocks have been shown to be functions of density, porosity, grain size and shape, cementation, and mineral composition. The first two properties are easy to measure and precise values may, be assigned for correlation purposes. Grain size and shape and cementation are difficult to quantify. There are, however, other related properties that can be used to characterize these properties for use in correlations. Permeability and formation resistivity factors are probably most closely related to these properties and are readily measurable as unique properties and are readily measurable as unique values. Precise mineral composition values are generally not available, and even A they were, it would be difficult to introduce them into correlations. The high thermal conductivity of quartz seems to have a predominating influence, and thus for most sandstones containing quartz in moderate amounts, the effects of other minerals can be ignored. Many efforts have been made to relate thermal conductivity to the physical properties of porous rocks. These efforts have been reviewed in rather complete detail by Scorer and Anand. Unfortunately, most of the correlations developed require a knowledge of the thermal conductivity of the rock matrix or the dry rock at some known porosity. Although some simple correlations have porosity. Although some simple correlations have been obtained, these are for specific systems and are not applicable generally. Probably the most useful work in this area is that reported by Zierfuss and Van der Vliet. Basing their analysis on 36 sandstones having a wide range in measured properties, they obtained a correlation between properties, they obtained a correlation between effective porosity and the product of thermal conductivity and formation resistivity factor. A fourth-order polynomial fit of thermal conductivity and fractional porosity was obtained by regression analysis. Their data also seemed to indicate that thermal conducting increases with permeability, this being attributed to conduction with permeability.
SPEJ
P. 267
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