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  • 1
    Publication Date: 2014-10-01
    Description: Reservoir quality prediction has historically been the ‘holy grail’ of reservoir geologists, yet few have succeeded at achieving this in a quantitative fashion. This study presents a new approach to pre-drill reservoir quality prediction that involves the integration of a variety of modelling techniques to understand, quantify and predict the geological processes that control reservoir quality. Since the initial reservoir quality framework is established at the time of deposition by a variety of depositional controls, this approach uses numerical process models to predict initial reservoir quality; results from these depositional models are then modified via a series of process modelling technologies to quantify and predict post-depositional modifications that have significantly affected reservoir quality in the interval of interest. This approach is illustrated using an example from the Early Cretaceous Shu'aiba Formation in eastern Saudi Arabia, where depositional facies, diagenesis and resulting reservoir quality are predicted and tested against well and seismic data, with generally positive results. Model-predicted sediment thicknesses match thicknesses measured in wells to within ±0.5%; depositional facies and diagenetic trends seen in key wells from the Shaybah field matched model-predicted facies and diagenesis; and model-predicted porosity matched observed porosity within ±1.8 porosity units.
    Print ISSN: 0305-8719
    Electronic ISSN: 2041-4927
    Topics: Geosciences
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  • 2
    Publication Date: 2013-05-25
    Description: CD8(+) T cell responses focus on a small fraction of pathogen- or vaccine-encoded peptides, and for some pathogens, these restricted recognition hierarchies limit the effectiveness of antipathogen immunity. We found that simian immunodeficiency virus (SIV) protein-expressing rhesus cytomegalovirus (RhCMV) vectors elicit SIV-specific CD8(+) T cells that recognize unusual, diverse, and highly promiscuous epitopes, including dominant responses to epitopes restricted by class II major histocompatibility complex (MHC) molecules. Induction of canonical SIV epitope-specific CD8(+) T cell responses is suppressed by the RhCMV-encoded Rh189 gene (corresponding to human CMV US11), and the promiscuous MHC class I- and class II-restricted CD8(+) T cell responses occur only in the absence of the Rh157.5, Rh157.4, and Rh157.6 (human CMV UL128, UL130, and UL131) genes. Thus, CMV vectors can be genetically programmed to achieve distinct patterns of CD8(+) T cell epitope recognition.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3816976/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3816976/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hansen, Scott G -- Sacha, Jonah B -- Hughes, Colette M -- Ford, Julia C -- Burwitz, Benjamin J -- Scholz, Isabel -- Gilbride, Roxanne M -- Lewis, Matthew S -- Gilliam, Awbrey N -- Ventura, Abigail B -- Malouli, Daniel -- Xu, Guangwu -- Richards, Rebecca -- Whizin, Nathan -- Reed, Jason S -- Hammond, Katherine B -- Fischer, Miranda -- Turner, John M -- Legasse, Alfred W -- Axthelm, Michael K -- Edlefsen, Paul T -- Nelson, Jay A -- Lifson, Jeffrey D -- Fruh, Klaus -- Picker, Louis J -- P01 AI094417/AI/NIAID NIH HHS/ -- P51 OD 011092/OD/NIH HHS/ -- R01 AI059457/AI/NIAID NIH HHS/ -- R01 AI060392/AI/NIAID NIH HHS/ -- U24 OD010850/OD/NIH HHS/ -- New York, N.Y. -- Science. 2013 May 24;340(6135):1237874. doi: 10.1126/science.1237874.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Vaccine and Gene Therapy Institute and Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR 97006, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23704576" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; CD8-Positive T-Lymphocytes/*immunology ; Cytokines/immunology ; Cytomegalovirus/genetics/*immunology ; Epitopes, T-Lymphocyte/*immunology ; Female ; Genetic Vectors/genetics/*immunology ; Histocompatibility Antigens Class II/immunology ; Humans ; Macaca mulatta ; Male ; Membrane Glycoproteins/genetics ; SAIDS Vaccines/administration & dosage/*immunology ; Viral Envelope Proteins/genetics
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2016-04-23
    Description: We observed the spiral galaxies M 51 and M 83 at 20 arscec spatial resolution with the bolometer array Aztronomical Thermal Emission Camera (AzTEC) on the JCMT in the 1.1 mm continuum, recovering the extended emission out to galactocentric radii of more than 12 kpc in both galaxies. The 1.1 mm-continuum fluxes are 5.6 ± 0.7 and 9.9 ± 1.4 Jy, with associated gas masses estimated at 9.4 x 10 9 M and 7.2 x 10 9 M for M 51 and M 83, respectively. In the interarm regions of both galaxies, the N(H 2 )/I(CO) (or X-factor) ratios exceed those in the arms by factors of ~1.5–2. In the inner discs of both galaxies, the X-factor is about 1 x 10 20 cm – 2 (K km s – 1 ) – 1 . In the outer parts, the CO-dark molecular gas becomes more important. While the spiral density wave in M 51 appears to influence the interstellar medium and stars in a similar way, the bar potential in M 83 influences the interstellar medium and the stars differently. We confirm the result of Foyle et al. that the arms merely heighten the star formation rate (SFR) and the gas surface density in the same proportion. Our maps reveal a threshold gas surface density for an SFR increase by two or more orders of magnitude. In both galaxy centres, the molecular gas depletion time is about 1 Gyr climbing to 10–20 Gyr at radii of 6–8 kpc. This is consistent with an inside-out depletion of the molecular gas in the discs of spiral galaxies.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
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  • 4
    Publication Date: 2011-05-13
    Description: The acquired immunodeficiency syndrome (AIDS)-causing lentiviruses human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) effectively evade host immunity and, once established, infections with these viruses are only rarely controlled by immunological mechanisms. However, the initial establishment of infection in the first few days after mucosal exposure, before viral dissemination and massive replication, may be more vulnerable to immune control. Here we report that SIV vaccines that include rhesus cytomegalovirus (RhCMV) vectors establish indefinitely persistent, high-frequency, SIV-specific effector memory T-cell (T(EM)) responses at potential sites of SIV replication in rhesus macaques and stringently control highly pathogenic SIV(MAC239) infection early after mucosal challenge. Thirteen of twenty-four rhesus macaques receiving either RhCMV vectors alone or RhCMV vectors followed by adenovirus 5 (Ad5) vectors (versus 0 of 9 DNA/Ad5-vaccinated rhesus macaques) manifested early complete control of SIV (undetectable plasma virus), and in twelve of these thirteen animals we observed long-term (〉/=1 year) protection. This was characterized by: occasional blips of plasma viraemia that ultimately waned; predominantly undetectable cell-associated viral load in blood and lymph node mononuclear cells; no depletion of effector-site CD4(+) memory T cells; no induction or boosting of SIV Env-specific antibodies; and induction and then loss of T-cell responses to an SIV protein (Vif) not included in the RhCMV vectors. Protection correlated with the magnitude of the peak SIV-specific CD8(+) T-cell responses in the vaccine phase, and occurred without anamnestic T-cell responses. Remarkably, long-term RhCMV vector-associated SIV control was insensitive to either CD8(+) or CD4(+) lymphocyte depletion and, at necropsy, cell-associated SIV was only occasionally measurable at the limit of detection with ultrasensitive assays, observations that indicate the possibility of eventual viral clearance. Thus, persistent vectors such as CMV and their associated T(EM) responses might significantly contribute to an efficacious HIV/AIDS vaccine.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3102768/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3102768/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hansen, Scott G -- Ford, Julia C -- Lewis, Matthew S -- Ventura, Abigail B -- Hughes, Colette M -- Coyne-Johnson, Lia -- Whizin, Nathan -- Oswald, Kelli -- Shoemaker, Rebecca -- Swanson, Tonya -- Legasse, Alfred W -- Chiuchiolo, Maria J -- Parks, Christopher L -- Axthelm, Michael K -- Nelson, Jay A -- Jarvis, Michael A -- Piatak, Michael Jr -- Lifson, Jeffrey D -- Picker, Louis J -- HHSN261200800001E/PHS HHS/ -- HHSN272200900037C/PHS HHS/ -- P51 RR00163/RR/NCRR NIH HHS/ -- R01 AI060392/AI/NIAID NIH HHS/ -- R01 AI060392-05/AI/NIAID NIH HHS/ -- R24 RR016001/RR/NCRR NIH HHS/ -- R56 AI060392/AI/NIAID NIH HHS/ -- R56 AI060392-06/AI/NIAID NIH HHS/ -- U24 OD010850/OD/NIH HHS/ -- England -- Nature. 2011 May 26;473(7348):523-7. doi: 10.1038/nature10003. Epub 2011 May 11.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Vaccine and Gene Therapy Institute, Department of Molecular Microbiology, Oregon Health & Science University, Beaverton, Oregon 97006, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21562493" target="_blank"〉PubMed〈/a〉
    Keywords: AIDS Vaccines/immunology ; Animals ; CD4-Positive T-Lymphocytes/immunology ; CD8-Positive T-Lymphocytes/immunology ; Cytomegalovirus/genetics ; DNA, Viral/analysis ; Genetic Vectors/genetics ; Immunity, Mucosal/immunology ; Immunologic Memory/*immunology ; Macaca mulatta/blood/immunology/virology ; Male ; RNA, Viral/analysis ; SAIDS Vaccines/genetics/*immunology ; Simian Acquired Immunodeficiency Syndrome/blood/*immunology/*prevention & ; control/virology ; Simian Immunodeficiency Virus/growth & development/*immunology/isolation & ; purification/*pathogenicity ; T-Lymphocytes/*immunology ; Time Factors ; Vaccines, DNA/genetics/immunology ; Viral Load ; Virus Replication
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 5
    Publication Date: 2013-09-13
    Description: Established infections with the human and simian immunodeficiency viruses (HIV and SIV, respectively) are thought to be permanent with even the most effective immune responses and antiretroviral therapies only able to control, but not clear, these infections. Whether the residual virus that maintains these infections is vulnerable to clearance is a question of central importance to the future management of millions of HIV-infected individuals. We recently reported that approximately 50% of rhesus macaques (RM; Macaca mulatta) vaccinated with SIV protein-expressing rhesus cytomegalovirus (RhCMV/SIV) vectors manifest durable, aviraemic control of infection with the highly pathogenic strain SIVmac239 (ref. 5). Here we show that regardless of the route of challenge, RhCMV/SIV vector-elicited immune responses control SIVmac239 after demonstrable lymphatic and haematogenous viral dissemination, and that replication-competent SIV persists in several sites for weeks to months. Over time, however, protected RM lost signs of SIV infection, showing a consistent lack of measurable plasma- or tissue-associated virus using ultrasensitive assays, and a loss of T-cell reactivity to SIV determinants not in the vaccine. Extensive ultrasensitive quantitative PCR and quantitative PCR with reverse transcription analyses of tissues from RhCMV/SIV vector-protected RM necropsied 69-172 weeks after challenge did not detect SIV RNA or DNA sequences above background levels, and replication-competent SIV was not detected in these RM by extensive co-culture analysis of tissues or by adoptive transfer of 60 million haematolymphoid cells to naive RM. These data provide compelling evidence for progressive clearance of a pathogenic lentiviral infection, and suggest that some lentiviral reservoirs may be susceptible to the continuous effector memory T-cell-mediated immune surveillance elicited and maintained by cytomegalovirus vectors.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3849456/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3849456/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hansen, Scott G -- Piatak, Michael Jr -- Ventura, Abigail B -- Hughes, Colette M -- Gilbride, Roxanne M -- Ford, Julia C -- Oswald, Kelli -- Shoemaker, Rebecca -- Li, Yuan -- Lewis, Matthew S -- Gilliam, Awbrey N -- Xu, Guangwu -- Whizin, Nathan -- Burwitz, Benjamin J -- Planer, Shannon L -- Turner, John M -- Legasse, Alfred W -- Axthelm, Michael K -- Nelson, Jay A -- Fruh, Klaus -- Sacha, Jonah B -- Estes, Jacob D -- Keele, Brandon F -- Edlefsen, Paul T -- Lifson, Jeffrey D -- Picker, Louis J -- HHSN261200800001E/PHS HHS/ -- P01 AI094417/AI/NIAID NIH HHS/ -- P51OD011092/OD/NIH HHS/ -- R01 AI060392/AI/NIAID NIH HHS/ -- R01 DE021291/DE/NIDCR NIH HHS/ -- R37 AI054292/AI/NIAID NIH HHS/ -- U19 AI095985/AI/NIAID NIH HHS/ -- U19 AI096109/AI/NIAID NIH HHS/ -- U24 OD010850/OD/NIH HHS/ -- U42 OD010426/OD/NIH HHS/ -- England -- Nature. 2013 Oct 3;502(7469):100-4. doi: 10.1038/nature12519. Epub 2013 Sep 11.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Vaccine and Gene Therapy Institute and Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24025770" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cytomegalovirus/genetics/immunology ; Female ; Macaca mulatta ; Male ; Molecular Sequence Data ; SAIDS Vaccines/*immunology ; Simian Acquired Immunodeficiency Syndrome/*prevention & control/virology ; Simian Immunodeficiency Virus/*immunology ; Time Factors ; Vaccines, Attenuated/immunology ; Viral Load ; Virus Replication/physiology
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 6
    Publication Date: 2016-01-23
    Description: Major histocompatibility complex E (MHC-E) is a highly conserved, ubiquitously expressed, nonclassical MHC class Ib molecule with limited polymorphism that is primarily involved in the regulation of natural killer (NK) cells. We found that vaccinating rhesus macaques with rhesus cytomegalovirus vectors in which genes Rh157.5 and Rh157.4 are deleted results in MHC-E-restricted presentation of highly varied peptide epitopes to CD8alphabeta(+) T cells, at ~4 distinct epitopes per 100 amino acids in all tested antigens. Computational structural analysis revealed that MHC-E provides heterogeneous chemical environments for diverse side-chain interactions within a stable, open binding groove. Because MHC-E is up-regulated to evade NK cell activity in cells infected with HIV, simian immunodeficiency virus, and other persistent viruses, MHC-E-restricted CD8(+) T cell responses have the potential to exploit pathogen immune-evasion adaptations, a capability that might endow these unconventional responses with superior efficacy.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4769032/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4769032/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hansen, Scott G -- Wu, Helen L -- Burwitz, Benjamin J -- Hughes, Colette M -- Hammond, Katherine B -- Ventura, Abigail B -- Reed, Jason S -- Gilbride, Roxanne M -- Ainslie, Emily -- Morrow, David W -- Ford, Julia C -- Selseth, Andrea N -- Pathak, Reesab -- Malouli, Daniel -- Legasse, Alfred W -- Axthelm, Michael K -- Nelson, Jay A -- Gillespie, Geraldine M -- Walters, Lucy C -- Brackenridge, Simon -- Sharpe, Hannah R -- Lopez, Cesar A -- Fruh, Klaus -- Korber, Bette T -- McMichael, Andrew J -- Gnanakaran, S -- Sacha, Jonah B -- Picker, Louis J -- HHSN272201100013C/AI/NIAID NIH HHS/ -- HHSN272201100013C/PHS HHS/ -- P01 AI094417/AI/NIAID NIH HHS/ -- P01-AI094417/AI/NIAID NIH HHS/ -- P50-GM065794/GM/NIGMS NIH HHS/ -- P51 OD011092/OD/NIH HHS/ -- P51-OD011092/OD/NIH HHS/ -- R01 AI059457/AI/NIAID NIH HHS/ -- R01 AI095113/AI/NIAID NIH HHS/ -- R01 AI117802/AI/NIAID NIH HHS/ -- R01 DE021291/DE/NIDCR NIH HHS/ -- R01-AI059457/AI/NIAID NIH HHS/ -- R01-AI095113/AI/NIAID NIH HHS/ -- R01-AI117802/AI/NIAID NIH HHS/ -- R01-DE021291/DE/NIDCR NIH HHS/ -- R37 AI054292/AI/NIAID NIH HHS/ -- R37-AI054292/AI/NIAID NIH HHS/ -- U24 OD010850/OD/NIH HHS/ -- U24-OD010850/OD/NIH HHS/ -- UM1 AI100645/AI/NIAID NIH HHS/ -- UM1-AI100645-01/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 2016 Feb 12;351(6274):714-20. doi: 10.1126/science.aac9475. Epub 2016 Jan 21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Vaccine and Gene Therapy Institute and Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR 97006, USA. ; Nuffield Department of Medicine, University of Oxford, Oxford OX37FZ, UK. ; Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. ; Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. The New Mexico Consortium, Los Alamos, NM 87545, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26797147" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antigen Presentation ; Antigenic Variation ; CD8-Positive T-Lymphocytes/*immunology ; Cytomegalovirus/genetics/*immunology ; Epitopes, T-Lymphocyte/chemistry/*immunology ; Genetic Vectors/genetics/immunology ; Histocompatibility Antigens Class I/chemistry/*immunology ; Host-Pathogen Interactions/immunology ; Immune Evasion ; Killer Cells, Natural/immunology ; Macaca mulatta ; Protein Structure, Secondary ; Simian Immunodeficiency Virus/*immunology ; Vaccination
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 7
    ISSN: 1432-1041
    Keywords: Congestive heart failure ; Captopril ; sublingual ; pharmacokinetic ; pharmacodynamic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: The pharmacokinetics and pharmacodynamics of buffered sublingual captopril were assessed in patients with congestive heart failure (CHF). Methods: The study was carried out in a randomised single-blind cross-over fashion (n=6, 4 males and 2 females) and involved two study days, at least 7 days apart. Baseline measurements were carried out for plasma renin activity (PRA), blood pressure (B.P.) and heart rate (H.R.). Captopril (12.5 mg) was administered sublingually with dibasic potassium phosphate which maintained salivary pH at 7, or perorally with 100 ml of water. Further B.P., H.R. measurements and venous blood samples were taken over a 3 hour period post-drug administration. Blood samples were analysed for captopril and PRA levels. Results: tmax after buffered sublingual administration of captopril, which ranged from 40–60 min (median=40 min), was significantly shorter than after peroral administration (range 60–120 min, median=90 min). Cmax was slightly greater after buffered sublingual than after peroral administration with mean values of 108.2 vs. 94.0 ng·ml−1. AUC values were similar after both routes of administration. Systolic and diastolic B.P. vs. time profiles for each administration method were significantly different i.e. sublingual administration produced an earlier reduction in B.P., however, HR did not differ significantly between the two routes. Conclusion: The data indicate that this novel administration method of captopril leads to an increased rate, but an unchanged extent of captopril absorption, suggesting a modest therapeutic advantage with the use of buffered sublingual captopril if a rapid reduction in blood pressure is required.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 54 (1998), S. 609-614 
    ISSN: 1432-1041
    Keywords: Key words Enalapril ; Lisinopril ; Buccal absorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: The buccal absorption of captopril does not exhibit the classical pH/partition hypothesis, suggesting that mechanisms other than passive diffusion are involved in its absorption; animal studies have suggested that a peptide carrier-mediated transport system may be responsible for its absorption. The present study evaluated the effects of pH on octanol partitioning, and on the buccal absorption of enalapril and lisinopril, using in vitro techniques and buccal partitioning in human volunteer subjects. Methods: The partitioning of enalapril and lisinopril into n-octanol was examined over the pH range of 3–9 at room temperature. Results: Enalapril exhibited maximal partitioning into the organic phase at pH 4–5; minimal partitioning was recorded at pH values 8 and 9. The partitioning of lisinopril into n-octanol was found to be maximal at pH 9 and minimal at pH 3. Using the buccal absorption technique, the partitioning of enalapril and lisinopril (0.5 mg), was examined in six healthy male volunteers from buffered solutions (pH 3, 4, 5, 6, 7, 8 and 9). In the case of enalapril, lowest buccal partitioning occurred at pH 3, 8 and 9, while maximal partitioning occurred at pH 5; absorption of lisinopril was not extensive at any pH, but was greatest at pH 6. These results, in addition to the n-octanol partition coefficients, indicated that enalapril obeyed the normal lipid partition hypothesis with respect to buccal absorption. The buccal absorption of lisinopril also obeyed the lipid partition hypothesis over the pH range 3–7. These findings are in direct contrast to those for captopril. The buccal partitioning experiments were repeated at the maximal pH for absorption for each angiotensin converting enzyme (ACE) inhibitor, but with the addition of cephradine (0.05 mmol · l−1). Conclusion: The data indicated that the presence of this peptide transport inhibitor had no effect on the buccal absorption of enalapril (0.06 mmol · l−1) and lisinopril (0.057 mmol · l−1), which suggests that both drugs do not share a common buccal absorption pathway with cephradine.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 48 (1995), S. 373-379 
    ISSN: 1432-1041
    Keywords: Captopril ; sublingual ; pharmacokinetics ; pharmacodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract The effect of pH on the buccal and sublingual absorption of captopril was evaluated using in vitro techniques and human studies. Partitioning of captopril into n-octanol was lowest over the pH range 5 to 8 and highest at pH values 3, 4 and 9. Using the buccal absorption technique, the partitioning of captopril (2 mg) was examined in six healthy male volunteers from buffered solutions (pH 3, 4, 5, 6, 7, 8, and 9). Lowest buccal partitioning occurred at pH 3 while maximal buccal partitioning occurred at pH 7. These data clearly indicated that the buccal absorption of captopril did not obey the classical pH/partition hypothesis suggesting that mechanisms other than passive diffusion were involved in its absorption. Captopril pharmacokinetic and pharmacodynamic parameters were determined after administration of buffered sublingual captopril (pH 7, optimal pH for absorption as determined from the buccal partitioning data) and unbuffered sublingual captopril. The study was performed in eight healthy volunteers in a randomised single-blind cross-over fashion. The tmax for captopril was found to be approximately 11 minutes earlier after buffered versus unbuffered sublingual administration and AUC0–30 min increased by approximately 30% in the case of buffered captopril. Cpmax, AUC0–180 min and relative bioavailability did not differ between the buffered and unbuffered administration. Pharmacodynamic parameters (BP, heart rate and plasma renin activity) did not differ significantly between buffered and unbuffered sublingual administration. The increased rate of captopril absorption after buffered sublingual administration was small and is likely to offer little therapeutic advantage over conventional sublingual formulation.
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  • 10
    ISSN: 1432-1041
    Keywords: Key words Congestive heart failure ; Captopril; sublingual ; pharmacokinetic ; pharmacodynamic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: The pharmacokinetics and pharmacodynamics of buffered sublingual captopril were assessed in patients with congestive heart failure (CHF). Methods: The study was carried out in a randomised single-blind cross-over fashion (n = 6, 4 males and 2 females) and involved two study days , at least 7 days apart. Baseline measurements were carried out for plasma renin activity (PRA), blood pressure (B.P.) and heart rate (H.R.). Captopril (12.5 mg) was administered sublingually with dibasic potassium phosphate which maintained salivary pH at 7, or perorally with 100 ml of water. Further B.P., H.R. measurements and venous blood samples were taken over a 3 hour period post-drug administration. Blood samples were analysed for captopril and PRA levels. Results: tmax after buffered sublingual administration of captopril, which ranged from 40–60 min (median = 40  min), was significantly shorter than after peroral administration (range 60–120 min, median = 90 min). Cmax was slightly greater after buffered sublingual than after peroral administration with mean values of 108.2 vs. 94.0 ng ⋅ml−1. AUC values were similar after both routes of administration. Systolic and diastolic B.P. vs. time profiles for each administration method were significantly different i.e. sublingual administration produced an earlier reduction in B.P., however, HR did not differ significantly between the two routes. Conclusion: The data indicate that this novel administration method of captopril leads to an increased rate, but an unchanged extent of captopril absorption, suggesting a modest therapeutic advantage with the use of buffered sublingual captopril if a rapid reduction in blood pressure is required.
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