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Dive into the research topics where G Bridger is active.

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Featured researches published by G Bridger.


International Journal of Pharmaceutics | 1999

Evaluation of the potential of ion pair formation to improve the oral absorption of two potent antiviral compounds, AMD3100 and PMPA.

J. Van Gelder; Myriam Witvrouw; Christophe Pannecouque; G Henson; G Bridger; Lieve Naesens; E. De Clercq; Pieter Annaert; M Shafiee; G. Van den Mooter; Renaat Kinget; Patrick Augustijns

9-(2-phosphonyomethoxypropyl)adenine (PMPA) and AMD3100 are highly potent and selective antiretroviral agents. Since PMPA is negatively charged and AMD3100 positively charged at physiological pH, their transepithelial transport and their potential for oral drug delivery is very low. In this study, ion pair formation was evaluated as a possible strategy to enhance transepithelial transport of PMPA and AMD3100. Positively charged counter ions such as t-hexyl-, t-heptyl-, t-octylammonium bromide and dodecyl-, tetradecyl-, hexadecyltrimethylammonium bromide were used to form ion pairs with PMPA, while sodium taurodeoxycholate (in vitro experiments) and sodium taurocholate (in vivo experiments) were used as counter ions for AMD3100. The effect of counter ions on transepithelial transport of PMPA (1 mM) and AMD3100 (1 mM) was investigated by measuring the flux across Caco-2 monolayers. An enhancement in drug transport could be observed at a concentration of 2 mM of hexadecyltrimethylammonium bromide (counter ion for PMPA) and 10 mM of sodium taurodeoxycholate (counter ion for AMD3100), but at the concentrations used, the absorption enhancing effect could be attributed to a reduction of the integrity of the monolayers. When AMD3100 transport was tested at a concentration of 200 microM, no flux was observed, even in the presence of relatively high concentrations of counter ion (20 times the concentration of AMD3100). Results obtained from partitioning studies of the drugs in the presence or absence of counter ion revealed that competition by other ions was responsible for the absence of an effect: when pure water was used as the aqueous phase, a reduction up to 24.4+/-1.4% and 17.0+/-1.3% of the initial aqueous concentration was observed for PMPA and AMD3100, respectively; however, as soon as other ions were present in the aqueous phase, the effect of the counter ion was diminished (25-50 mOsm) or completely abolished (270-305 mOsm). The absorption enhancing effect of counter ions was also studied in vivo: pharmacokinetic studies in rabbits showed that the oral bioavailability of AMD3100 in the presence of 4 equivalents of taurocholic acid remained very low and was only 3.2-fold better (i.e. 3.6%) in comparison to pure AMD3100. In view of the results obtained in the Caco-2 system, this absorption enhancement can be attributed to an effect on monolayer integrity rather than to the potential to form ion pairs. We can conclude that the formation of ion pairs may not be very efficient as a strategy to enhance transepithelial transport of charged hydrophilic compounds, as competition by other ions may abolish the beneficial effect of counter ions.


Molecular Pharmacology | 1999

Activity of Different Bicyclam Derivatives against Human Immunodeficiency Virus Depends on Their Interaction with the CXCR4 Chemokine Receptor

José A. Esté; Cecilia Cabrera; Erik De Clercq; Sofie Struyf; Jo Van Damme; G Bridger; Renato T. Skerlj; Michael J. Abrams; Geoffrey Henson; Arantxa Gutierrez; Bonaventura Clotet; Dominique Schols


Abstract book | 2003

Anti-HIV activity profile of AMD070, an orally bioavailable CXCR4 antagonist

Dominique Schols; Sandra Claes; Sigrid Hatse; Katrien Princen; Kurt Vermeire; Erik De Clercq; Renato Skerlj; G Bridger; Gary Calandra


Abstract book | 2004

In vitro anti-HIV activity profile of AMD887, a novel CCR5 antagonist, in combination with the CXCR4 inhibitor AMD070

Dominique Schols; Kurt Vermeire; Sigrid Hatse; Katrien Princen; Erik De Clercq; Gary Calandra; Simon P. Fricker; Kim L. Nelson; Jean Labrecque; David Surrey Bogucki; Yuanxi Zhou; Renato Skerlj; G Bridger


Abstract book | 2005

Multi-drug resistant HIV-1 is sensitive to inhibition by chemokine receptor antagonists

Dominique Schols; Kurt Vermeire; S Fransen; W Huang; J Toma; J Whitcomb; C Petropoulos; Gary Calandra; G Bridger


Antiviral Research | 2004

Virus resistance to the CXCR4 inhibitor AMD070 develops slowly and does not induce a co-receptor switch

Kurt Vermeire; Sigrid Hatse; Katrien Princen; Erik De Clercq; Gary Calandra; Renato Skerlj; G Bridger; Dominique Schols


Antiviral Research | 2004

Anti-HIV activity profile of a novel CCR5 inhibitor, AMD887, in combination with the CXCR4 inhibitor AMD070

Dominique Schols; Kurt Vermeire; Sigrid Hatse; Katrien Princen; Erik De Clercq; Gary Calandra; Simon P. Fricker; Kim L. Nelson; Jean Labrecque; David Surrey Bogucki; Yuanxi Zhou; Renato Skerlj; G Bridger


Antiviral Research | 1992

Potent and selective inhibition of HIV-1 and HIV-2 replication by a novel class of bicyclams targeted at viral uncoating

Erik De Clercq; N Yamamoto; Rudi Pauwels; Masanori Baba; Dominique Schols; Hiroshi Nakashima; Jan Balzarini; Zeger Debyser; Ba Murrer; D Schwartz; D Thornton; G Bridger; Simon P. Fricker; G Henson; M Abrams; D Picker


Abstract book | 2006

Small molecule receptor inhibitors as a novel strategy for the inhibition of human immunodeficiency virus (HIV) infection

Kurt Vermeire; Thomas W. Bell; G Bridger; Dominique Schols


Journal of Biological Regulators and Homeostatic Agents | 2004

Establishment of a novel CCR5 and CXCR4 expressing CD4+ cell line which is suitable for high-throughput evaluation of HIV/coreceptor inhibitors

Katrien Princen; Sigrid Hatse; Kurt Vermeire; G Bridger; Erik De Clercq; Dominique Schols

Collaboration


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Dominique Schols

Rega Institute for Medical Research

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Kurt Vermeire

Rega Institute for Medical Research

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Sigrid Hatse

Rega Institute for Medical Research

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Katrien Princen

Rega Institute for Medical Research

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Erik De Clercq

Rega Institute for Medical Research

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Erik De Clercq

Rega Institute for Medical Research

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Patrick Matthys

Katholieke Universiteit Leuven

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