Abstract:
PURPOSE:The objective of this study was to determine the influence of the peptide bond with emphasis on the carbonyl group on the interaction with and transport by the intestinal small-peptide carrier. Therefore enalapril, a known substrate for the small-peptide carrier, has been modified to an analogue with a reduced peptide bond, enamipril. The transport characteristics of both compounds have been determined. METHODS:The in vitro transport studies were performed using rat ileum in Ussing chambers. The transport of enalapril and enamipril were measured in a concentration range from 0.5-8 mM in both directions across the ileum. in the presence and absence of inhibitors. The interaction with the small-peptide carrier was studied by evaluating the ability of enalapril and its analogue enamipril to inhibit the transport rate of amoxycillin. RESULTS:Enalapril shows, besides passive diffusion (P(m)3.06+/-0.14 . 10(-6)cm/s), saturable transport kinetics (Jmax = 16+/-5 nmol/h.cm2, Km = 1.86+/-0.64 mM) which can be inhibited with 10 mM cephalexin. The analogue with a reduced peptide bond does not show saturable transport from the mucosal to the serosal side, and cephalexin does not inhibit the flux of enamipril. However, the transport of enamipril from the serosal to mucosal side of the intestinal membrane is saturable and can be inhibited by 100 microM verapamil. Although enamipril is not a substrate for the small-peptide carrier in contrast to enalapril, both enalapril and enamipril are able to inhibit the active transport of amoxycillin with a K(i) of 0.41+/-0.24 mM and 0.24+/-0.12 mM respectively. CONCLUSIONS:The reduction of the peptide bond of enalapril results in a compound, enamipril, which does not show polarized and saturable transport from the mucosal to the serosal side of the intestinal tissue. Also because the transport of enamipril cannot be inhibited by cephalexin, the analogue with the reduced peptide bond is no longer a substrate for the intestinal small-peptide carrier. Therefore, it can be concluded that the carbonyl group is an essential structural requirement for transport by the small-peptide carrier. In contrast, the interaction with the small-peptide carrier is still present, shown by the inhibition of the fluxes of amoxycillin. Reduction of the peptide bond of enalapril resulted in a new substrate for the P-glycoprotein efflux pump.
journal_name
Pharm Resjournal_title
Pharmaceutical researchauthors
Schoenmakers RG,Stehouwer MC,Tukker JJdoi
10.1023/a:1018866611555subject
Has Abstractpub_date
1999-01-01 00:00:00pages
62-8issue
1eissn
0724-8741issn
1573-904Xjournal_volume
16pub_type
杂志文章abstract:PURPOSE:To develop a new bionic system from an existing drug dissolution/absorption simulating system (DDASS) to simultaneously predict the release and absorption of enteric-coated formulations. METHODS:In accordance with the pH-dependent characteristics of enteric-coated formulations, the modified DDASS was designed ...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-012-0905-3
更新日期:2013-02-01 00:00:00
abstract::An empirical mass-transfer model for enteric-coating dissolution that uses in vivo dissolution data to characterize the pH-dependent solubility properties of the polymer film and a mass-transfer coefficient determined from in vivo dissolution or disintegration studies is developed. Once the in vivo mass-transfer coeff...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1018986827350
更新日期:1993-02-01 00:00:00
abstract:PURPOSE:Adjuvants are required to ensure the efficacy of subunit vaccines. Incorporating molecular immunopotentiators within particles could overcome drawbacks of molecular adjuvants (such as solubility and toxicity), and improve adjuvanticity of particles, achieving stronger adjuvant activity. Aim of this study is to ...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-015-1666-6
更新日期:2015-09-01 00:00:00
abstract:PURPOSE:The purpose of this work was to investigate the mechanisms of cocrystal formation during cogrinding and storage of solid reactants, and to establish the effects of water by cogrinding with hydrated form of reactants and varying RH conditions during storage. METHODS:The hydrogen bonded 1:1 carbamazepine-sacchar...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-006-9110-6
更新日期:2006-10-01 00:00:00
abstract:PURPOSE:The major objectives of this study were to 1) develop a new mathematical model describing all phases of drug release from bioerodible microparticles; 2) evaluate the validity of the theory with experimental data; and 3) use the model to elucidate the release mechanisms in poly(lactide-co-glycolide acid)-based m...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1021457911533
更新日期:2002-12-01 00:00:00
abstract::Liver fibrosis is a pathological condition originating from liver damage that leads to excess accumulation of extracellular matrix (ECM) proteins in the liver. Viral infection, chronic injury, local inflammatory responses and oxidative stress are the major factors contributing to the onset and progression of liver fib...
journal_title:Pharmaceutical research
pub_type: 杂志文章,评审
doi:10.1007/s11095-014-1497-x
更新日期:2015-02-01 00:00:00
abstract:PURPOSE:Delivery of therapeutics to neurons is paramount to treat neurological conditions, including many lysosomal storage disorders. However, key aspects of drug-carrier behavior in neurons are relatively unknown: the occurrence of non-canonical endocytic pathways (present in other cells); whether carriers that trave...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-014-1531-z
更新日期:2015-04-01 00:00:00
abstract::A simple viscometric method was used to quantify mucin-polymer bioadhesive bond strength. Viscosities of 15% (w/v) porcine gastric mucin dispersions in 0.1 N HCl (pH 1) or 0.1 N acetate buffer (pH 5.5) were measured with a Brookfield viscometer in the absence (eta m) or presence (eta t) of selected neutral, anionic, a...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1015812615635
更新日期:1990-05-01 00:00:00
abstract:PURPOSE:The purpose of this study was to assess the antifungal activity and renal and hepatic toxicity of amphotericin B (AmpB) following administration of Fungizone (FZ) and a heat-treated form of FZ (HFZ) to rats infected with Aspergillus fumigatus. METHODS:Infected rats were administered FZ and HFZ at a dosing regi...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/b:pham.0000041449.46054.b4
更新日期:2004-09-01 00:00:00
abstract:PURPOSE:Changes in drug absorption and first-pass metabolism have been reported throughout the pediatric age range. Our aim is to characterize both intestinal and hepatic CYP3A-mediated metabolism of midazolam in children in order to predict first-pass and systemic metabolism of CYP3A substrates. METHODS:Pharmacokinet...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-018-2458-6
更新日期:2018-07-30 00:00:00
abstract:PURPOSE:To investigate the effect of polyelectrolytes on the formation and physicochemical properties of chitosan nanoparticles (CS-NPs) used for the delivery of an anticancer drug, doxorubicin (DOX). METHOD:Three DOX-loaded CS-NPs were formulated with tripolyphosphate (CS-TP/DOX NPs), dextran sulfate (CS-DS/DOX NPs),...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-013-1251-9
更新日期:2014-05-01 00:00:00
abstract::Transport studies using intestinal brush-border membrane vesicles isolated from rats and rabbits have failed to demonstrate proton- or Na(+)-dependent carrier-mediated transport of thyrotropin-releasing hormone (TRH), despite a pharmacologically relevant oral bioavailability. To examine the hypothesis that reported le...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1018947430018
更新日期:1993-05-01 00:00:00
abstract::Loracarbef is an oral 1-carba-1-dethiacephalosporin antibiotic structurally related to cefaclor. Like many beta-lactam antibiotics, loracarbef exists in several hydrated crystalline forms. The pH-solubility profile curve for loracarbef monohydrate is U-shaped, resembling those of other zwitterionic cephalosporins. Lor...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1018949709797
更新日期:1992-02-01 00:00:00
abstract:PURPOSE:To study epidermal and polyethylene membrane penetration and retention of the sunscreen benzophenone-3 (BP) from a range of single solvent vehicles and evaluate solvent effects on permeability parameters. METHODS:The solubility of BP was measured in a number of solvents. Penetration of BP across human epidermi...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1011958006973
更新日期:1998-12-01 00:00:00
abstract::The immune system has the ability to recognize and kill pre-cancer and cancer cells. However, with the immune system's surveillance, the survival tumor cells learn how to escape the immune system after immunoselection. Cancer immunotherapy develops strategies to overcome these problems. Nanomedicine applications in ca...
journal_title:Pharmaceutical research
pub_type: 杂志文章,评审
doi:10.1007/s11095-010-0258-8
更新日期:2011-02-01 00:00:00
abstract:PURPOSE:Topoisomerase II (Topo II) preferentially cuts DNA at alternating purine-pyrimidine repeats. Different Topo II poisons may affect Topo II to produce distinct drug-specific DNA cleavage patterns. GL331 is a new podophyllotoxin derivative exhibiting potent Topo II-poisoning activity. Therefore, the sequence selec...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1011048831698
更新日期:2001-06-01 00:00:00
abstract:PURPOSE:To develop a safe and effective non-viral vector for gene delivery and transfection in macrophages for potential anti-inflammatory therapy. METHODS:Solid nanoparticles-in-emulsion (NiE) multi-compartmental delivery system was designed using plasmid DNA-encapsulated type B gelatin nanoparticles suspended in the...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-012-0677-9
更新日期:2012-06-01 00:00:00
abstract::The three-dimensional structures and molecular electrostatic potentials of the cis(Z) and trans(E)-isomers of flupenthixol and clopenthixol were examined by computer graphics and molecular mechanical and quantum mechanical calculations, and their internal molecular motions were studied by molecular dynamics simulation...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1015842926345
更新日期:1991-04-01 00:00:00
abstract:PURPOSE:To examine and determine the sites and the kinetics of IgG1 mAb modifications from both in vitro (rat plasma and PBS) and in vivo (rat model) time-course studies. METHODS:A comprehensive set of protein characterization methods, including RPLC/MS, LC-MS/MS, iCIEF, capSEC, and CE-SDS were performed in this repor...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-012-0860-z
更新日期:2013-01-01 00:00:00
abstract:PURPOSE:To examine the transport characteristics of the multidrug resistance-associated protein (MRP) substrate fluorescein across the isolated rat small intestinal segments. METHODS:The transport of fluorescein was studied in side-by-side diffusion chambers under short-circuited conditions at physiological pH. RESUL...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/b:pham.0000022410.89709.c3
更新日期:2004-04-01 00:00:00
abstract:PURPOSE:The discovery of nano drug delivery system has rendered a great hope for improving cancer therapy. However, there are some inevitable obstacles that constrain its development, such as the physical and biological barriers, the toxicity of carrier materials and the physiological toxicity of drugs. Here, we report...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-019-2709-1
更新日期:2019-12-10 00:00:00
abstract::We describe an assay for acrolein in urine, employing derivatization with m-aminophenol in the presence of ferrous sulfate solution in sulfuric acid. The derivative (7-OH quinoline; DER) and the internal standard (quinine-bisulfate; IS) were separated on a 10-micron particle, 8 mm x 10-cm C18 cartridge in conjunction ...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1018964401677
更新日期:1993-11-01 00:00:00
abstract:PURPOSE:To develop a non-viral gene delivery system in the form of an oil-in-water (o/w) lipid emulsion. METHOD:Cationic lipid emulsions were formulated with soybean oil, 1,2-dioleoyl-sn-glycero-3-trimethylammonium-propane (DOTAP) as a cationic emulsifier and other co-emulsifiers. The physical characteristics of the l...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1007553106681
更新日期:2000-03-01 00:00:00
abstract:PURPOSE:The passage of molecules across cell membranes is a crucial step in many physiological processes. We therefore seek physical models of this process, in order to predict permeation for new molecules, and to better understand the important interactions which determine the rate of permeation. METHODS:Several sets...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1007543708522
更新日期:2000-08-01 00:00:00
abstract:PURPOSE:Solid dispersions (SDs) represent the most common formulation technique used to increase the dissolution rate of a drug. In this work, the three most common methods used to prepare SDs, namely spray-drying, solvent-casting and freeze-drying, have been compared in order to investigate their effect on increasing ...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-020-2778-1
更新日期:2020-02-19 00:00:00
abstract::Fibers were spun by the downward configuration of the wet spinning technique. This configuration is capable of encapsulating nonspherical and/or coarse particles. We examined encapsulation of propranolol hydrochloride and the ability of the fibers to act as a sustained-release delivery system for propranolol hydrochlo...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1015982521706
更新日期:1989-12-01 00:00:00
abstract:PURPOSE:To evaluate the effect of the size of low molecular weight hyaluronan (LMW-HA) oligomers on the targeting ability of the HA-containing copolymers to the CD44-overexpressing cells for delivering Paclitaxel (PTX) to ovarian cancer. METHODS:LMW-HA oligosaccharides of 4, 6, 8, 10, 12 and 14 sugar residues were att...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-012-0672-1
更新日期:2012-04-01 00:00:00
abstract:PURPOSE:The purpose of this study was to evaluate the feasibility of delivering vapreotide, a somatostatin analogue, by transdermal iontophoresis. METHODS:In vitro experiments were conducted using dermatomed porcine ear skin and heat-separated epidermis. In addition to quantifying vapreotide transport into and across ...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-005-5276-6
更新日期:2005-08-01 00:00:00
abstract:PURPOSE:A novel photo-activated targeted chemotherapy was developed by photochemical internalization (PCI) of glutathione-sensitive polymeric micelles incorporating camptothecin (CPT) prepared from thiolated CPT (CPT-DP) and thiolated poly(ethylene glycol)-b-poly(glutamic acid) (PEG-b-P(Glu-DP)) METHODS: PEG-b-P(Glu-DP...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-008-9712-2
更新日期:2009-01-01 00:00:00
abstract:PURPOSE:To study the oxidative degradation of drugs using a hydrophilic free radical initiator, 2,2'-Azobis(-amidinopropane) dihydrochloride (AAPH). METHODS:AAPH was used as the free radical initiator to study oxidation of three model compounds (A, B, and C), which represent different oxidizable moieties. In the solut...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-004-1199-x
更新日期:2005-02-01 00:00:00