Abstract：
:The transient dynamic swelling and dissolution behavior during the release of a growth hormone releasing peptide, [D-Trp2-D-Phe5]GHRP, from erodible, non-cross-linked poly(methyl methacrylate-co-methacrylic acid) (PMMA/MAA) beads has been investigated at pH 7.4 as a function of buffer concentration. Although the swelling front penetration shows a ionization-limited behavior similar to that of nonerodible cross-linked PMMA/MAA beads, the normalized diameter of the polymer beads exhibits a brief initial rise followed by an extended linear decline due to establishment of the polymer dissolution process. This is consistent with the general kinetic scheme of dissolution of glassy polymers originally predicted for the slab geometry. In all cases, the initial gel thickness increases as a result of the ionization and swelling of the glassy PMMA/MAA beads. This is followed by an extended period of constant gel thickness due to the onset of polymer dissolution and the synchronization of movement of the swelling and dissolution fronts. The resulting constant gel layer thickness as well as the onset and duration of front synchronization shows an increasing trend with decreasing buffer concentrations. As a result, the corresponding peptide release is slower and the release duration longer at lower buffer concentrations. This is believed to be the first time that a synchronization of swelling and dissolution fronts has been documented for a spherical erodible sample. Although such synchronization of fronts does not result in a constant rate of peptide release due to the spherical geometry, some non-Fickian release characteristics have been observed.
journal_name
Pharm Resjournal_title
Pharmaceutical researchauthors
Lee PIdoi
10.1023/a:1018902404036subject
Has Abstractpub_date
1993-07-01 00:00:00pages
980-5issue
7eissn
0724-8741issn
1573-904Xjournal_volume
10pub_type
杂志文章abstract：PURPOSE:To identify and quantify, in vitro and in vivo (in humans), the charge-carrying species during transdermal iontophoresis of lidocaine hydrochloride as a function of the concentration of drug relative to that of sodium chloride in the anodal solution. METHODS:In vitro experiments in standard diffusion cells qua...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1013370529366
更新日期：2001-12-01 00:00:00
abstract：PURPOSE:To study the expression of P-glycoprotein (P-gp), lung resistance-related protein (LRP), and caveolin-1 (cav-1) in the human bronchial epithelial cell line 16HBE14o-. METHODS:The presence of P-gp, LRP, and cav-1 in 16HBE14o- cell layers was evaluated using immunocytochemical staining and visualization with con...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1023230328687
更新日期：2003-04-01 00:00:00
abstract：:5'-Ester derivatives of 5-iodo-2'-deoxyuridine (IDU) with varying degrees of lipophilicity were examined to evaluate the effectiveness of lipophilic ester prodrugs for enhanced and sustained delivery of IDU to the brain parenchyma. Approximately 1.0% (1.0 +/- 0.19; n = 4) of the total radioactivity was found in the br...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1015803922401
更新日期：1992-09-01 00:00:00
abstract：PURPOSE:This study investigated the penetration of lidocaine around and through a sutured incision following the application of iontophoretic and passive patches in the CD Hairless rat. MATERIALS AND METHODS:Concentrations in localized areas (suture, dermis, subcutaneous, and vascular) were determined using microdialy...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1007/s11095-007-9490-2
更新日期：2008-08-01 00:00:00
abstract：PURPOSE:Novel multidrug resistance (mdr) modulators have been proved as inhibitors of P-glycoprotein (P-gp). We first investigated the in vitro effects of selected compounds in human cancer cells on multidrug resistance reversal effects compared to drug standards and on P-gp induction to characterize the potential of t...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1007/s11095-008-9736-7
更新日期：2009-01-01 00:00:00
abstract：:A method to provide near-constant sustained release of high molecular weight, water-soluble proteins from polyanhydride microspheres is described. The polyanhydrides used were poly(fatty acid dimer) (PFAD), poly(sebacic acid) (PSA), and their copolymers [P(FAD-SA)]. P(FAD-SA) microspheres containing proteins of differ...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1018929531410
更新日期：1993-04-01 00:00:00
abstract：PURPOSE:This study aims to develop a characterization method for coating structure based on image analysis, which is particularly promising for the rational design of coated particles in the pharmaceutical industry. METHODS:The method applies the MATLAB image processing toolbox to images of coated particles taken with...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1007/s11095-008-9805-y
更新日期：2009-04-01 00:00:00
abstract：:The release of lithium carbonate incorporated into polymethylmethacrylate, polyvinyl chloride, hydrogenated vegetable oil, and carbomer matrix tablets was studied in vitro. The formulation containing 10% carbomer showed a sustained-release profile comparable to that of a standard, commercially available, sustained-rel...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1015863204732
更新日期：1990-04-01 00:00:00
abstract：:The absorption of insulin across the vaginal mucosa into the systemic circulation was studied in ovariectomized rats given subsequent estrogen treatment. Blood glucose levels were determined as an indirect measure of insulin absorption, and the effect of various enhancers on the hypoglycemic response was investigated....
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1015892630637
更新日期：1992-07-01 00:00:00
abstract：:A method of immobilizing urokinase on albumin microspheres has been developed. Laser scattering, which was used to follow particle size from the initial emulsification stage to the final aqueous resuspension of the microsphere stage, showed that particle coalescence and crosslinking were critical parameters in manufac...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1015855622459
更新日期：1992-06-01 00:00:00
abstract：PURPOSE:To characterize the uptake mechanism of zidovudine (AZT), a nucleoside reverse transcriptase inhibitor, in syncytiotrophoblast cells using the TR-TBT 18d-1 cell line previously established by our group. MATERIALS AND METHODS:The effects of several transporter inhibitors on the initial and steady-state apical u...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1007/s11095-008-9564-9
更新日期：2008-07-01 00:00:00
abstract：PURPOSE:The aim of this study is to investigate the effects of 50% ethyl acetate extracts of grapefruit juice (GFJ) and orange juice (OJ) on the transport activity of P-glycoprotein (P-gp) in the rat small intestine. METHODS:The efflux of P-gp substrates from rat everted sac in the absence or presence of verapamil, GF...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1016100715125
更新日期：2002-06-01 00:00:00
abstract：:To clarify the mechanism by which basic drugs accumulate in the lung, the binding selectivity of drugs to different subcellular structures of the perfused rat lung was examined. Imipramine, quinine, and metoclopramide were used as examples of basic drugs. The accumulation of basic drugs was highest in the mitochondria...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1016481911538
更新日期：1987-02-01 00:00:00
abstract：PURPOSE:Generation of valuable information about the biphasic geometrical configuration of porcine stratum corneum from Very Small Angle Neutron Scattering (VSANS) data and investigation of its effect on the corresponding effective diffusivity. METHODS:Spectra of porcine stratum corneum are mathematically transformed ...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1026453628800
更新日期：2000-09-01 00:00:00
abstract：PURPOSE:To develop a liposomal system with high drug loading (DL) for intravenous (i.v.) delivery of a poorly water-soluble basic drug, asulacrine (ASL). METHODS:A thin-film hydration and extrusion method was used to fabricate the PEGylated liposomal membranes followed by a freeze and thaw process. A novel active drug...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1007/s11095-014-1551-8
更新日期：2015-04-01 00:00:00
abstract：PURPOSE:This study was aimed at developing a new active loading method to stably encapsulate staurosporine (STS), a water insoluble drug, into lipid-based nanoparticles (LNPs) for drug targeting to tumors. METHODS:A limited amount of DMSO was included during the active loading process to prevent precipitation and faci...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1007/s11095-015-1854-4
更新日期：2016-05-01 00:00:00
abstract：PURPOSE:To develop a new technique, spray freeze drying, for preparing protein aerosol powders. Also, to compare the spray freeze-dried powders with spray-dried powders in terms of physical properties and aerosol performance. METHODS:Protein powders were characterized using particle size analysis, thermogravimetric an...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1018828425184
更新日期：1999-02-01 00:00:00
abstract：PURPOSE:To identify High Molecular Weight Products (HMWP) formed in human insulin formulation during storage. METHODS:Commercial formulation of human insulin was stored at 37°C for 1 year and HMWP was isolated using preparative size exclusion chromatography (SEC) and reverse phase (RP) chromatography. The primary stru...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1007/s11095-014-1600-3
更新日期：2015-06-01 00:00:00
abstract：:Enoximone and piroximone are cardiotonic agents for use in patients with congestive heart failure. Electroanalytical studies revealed that the dihydroimidazolone functionality was oxidizable and that this property can be analytically useful. The compounds undergo a two-electron, irreversible oxidation in neutral to ac...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1015811830830
更新日期：1991-07-01 00:00:00
abstract：:A two-step analytic procedure to determine the rate and extent of metabolite production following administration of the parent compound is described. The procedure provides the rate and extent of metabolite production as a function of time by application of the general model independent approach of deconvolution. The ...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1015951426191
更新日期：1988-06-01 00:00:00
abstract：PURPOSE:To assess the role of intestinal CYP2D6 in oral first-pass drug clearance by comparing the enzyme content and catalytic activity of a prototype CYP2D6 substrate, metoprolol, between microsomes prepared from human intestinal mucosa and from human livers. METHODS:Microsomes were prepared from a panel of 31 human...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1018989211864
更新日期：1999-08-01 00:00:00
abstract：PURPOSE:Empirical formulae relate the mean size of primary droplets from jet and ultrasonic nebulizers to a fluid's physicochemical properties. Although the size selective "filtering" effects of baffling and evaporation may modify the secondary aerosol produced, this research sought to evaluate whether viscosity and su...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1016205520044
更新日期：1995-11-01 00:00:00
abstract：:Polymeric biomaterials have extensively been used in medicinal applications. However, factors that determine their biocompatibility are still not very clear. This article reviews various effects of the chemical structure and the surface properties of polymeric biomaterials on their biocompatibility, including protein ...
journal_title：Pharmaceutical research
pub_type： 杂志文章,评审
doi：10.1023/b:pham.0000036909.41843.18
更新日期：2004-08-01 00:00:00
abstract：PURPOSE:Polyesters with hydrophilic domains, i.e., poly(D,L-lactic-co-glycolic-co-hydroxymethyl glycolic acid) (PLGHMGA) and a multiblock copolymer of poly(ε-caprolactone)-PEG-poly(ε-caprolactone) and poly(L-lactide) ((PC-PEG-PC)-(PL)) are expected to cause less acylation of encapsulated peptides than fully hydrophobic...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1007/s11095-015-1685-3
更新日期：2015-09-01 00:00:00
abstract：PURPOSE:The sensitivity and effectiveness of indirect metrics proposed for the assessment of comparative absorption rates in bioequivalence studies [Cmax, Tmax, partial AUC (AUCp), feathered slope (SLf), intercept metric (I)] were originally tested by assuming first-order absorption. The present study re-evaluates thei...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1007521016985
更新日期：2000-05-01 00:00:00
abstract：:Gene delivery systems are designed to control the location of administered therapeutic genes within a patient's body. Successful in vivo gene transfer may require (i) the condensation of plasmid and its protection from nuclease degradation, (ii) cellular interaction and internalization of condensed plasmid, (iii) esca...
journal_title：Pharmaceutical research
pub_type： 杂志文章,评审
doi：10.1023/a:1012187414126
更新日期：1997-07-01 00:00:00
abstract：:Under the heading "Methods-Synthesis of the Bioreducible Modified-PAE (mPAE)", on page 3, line 14-17, there is an error. The quantity unit of PAE and 2-iminothiolane hydrochloride needs to be corrected to mg instead of g. ...
journal_title：Pharmaceutical research
pub_type： 杂志文章,已发布勘误
doi：10.1007/s11095-018-2488-0
更新日期：2018-09-05 00:00:00
abstract：PURPOSE:Three types of acyl tetragastrin (TG), acetyl-TG (C2-TG), butyryl-TG (C4-TG) and caproyl-TG (C6-TG) were synthesized and their in vitro intestinal permeability characteristics were examined using Caco-2 monolayers. METHODS:The disappearance of acyl-TGs from the apical side of Caco-2 monolayers was estimated by...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1011997404306
更新日期：1998-09-01 00:00:00
abstract：:We investigated the effects of increased concentrations of the solutes, salicylic acid, benzoic acid, and o-, m-, and p-methoxy benzoic acids, on the anisotropic properties of a liquid crystal solvent. The lamellar liquid crystal was composed of 37% polyoxyethylene (20) isohexadecyl ether in aqueous buffer of pH 1. Ph...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1018920118631
更新日期：1993-05-01 00:00:00
abstract：PURPOSE:To evaluate the use of an in vitro intestinal permeability model to predict rat and human absorption as well as to evaluate the use of an internal standard to control for intra- and inter-rat variability. METHODS:In vivo peroral absorption and in vitro steady-state intestinal permeability coefficients were det...
journal_title：Pharmaceutical research
pub_type： 杂志文章
doi：10.1023/a:1012148300807
更新日期：1997-12-01 00:00:00
