Abstract:
PURPOSE:The aim of the study is to investigate the effect of polymer blending on entrapment and release of ganciclovir (GCV) from poly(D,L-lactide-co-glycolide) (PLGA) microspheres using a set of empirical equations. METHODS:Two grades of PLGA, PLGA 7525 [D,L-lactide:glycolide(75:25), MW 90,000-126,000 Da] and Resomer RG 502H [D,L-lactide:glycolide(50:50), MW 8000 Da], were employed in the preparation of PLGA microspheres. Five sets of microsphere batches were prepared with two pure polymers and their 1:3, 1:1, and 3:1 blends. Drug entrapment, surface morphology, particle size analysis, drug release, and differential scanning calorimetric studies were performed. In vitro drug-release data were fitted to a set of empirical sigmoidal equations by nonlinear regression analysis that could effectively predict various parameters that characterize both diffusion and degradation cum diffusion-controlled release phases of GCV. RESULTS:Entrapment efficiencies of GCV ranged from 47 to 73%. Higher amounts of GCV were entrapped in polymer blend microspheres relative to individual polymers. Triphasic GCV release profiles were observed, which consisted of both diffusion and degradation cum diffusion-controlled phases. In vitro GCV release was shortest for Resomer RG 502H microsphere (10 days) and longest for PLGA 7525 microspheres (90 days). Upon blending, the duration of release gradually decreased as the content of Resomer RG 502H in the matrix was raised. Equations effectively estimated the drug-release rate constants during both the phases with high R2 values (>0.990). GCV release was slower from the blend microsphere during the initial diffusion phase. Majority of entrapped drug (70-95%) was released during the matrix degradation cum diffusion phase. CONCLUSIONS:Drug entrapment and release parameters estimated by the equations indicate more efficient matrix packing between PLGA 7525 and Resomer RG 502H in polymer-blended microspheres. The overall duration of drug release diminishes with rising content of Resomer RG 502H in the matrix. Differential scanning calorimetry studies indicate stronger binding between the polymers in the PLGA 7525/Resomer RG 502HColon, two colons 3:1 blend. Polymer blending can effectively alter drug-release rates of controlled delivery systems in the absence of any additives.
journal_name
Pharm Resjournal_title
Pharmaceutical researchauthors
Duvvuri S,Gaurav Janoria K,Mitra AKdoi
10.1007/s11095-005-9042-6subject
Has Abstractpub_date
2006-01-01 00:00:00pages
215-23issue
1eissn
0724-8741issn
1573-904Xjournal_volume
23pub_type
杂志文章abstract:PURPOSE:Iontophoresis was employed for enhancing the transdermal delivery of acyclovir through nude mouse skin in vitro, with the aim of understanding the mechanisms responsible for drug transport, in order to properly set the conditions of therapeutical application. METHODS:Experiments were done in horizontal diffusi...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1016284815501
更新日期:1995-11-01 00:00:00
abstract:PURPOSE:Nonlinear conjugation metabolic rate of valproic acid (VPA) has been speculated previously from plasma elimination and liver concentration of VPA in guinea pigs. The purposes of the present study were to assess our speculation by direct measurement of VPA glucuronidation rate in vitro. METHODS:VPA at various c...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1016028707130
更新日期:1996-08-01 00:00:00
abstract::A procedure is described that is suitable for the radioimmunoassay (RIA) of 9-[(l,3-dihydroxy-2-propoxy)-methyl]guanine (DHPG) in plasma or serum at concentrations as low as 0.7 ng/ml (2.75 × 10(-9) M). Antiserum was prepared by coupling DHPG monohemisuccinate to bovine serum albumin and immunizing rabbits with the re...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/A:1016397520991
更新日期:1986-04-01 00:00:00
abstract:PURPOSE:To investigate the moisture-induced aggregation (i.e., a loss of solubility in water) of DNA in a solid state and to develop rational strategies for its prevention. METHODS:Lyophilized calf thymus DNA was exposed to relative humidity (RH) levels from 11% to 96% at 55 degrees C. Following a 24-h incubation unde...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-006-9138-7
更新日期:2007-01-01 00:00:00
abstract:PURPOSE:This study aimed to assess impact of different vehicles for laser-assisted skin drug delivery. We also tried to uncover the mechanisms by which different vehicles affect laser-aided skin permeation. METHODS:Full-surface ablative (conventional) and fractional lasers were used to irradiate nude mouse skin. Imiqu...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-013-1167-4
更新日期:2014-02-01 00:00:00
abstract:PURPOSE:The aim was to investigate the influence of polymer content and molecular weight on the morphology and heat- and moisture-induced transformations, as indicators of stability, of spray-dried composite particles of amorphous lactose and poly(vinylpyrrolidone) (PVP). METHODS:Amorphous lactose and composite partic...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1024462306941
更新日期:2003-07-01 00:00:00
abstract:PURPOSE:To assess the blood-brain barrier (BBB) permeability of 12 clinically-used drugs in mdr1a(+/+) and mdr1a(-/-) mice, and investigate the influence of lipophilicity, nonspecific brain tissue binding, and P-gp-mediated efflux on the rate of brain uptake. METHODS:The BBB partition coefficient (PS) was determined u...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-009-9876-4
更新日期:2009-07-01 00:00:00
abstract:PURPOSE:To characterize the electrochemical behavior of the photodegradation product of nifedipine, i.e., 2,6-dimethyl-4-(2-nitrosophenyl)-3,5-pyridine-carboxylic acid dimethyl ester (NPD) in different electrolytic media. We also evaluated the interaction between free radicals generated from NPD and xeno/endobiotics. ...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1015112216360
更新日期:2002-04-01 00:00:00
abstract:PURPOSE:To apply physiologically-based pharmacokinetic (PBPK) modeling to investigate the consequences of reduction in activity of hepatic and intestinal uptake and efflux transporters by cyclosporine and its metabolite AM1. METHODS:Inhibitory potencies of cyclosporine and AM1 against OATP1B1, OATP1B3 and OATP2B1 were...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-012-0918-y
更新日期:2013-03-01 00:00:00
abstract::A biopharmaceutics drug classification scheme for correlating in vitro drug product dissolution and in vivo bioavailability is proposed based on recognizing that drug dissolution and gastrointestinal permeability are the fundamental parameters controlling rate and extent of drug absorption. This analysis uses a transp...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1016212804288
更新日期:1995-03-01 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 influence of the jejunal bloodflow on the absorption of theophylline was investigated. The bloodflow through a segment under investigation was varied by changing the systemic blood pressure by means of a donor blood infusion into the jugular vein or by an infusion of isoprenaline or levarterenol into a femoral vei...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/A:1016374508542
更新日期:1984-01-01 00:00:00
abstract:PURPOSE:Study on curcumin dissolved in natural deep eutectic solvents (NADES) was aimed at exploiting their beneficial properties as drug carriers. METHODS:The concentration of dissolved curcumin in NADES was measured. Simulated gastrointestinal fluids were used to determine the concentration of curcumin and quantum c...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-019-2643-2
更新日期:2019-06-03 00:00:00
abstract:PURPOSE:We aimed to assess the fate of β-arteether lipid-based drug delivery systems (AE-LBDDS) in terms of resistance to lipolysis and permeation across intestinal cells. METHODS:AE-LBDDS contained Tween 80 or Cremophor EL as surfactants, ethanol, Maisine 35-1 and vegetable oil. The solubilization behavior of AE was ...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-013-1094-4
更新日期:2013-10-01 00:00:00
abstract:PURPOSE:The aim of this study was to investigate the effect of hepatic or renal insufficiency on the pharmacokinetics of paclitaxel in rats. METHODS:Rats were treated with carbon tetrachloride (CCl4; 0.5 ml/kg) to induce hepatic failure or were subjected to 5/6 nephrectomy (5/6 Nx) to induce renal failure. Paclitaxel ...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-004-1190-6
更新日期:2005-02-01 00:00:00
abstract:PURPOSE:Overexpression of the serine protease urokinase (uPA) is recognised as an important biomarker of metastatic disease and a druggable anticancer target. Plasminogen activator inhibitor type-2 (PAI-2/SerpinB2) is a specific uPA inhibitor with proven potential for use in targeted therapy. However, PAI-2 is rapidly ...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-014-1517-x
更新日期:2015-03-01 00:00:00
abstract:PURPOSE:This study examined the rheological and textural characteristics (hardness, compressibilty, adhesiveness and cohesiveness) of bioadhesive oral gels containing the antimicrobial agent chlorhexidine. METHODS:Textural analysis was performed using a Stable Micro Systems texture analyser (model TA-XT 2) in texture ...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1012091231023
更新日期:1997-04-01 00:00:00
abstract:PURPOSE:A plasmid-based gene expression system was complexed with protective, interactive, and non-condensing (PINC) polymer system and administered with Medi-Jector, a needle-free injection device (NFID), to achieve high and sustained levels of antigen-specific antibodies in blood circulation. METHODS:Human growth ho...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1018834305079
更新日期:1999-06-01 00:00:00
abstract:PURPOSE:Novel itraconazole (ITZ)-based dry powders for inhalation (DPI) were optimized for aerodynamic and dissolution properties and contained excipients that are acceptable for inhalation. METHODS:The DPI were produced by spray drying solutions. The drug content, crystallinity state, and morphological evaluation of ...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-012-0779-4
更新日期:2012-10-01 00:00:00
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journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/b:pham.0000026434.82855.69
更新日期:2004-05-01 00:00:00
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journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-006-9177-0
更新日期:2007-03-01 00:00:00
abstract:PURPOSE:Long-acting injectables (LAIs) are increasingly recognized as an effective therapeutic approach for treating chronic conditions. Many LAIs are formulated to create a poorly soluble depot from which the active agent is delivered over time. This long residing depot can cause localized chronic-active inflammation ...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-014-1308-4
更新日期:2014-08-01 00:00:00
abstract:PURPOSE:To study the influence of cytotoxicity of macromolecules, VEGF gene expression, and vascular permeability on the enhanced permeability and retention (EPR) effect. METHODS:Mice bearing xenografts of A2780 multidrug resistant human ovarian carcinoma were treated by free doxorubicin (DOX) and N-(2-hydroxypropyl)m...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1007500412442
更新日期:2000-05-01 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:Predicting human skin permeability of chemical compounds accurately and efficiently is useful for developing dermatological medicines and cosmetics. However, previous work have two problems; 1) quality of databases used, and 2) methods for prediction models. In this paper, we attempt to solve these two problems...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-015-1629-y
更新日期:2015-07-01 00:00:00
abstract::The effect of γ-cyclodextrin and its four derivatives on the solubility of progesterone in phosphate buffer pH 7.4 was investigated. γ-Cyclodextrin forms a complex precipitating from solution at low cyclodextrin concentrations. No precipitation of complexes was observed with the γ-cyclodextrin derivatives. This change...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/A:1016301919928
更新日期:1985-11-01 00:00:00
abstract::Gallopamil is a calcium-channel antagonist with reported activity in experimental animals three to five times higher than that of verapamil. An automated high-performance liquid chromatographic (HPLC) method with fluorescence detection is described for the simultaneous determination of gallopamil and its metabolite no...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1016401405119
更新日期:1987-08-01 00:00:00
abstract:PURPOSE:Paclitaxel is active and widely used to treat multiple types of solid tumors. The commercially available paclitaxel formulation uses Cremophor/ethanol (C/E) as the solubilizers. Other formulations including nanoparticles have been introduced. This study evaluated the effects of nanoparticle formulation of pacli...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1007/s11095-005-4581-4
更新日期:2005-06-01 00:00:00
abstract::Moisture sorption characteristics and the effect of moisture content on the compression properties of two dextrose-based directly compressible diluents, namely, Emdex (diluent A) and Sweetrex (diluent B) were studied. Both diluents sorbed moisture rapidly at relative humidities greater than 60%. For both the diluents,...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1015889414533
更新日期:1991-03-01 00:00:00
abstract::A fluorescence measurement system and methods of data analysis were developed to measure rapid kinetics of transdermal transport in vitro. Three variations on the technique were demonstrated, where the receptor compartment concentration was determined by: 1) fluorescence measurements of aliquots removed at discrete ti...
journal_title:Pharmaceutical research
pub_type: 杂志文章
doi:10.1023/a:1016254013374
更新日期:1995-04-01 00:00:00