Abstract：
:Aliphatic polyesters have great utility as temporary prosthetics and surgical aids, and in drug delivery systems. Knowledge of the mechanism and pathways of hydrolysis can form a basis for the design and selection of a controlled-release system. Because of the importance of hydrolysis to the properties of such a system, a technique was developed to accurately determine the specific rate constants and relevant kinetic parameters for the specific oligomers from the reaction mixture of polyesters undergoing hydrolysis. A detailed kinetic analysis of the acid hydrolysis of well-characterized oligomers of polyesters is presented. Several oligomers of poly(butylene tartrate)s were synthesized and their kinetic behavior was studied under acidic conditions. The oligomers and their degradation products were monitored by HPLC and identified by fast-atom bombardment mass spectrometry. From the rates of hydrolysis measured from pH 1 to 3.0 and at temperature of 75 degrees C, it becomes evident that the degradation of the oligomers obeys pseudo-first-order kinetics. The rate of hydrolysis among the homologous series of oligomers increases as the molecular weight increases. The hydrolysis was catalyzed by hydrogen ion; the catalytic rate constant increased predictably with the number of ester linkages present in the molecule. The reaction is first order with respect to the catalyst concentration and the number of ester linkages. Good agreement was obtained with a model in which the individual rate of bond cleavage depends only on the statistical factor. The technique described in this paper is unique for the determination of polyester hydrolysis pathways and isolation of any structural effects on the rates of hydrolysis.
journal_name
J Pharm Scijournal_title
Journal of pharmaceutical sciencesauthors
Maniar ML,Kalonia DS,Simonelli APdoi
10.1002/jps.2600800815subject
Has Abstractpub_date
1991-08-01 00:00:00pages
778-82issue
8eissn
0022-3549issn
1520-6017pii
S0022-3549(15)48622-8journal_volume
80pub_type
杂志文章abstract：:One of the challenges with predictive modeling is how to quantify the reliability of the models' predictions on new objects. In this work we give an introduction to conformal prediction, a framework that sits on top of traditional machine learning algorithms and which outputs valid confidence estimates to predictions ...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1016/j.xphs.2020.09.055
更新日期：2021-01-01 00:00:00
abstract：:The comparative pharmacokinetics of free MTP-PE (muramyl tripeptide phosphatidyl ethanolamine) and MTP-PE entrapped in negatively charged multilamellar liposomes (liposomal MPT-PE) was evaluated in rats at a bolus intravenous (i.v.) dose of 0.2 mg/kg and in dogs at a bolus i.v. dose of 0.1 mg/kg. Additional studies we...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600821005
更新日期：1993-10-01 00:00:00
abstract：:The tissue:plasma partition coefficients (Kp ) are good indicators of the extent of tissue distribution. Therefore, advanced tissue composition-based models were used to predict the Kp values of drugs under in vivo conditions on the basis of in vitro and physiological input data. These models, however, focus on animal...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.24427
更新日期：2015-06-01 00:00:00
abstract：:Microbicide intravaginal rings (IVRs) are a promising woman-controlled strategy for preventing sexual transmission of human immunodeficiency virus (HIV). An IVR was prepared and developed from polyether urethane (PU) elastomers for the sustained delivery of UC781, a highly potent nonnucleoside reverse transcriptase in...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.22781
更新日期：2012-02-01 00:00:00
abstract：:An assay is described for the determination of the H2-receptor antagonist, cimetidine, in human plasma and urine. Alkalinized plasma or urine was extracted with methylene chloride, the organic phase was evaporated, and the reconstituted residue was analysed by high-pressure liquid chromatography (HPLC) using a reverse...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600710528
更新日期：1982-05-01 00:00:00
abstract：:The assay of suppositories containing pentobarbital and/or pyrilamine in a water-soluble polyethylene glycol base by high-pressure liquid chromatography is described. No extraction is required. The suppository is dissolved in the mobile phase. This solution is diluted with an internal standard stock solution containin...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600680524
更新日期：1979-05-01 00:00:00
abstract：:Previously, 1 mL of purified water (hyposmotic) or saline (isosmotic) which dissolved 200 μM of FITC-dextran (FD-4), a nonabsorbable marker, was orally administered to rats, and luminal concentration-time profile of FD-4 was directly measured. In this study, at first, luminal FD-4 concentration was measured after oral...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1016/j.xphs.2020.03.005
更新日期：2020-06-01 00:00:00
abstract：:The purpose of this work was to investigate the self-associating behavior observed in high concentration monoclonal antibody (MAb1) solutions at pH 6.0. Zeta potential measurements over the pH range (4.0-9.0) showed lower net charges present on the molecule at pH 6.0 and 7.0. The point of zero charge or crossover from...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.21898
更新日期：2010-03-01 00:00:00
abstract：:A novel method is described for the preparation of sterile and pyrogen-free submicron liposomes of narrow size distribution. The method is based on the formation of a homogeneous dispersion of lipids in water-soluble carrier materials. To obtain the lipid-containing solid dispersion, liposome-forming lipids and water-...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.20055
更新日期：2004-06-01 00:00:00
abstract：:Thiamine hydrochloride (Vitamin B(1), THCl) can exist as a nonstoichiometric hydrate (NSH) and as a hemihydrate (HH). NSH can contain up to approximately 1 molar equivalent of water and be dehydrated to an isomorphic desolvate (ID) with minimal change in lattice structure. Crystallographic and spectroscopic techniques...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.21876
更新日期：2010-02-01 00:00:00
abstract：:Solid dispersion (SD) of indomethacin with crospovidone (CrosPVP) shows useful characteristics for preparation of dosage forms. This study aimed to determine the types of drugs that could adopt a stable amorphous form in SD. Twenty compounds with various melting points (70-218 degrees C), molecular weights (135-504) a...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.20794
更新日期：2007-06-01 00:00:00
abstract：:High yields of potential glycol metabolites of p-synephrine, epinephrine, octopamine, and normacromerine can be obtained from the readily available monosubstituted and disubstituted acetophenones. The general procedure involves alpha-bromination followed by displacement with acetate ion and reduction with lithium alum...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600750621
更新日期：1986-06-01 00:00:00
abstract：:Ambrisentan is a nonsulfonamide, ET(A)-selective endothelin receptor antagonist (ERA) approved for the treatment of pulmonary arterial hypertension (PAH), and tadalafil is a phosphodiesterase type 5 (PDE-5) inhibitor under investigation for treatment of PAH. Due to the potential combination use, the pharmacokinetic (P...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章,随机对照试验
doi：10.1002/jps.21789
更新日期：2009-12-01 00:00:00
abstract：:The present study aimed to develop optimized quercetin (QT)-loaded self-nanoemulsifying drug delivery system (SNEDDS) that offers protective effect against liver damage. Solubility study of QT in different oils, surfactants, and cosurfactants was performed. Ternary phase mixtures of the selected components were constr...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.23834
更新日期：2014-02-01 00:00:00
abstract：:Three polymorphs (forms I-III), a monohydrate (form S2), and three new solvates [4:1 hydrate (form S1), monohydrate (form S3), and methanol half-solvate (form S4)] were isolated and characterized by X-ray powder diffractometry (XRPD), IR spectroscopy, differential scanning calorimetry (DSC), hot stage microscopy, solu...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600841007
更新日期：1995-10-01 00:00:00
abstract：:We investigated the effects of excipients in solutions of keratinocyte growth factor 2 (KGF-2) on protein aggregation during agitation as well as on interfacial shear rheology at the air-water interface. Samples were incubated with or without agitation, and in the presence or absence of the excipients heparin, sucrose...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.23622
更新日期：2013-08-01 00:00:00
abstract：:A method is described for screening compounds that inhibit crystallization in solution to enable more accurate measurement of amorphous drug solubility. Three polymers [polyvinylpyrrolidone, hydroxypropyl methylcellulose, and hydroxypropyl methylcellulose acetate succinate (HPMCAS)] were screened for their ability to ...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.22643
更新日期：2011-10-01 00:00:00
abstract：:Quantitative prediction of unbound drug fraction (fu) is essential for scaling pharmacokinetics through physiologically based approaches. However, few attempts have been made to evaluate the projection of fu values under pathological conditions. The primary objective of this study was to predict fu values (n = 105) of...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1016/j.xphs.2018.02.021
更新日期：2018-07-01 00:00:00
abstract：:The chemical stability of the novel anticancer agent carzelesin in aqueous buffer/acetonitrile (1:1, v/v) mixtures has been investigated utilizing a stability-indicating reversed-phase high-performance liquid chromatographic assay. The degradation kinetics of carzelesin has been studied as a function of pH, buffer com...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1021/js960005n
更新日期：1996-11-01 00:00:00
abstract：:A new parameter, the kinetic ratio, is suggested for estimating product potency during storage under ambient warehouse temperatures. Actual warehouse temperature data were integrated using Arrhenius kinetics, and the resulting potency errors, due both to the integration method and to temperature averaging, were evalua...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600690318
更新日期：1980-03-01 00:00:00
abstract：:In this work, the production of dexametasone and dexametasone acetate microparticles is proposed using supercritical-assisted atomization (SAA). This process is based on the solubilization of supercritical carbon dioxide in a liquid solution containing the drug; then, the ternary mixture is sprayed through a nozzle an...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.20703
更新日期：2006-09-01 00:00:00
abstract：:Successful development of stable solid protein formulations usually requires the addition of one or several excipients to achieve optimal stability. In these products, there is a potential risk of an inhomogeneous distribution of the various ingredients, specifically the ratio of protein and stabilizer may vary. Such ...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章,评审
doi：10.1016/j.xphs.2019.10.010
更新日期：2020-01-01 00:00:00
abstract：:Membrane permeation enhancers have received significant attention in recent years for enabling the oral absorption of poorly permeable drug molecules. In this study, we investigated the ability of His-Ala-Val (HAV) and Ala-Asp-Thr (ADT) peptides derived from the extracellular-1 (EC1) domain of E-cadherin proteins to i...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1016/j.xphs.2020.12.018
更新日期：2020-12-23 00:00:00
abstract：:In previous studies (Yoneto et al., 1995. J Pharm Sci 84:312-317; Kim et al., 1992. Int J Pharm 80:17-31; and Warner et al., 2001. J Pharm Sci 90:1143-53), the transport enhancing effects of four homologous series of enhancers-the n-alkanols, 1-alkyl-2-pyrrolidones, 1,2-alkanediols, and N,N-dimethylalkanamides - on th...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.10269
更新日期：2003-02-01 00:00:00
abstract：:The placental and nonplacental clearances of metoclopramide were studied in nine chronically instrumented, near-term pregnant sheep using a two-compartment open model. Metoclopramide was administered to the ewe and fetus on separate occasions as an initial iv bolus loading dose followed by a constant-rate infusion, wi...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600791204
更新日期：1990-12-01 00:00:00
abstract：:The aim of this study is to prepare novel pH-sensitive beads to obtain a gastric mucosa protective formulation and to ensure drug delivery into the intestine. Diclofenac sodium was used as a model drug. Bead formation was achieved by ionotropic gelation method using three-component gel system containing sodium alginat...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.21713
更新日期：2009-11-01 00:00:00
abstract：:Maintaining good content uniformity (CU) is a significant challenge for low-dose oral tablets in particular when using direct compression (DC). Using 6 model active pharmaceutical ingredients, we show that a platform DC tablet formulation suitable for developing low-dose API with excellent CU can be developed. This pl...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1016/j.xphs.2017.03.005
更新日期：2017-07-01 00:00:00
abstract：:Literature data relevant to the decision to allow a waiver of in vivo bioequivalence (BE) testing for the approval of immediate release (IR) solid oral dosage forms containing metronidazole are reviewed. Metronidazole can be assigned to Biopharmaceutics Classification System Class I. Most BE studies that were identifi...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.22409
更新日期：2011-05-01 00:00:00
abstract：:Isoperibol calorimetry was used to evaluate protein/carbohydrate interactions after freeze drying. rh-DNase, rh-GH, rh-MetGH, and rh-IGF-I were freeze dried with either mannitol, sucrose, trehalose, or dextran at concentrations ranging from 0% to 100% (w/w). Enthalpies of solution for both freeze-dried and physical mi...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.10023
更新日期：2002-01-01 00:00:00
abstract：:Plasma and various organ concentrations of canrenone, canrenoate, and total 3H-activity were measured following single doses of 20 mg of 3H-canrenoate/kg iv to rabbits. Organs studied included heart, lungs, brain, kidneys, liver, adrenal glands, and spleen. Canrenoate was shown to be in rapid equilibrium with canrenon...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600660237
更新日期：1977-02-01 00:00:00
