Abstract：
:The degradation kinetics of phentolamine hydrochloride in aqueous solution over a pH range of 1.2 to 7.2 and its stability in propylene glycol- or polyethylene glycol 400-based solutions were investigated. The observed rate constants were shown to follow apparent first-order kinetics in all cases. The pKa determination for phentolamine hydrochloride was found to be 9.55 +/- 0.10 (n = 5) at 25 +/- 0.2 degrees C. This indicated the protonated form of phentolamine occurs in the pH range of this study. The pH-rate profile indicated a pH-independent region (pH 3.1-4.9) exists with a minimum rate around pH 2.1. The catalytic effect of acetate and phosphate buffer species is ordinary. The catalytic rate constants imposed by acetic acid, acetate ion, dihydrogen phosphate ion, and monohydrogen phosphate ion were determined to be 0.018, 0.362, 0.036, and 1.470 L mol-1 h-1, respectively. The salt effect in acetate and phosphate buffers followed the modified Debye-Huckel equation quite well. The ZAZB value obtained from the experiment closely predicts the charges of the reacting species. The apparent energy of activation was determined to be 19.72 kcal/mol for degradation of phentolamine hydrochloride in pH 3.1, 0.1 M acetate buffer solution at constant ionic strength (mu = 0.5). Irradiation with 254 nm UV light at 25 +/- 0.2 degrees C showed a ninefold increase in the degradation rate compared with the light-protected control. Propylene glycol had little or no effect on the degradation of phentolamine hydrochloride at 90 +/- 0.2 degrees C; however, polyethylene glycol 400 had a definite effect.
journal_name
J Pharm Scijournal_title
Journal of pharmaceutical sciencesauthors
Wang DP,Tu YH,Allen LV Jrdoi
10.1002/jps.2600771116subject
Has Abstractpub_date
1988-11-01 00:00:00pages
972-6issue
11eissn
0022-3549issn
1520-6017pii
S0022-3549(15)47831-1journal_volume
77pub_type
杂志文章abstract：:Controlling residual solvent levels is a major concern in pharmaceutical freeze-drying from co-solvent systems. This review provides an overview of the factors influencing this process and estimates their potential to reduce residual solvents in freeze-dried products. Decreased solvent contents are potentially correla...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章,评审
doi：10.1016/j.xphs.2018.04.001
更新日期：2018-08-01 00:00:00
abstract：:The estimation of Michaelis-Menten pharmacokinetic parameters in patients with epilepsy receiving phenytoin continues to be a vexing problem. The various approximate methods suggested in the literature have serious shortcomings, primarily due to the role of the error term in the statistical model. In this report we pr...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600780514
更新日期：1989-05-01 00:00:00
abstract：:A physical model approach to the topical delivery of a vidarabine ester prodrug was investigated. It involved modeling, theoretical simulations, experimental method development for factoring and quantifying parameters, and, finally, employment of the deduced parameters to determine the steady-state species fluxes and ...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600681104
更新日期：1979-11-01 00:00:00
abstract：:The pneumococcal histidine triad protein D (PhtD) is believed to play a central role in pneumococcal metal ion homeostasis and has been proposed as a promising vaccine candidate against pneumococcal disease. To investigate for potential stabilizers, a panel of physiologically relevant metals was screened using the the...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1016/j.xphs.2017.06.003
更新日期：2017-10-01 00:00:00
abstract：:A fully automated system for dissolution rate analysis of potassium in slow release tablets is described. Aliquots are removed after 1, 2, and 4 hr from six samples, and potassium is analyzed in a flame photometer at 768 nm. A complete study of six samples takes 5.5 hr. The system may be run overnight. During the time...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600650308
更新日期：1976-03-01 00:00:00
abstract：:A spectrophotofluorometric assay for coralyne sulfoacetate was developed. Caralyne was extracted from serum samples with n-butyl alcohol, and the drug concentrations were determined fluorometrically at 475 nm when the extract was excited at 325 nm. A biphasic serum decay curve for coralyne was observed for both dogs a...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600670942
更新日期：1978-09-01 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：:An alumina (Al(2)O(3))-steroid-ethanol model is used for forced degradation testing of corticosteroids to predict chemical stability and degradation products in pressurized metered-dose inhaler (pMDI) solution formulations. The model involves an ethanolic solution of a test steroid with Al(2)O(3), stressed at elevated...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.23111
更新日期：2012-06-01 00:00:00
abstract：:Accelerated stability studies (37 degrees, 47 degrees, and 57 degrees) were conducted on buffered aqueous solutions (pH 7.4, 8.4, and 9.4) of hydrocortisone in the presence of various molar ratios of D-fructose. First-order degradation was observed. Significant improvement in hydrocortisone stability was seen in those...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600720930
更新日期：1983-09-01 00:00:00
abstract：:Despite being a major breakthrough in multiple myeloma therapy, carfilzomib (CFZ, a second-generation proteasome inhibitor drug) has been largely ineffective against solid cancer, possibly due to its pharmacokinetic drawbacks including metabolic instability. Recently, quinic acid (QA, a low-affinity ligand of selectin...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1016/j.xphs.2020.01.008
更新日期：2020-04-01 00:00:00
abstract：:Recent oxidation events on monoclonal antibody candidates prompted us to investigate the mechanism of oxidation of Met, Trp, and His residues and to search for suitable stabilizers. By using parathyroid hormone (1-34), PTH, as a model protein and various oxidants, aided by liquid chromatography, peptide mapping, and m...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.21746
更新日期：2009-12-01 00:00:00
abstract：:Isothermal crystallization of amorphous nifedipine, phenobarbital, and flopropione was studied at temperatures above and below their glass transition temperatures (T(g)). A sharp decrease in the crystallization rate with decreasing temperature was observed for phenobarbital and flopropione, such that no crystallizatio...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/(SICI)1520-6017(200003)89:3<408::AID-JPS11
更新日期：2000-03-01 00:00:00
abstract：:Understanding the effect of surfactant properties is critical when designing vesicular delivery systems. This review evaluates previous studies to explain the influence of surfactant properties on the behavior of lipid vesicular systems, specifically their size, charge, stability, entrapment efficiency, pharmacokineti...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章,评审
doi：10.1016/j.xphs.2018.01.005
更新日期：2018-05-01 00:00:00
abstract：:The solubility of ergotamine tartrate in aqueous solutions of tartaric acid, citric acid, hydrochloric acid, and caffeine and the dissolution rate of ergotamine tartrate in aqueous mixtures containing hydrochloric acid, caffeine, citric acid, or sodium acetate were studied. The Noyes-Whitney model of dissolution is us...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600690723
更新日期：1980-07-01 00:00:00
abstract：:A rapid and accurate method for the quantitative determination of the extent and ratio of amino and carboxyl group trimethylsilylation of 6-aminopenicillanic acid, 7-amino-3-methyl-delta3-cephem-4-carboxylic acid, and 7-amino-3-acetoxymethyl-delta3-cephem-4-carboxylic acid is presented. The method utilizes NMR spectro...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600661230
更新日期：1977-12-01 00:00:00
abstract：:The ratio between ocular and systemic drug concentrations describes the relative safety of ophthalmic dosage forms of the same drug in terms of its systemic side effects. In this study, we evaluated the effects of epinephrine pretreatment and solution pH on the aqueous humor:plasma and iris-ciliary body:plasma ratios ...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600790808
更新日期：1990-08-01 00:00:00
abstract：:In 2005, the World Health Organization (WHO) proposed that provided an active pharmaceutical ingredient could meet certain criteria, bioequivalence could be evaluated with a set of laboratory tests, obviating the need for expensive and time-consuming pharmacokinetic studies in humans. The aim of this work was to deter...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.22349
更新日期：2011-03-01 00:00:00
abstract：:To evaluate the regional delivery of conventional aerosol medications, a new whole-lung computational fluid dynamics modeling approach was applied for metered dose inhaler (MDI) and dry powder inhaler (DPI) aerosols delivered to healthy and constricted airways. The computational fluid dynamics approach included comple...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1016/j.xphs.2015.11.027
更新日期：2016-01-01 00:00:00
abstract：:The present work employs recent advances in high-resolution real-time magnetic resonance imaging (MRI) to investigate the disintegration process of tablets containing disintegrants. A temporal resolution of 75 ms and a spatial resolution of 80 × 80 µm with a section thickness of only 600 µm were achieved. The histogra...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.23789
更新日期：2014-01-01 00:00:00
abstract：:There is a need to identify suitable blends of solvents to dissolve drugs. Empirical approaches, such as trial-and-error and response surface, require several solubility measurements. In this study the UNIFAC method was used to predict solubility in highly nonideal multicomponent systems in which only the solute entha...
journal_title：Journal of pharmaceutical sciences
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doi：10.1002/jps.2600740610
更新日期：1985-06-01 00:00:00
abstract：:Release characteristics of two ethylated beta-cyclodextrins [heptakis(2,6-di-O-ethyl)-beta-cyclodextrin (diethyl-beta-cyclodextrin) and heptakis(2,3,6-tri-O-ethyl)-beta-cyclodextrin (triethyl-beta-cyclodextrin)] as sustained-release drug carriers were evaluated using diltiazem hydrochloride, a water-soluble calcium an...
journal_title：Journal of pharmaceutical sciences
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doi：10.1002/jps.2600790211
更新日期：1990-02-01 00:00:00
abstract：:The mechanism of organic solvent evaporation during microencapsulation and its role during microsphere hardening has been investigated. Evaporation and encapsulation studies were carried out in a jacketed beaker, filled with aqueous hardening solution, which was maintained at constant temperature and constant stirring...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：
更新日期：1999-10-01 00:00:00
abstract：:A high-pressure liquid chromatographic method suitable for determining plasma metoclopramide levels at normal (10-20 mg) doses is described. Eight metabolites as well as metclopramide were isolated and identified in rat, dog. and human urine. The only common metabolite in these species is 2-[(4-amino-5-chloro-2-metho...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600661128
更新日期：1977-11-01 00:00:00
abstract：:The dissolution characteristics of dicumarol were markedly enhanced by preparing dispersions of drug in polyethylene glycol 4000. Solid dispersions of varying weight fractions were formed by a melt method without measurable drug degradation or evaporation. There were no significant differences in dissolution rates amo...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600701217
更新日期：1981-12-01 00:00:00
abstract：:The purpose of the study is to understand the effect of altitude on the performance of selected pressurized metered dose inhalers (pMDIs) and dry powder inhalers (DPIs). A testing apparatus that created consistent breath profiles through the Alberta Idealized Throat was designed to test five pMDIs and two DPIs at alti...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.24032
更新日期：2014-07-01 00:00:00
abstract：:Tablet characteristics of tensile strength and disintegration time were predicted using residual stress distribution, simulated by the finite element method (FEM). The Drucker-Prager Cap (DPC) model was selected as the method for modeling the mechanical behavior of pharmaceutical powders composed of lactose (LAC), cor...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.23675
更新日期：2013-10-01 00:00:00
abstract：:Certain disulfide analogues of cystamine were prepared and evaluated for the ability to inhibit gamma-glutamylcysteine synthetase (GCS), the rate-limiting enzyme in glutathione synthesis. The compound SAPH-3 disulfide (2a) was found to be the most effective inactivator of GCS reported to date. Studies of structural an...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.2600800404
更新日期：1991-04-01 00:00:00
abstract：:Using two UV-spectrophotometric methods, the hydrolysis of tinidazole was studied at pH 1.00-8.45 at 80 degrees C. The reaction followed apparent first-order kinetics throughout the studied range. No kinetic salt effect was detected, indicating that at least one of the reacting partners forming the transition state ha...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1002/jps.10349
更新日期：2003-04-01 00:00:00
abstract：:The liquid sponge phase, a bicontinuous lipid-water system, formed in solvent-monoolein-water systems was investigated with respect to drug compatibility. The solvents propylene glycol and poly(ethylene glycol) swell the bicontinuous cubic phase of the monoolein-water system and form the sponge phase at constant water...
journal_title：Journal of pharmaceutical sciences
pub_type： 杂志文章
doi：10.1021/js980209z
更新日期：1998-12-01 00:00:00
abstract：:Drug stability studies are expensive and time consuming. Multiple batches are studied to ensure that a product will consistently remain within specifications for its entire expiration dating period. Some of these studies involve the same drug products in similar packages or in multiple strengths. Application of sound ...
journal_title：Journal of pharmaceutical sciences
pub_type： 指南,杂志文章
doi：10.1002/jps.2600841112
更新日期：1995-11-01 00:00:00
