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1.
HCA Healthc J Med ; 5(3): 343-351, 2024.
Article in English | MEDLINE | ID: mdl-39015589

ABSTRACT

Background: Well-being initiatives are essential components in fostering an engaged workforce and creating an effective health care ecosystem. Health care professional (HCP) burnout is widespread and has worsened since the COVID-19 pandemic. In 2014, with Health Resources and Services Administration funding support, the Andrew Weil Center for Integrative Medicine created an online course for HCP well-being. It was subsequently studied in medical residents and revised in 2020. In this study, we explore the impact of the course across larger systems, as well as the long-term impact on HCPs. Methods: The Health Care Professional Well-Being course is 4.5 hours of interactive online education that explores personal well-being, promoters and detractors of well-being, and systemic factors that influence the overall impact of well-being in health care systems. Participants were recruited through institutional members of the Academic Consortium for Integrative Medicine and Health and were randomized to either active or waitlist control groups. Assessments were taken pre-course, 1-month post-course, and 6-months post-course in the areas of burnout, compassion, resiliency, and lifestyle behaviors. Results: Burnout measures of depersonalization and emotional exhaustion showed a significant improvement amongst active participants, sustained for 6 months after the course. However, no significant improvement in either the resiliency or the compassion measurements was noted for the active group. Initially, the active group showed improvement in personal accomplishment; however, both groups showed a decline overall. Most noteworthy, a large number of active participants demonstrated adoption of new health-promoting behavior; 95% incorporated at least 1 new lifestyle behavior learned from the course. Conclusion: This study of a brief, asynchronous, online well-being course with interprofessional HCPs, demonstrates that the course is associated with improvement in individual burnout measures and can educate HCPs about healthy behaviors and a framework for professional engagement.

2.
Eur J Pharm Biopharm ; 154: 195-209, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32681966

ABSTRACT

Elucidating the impact of excipient variability on oral product performance in a biopharmaceutical perspective would be beneficial and allow excipient implementation on Quality by Design (QbD) approaches. The current study investigated the impact of varying viscosity of binders (hypromellose (HPMC)) and superdisintegrants (sodium starch glycolate (SSG)) and particle size distribution of lubricants (magnesium stearate (MgSt)) on the in vitro dissolution of a highly and a poorly soluble drug from immediate release formulations. Compendial (pharmacopoeia buffers) and biorelevant (media simulating the gastrointestinal fluids) media and the USP 2 and USP 4 apparatuses were used to assess the exerted excipient effects on drug dissolution. Real-time dissolution UV imaging provided mechanistic insights into disintegration and dissolution of the immediate release formulations. Varying the viscosity type of HPMC or SSG did not significantly affect drug dissolution irrespective of the compound used. Faster drug dissolution was observed when decreasing the particle size of MgSt for the highly soluble drug. The use of real-time dissolution UV Imaging revealed the influential role of excipient variability on tablet disintegration, as for the highly soluble drug, tablets containing high viscosity HPMC or low particle size MgSt disintegrated faster as compared to the control tablets while for the poorly soluble drug, slower tablet disintegration was observed when increasing the viscosity of the HPMC as compared to the control tablets. Changes in drug dissolution when varying excipients may be anticipated if the excipient change has previously affected drug solubility. The use of multivariate data analysis revealed the influential biopharmaceutical factors such as critical excipient types/properties, drug aqueous solubility, medium/hydrodynamic characteristics affecting the impact of excipient variability on in vitro drug dissolution.


Subject(s)
Biological Products/pharmacokinetics , Chemistry, Pharmaceutical/methods , Drug Liberation , Excipients/pharmacokinetics , Biological Products/chemistry , Carbamazepine/chemistry , Carbamazepine/pharmacokinetics , Excipients/chemistry , Solubility , Stearic Acids/chemistry , Stearic Acids/pharmacokinetics , Tablets
3.
AAPS J ; 22(4): 75, 2020 05 21.
Article in English | MEDLINE | ID: mdl-32440810

ABSTRACT

Excipients are major components of oral solid dosage forms, and changes in their critical material attributes (excipient variability) and/or amount (excipient variation) in pharmaceutical formulations may present a challenge for product performance. Understanding the biopharmaceutical factors affecting excipient performance is recommended for the successful implementation of excipient variability on Quality by Design (QbD) approaches. The current study investigated the impact of magnesium stearate (MgSt) variability on the apparent solubility of drugs with a wide range of physicochemical properties (drug ionization, drug lipophilicity, drug aqueous solubility). Compendial and biorelevant media were used to assess the role of gastrointestinal (GI) conditions on the excipient effects on drug apparent solubility. The lipophilic nature of MgSt decreased the apparent solubility of most compounds. The reduction in drug apparent solubility was more pronounced for highly soluble and/or highly ionized drugs and in presence of more highly crystalline or smaller particle size MgSt. The use of multivariate data analysis revealed the critical physicochemical and biopharmaceutical factors and the complex nature of excipient variability on the reduction in drug apparent solubility. The construction of a roadmap combining drug, excipient and medium characteristics allowed the identification of the cases where the presence of excipient or excipient variability may present risks for oral drug performance.


Subject(s)
Chemistry, Pharmaceutical/methods , Stearic Acids/chemistry , Stearic Acids/pharmacokinetics , Chemical Phenomena , Particle Size , Solubility , X-Ray Diffraction/methods
4.
AAPS J ; 22(2): 49, 2020 02 18.
Article in English | MEDLINE | ID: mdl-32072317

ABSTRACT

Identification of the biopharmaceutical risks of excipients and excipient variability on oral drug performance can be beneficial for the development of robust oral drug formulations. The current study investigated the impact of Hypromellose (HPMC) presence and varying viscosity type, when used as a binder in immediate release formulations, on the apparent solubility of drugs with wide range of physicochemical properties (drug ionization, drug lipophilicity, drug aqueous solubility). The role of physiological conditions on the impact of excipients on drug apparent solubility was assessed with the use of pharmacopoeia (compendial) and biorelevant media. Presence of HPMC affected drug solubility according to the physicochemical properties of studied compounds. The possible combined effects of polymer adsorption (drug shielding effect) or the formation of a polymeric viscous layer around drug particles may have retarded drug dissolution leading to reduced apparent solubility of highly soluble and/or highly ionized compounds and were pronounced mainly at early time points. Increase in the apparent solubility of poorly soluble low ionized drugs containing a neutral amine group was observed which may relate to enhanced drug solubilization or reduced drug precipitation. The use of multivariate data analysis confirmed the importance of drug physicochemical properties on the impact of excipients on drug apparent solubility and revealed that changes in HPMC material properties or amount may not be critical for oral drug performance when HPMC is used as a binder. The construction of a roadmap combining drug, excipient, and medium characteristics allowed the identification of the cases where HPMC presence may present risks in oral drug performance and bioavailability.


Subject(s)
Excipients/chemistry , Hypromellose Derivatives/chemistry , Pharmaceutical Preparations/chemistry , Administration, Oral , Adsorption , Biological Availability , Drug Compounding , Models, Chemical , Pharmaceutical Preparations/administration & dosage , Solubility , Viscosity
5.
Int J Pharm ; 577: 119080, 2020 Mar 15.
Article in English | MEDLINE | ID: mdl-31988030

ABSTRACT

Superdisintegrants are a key excipient used in immediate release formulations to promote fast tablet disintegration, therefore understanding the impact of superdisintegrant variability on product performance is important. The current study examined the impact of superdisintegrant critical material attributes (viscosity for sodium starch glycolate (SSG), particle size distribution (PSD) for croscarmellose sodium (CCS)) on their performance (swelling) and on drug dissolution using surface dissolution UV imaging. Acidic and basic pharmacopoeia (compendial) media were used to assess the role of varying pH on superdisintegrant performance and its effect on drug dissolution. A highly soluble (paracetamol) and a poorly soluble (carbamazepine) drug were used as model compounds and drug compacts and drug-excipient compacts were prepared for the dissolution experiments. The presence of a swelled SSG or CCS layer on the compact surface, due to the fast excipient hydration capacity, upon contact with dissolution medium was visualized. The swelling behaviour of superdisintegrants depended on excipient critical material attributes and the pH of the medium. Drug dissolution was faster in presence compared to superdisintegrant absence due to improved compact wetting or compact disintegration. The improvement in drug dissolution was less pronounced with increasing SSG viscosity or CCS particle size. Drug dissolution was slightly more complete in basic compared to acidic conditions in presence of the studied superdisintegrants for the highly soluble drug attributed to the increased excipient hydration capacity and the fast drug release through the swelled excipient structure. The opposite was observed for the poorly soluble drug as potentially the improvement in drug dissolution was compromised by drug release from the highly swelled structure. The use of multivariate data analysis revealed the influential role of excipient and drug properties on the impact of excipient variability on drug dissolution.


Subject(s)
Excipients/chemistry , Technology, Pharmaceutical , Ultraviolet Rays , Acetaminophen/chemistry , Carbamazepine/chemistry , Carboxymethylcellulose Sodium/chemistry , Drug Liberation , Hydrogen-Ion Concentration , Particle Size , Solubility , Starch/analogs & derivatives , Starch/chemistry , Tablets , Viscosity
6.
Eur J Pharm Biopharm ; 111: 1-15, 2017 Feb.
Article in English | MEDLINE | ID: mdl-27845182

ABSTRACT

Implementation of Quality by Design approaches in pharmaceutical industry requires a sound understanding of the parameters triggering final product variability. Excipients, although generally regarded as inert components, are of great significance in terms of solid dosage form development and any variation in the material attributes may impact drug product performance. Sourcing, production and processing are contributing factors to excipient variability. Interchange between different suppliers can lead to final products with different quality attributes. Identification of excipient critical material attributes is not straightforward, as criticality must be linked to functionality and it is well recognized that the mechanisms by which excipients exert their action are not fully understood. Investigating the impact of excipient variability on in vitro dissolution could enable scientists to get an insight on the in vivo behavior of drug products and potentially tolerate variability. A thorough understanding of excipient material properties, product components interactions and the effect of the gastrointestinal tract heterogeneity on excipients and drug release is recommended. This review aims to present current knowledge on excipient critical material attributes and their link to biopharmaceutical behavior and dissolution characteristics. Attempts to describe the impact of physiological conditions on excipient functionality are also addressed. Excipient properties that are considered crucial to drug product performance in a biorelevant perspective are elucidated.


Subject(s)
Chemistry, Pharmaceutical/methods , Drug Design , Excipients/chemistry , Calcium Phosphates/chemistry , Cellulose/chemistry , Dosage Forms , Gastrointestinal Tract/drug effects , Humans , Hydrogen-Ion Concentration , Lactose/chemistry , Materials Testing , Molecular Conformation , Particle Size , Polymers/chemistry , Porosity , Solubility , Technology, Pharmaceutical/methods , Temperature
7.
Child Care Health Dev ; 41(6): 928-37, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26032706

ABSTRACT

BACKGROUND: Many previous studies that have investigated hospital admissions in children and young people with cerebral palsy lack information on cerebral palsy severity and complexity. Consequently, little is known about factors associated with the frequency and type of hospital admissions in this population. This study used hospital admission data available for all children and young people known to a population-based cerebral palsy register to describe the patterns of use of tertiary paediatric hospital services over a 5-year period. METHODS: This was a retrospective cohort analysis of routinely collected admission data from the two tertiary paediatric hospitals in the Australian state of Victoria. Data on admissions of individuals born between 1993 and 2008 registered on the Victorian Cerebral Palsy Register were analysed (n = 2183). RESULTS: Between 2008 and 2012, 53% of the cohort (n = 1160) had at least one same-day admission, and 46% (n = 996) had one or more multi-day admissions. Those with a moderate to severe motor impairment and those with a co-diagnosis of epilepsy had more admissions, and for multi-day admissions, longer lengths of stay, P < 0.05. Across all severity levels, respiratory and musculoskeletal diseases were the most frequently reported reasons for medical and surgical admissions, respectively. All-cause readmission rates for urgent multi-day stays within 7, 30 and 365 days of an index admission were 10%, 23% and 63%, respectively. CONCLUSIONS: The reasons for hospital admissions reported here reflect the range of comorbidities experienced by children and young people with cerebral palsy. This study highlights priority areas for prevention, early diagnosis and medical management in this group. Improved primary and secondary prevention measures may decrease non-elective hospital admissions and readmissions in this group and reduce paediatric inpatient resource use and healthcare expenditure attributable to cerebral palsy.


Subject(s)
Cerebral Palsy/complications , Hospitalization/statistics & numerical data , Hospitals, Pediatric/statistics & numerical data , Adolescent , Cerebral Palsy/epidemiology , Cerebral Palsy/therapy , Child , Child, Preschool , Comorbidity , Humans , Infant , Infant, Newborn , Length of Stay/statistics & numerical data , Patient Admission/statistics & numerical data , Patient Readmission/statistics & numerical data , Registries , Respiration Disorders/epidemiology , Respiration Disorders/etiology , Respiration Disorders/therapy , Retrospective Studies , Victoria/epidemiology , Young Adult
8.
Acta Crystallogr D Biol Crystallogr ; 59(Pt 7): 1320-2, 2003 Jul.
Article in English | MEDLINE | ID: mdl-12832799

ABSTRACT

The gene for the DNA-binding protein Sso10a from the hyperthermophilic archaeon Sulfolobus solfataricus was cloned and overexpressed in Escherichia coli. Crystals of the purified protein have been grown that diffract to beyond 2.15 A resolution. The protein crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 57.24, b = 60.16, c = 69.96 A. With one dimer per asymmetric unit, the crystal to volume per protein mass (V(M)) is 2.9 A(3) Da(-1) and the solvent content is approximately 57%. Complete X-ray diffraction native data were collected from a single crystal and processed to 2.15 A.


Subject(s)
DNA-Binding Proteins/chemistry , Sulfolobus/chemistry , Amino Acid Sequence , Archaeal Proteins/chemistry , Archaeal Proteins/genetics , Archaeal Proteins/isolation & purification , Cloning, Molecular , Crystallization , DNA-Binding Proteins/genetics , DNA-Binding Proteins/isolation & purification , Sequence Alignment , X-Ray Diffraction
9.
Int J Pharm ; 242(1-2): 295-9, 2002 Aug 21.
Article in English | MEDLINE | ID: mdl-12176267

ABSTRACT

Particle size and particle size distribution can have a fundamental effect on the physical properties of colloidal dispersions. For many systems the measurement of average particle size is not sufficient, the presence of different size populations will have a strong influence on properties and could be related to the production process. Hydrodynamic chromatography (HDC) provides a method for the separation of polymers in solution or particles in suspension based on their size. In a packed column, the separation takes place in the inter-particle channels and the elution order is from large to small, analogous to gel permeation chromatography. The dynamic range of packed column HDC is from molecular size up to particles of greater than 1 microm. New instrumentation which can be used to determine the particle size distribution of a range of colloidal dispersions by packed column HDC is described. Data to support accuracy and precision of average particle size determination is presented as well as a number of case studies to illustrate the applicability of the technique to samples with polydisperse or multi-modal particle size distributions.


Subject(s)
Nanotechnology/methods , Chromatography , Colloids , Excipients , Hydrogen-Ion Concentration , Latex , Microspheres , Particle Size , Polystyrenes
11.
Acta Crystallogr D Biol Crystallogr ; 57(Pt 2): 304-5, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11173488

ABSTRACT

Wheat-germ protein L-isoaspartyl O-methyltransferase (WPIMT) can initiate the conversion of L-isoaspartyl residues in a protein or peptide, which accumulate during the aging process in wheat-germ seeds, to normal L-aspartyl groups. The recombinant protein of WPIMT was overexpressed in Escherichia coli and purified to homogeneity. The protein was crystallized in the presence of S-adenosine-L-homocysteine using 2-methyl-2,4-pentanediol. Preliminary X-ray analysis indicated a tetragonal space group P4(1)2(1)2 or P4(3)2(1)2, with unit-cell parameters a = b = 77.3, c = 152.9 A for cryofrozen crystals at 90 K. The crystals diffracted to 3.3 A and contain two molecules per asymmetric unit.


Subject(s)
Protein Methyltransferases/chemistry , Triticum/enzymology , Cloning, Molecular , Crystallization , Crystallography, X-Ray , Escherichia coli , Protein D-Aspartate-L-Isoaspartate Methyltransferase , Protein Methyltransferases/isolation & purification , Recombinant Proteins/chemistry , Recombinant Proteins/isolation & purification , Seeds/enzymology
12.
Acta Crystallogr D Biol Crystallogr ; 57(Pt 1): 134-6, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11134935

ABSTRACT

Glutathione S-transferases (GSTs) belong to a family of detoxification enzymes that conjugate glutathione to various xenobiotics, thus facilitating their expulsion from the cell. GST activity is elevated in many insecticide-resistant insects, including the DDT-resistant malaria vector Anopheles gambiae. Crystals of the recombinant form of a GST from A. gambiae, agGST1-6, have been grown in at least five different crystal forms, with a broad range of diffraction resolution limits. A complete 2.0 A data set has been collected on a C-centered orthorhombic crystal form with unit-cell parameters a = 99.0, b = 199.4, c = 89.6 A. A search for heavy-atom derivatives has been initiated, along with phase-determination efforts by molecular replacement.


Subject(s)
Anopheles/enzymology , DDT , Glutathione Transferase/chemistry , Insecticide Resistance , Animals , Crystallization , Crystallography, X-Ray , Protein Conformation , Recombinant Proteins/chemistry
13.
Acta Crystallogr D Biol Crystallogr ; 55(Pt 9): 1604-5, 1999 Sep.
Article in English | MEDLINE | ID: mdl-10489460

ABSTRACT

Crystals of the restriction endonuclease EcoRII have been obtained by the vapor-diffusion technique in the presence of ammonium sulfate or polyethylene glycol. The best crystals were grown with ammonium sulfate as a precipitant. Crystals with dimensions of up to 0.6 x 0. 6 x 0.6 mm have been observed. The crystals diffract to about 4.0 A resolution at a cryo-temperature of 100 K using a rotating-anode X-ray source and a Rigaku R-AXIS IV imaging-plate detector. The space group has been determined to be either I23 or I2(1)3, with unit-cell parameters a = b = c = 160.3 A, alpha = beta = gamma = 90 degrees. The crystal asymmetric unit contains two protein molecules, and self-rotation function analysis shows a pseudo-twofold symmetry relating the two monomers. Attempts to improve the resolution of crystal diffraction and to search for heavy-atom derivatives are under way.


Subject(s)
Deoxyribonucleases, Type II Site-Specific/chemistry , Ammonium Sulfate , Chemical Precipitation , Crystallization , Diffusion , Molecular Weight , Polyethylene Glycols , Volatilization , X-Ray Diffraction
14.
Planta Med ; 65(8): 747-9, 1999 Dec.
Article in English | MEDLINE | ID: mdl-10630119

ABSTRACT

The crude chloroform bark extract of Piper caninum (Piperaceae) exhibits antibacterial activity against the Gram-positive bacteria, Bacillus cereus, Staphylococcus aureus, and Streptococcus pneumoniae. The antibacterial agents in this extract have been isolated using bioactivity-directed chromatographic techniques and identified by NMR spectroscopy as (+)-bornyl p-coumarate and bornyl caffeate. A single-crystal X-ray structure has been carried out on (+)-bornyl p-coumarate. The compound crystallizes in the orthorhombic space group P2(1)2(1)2(1) (#19) with a = 12.659(4), b = 13.281(4), and c = 10.177(3) A. Fullmatrix least-squares refinement converged at R = 0.047, and Rw = 0.058.


Subject(s)
Anti-Bacterial Agents/chemistry , Coumaric Acids/chemistry , Plants, Medicinal/chemistry , Esters , Models, Molecular , Molecular Structure
15.
J Exp Anal Behav ; 72(1): 97-115, 1999 Jul.
Article in English | MEDLINE | ID: mdl-16812912
16.
Eur J Pharm Sci ; 6(2): 153-63, 1998 Apr.
Article in English | MEDLINE | ID: mdl-9795038

ABSTRACT

The use of biodegradable particles as oral delivery vehicles for macromolecular drugs was investigated. We evaluated the binding, uptake and absorption of poly-dl-lactide (PLA) micro- and nanoparticles in Caco-2 monolayers and in ileal tissue and gut associated lymphoid tissue (GALT) of anaesthetised rats and rabbits. Using a range of experimental techniques, we found that approximately 10% of administered micro- and nanoparticles were adsorbed to the apical membranes of each of the five intestinal models. Nanoparticles were found to be absorbed better than microparticles. Overall, little discrimination in uptake patterns was evident between Peyer's patch (PP) and non-PP tissue while rat ileum showed a greater uptake capacity than rabbit. Our results show that uptake of PLA particles was low capacity, size-dependent and predominantly transcellular in all systems. A low proportion of the apically-bound particles was absorbed, with uptake exclusion evident for particles >4microm. The affinity of PLA particles for intestinal epithelia and GALT needs to be greatly enhanced in order to achieve improved oral bioavailability of macromolecules.


Subject(s)
Ileum/metabolism , Polyesters/metabolism , Animals , Caco-2 Cells , Drug Carriers , Ferritins/analysis , Fluorescein/analysis , Humans , Ileum/ultrastructure , Lymphoid Tissue/metabolism , Microscopy, Confocal , Polyesters/chemistry , Rabbits , Rats , Rats, Wistar
17.
Behav Neurosci ; 110(6): 1487-91, 1996 Dec.
Article in English | MEDLINE | ID: mdl-8986349

ABSTRACT

Homing pigeon breeds, the product of artificial selection on the basis of navigational and spatial ability, differ from nonhoming breeds in hippocampal size and distribution of N-methyl-D-aspartate (NMDA) dependent receptors. The effects of MK-801 (0.1 mg/kg administered intraperitoneally), a noncompetitive NMDA antagonist, on spatial reference memory (RM) were compared between the 2 breeds in a radial arm maze task. MK-801 disrupted the acquisition of RM in the nonhoming group but not the homing group, which was equivalent to the 2 saline-only control groups. As in previous findings with mammals, working memory was not affected by MK-801. This behavioral dissociation, coupled with differences in NMDA-dependent long-term potentiation between breeds, suggests an exceptional opportunity to investigate the role and function of the dorsomedial telencephalon region in spatial RM, through anatomical, neurochemical, and behavioral comparisons between homing and nonhoming pigeon breeds.


Subject(s)
Columbidae/physiology , Dizocilpine Maleate/pharmacology , Maze Learning/drug effects , Memory/drug effects , Spatial Behavior/drug effects , Animals , Dose-Response Relationship, Drug , Hippocampus/chemistry , Hippocampus/drug effects , Long-Term Potentiation/drug effects , Receptors, N-Methyl-D-Aspartate/drug effects , Receptors, N-Methyl-D-Aspartate/physiology , Species Specificity
18.
J Chromatogr A ; 729(1-2): 297-300, 1996 Apr 05.
Article in English | MEDLINE | ID: mdl-9004953

ABSTRACT

A high-performance liquid chromatographic (HPLC) method was developed which involves the use of two 5-microns BDS silica gel columns (15 cm x 4.6 mm I.D.) in series for increased resolution and sensitivity, and an organic mobile phase for both extraction and elution of diltiazem. Plasma samples (400 microliters) were extracted using the organic mobile phase [n-hexane-methanol-dichloromethane-ammonia (370:35:30:0.3)] and the extracts were monitored at 240 nm. Desipramine (30 micrograms ml-1) was the internal standard. The limit of quantification in plasma was 20 ng ml-1 with a correlation coefficient of > or = 0.999 within the 20-800 ng ml-1 standard window. The inter- and intra-assay R.S.D.s were within 5%. The recovery of diltiazem varied from 101.1% at 20 ng ml-1 to 93.7% at 400 ng ml-1. The method was applied to the investigation of diltiazem absorption in a rat. Drug absorption was based on the intestinal single-pass perfusion model. The concentration of diltiazem in all test perfusion solutions was 1 mg ml-1 (2.4 mM) and the flow-rate through the system was 3.33.10(-3) ml s-1. A non-specific mucolytic absorption enhancer was also added to a diltiazem solution and studied in the in situ system. The pharmacokinetics of diltiazem hydrochloride were investigated in two study groups of Wistar rats (n = 4). A two-sample Student's t-test was employed to compare values of the area under the curve (AUC). The pharmacokinetic data indicated that the AUC in the group which received the enhancer [18.12 +/- 5.43 ng ml-1 h-1 (+/- S.D.)] was higher than that in the control group (11.49 +/- 3.67 ng h-1 ml-1), t-test; p = 0.0483. Hence it was shown that administration of an enhancer could increase the oral bioavailability of diltiazem.


Subject(s)
Calcium Channel Blockers/blood , Calcium Channel Blockers/pharmacokinetics , Diltiazem/blood , Diltiazem/pharmacokinetics , Absorption , Animals , Biological Availability , Calibration , Chromatography, High Pressure Liquid , Excipients , Male , Pilot Projects , Rats , Rats, Wistar , Spectrophotometry, Ultraviolet
19.
Psychon Bull Rev ; 3(4): 495-8, 1996 Dec.
Article in English | MEDLINE | ID: mdl-24213983

ABSTRACT

Auditory priming was examined in an implicit memory task, phoneme monitoring, that emphasized surface processing. The contribution of voice to priming was investigated in single- and multiplespeaker environments by repeating studied words at test in either the same voice or different voices. Multiple-speaker environments, which preserved both acoustic and word repetition, eliminated priming when more than two voice changes between words were introduced. When voice familiarity attenuated acoustic variability, priming was reestablished in the condition in which three voices were heard. Voice changes between study and test, which eliminated acoustic repetition, also abolished priming. Word frequency affected reaction times but not priming. This demonstrated that priming entailed subword processing rather than word processing. This study demonstrates that the significance of voice in implicit memory is dependent on the level of processing required by the task and the acoustic environment. Supported in part by an OMRDD Fellowship in the CSI/IBR Center for Developmental Disabilities to M. P., portions of this study were conducted in partial fulfillment of her requirements for the Ph.D. in the Department of Psychology of The City University of New York Graduate School and University Center.

20.
Alcohol Clin Exp Res ; 19(6): 1441-6, 1995 Dec.
Article in English | MEDLINE | ID: mdl-8749808

ABSTRACT

This study investigates the effects of n-6 polyunsaturated fatty acids (PUFAs), in the form of dietary Evening Primrose Oil (EPO) and safflower oil, on the development of tolerance to ethanol. The degree of fluorescence polarization of the fluoroprobes DPH, PROP-DPH, and TMA-DPH in isolated cortical synaptosomal membranes was measured. In addition, the development of tolerance, as shown by changes in synaptosomal membrane fluidity after an acute in vitro ethanol challenge, was also determined after 20 weeks of ethanol administration, either alone or together with a PUFA-enriched diet. Although the administration of EPO-enriched diet did not significantly render the inner core of the cortical synaptosomal membrane tolerant to the acute ethanol challenge, concomitant administration of ethanol and EPO was found to increase further the rigidity and tolerance to the acute ethanol challenge in the inner core. Chronic administration of safflower oil, which lacks gamma-linolenic acid (18:3, n-6) but like EPO contains linoleic acid, either alone or together with chronic ethanol had no effect on synaptosomal membrane fluidity after an acute ethanol challenge. The results suggest that gamma-linolenic acid or its metabolites may have an important role to play in the development of tolerance to chronic ethanol.


Subject(s)
Alcoholism/diet therapy , Dietary Fats, Unsaturated/administration & dosage , Fatty Acids, Essential/administration & dosage , Animals , Brain/drug effects , Drug Tolerance , Linoleic Acids , Male , Membrane Fluidity/drug effects , Oenothera biennis , Plant Oils , Rats , Rats, Sprague-Dawley , Safflower Oil/administration & dosage , Synaptosomes/drug effects , gamma-Linolenic Acid
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