ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1989.tb03400.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1989.tb03401.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1989.tb03402.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Drug delivery systems, offering controlled delivery of biologically active agents, are rapidly gaining importance in pharmaceutical research and development. To achieve controlled drug delivery, i.e., the administration of drugs so that optimal amount reaches the target site to cure or control the disease state, increasingly sophisticated systems containing different carriers have been developed. Macromolecules represent one of the carriers involved, and they have taken on a significantly prominent role in various modes of administration of therapeutic agents. Among macromolecules, for example, synthetic copolymers, polysaccharides, liposomes, polyanions and antibodies, as drug carriers, liposomes have proved most effective for diseases affecting the reticuloendothelial system and blood cells in particular.Liposomes, which are vesicles consisting of one or more concentrically ordered assemblies of phospholipids bilayers, range in size from a nanometer to several micrometers. Phospholipids such as egg phosphatidylcholine, phosphatidylserine, synthetic dipalmitoyl‐DL‐α‐phosphatidylcholine or phosphatidylinositol, have been used in conjunction with cholesterol and positively or negatively charged amphiphiles such as stearylamine or phosphatide acid. Alteration of surface charge has been shown to enhance drug incorporation and also influence drug release. Because of the multifold characteristics as drug carriers, liposomes have been investigated extensively as carriers of anticancer agents for the past several years. Liposomal entrapments include a variety of pharmacologically active compounds such as antimalarial, antiviral, anti‐inflammatory and antifungal agents as well as antibiotics, prostaglandins, steroids and bronchodilators to name a few. The liposomal entrapment has been shown to have considerable effect on the pharmacokinetics and tissue distribution of administered drugs.Despite the potential value of liposomes as unique carriers, the major obstacles are the first order targeting of a systemically given liposomes, physical stability and manufacture of the liposomal products and these problems still remain to be overcome. Drug delivery systems evolving in the 1980s have become increasingly dependent on fundamental cell‐biology and receptor‐mediated endocytotic mechanisms. Drug delivery systems during the 1990s may take advantage of the specificity of receptor‐mediated uptake mechanisms as well as polymer chemistry and cell‐biology in order to introduce more precise and efficient target‐specific delivery systems that are based especially on the l

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1989.tb03403.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The need for clinical pharmacology in research and education, drug development, and health care delivery is well known. However, a current profile of those working in the field is not available. The ACCP authorized a survey of clinical pharmacologists to provide such a profile. Members of the ACCP or ASCPT were solicited by mail with a self‐assessment questionnaire. A response rate of 37% was obtained. Demographic findings agree well with a previous study2limited to those with the M.D. Our results reveal that most clinical pharmacologists are between 30–59 years of age, have an MD, PhD or PharmD degree; most of those with MDs list their primary specialty as internal medicine, pediatrics, psychiatry, or anesthesiology. They affiliate with the respective departments (including pharmacology) in academia or hold positions in industry or government, but few are in clinical therapeutics per se. About 20% of those with only a MD or PharmD degree cite employment in health care delivery. However, a higher percentage of these respondents work in research and education rather than in drug development or health care delivery. For those with only a PhD, more work in drug development and research and education than in health care delivery. The highest proportion of respondents with any doctoral degree work in the Northeast. The average income is a function of rank, doctoral degree, specialty, department appointment, and type and location of employer. The profile of a typical clinical pharmacologist is presented. An analysis of clinical pharmacology manpower from several perspectives reveals a marked deficit, but the field itself is professionally and economically attractive. Lack of a well defined career track in academia and a poorly defined clinical role for MD clinical pharmacologists are proposed as reasons limiting entry of trainees. These and other results of the survey support an increased emphasis on training programs. Clinical pharmacologist involvement in health care delivery and drug development must be increased if the safe and effective use of new drugs is to be realized. Nine assessments and initiatives are formulated to accomplish this goal within the next dec

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1989.tb03404.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

We investigated whether the effect of nisoldipine on liver blood flow depends on its route of administration. Ten healthy subjects took nisoldipine I.V. (infusion) and orally (without and with sotalol pretreatment). Pharmacokinetics of nisoldipine was assessed and liver blood flow (ICG clearance) was measured before dosing and at the end of the infusion or during absorption. During I.V. infusion the ICG plasma clearance increased by only 14%, whereas the increase was 60% during absorption of nisoldipine. Nisoldipine increases liver blood flow considerably only during the absorption phase. A positive correlation was found between the increase in liver blood flow during absorption and the systemic availability of nisoldipine, suggesting that the differences in liver blood flow response to nisoldipine substantially contribute to the variability in pharmacokinetics of the drug.

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1989.tb03405.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

This study addresses the effect of the three major classes of antianginal agents on asymptomatic myocardial ischemia in patients with chronic stable angina pectoris. The authors found that each class (given as monotherapy) resulted in a 50% reduction in asymptomatic ischemia (both in the number of episodes and the ST product). Dual therapy resulted in an overall four fold reduction compared to placebo. Therapy also resulted in a beneficial alteration in the frequency distribution of asymptomatic ischemia. Stratification into three age groups demonstrated an equal prevalence of asymptomatic ischemia in each. All ages had nearly equivalent reductions in asymptomatic ischemia by monotherapy and dual therapy, but the youngest age group seemingly responded better to monotherapy than did the oldest age group.

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1989.tb03406.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

In a randomized cross‐over study the effect of verapamil on the pharmacokinetics of theophylline was evaluated in eight cigarette smoking male volunteers. Theophylline was administered as an intravenous infusion of aminophylline, 6 mg/kg based on ideal body weight, over 30 minutes in the control phase. In the treatment phase, aminophylline was administered after a four day regimen of oral verapamil 80 mg every 8 hours. Serial blood samples were collected over a 24 hour period following aminophylline administration. Theophylline serum concentrations were determined by a fluorescence polarization immunoassay, the Abbott TDxR. Theophylline clearance decreased by 11.5%, from a mean (±SD) of 1.39 ± 0.38 mL/min/kg in the control phase to 1.23 ± 0.21 mL/min/kg with the co‐administration of verapamil (P= 0.104). Theophylline elimination rate constant decreased by approximately 9.4% from 0.171 ± 0.032 to 0.155 + 0.023 hr−1during the treatment phase (P= 0.085). The area under the curve (AUC0‐∞) and volume of distribution at steady‐state (Vss) for theophylline were also not statistically different between the two study phases. These results are inconsistent with those of other investigators and the relevance of a potential theophylline‐verapamil drug interactio

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1989.tb03407.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The relationship between variations in small bowel transit time (SBTT) and the absorption of theophylline from a sustained‐release product was evaluated in a three‐way, randomized, crossover study in 12 healthy male nonsmokers. Subjects received sustained‐release theophylline (600 mg) with loperamide (8 mg every 6 hour × 8 doses), metoclopramide (15 mg every 6 hour × 8 doses) or placebo (every 6 hour × 8 doses). Theophylline solution (400 mg) was used as a reference standard. Serum samples were collected periodically for 72 hours for theophylline concentration determinations. SBTT was measured by the lactulose hydrogen breath test. Compared with placebo (98 ± 53 min), SBTT was increased with loperamide (211 ± 87 min; P<0.001) and decreased with metoclopramide (55 ± 18 min; P<0.001). Loperamide decreased the rate, but not the extent of theophylline absorption from this product. This was evident from the reduced Cmax, the prolonged Tmax, and the decreased fraction of the dose absorbed at 24 hours, while the area under the curves remained the same. In contrast, metoclopramide had no effect either on rate or extent of absorption. The data suggest that the effect of loperamide on these absorption parameters was due to an increase in the dissolution time of this sustained‐re

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1989.tb03408.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Droxicam is a new nonsteroidal anti‐inflammatory drug that is a pro‐drug of piroxicam. The influence of gastric emptying rate on droxicam pharmacokinetics has been investigated in eight healthy male volunteers. A single, 20 mg dose was administered p.o. together with 1500 mg of paracetamol. Gastric transit was experimentally modified by administration of propantheline (45 mg, p.o.) or metoclopramide (10 mg, i.v.) simultaneously with the droxicam and the paracetamol. Plasma levels of paracetamol were used as markers of gastric transit. The plasma concentrations of piroxicam, the active substance from droxicam, were determined by a high‐performance liquid chromatographic method. The pharmacokinetic parameters of droxicam were: Cmax= 1.03 ± 0.16 μg/mL (mean ± SD), Tmax= 11.1 ± 5.7 hr, AUC = 115.7 ± 29.6 μg hr/mL, T1/2a = 2.64 ± 0.72 hr, T1/2el = 73.6 ± 16.7 hr, CL/F = 3.06 ± 0.80 mL/min and MRT = 111.1 ± 23.5 hr. Following modification of gastric emptying, only Tmax(droxicam + metoclopramide = 25.0 ± 10.8 hr and droxicam + propantheline = 20.8 ± 8.8 hr) underwent significant change (P<0.05). These results indicate that absorption rate of droxicam has been modified but bioavailability does not suffer modification in conditions of altered

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1989.tb03409.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY