BMC Clinical Pharmacology最新文献

Background: AVI-014 is an egg white-derived, recombinant, human granulocyte colony-stimulating factor (G-CSF). This healthy volunteer study is the first human investigation of AVI-014.

Methods: 24 male and female subjects received a single subcutaneous injection of AVI-014 at 4 or 8 mcg/kg. 16 control subjects received 4 or 8 mcg/kg of filgrastim (Neupogen, Amgen) in a partially blinded, parallel fashion.

Results: The Geometric Mean Ratio (GMR) (90% CI) of 4 mcg/kg AVI-014/filgrastim AUC(0-72 hr) was 1.00 (0.76, 1.31) and Cmax was 0.86 (0.66, 1.13). At the 8 mcg/kg dose, the AUC(0-72) GMR was 0.89 (0.69, 1.14) and Cmax was 0.76 (0.58, 0.98). A priori pharmacokinetic bioequivalence was defined as the 90% CI of the GMR bounded by 0.8-1.25. Both the white blood cell and absolute neutrophil count area under the % increase curve AUC(0-9 days) and Cmax (maximal % increase from baseline)GMR at 4 and 8 mcg/kg fell within the 0.5-2.0 a priori bound set for pharmacodynamic bioequivalence. The CD 34+ % increase curve AUC(0-9 days) and Cmax GMR for both doses was approximately 1, but 90% confidence intervals were large due to inherent variance, and this measure did not meet pharmacodynamic bioequivalence. AVI-014 demonstrated a side effect profile similar to that of filgrastim.

Conclusion: AVI-014 has safety, pharmacokinetic, and pharmacodynamic properties comparable to filgrastim at an equal dose in healthy volunteers. These findings support further investigation in AVI-014.

Background: Demonstration of equivalent amounts of the same active pharmaceutical ingredient (API) between generic and innovator products (pharmaceutical equivalence) is a basic requirement of regulatory agencies for intravenous generic drugs prior to clinical use, and constitutes the pivotal point to assume therapeutic equivalence. Physicochemical methods are preferred instead of biological assays to determine concentration of drugs in biological fluids, but it does not permit direct quantification of potency. Here, we report a microbiological assay using large plates designed to determine potency and concentration of pharmaceutical-grade antibiotics for injection and a statistical method to assess the in vitro equivalence of generic products with respect to the innovator.

Methods: The assay is based on the concentration-dependent variation of the inhibitory effect of antibiotics on reference bacteria (B. subtilis ATCC 6633, S. aureus ATCC 6538p and S. epidermidis ATCC 12228) in a seeded agar (Difco Antibiotic Media), producing a concentration-response linear relationship with two parameters: y-intercept (concentration) and slope (potency). We compared the parameters of 22 generic products (amikacin 4, gentamicin 15, and vancomycin 3 products) against the innovator and the reference powder by Overall Test for Coincidence of the Regression Lines (Graphpad Prism 5.0).

Results: The validation method yielded excellent results for linearity (r(2) > or = 0.98), precision (intra-assay variation < or = 11%; inter-assay variation < or = 10%), accuracy, and specificity tests according to international pharmacopoeial requirements. Except for one generic of vancomycin that had 25% more API (P(y-intercept) = 0.001), the pharmaceutical equivalence was demonstrated in 21 generics with undistinguishable slopes and intercepts (P > 0.66). Potency estimates were 99.8 to 100.5, 99.7 to 100.2 and 98.5 to 99.9% for generic products of amikacin, gentamicin and vancomycin, respectively.

Conclusion: The proposed method allows rapid, cost-saving, precise, and accurate determination of pharmaceutical equivalence of drugs in pharmaceutical dosage-form, and may be used as a technique for testing generic antibiotics prior to their approval for human use.

Background: Bone resorption displays marked diurnal variation. Reversible inhibition of bone resorption may result in best possible efficacy when bone resorption peaks. The aim of the study was to assess the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of 0.8 mg of oral salmon calcitonin (sCT) and the effect of timing of drug intake.

Methods: The study was a randomized, double-blind, double-dummy, placebo-controlled, phase I study to assess the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of 0.8 mg of oral sCT in healthy postmenopausal women. Totally 81 subjects were included, aimed at investigation of a morning dose given at 8:00 (n = 42), a pre-dinner dose given at 17:00 (n = 20), and an evening dose given at 22:00 (n = 19). Plasma sCT concentrations and bone resorption (C-terminal-telopeptide of collagen type I (CTX-I)) was assessed.

Results: Morning and pre-dinner dosing led to comparable concentration of sCT of 45 pg/ml, whereas there was a tendency towards lower Cmax for the evening dosing having a mean of 24 pg/ml. The maximum difference from placebo was observed 1 to 3 hours post-dose with a 40 to 50% suppression consequent to morning dose, and about 75% suppression after pre-dinner and evening dose, due to the increase bone resorption as a result of circadian variation.

Conclusion: The study suggests that orally administered 0.8 mg of salmon calcitonin was effective in suppression of serum CTX irrespective of time of dosing. The pre-dinner dosing resulted in optimum efficacy response corresponding to an overall suppression of bone resorption by 25%.

Background: Prior studies suggested low density lipoprotein particle (LDLP) size is a predictor of atherosclerosis. Knowledge of effects of lipid lowering drugs on lipoprotein subclasses is useful. We treated subjects with hyperlipidemia sequentially with statins and fibrates, the 2 main classes of lipid lowering therapy and studied changes in NMR lipoprotein subclasses.

Methods: 35 subjects (21 males; 60 +/- 12 y) were enrolled in a crossover study. Subjects had baseline lipid profile & apoB. Lipoprotein subclasses, particle numbers and diameters were assessed with NMR spectroscopy. Subjects were randomized to simvastatin 20 mg or fenofibrate 200 mg. Repeat testing was done at 12 weeks. After 6 week washout, subjects were started on alternate drug for 12 weeks with pre/post tests.

Results: Both therapies resulted in expected changes in lipids and apoB. Decreases in total cholesterol, LDL and apoB were greater with simvastatin. Fenofibrate led to small increase in HDL. Both therapies decreased LDLP. Reduction in LDLP was greater with simvastatin (32%, p < .001) compared to fenofibrate (17%; p = .036 vs pre; p = .027 vs simvastatin end). Fenofibrate resulted in 17% rise in large LDLP (p = .06 vs pre) and 32% drop in small LDLP (p = .007 vs pre). Simvastatin led to decrease in both LDLP fractions (19% large LDLP; p = .001 vs fenofibrate end; 34% small LDLP, p = .019 vs pre). With fenofibrate, LDLP size increased from 20.4 nm to 20.8 nm (p = .037). There was no change in LDLP size with simvastatin. There was 18% increase in HDL particle number (HDLP) with fenofibrate (p = .05). There were no changes in HDLP with simvastatin. There were no changes in HDLP size with either drug. Pre- and post-therapy LDLP/HDLP ratio was similar with fenofibrate but was reduced by simvastatin (p = .045).

Conclusion: Simvastatin reduced LDLP across all subclasses with no effect on size. Simvastatin had no effect on HDLP. Fenofibrate had weak effect on LDLP number but increased LDLP size by raising large LDLP and reducing small LDLP. Fenofibrate had weak effect on HDLP number with no change in size. Importantly, net atherogenic to antiatherogenic lipoprotein ratio (LDLP/HDLP) was reduced by simvastatin but not by fenofibrate.

Background: Prescribing errors are common in hospital settings. Regular review of medication charts is recommended as a way to reduce errors but it is not clear how often this happens. The aim of this study was to determine the frequency with which specialist physicians reviewed medication charts during ward rounds.

Methods: An observer noted how often consultant physicians at Auckland City Hospital reviewed medication charts during ward rounds. The physicians were not aware that they were being observed.

Results: Twenty-one physicians were observed over a 26 week period. The general physicians reviewed the medication charts on 77% of occasions (range: 45% - 100%) during routine ward rounds and 65% of the time (range: 41% - 80%) on post admission rounds. Subspecialty physicians who did not see more than 8 patients on their rounds reviewed medication charts more frequently (88%) than those specialties where more than 8 patients were seen on average (61%).

Conclusion: The physicians did not review medication charts on all ward rounds and there was considerable variation in how often they did this. There is some evidence that the frequency with which charts are reviewed decreases as the number of patients seen increases. More efforts should be made to encourage regular review of medication charts.

Background: In the region of Västra Götaland in Sweden, prescribing guidelines, drawn up by 24 expert groups and determined by the regional board for drugs, are since 2006 available in the form of an annually published booklet. This study investigates, for the first time, the use of and attitudes towards this publication.

Methods: A questionnaire was administered to doctors working in primary health care in the region of Västra Götaland in Sweden. Questions included characteristics of the responding doctor and use of the prescribing guidelines booklet, as well as attitude questions constructed as statements to which the responder should grade his level of agreement from 1 (total disagreement) to 6 (total agreement).

Results: Totally 603 filled-in questionnaires were returned (estimated response rate 60%). The majority of the doctors (n = 571, 97%) responded that they use the prescribing guidelines booklet, and when prescribing a drug for a new diagnosis, a drug from the booklet is chosen in most cases [median (25th - 75th percentile) 80 (75-90)]. However, at renewal of a drug prescription, active change to a drug from the prescribing guidelines booklet occurs less often [median (25th - 75th percentile) 50 (20-70)]. The booklet also includes short therapy advice sections, which 231 doctors (42%) use every day and 191 (34%) use every week. The attitudes towards the prescribing guidelines booklet were generally positive. Doctors in privately run primary health care units and doctors running their own business were generally more negative and judged themselves to be less adherent to the prescribing guidelines booklet compared with doctors in publicly run primary health care units.

Conclusion: The prescribing guidelines booklet is frequently used and is generally appreciated, though differences exist between subgroups of users.

Background: The aim of this study was to evaluate long-term platinum retention in patients treated with cisplatin and oxaliplatin.

Methods: 45 patients, treated 8-75 months before participating in this study, were included. Platinum levels in plasma and plasma ultrafiltrate (pUF) were determined. In addition, the reactivity of platinum species in pUF was evaluated. Relationships between platinum retention and possible determinants were evaluated.

Results: Platinum plasma concentrations ranged between 142-2.99 x 10(3) ng/L. Up to 24% of plasma platinum was recovered in pUF. No platinum-DNA adducts in peripheral blood mononuclear cells (PBMCs) could be detected. Ex vivo incubation of DNA with pUF of patients revealed that up to 10% of the reactivity of platinum species was retained. Protein binding proceeded during sample storage. Sodium thiosulfate (STS) appeared to release platinum from the plasma proteins. Platinum levels were related to time, dose, STS co-administration, and glomerular filtration rates (GFR).

Conclusion: Our data suggest that plasma platinum levels are related to time, age, dose, GFR, and STS use. Platinum in plasma, probably, represent platinum eliminated from regenerating tissue. Platinum species in pUF were partly present in a reactive form. The effects of the reactivity on long-term consequences of Pt-containing chemotherapy, however, remains to be established.

Background: There is a scarcity of studies addressing the factors associated with impaired fasting glucose in Chinese patients with uncomplicated hypertension. We included 1,218 patients newly prescribed a single antihypertensive drug in the public primary healthcare setting in Hong Kong, where their fasting glucose levels were measured 6-7 weeks after the first-ever antihypertensive prescription.

Methods: The odds ratios of having above borderline (> or = 6.1 mmol/l) and adverse (> or = 7.0 mmol/l) glucose levels, respectively, were studied according to patient age, gender, socioeconomic status, clinic types and antihypertensive drug classes by multivariable regression analyses.

Results: The fasting glucose levels were statistically similar (p = 0.786) among patients prescribed thiazide diuretics (5.48 mmol/l, 95%, 5.38, 5.59), calcium channel blockers (5.46 mmol/l, 95% C.I. 5.37, 5.54), beta-blockers (5.42 mmol/l, 95% C.I. 5.34, 5.51) and drugs acting on the renin angiotensin system (RAS) [5.41 mmol/l, 95% C.I. 5.20, 5.61]. Multivariate analyses reported no significant associations between antihypertensive drug class and impaired fasting glucose. Elderly patients and male gender were significantly more likely to present with above borderline and adverse readings respectively.

Conclusion: Clinicians should be aware of the increased risk of impaired fasting glucose in these groups, and use of thiazides should not in itself deter its use as a first-line antihypertensive agent among ethnic Chinese patients.

Background: To investigate the influence of water intake and dose timing on the pharmacokinetic and pharmacodynamic parameters of an oral formulation of salmon calcitonin (sCT).

Methods: The study was a randomized, partially-blind, placebo-controlled, single dose, exploratory crossover phase I study. 56 healthy postmenopausal women were randomly assigned to receive five treatments. The treatments comprised a combination of study medication (SMC021 (0.8 mg sCT + 200 mg 5-CNAC), SMC021 placebo, or 200 IU Miacalcic NS nasal spray), water volume given with the tablet (50 or 200 ml water), and time between dosing and meal (10, 30, or 60 minutes pre-meal). Plasma sCT levels and changes in the bone resorption (C-terminal telopeptide of collagen type I) was investigated. Trial regristration.

Results: Oral delivery of 0.8 mg of sCT with 50 ml of water compared to that with 200 ml water resulted in a two-fold increase in maximum concentration (Cmax and AUC0-4) of plasma sCT but comparable time to reach maximum concentration (Tmax). The sCT AUC0-4 with 50 ml of water was 4-fold higher than that obtained with nasal calcitonin. The increased absorption of sCT resulted in increased efficacy demonstrated by AUC of the relative change of serum CTX-I measured in the 6 hours post dosing.

Conclusion: 0.8 mg sCT with 50 ml of water taken 30 and 60 minutes prior to meal time resulted in optimal pharmacodynamic and pharmacokinetic parameters. The data suggest that this novel oral formulation may have improved absorption and reduction of bone resorption compared to that of the nasal form.

Background: We studied the pharmacology of l-methamphetamine, the less abused isomer, when used as a nasal decongestant.

Methods: 12 subjects self-administered l-methamphetamine from a nonprescription inhaler at the recommended dose (16 inhalations over 6 hours) then at 2 and 4 (32 and 64 inhalations) times this dose. In a separate session intravenous phenylephrine (200 microg) and l-methamphetamine (5 mg) were given to define alpha agonist pharmacology and bioavailability. Physiological, cardiovascular, pharmacokinetic, and subjective effects were measured.

Results: Plasma l-methamphetamine levels were often below the level of quantification so bioavailability was estimated by comparing urinary excretion of the intravenous and inhaled doses, yielding delivered dose estimates of 74.0 +/- 56.1, 124.7 +/- 106.6, and 268.1 +/- 220.5 microg for ascending exposures (mean 4.2 +/- 3.3 microg/inhalation). Physiological changes were minimal and not dose-dependent. Small decreases in stroke volume and cardiac output suggesting mild cardiodepression were seen.

Conclusion: Inhaled l-methamphetamine delivered from a non-prescription product produced minimal effects but may be a cardiodepressant.