BMC Clinical Pharmacology - Latest Articles

Bioavailability of ibuprofen following oral administration of standard ibuprofen, sodium ibuprofen or ibuprofen acid incorporating poloxamer in healthy volunteers

Peter Dewland — 2009-12-04T00:00:00Z

Background: The aim of this study was to compare the pharmacokinetic properties of sodium ibuprofen and ibuprofen acid incorporating poloxamer with standard ibuprofen acid tablets. Methods: Twenty-two healthy volunteers were enrolled into this randomised, single-dose, 3-way crossover, open-label, single-centre, pharmacokinetic study. After 14 hours' fasting, participants received a single dose of 2 x 200 mg ibuprofen acid tablets (standard ibuprofen), 2 x 256 mg ibuprofen sodium dihydrate tablets (sodium ibuprofen; each equivalent to 200 mg ibuprofen acid) and 2 x 200 mg ibuprofen acid incorporating 60 mg poloxamer 407 (ibuprofen/poloxamer). A washout period of 2-7 days separated consecutive dosing days. On each of the 3 treatment days, blood samples were collected post dose for pharmacokinetic analyses and any adverse events recorded. Plasma concentration of ibuprofen was assessed using a liquid chromatographic-mass spectrometry procedure in negative ion mode. A standard statistical ANOVA model, appropriate for bioequivalence studies, was used and ratios of 90% confidence intervals (CIs) were calculated. Results: Tmax for sodium ibuprofen was less than half that of standard ibuprofen (median 35 min vs 90 min, respectively; P=0.0002) and Cmax was significantly higher (41.47 mug/mL vs 31.88 ug/mL; ratio test/reference = 130.06%, 90% CI 118.86-142.32%). Ibuprofen/poloxamer was bioequivalent to the standard ibuprofen formulation, despite its Tmax being on average 20 minutes shorter than standard ibuprofen (median 75 mins vs 90 mins, respectively; P=0.1913), as the ratio of test/reference = 110.48% (CI 100.96-120.89%), which fell within the 80-125% limit of the CPMP and FDA guidelines for bioequivalence. The overall extent of absorption was similar for the three formulations, which were all well tolerated. Conclusions: In terms of Tmax, ibuprofen formulated as a sodium salt was absorbed twice as quickly as from standard ibuprofen acid. The addition of poloxamer to ibuprofen acid did not significantly affect absorption.

In vivo administration of BL-3050: highly stable engineered PON1-HDL complexes

Leonid Gaidukov — 2009-11-17T00:00:00Z

Background: Serum paraoxonase (PON1) is a high density lipoprotein (HDL)-associated enzyme involved in organophosphate (OP) degradation and prevention of atherosclerosis. PON1 comprises a potential candidate for in vivo therapeutics, as an anti-atherogenic agent, and for detoxification of pesticides and nerve agents. Because human PON1 exhibits limited stability, engineered, recombinant PON1 (rePON1) variants that were designed for higher reactivity, solubility, stability, and bacterial expression, are candidates for treatment. This work addresses the feasibility of in vivo administration of rePON1, and its HDL complex, as a potentially therapeutic agent dubbed BL-3050. Methods: For stability studies we applied different challenges related to the in vivo disfunctionalization of HDL and PON1 and tested for inactivation of PON1's activity. We applied acute, repetitive administrations of BL-3050 in mice to assess its toxicity and adverse immune responses. The in vivo efficacy of recombinant PON1 and BL-3050 were tested with an animal model of chlorpyrifos-oxon poisoning. Results: Inactivation studies show significantly improved in vitro lifespan of the engineered rePON1 relative to human PON1. Significant sequence changes relative to human PON1 might hamper the in vivo applicability of BL-3050 due to adverse immune responses. However, we observed no toxic effects in mice subjected to repetitive administration of BL-3050, suggesting that BL-3050 could be safely used. To further evaluate the activity of BL-3050 in vivo, we applied an animal model that mimics human organophosphate poisoning. In these studies, a significant advantages of rePON1 and BL-3050 (>87.5% survival versus <37.5% in the control groups) was observed. Furthermore, BL-3050 and rePON1 were superior to the conventional treatment of atropine-2-PAM as a prophylactic treatment for OP poisoning. Conclusion: In vitro and in vivo data described here demonstrate the potential advantages of rePON1 and BL-3050 for treatment of OP toxicity and chronic cardiovascular diseases like atherosclerosis. The in vivo data also suggest that rePON1 and BL-3050 are stable and safe, and could be used for acute, and possibly repeated treatments, with no adverse effects.

Safety and Efficacy of Oral DMSA Therapy for Children with Autism Spectrum Disorders: Part B - Behavioral Results

James Adams — 2009-10-23T00:00:00Z

Background: This study investigated the effects of oral dimercapto succinic acid (DMSA) therapy on the behavioural symptoms of children with autism spectrum disorders (ASD) ages 3-8 years. Methods: Phase 1 involved 65 children with ASD who received one round of DMSA (3 days). Participants who had high urinary excretion of toxic metals were selected to continue on to phase 2. In phase 2, 49 participants were randomly assigned in a double-blind design to receive an additional 6 rounds of either DMSA or placebo. Results: The groups receiving one round and seven rounds of DMSA had significant improvements on all the assessment measures. For the seven round group, the degree of improvement on the assessment measures could be partially explained by a regression analysis based on excretion of toxic metals and changes in glutathione (adjusted R2 of 0.28-0.75, p < 0.02 in all cases). One round of DMSA had nearly the same benefit as seven rounds. The assessment measures correlated reasonably with one another at the beginning of the study (r = 0.60-0.87) and even better at the end of the study (r = 0.63-0.94). Conclusion: Overall, both one and seven rounds of DMSA therapy seems to be reasonably safe in children with ASD who have high urinary excretion of toxic metals, and possibly helpful in reducing some of the symptoms of autism in those children.

Safety and Efficacy of Oral DMSA Therapy for Children with Autism Spectrum Disorders: Part A - Medical Results

James Adams — 2009-10-23T00:00:00Z

Background: This study investigated the effect of oral dimercapto succinic acid (DMSA) therapy for children with autism spectrum disorders ages 3-8 years. Methods: Phase 1 involved 65 children who received one round of DMSA (3 days). Participants who had high urinary excretion of toxic metals were selected to continue on to phase 2. In phase 2, 49 participants were randomly assigned in a double-blind design to receive an additional 6 rounds of either DMSA or placebo. Results: DMSA greatly increased the excretion of lead, substantially increased excretion of tin and bismuth, and somewhat increased the excretion of thallium, mercury, antimony, and tungsten. There was some increase in urinary excretion of essential minerals, especially potassium and chromium. The Phase 1 single round of DMSA led to a dramatic normalization of RBC glutathione in almost all cases, and greatly improved abnormal platelet counts, suggesting a significant decrease in inflammation. Conclusion: Overall, DMSA therapy seems to be reasonably safe, effective in removing several toxic metals (especially lead), dramatically effective in normalizing RBC glutathione, and effective in normalizing platelet counts. Only 1 round (3 days) was sufficient to improve glutathione and platelets. Additional rounds increased excretion of toxic metals.

Evaluation of risk factor management of patients treated on an internal nephrology ward: a pilot study.

Gunar Stemer — 2009-09-06T00:00:00Z

Background: The objectives of this pilot study were to evaluate treatment quality for the risk factors of hypertension, diabetes and hyperlipidemia as well as the overall treatment quality for patients on an internal nephrology ward. This evaluation included the collection of data concerning the quality of therapeutic drug monitoring, drug use and potential drug-drug interactions. Establishing such baseline information highlights areas that have a need for further therapeutic intervention and creates a foundation for improving patient care, a subject that could be addressed in future clinical pharmacy research projects. Methods: Medical charts of patients treated on a single internal nephrology ward were retrospectively evaluated using a predefined data collection form. Assessment of further need for therapeutic intervention was performed. Results: For 76.5% (n = 78) of the total study population (n = 102), there was either a possibility (39.2%, n = 40) or a need (37.3%, n = 38) for further intervention based on the overall assessment. For the risk factors of hypertension, diabetes and hyperlipidemia, the proportions of patients that require further intervention were 78.8% (n = 71), 90.6% (n = 58) and 87.9% (n = 58), respectively. Patients with diabetes or hyperlipidemia were less likely to have optimal risk factor control. The number of drugs prescribed and the number of potential drug-drug interactions were significantly higher after in-hospital treatment. Conclusion: Risk factor treatment needs optimisation. Risk factor management, systematic medication reviews, and screening for and management of potential drug-drug interactions deserve great attention. Clinical pharmacy services could help in the achievement of treatment goals.

Perceptions of doctors to adverse drug reaction reporting in a teaching hospital in Lagos, Nigeria

Kazeem Oshikoya — 2009-08-11T00:00:00Z

Background: Spontaneous adverse drug reaction (ADR) reporting is the cornerstone of pharmacovigilance. ADR reporting with Yellow Cards has tremendously improved pharmacovigilance of drugs in many developed countries and its use is advocated by the World Health Organization (WHO). This study was aimed at investigating the knowledge and attitude of doctors in a teaching hospital in Lagos, Nigeria on spontaneous ADR reporting and to suggest possible ways of improving this method of reporting. Methods: A total of 120 doctors working at the Lagos State University Teaching Hospital (LASUTH), in Nigeria were evaluated with a questionnaire for their knowledge and attitudes to ADR reporting. The questionnaire sought the demographics of the doctors, their knowledge and attitudes to ADR reporting, the factors that they perceived may influence ADR reporting, and their levels of education and training on ADR reporting. Provision was also made for suggestions on the possible ways to improve ADR reporting. Results: The response rate was 82.5%. A majority of the respondents (89, 89.9%) considered doctors as the most qualified health professionals to report ADRs. Forty (40.4%) of the respondents knew about the existence of National Pharmacovigilance Centre (NPC) in Nigeria. Thirty-two (32.3%) respondents were aware of the Yellow Card reporting scheme but only two had ever reported ADRs to the NPC. About half (48.5%) of the respondents felt that all serious ADRs could be identified after drug marketing. There was a significant difference between the proportion of respondents who felt that ADR reporting should be either compulsory or voluntary (χ2 = 38.9, P < 0.001). ADR reporting was encouraged if the reaction was serious (77, 77.8%) and unusual (70, 70.7%). Education and training was the most recognised means of improving ADR reporting. Conclusion: The knowledge of ADRs and how to report them are inadequate among doctors working in a teaching hospital in Lagos, Nigeria. More awareness should be created on the Yellow Card reporting scheme. Continuous medical education, training and integration of ADR reporting into the clinical activities of the doctors would likely improve reporting.

A Phase 1 Trial of pharmacologic interactions between transdermal selegiline and a 4-hour cocaine infusion

Debra Harris — 2009-08-01T00:00:00Z

Background: The selective MAO-B inhibitor selegiline has been evaluated in clinical trials as a potential medication for the treatment of cocaine dependence. This study evaluated the safety of and pharmacologic interactions between 7 days of transdermal selegiline dosed with patches (Selegiline Transdermal System, STS) that deliver 6 mg/24 hours and 2.5 mg/kg of cocaine administered over 4 hours. Methods: Twelve nondependent cocaine-experienced subjects received deuterium-labeled cocaine-d5 intravenously (IV) 0.5 mg/kg over 10 minutes followed by 2 mg/kg over 4 hours before and after one week of transdermal selegiline 6 mg/24 hours. Plasma and urine were collected for analysis of selegiline, cocaine, catecholamine and metabolite concentrations. Pharmacodynamic measures were obtained. Results: Selegiline did not change cocaine pharmacokinetic parameters. Selegiline administration increased phenylethylamine (PEA) urinary excretion and decreased urinary MHPG-sulfate concentration after cocaine when compared to cocaine alone. No serious adverse effects occurred with the combination of selegiline and cocaine, and cocaine-induced physiological effects were unchanged after selegiline. Only 1 peak subjective cocaine effects rating changed, and only a few subjective ratings decreased across time after selegiline. Conclusion: No pharmacological interaction occurred between selegiline and a substantial dose of intravenous cocaine, suggesting the combination will be safe in pharmacotherapy trials. Selegiline produced few changes in subjective response to the cocaine challenge perhaps because of some psychoactive neurotransmitters changing in opposite directions.

Effect of buspirone on thermal sensory and pain thresholds in human volunteers

Goran Pavlakovic — 2009-05-29T00:00:00Z

Background: Buspirone is a partial 5-HT1A receptor agonist. Animal studies have shown that modulation of serotoninergic transmission at the 5-HT1A receptor can induce analgesia in acute pain models. However, no studies have been published so far on the effects of serotonin receptor agonists on pain perception in humans. Methods: The effects of buspirone (30 mg p.o.) on thermal sensory and pain thresholds were investigated in twelve female volunteers (26 ± 2 yrs) in a prospective, randomized, double-blind, double-dummy, placebo-controlled study with morphine (10 mg i.v.) as positive control. Results: Morphine significantly increased the heat pain detection threshold (ΔT: placebo 1.0°C and 1.3°C, p < 0.05) at 60 minutes. Buspirone caused mild sedation in six participants at 60 minutes, but was without effect on any of the measured parameters. Conclusion: Buspirone in the maximal recommended dose was without significant effect on thermal pain. However, as it is only a partial agonist at the 5-HT1A receptor and also acts on other receptor types, the negative results of the present study do not rule out a possible analgesic effect of more specific 5-HT1A receptor agonists.

Dispensed drugs and multiple medications in the Swedish population: an individual-based register study

Bo Hovstadius — 2009-05-27T00:00:00Z

Background: Multiple medications is a well-known potential risk factor in terms of patient's health. The aim of the present study was to estimate the prevalence of dispensed drugs and multiple medications in an entire national population, by using individual based data on dispensed drugs. Methods: Analyses of all dispensed out-patient prescriptions in 2006 from the Swedish prescribed drug register. As a cut-off for multiple medications, we applied five or more different drugs dispensed (DP ≥ 5) at Swedish pharmacies for a single individual during a 3-month, a 6-month, and a 12-month study period. For comparison, results were also calculated with certain drug groups excluded. Results: 6.2 million individuals received at least one dispensed drug (DP ≥ 1) during 12 months in 2006 corresponding to a prevalence of 67.4%; 75.6% for females and 59.3% for males. Individuals received on average 4.7 dispensed drugs per individual (median 3, Q1–Q3 2–6); females 5.0 (median 3, Q1–Q3 2–7), males 4.3 (median 3, Q1–Q3 1–6).The prevalence of multiple medications (DP ≥ 5) was 24.4% for the entire population. The prevalence increased with age. For elderly 70–79, 80–89, and 90-years, the prevalence of DP ≥ 5 was 62.4, 75.1, and 77.7% in the respective age groups. 82.8% of all individuals with DP ≥ 1 and 64.9% of all individuals with DP ≥ 5 were < 70 years.Multiple medications was more frequent for females (29.6%) than for males (19.2%). For individuals 10 to 39 years, DP ≥ 5 was twice as common among females compared to males. Sex hormones and modulators of the genital system excluded, reduced the relative risk (RR) for females vs. males for DP ≥ 5 from 1.5 to 1.4.The prevalence of DP ≥ 1 increased from 45.1 to 56.2 and 67.4%, respectively, when the study period was 3, 6, and 12 respectively months and the corresponding prevalence of DP ≥ 5 was 11.3, 17.2, and 24.4% respectively. Conclusion: The prevalence of dispensed drugs and multiple medications were extensive in all age groups and were higher for females than for males. Multiple medications should be regarded as a risk in terms of potential drug-drug interactions and adverse drug reactions in all age groups.

Bioequivalence of HX575 (recombinant human epoetin alfa) and a comparator epoetin alfa after multiple intravenous administrations: an open-label randomised controlled trial

Fritz Sorgel — 2009-05-22T00:00:00Z

Background: HX575 is a human recombinant epoetin alfa that was approved for use in Europe in 2007 under the European Medicines Agency biosimilar approval pathway. Therefore, in order to demonstrate the bioequivalence of HX575 to an existing epoetin alfa, the pharmacokinetic and pharmacodynamic response to steady state circulating concentrations of HX575 and a comparator epoetin alfa were compared following multiple intravenous administrations. Methods: An open, randomised, parallel group study was conducted in 80 healthy adult males. Subjects were randomised to multiple intravenous doses of 100 IU/kg body weight of HX575 or of the comparator epoetin alfa three-times-weekly for four weeks. Serum epoetin concentrations were measured using an enzyme-linked immunosorbent assay and pharmacokinetic parameters for the two treatments were compared. The time course and area under the effect curve ratio of haematological characteristics were used as surrogate parameters for efficacy evaluation. Results: The haematological profiles of both treatments were similar, as determined from their population mean curves and the AUECHb ratio and 90% confidence interval (99.9% [98.5–101.2%]), the primary pharmacodynamic endpoint of this study. The pharmacokinetic parameters after the treatments showed minor differences after single dosing, but not at steady state doses. After multiple doses, HX575 was bioequivalent to the comparator with respect to the rate and extent of exposure of exogenous epoetin (AUCτ ratio and 90% confidence interval: 89.2% [82.5–96.2%]). Study medication was well tolerated with no clinically relevant differences between safety profiles of the treatments. Anti-epoetin antibodies were not detected. Conclusion: HX575 and the comparator epoetin alfa were bioequivalent at steady state circulating drug concentrations with respect to their pharmacokinetic profile and pharmacodynamic action. This supports the conclusion that HX575 and the comparator epoetin alfa, when administered intraveneously, will be equally efficacious and may be interchangeable as therapy.