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I Burnett

Publications and source records attributed to I Burnett.

9 recordsLinked to original sources
PubMed2006

A pharmacokinetic study investigating the rate of absorption of a 500 mg dose of a rapidly absorbed paracetamol tablet and a standard paracetamol tablet.

OBJECTIVE: A rapidly absorbed tablet formulation of paracetamol containing sodium bicarbonate (PS) has been previously shown to be absorbed at least twice as fast as a standard paracetamol tablet (P) at a 1 g dose. In South America and Asia it is customary for patients to take a 500 mg dose of analgesic. The objective of this pharmacokinetic study was to compare the rate of absorption of PS versus P at a 500 mg dose. RESEARCH DESIGN AND METHODS: An open, randomized, single dose, cross-over study. Thirty Hispanic healthy volunteers randomly received a 500 mg dose taken orally with 50 mL of water 2 h after a standard breakfast. Blood samples were taken up to 10 h post-dose. Plasma concentrations of paracetamol were determined by HPLC with UV detection. MAIN OUTCOME MEASURES: AUC(0-30 min), C(plasma 30 min) and T(max) were analyzed non-parametrically by the Wilcoxon's rank sum test. A linear mixed effects model was used to analyze the logarithmically transformed AUC(0-alpha) and C(max). Bioequivalence was accepted if the 90% confidence intervals (CI) for the ratio of the means of the primary pharmacokinetic variable AUC(0-alpha) lay completely within the range 0.80-1.25. RESULTS: AUC(0-30 min) and C(plasma 30 min) were significantly greater and T(max) was significantly shorter (all p < 0.0001) for PS versus P. The formulations were bioequivalent for AUC(0-alpha) (90% CI 0.99:1.05) and no statistical difference was seen for C(max) (95% CI 0.91:1.14). CONCLUSIONS: Paracetamol was absorbed at least twice as fast from PS compared to P at a 500 mg dose. The extent of absorption was equivalent for both formulations.

Absorption↗
PubMed2002

Analgesic efficacy of sustained release paracetamol in patients with osteoarthritis of the knee.

AIMS: Paracetamol is widely recommended as the initial treatment for pain associated with osteoarthritis (OA). A sustained release (SR) paracetamol formulation (Panadol Extend) was compared with standard immediate release (IR) paracetamol (Panadol) in patients with knee pain secondary to OA. The primary parameter for assessment of efficacy was patient-assessed global pain relief as determined on day 8 of the treatment period. METHODS: A double-blind, double-dummy, randomized study was conducted. Patients (n=403) were treated for 7 days with paracetamol 4 g day(-1) (SR paracetamol, two 665 mg tablets taken three times daily; IR paracetamol, two 500 mg tablets taken four times daily). Patients completed daily pain measurements and assessed global pain relief at the end of the study. Therapeutic noninferiority was defined on the basis of achieving statistical noninferiority for global pain relief. RESULTS: Analysis of the primary parameter for the intention to treat population showed that the difference in proportion of patients (SR-IR paracetamol) achieving a successful response on day 8 was -0.7%; 90% CI (-8.82%, 7.45%), P=0.890. For the per protocol population the difference in proportion was -3.0%; 90% CI (-11.61%, 5.66%), P=0.571. As the lower bound of the 90% CI for the treatment difference in each case was greater than the prespecified value (-15%), SR paracetamol was considered to be statistically noninferior to IR paracetamol in terms of pain relief. The treatments were not significantly different for any of the secondary parameters in either populations. CONCLUSIONS: SR paracetamol taken three times daily was statistically and therapeutically noninferior to IR paracetamol taken four times daily in patients with knee pain due to OA. SR paracetamol may be more convenient for patients with chronic pain and has the potential to enhance compliance and therefore pain relief.

Acetaminophen↗
PubMed2002

A new rapidly absorbed paracetamol tablet containing sodium bicarbonate. I. A four-way crossover study to compare the concentration-time profile of paracetamol from the new paracetamol/sodium bicarbonate tablet and a conventional paracetamol tablet in fed and fasted volunteers.

The primary objective of this four-way crossover study was to compare the concentration-time profile of paracetamol from a new rapidly absorbed paracetamol tablet containing sodium bicarbonate (PS) with a conventional paracetamol tablet (P), in a panel of 28 fed and fasted healthy volunteers. The results demonstrated that paracetamol was absorbed more rapidly from tablets containing sodium bicarbonate compared to conventional tablets, as indicated by a shorter tmax in both the fed and fasted state and a higher Cmax in the fasted state. The two formulations were bioequivalent with respect to area under curve (AUC). Food did not affect the extent of absorption from either formulation, as indicated by AUC, however, food did reduce the rate of absorption from both formulations, as indicated by a longer tmax and a lower Cmax. Metabolic activation of paracetamol to its oxidation metabolites, as assessed by combined partial clearances to subsequent secondary metabolites cysteine and mercapturic acid conjugates, indicated that the two formulations were bioequivalent in this respect.

Acetaminophen↗
PubMed1998

Evaluation of an electronic hand-held spirometer in patients with asthma.

In this pilot study we assessed patient compliance and acceptability of data recorded in the home environment by asthmatics using a Vitalograph 2110 spirometer which measures peak expiratory flow rate (PEFR) and forced expiratory volume in 1 s (FEV1). This meter automatically time and date stamps all measurements and can also assess the technical acceptability of results. Data are uploaded to a personal computer for review and analysis. We recruited 30 patients (10 male and 20 female, age range 21-72 years) from the chest clinic at Guy's Hospital (n = 20) and from a GP clinic (n = 10). Patients were asked to record spirometry data using the meter at set times (8.00 a.m. and 8.00 p.m.) for 2 weeks. The spirometer incorporated an alarm to remind patients to take measurements. All patients completed the study. Mean (SD) compliance with spirometer use was 100.8% (49.9%). Nineteen patients had a compliance rate of between 80% and 120% of expected use. Timing of recordings was compared with the scheduled times of 8.00 a.m. and 8.00 p.m. Values recorded with +/- 2 h were judged as acceptable. For morning recordings 67.4% of all values and for evening recordings 71.7% of all values met this criterion. Technical acceptability of spirometry data was also assessed by using quality assurance criteria recorded by the spirometer. Valid tests were performed for 75.2% of all recordings. Twenty-two patients performed valid tests for 80-100% of the time. We suggest that the use of an electronic meter in the home environment is practical and is likely to generate more accurate and reliable data.

Adult↗
PubMed1993

Immune response of human volunteers and animals to vaccination with egg-grown influenza A (H1N1) virus is influenced by three amino acid substitutions in the haemagglutinin molecule.

Inactivated subunit vaccines were prepared from high-growth reassortants derived from two separate egg isolates from a single clinical specimen of influenza A (H1N1) virus. One of these reassortants, NIB-14, was antigenically indistinguishable from isolates made in tissue culture, while the other, NIB-17, was antigenically different and typical of egg isolates. The viruses differed by three amino acid residues in the haemagglutinin (HA) molecule and the anti-HA serological response induced was studied in animal models and human volunteers. In the volunteer groups both vaccines induced very high levels of circulating haemagglutination inhibition antibodies but with different serological specificities. Both NIB-14 and NIB-17 vaccines induced high levels of cross-reactive antibodies capable of reacting with both strains, but only NIB-14 vaccine induced significant levels of strain-specific antibodies capable of reacting exclusively with the homologous strain. Antisera containing only cross-reactive antibodies proved as capable of virus neutralization as antisera containing high levels of strain-specific antibodies. We extended the argument that epidemic strains are antigenically more closely related to tissue culture isolates and established that viruses which differ by only single amino acids at critical points in the HA structure can induce a significantly different immune response when used as inactivated vaccines.

Adolescent↗