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Notes: Abstract Objective: To assess the cardiovascular and metabolic responses to increasing doses of formoterol administered from a dry powder inhaler. Methods: Twenty patients with mild to moderate asthma were given 12, 24, 48 and 96 μg of formoterol or a matched placebo on separate days. The doses were administered using a randomised, cross-over, double-blind design. The effects on heart rate, blood pressure, electromechanical systole (QS2I), the electrocardiographic QTc interval, plasma potassium (K); blood glucose and FEV1 were assessed prior to, and for 9 h following each dose. Results: There was no difference between the maximum effects of formoterol 12 μg and placebo; the 24 μg dose significantly decreased plasma K (−0.2 mmol · l−1) and increased blood glucose (1.8 mmol · l−1) compared to placebo. The two highest doses affected most of the variables with the 96 μg dose being significantly different from placebo for all indices, heart rate (9 beats · min−1), systol BP (4 mmHg), diastolic BP (−3 mmHg), QS2I (−11 ms), QTc (17 ms), plasma K (−0.5 mmol · l−1) and blood glucose (2.6 mmol · l−1). All doses of formoterol increased FEV1. Conclusion: Although there were dose-dependent effects on the extrapulmonary measurements, only the effects at the highest dose may be of clinical significance.

Notes: Abstract Objective: The pharmacokinetics of the long-acting β2-agonist formoterol fumarate, which is a racemate of the (S,S)- and (R,R)-enantiomers were evaluated in 12 healthy (eight male, four female) volunteers after a single inhaled high dose of 120 μg of formoterol fumarate. The tolerability and safety were also assessed. Methods: Each volunteer inhaled the single 120-μg dose through the Aerolizer device within 2–5 min, using ten 12-μg dry powder capsules for inhalation. Formoterol, i.e., the sum of both enantiomers, was determined in plasma over 24 h, whereas the separate enantiomers were determined in urine over 48 h. Incidence, seriousness and severity of adverse experiences, electrocardiogram (ECG), including the corrected QT interval (QTc) calculation, systolic blood pressure, heart rate, and plasma potassium levels were recorded. Results: In nine of the 12 volunteers, the peak plasma concentration of formoterol was observed already at 5 min after inhalation. The absorption kinetics were complex, as depicted by multiple peaks or shoulders within 0.5–6 h after inhalation. Mean with (SD; n = 12) of maximum concentration (Cmax) and area under the curve (AUC) of formoterol in plasma were 266 (108) pmol · l−1 and 1330 (398) pmol · h · l−1, respectively. The moderate inter-individual variability in systemic exposure of formoterol reflects the homogeneous pharmacokinetics of the drug. A predominant slow elimination of formoterol from plasma with a mean half-life (t1/2) of 10 h was demonstrated. Assuming linear kinetics in plasma suggested by urinary data, the steady-state trough plasma levels of formoterol for a b.i.d. dosing regimen are predicted to amount to 20% of Cmax. In urine, mean with (SD; n = 10) of the amount excreted over 48 h was 3.61 (0.89)% of dose for the pharmacologically active (R,R)-enantiomer and 4.80 (1.33)% of dose for the (S,S)-enantiomer. The terminal half-lives calculated from the excretion rate-time curves, i.e., 13.9 h and 12.3 h for the (R,R)- and (S,S)-enantiomer, respectively, confirm the slow elimination of formoterol from plasma. The dose inhaled was 10 times the most frequently recommended dose (12 μg) and 5 times the highest recommended dose (24 μg). Ten of 12 subjects experienced mild and transient nervousness. Pulse readings demonstrated the maximum mean increase of 25.8 beats · min−1 at 6 h. The mean maximum QTc increase was 25 msec at 6 h. Pulse and QTc values returned to baseline or close to baseline values at 24 h or before. Potassium levels in plasma decreased in eight out of 12 subjects; the lowest mean value was 3.53 mmol · l−1 at 2 h post-dose. The lowest individual potassium measurement was 2.95 mmol · l−1 between 15 min and 6 h. By 8 h post-dose all values had returned to within the normal ranges. Conclusions: The extremely fast appearance of formoterol in plasma shows the predominance of airways absorption shortly after inhalation. Due to a terminal elimination half-life of about 10 h, sustained systemic concentrations of formoterol are predicted for a twice daily treatment regimen without noteworthy accumulation. The excreted amounts in percent of dose of the enantiomers in urine and the enantiomer ratio are similar to data reported previously after lower doses and suggest linear kinetics for doses between 12 μg and 120 μg of formoterol fumarate. The expected side effects on heart rate, QTc interval, and plasma potassium were small and had no clinical consequences in spite of the very high dose of 120 μg (5 to 10 times the recommended therapeutic dose of Foradil). It should be noted that the impact of high doses may be greater in patients. Nevertheless these findings provide reassurance on the safety margin of formoterol after accidental and intentional overdosing.

Notes: Summary A Daucus carota cell line selected as resistant to N-(phosphonomethyl)-glycine (glyphosate) was found to have increased levels of 5-enolpyruvylshikimic acid-3-phosphate synthase (EPSPS) activity of 5.5 times over wild-type carrot and an EPSPS protein level increase of 8.7 times as confirmed by Western hybridization analysis. Southern blot hybridization using a petunia EPSPS probe showed increases in the number of copies of EPSPS genes in the glyphosate-resistant line which correlated with the higher levels of the EPSPS enzyme. The mechanism of resistance to glyphosate is therefore due to amplification of the EPSPS gene. To examine the stability of the amplified genes, cloned lines selected as doubly resistant to Dl-5-methyltryptophan (5MT) and azetidine-2-carboxylate (A2C) were fused with the amplified EPSPS glyphosate-resistant cell line. Somatic hybrids expressed resistances to 5MT in a semidominant fashion while A2C and glyphosate resistance was expressed as dominant, or semi-dominant traits, in a line-specific manner. The hybrid lines possessed additive chromosome numbers of the parental lines used and no double minute chromosomes were observed. The glyphosate-resistant parental line and most somatic hybrids retained the amplified levels of EPSPS in the absence of selection pressure over a 3-year period.