No / A novel high-performance liquid chromatography (HPLC) assay for the estimation of formoterol in urine samples was developed and validated. A solid phase extraction (SPE) using Oasis HLB was optimised to isolate formoterol from a urine matrix followed by HPLC with UV detection. This extraction procedure concentrated the final analyte forty times so that UV detection can be used to determine even a low concentration of formoterol in urine samples. The urinary assay was performed in accordance with FDA and ICH regulations for the validation of bioanalytical samples. The samples were injected onto a C18 Spherisorb® (250 mm x 4.6 mm x 5 ¿m) analytical column maintained at 30 °C. The mobile phase consisted of 5 mM of potassium dihydrogen orthophosphate buffer (adjusted to pH 3 with ortho phosphoric acid):acetonitrile (ACN) (70:30, v/v), and the formoterol peak was detected at wavelength 214 nm. The extraction recovery of formoterol from the urine sample was >95%. The calibration curve was linear (r2=0.99) over formoterol concentrations ranging from 1.5 to 25 ng/mL (n=6). The method had an accuracy of >92% and intra and inter-day precision CV% of <3.9% and <2.2%, respectively, at three different concentrations low, medium and high (10, 15, 20 ng/mL). The limit of quantification (LOQ) for formoterol was found to be 1.50 ng/mL. The accuracy and precision at the LOQ level were 95% and %CV <3.7% (n = 10), respectively. The method reported is simple, reliable, precise, and accurate and has the capacity to be used for determination of formoterol in urine samples.

Asthma is a chronic inflammatory airway disease, and its treatment is frequently challenging despite detailed national and international guidelines. While basic antiinflammatory therapy usually consists of inhaled corticosteroids in doses adapted to the asthma severity, add-on treatment with bronchodilators is essential in more severe asthma. Only recently, the long-acting anticholinergic tiotropium was introduced into the GINA guidelines. This review reports on the studies that have been performed with tiotropium in adult asthmatic patients. Following early proof-of-concept studies, several studies with tiotropium as an add-on therapy to inhaled corticosteroids (ICS), with or without a long-acting beta agonist (LABA), demonstrated convincing clinical benefit for patients. Important lung function parameters and quality of life scores significantly improved shortly after onset of the add-on therapy with tiotropium, and some studies even demonstrated non-inferiority against salmeterol. All studies reported an excellent safety profile of tiotropium. The still growing body of tiotropium studies, both in adults and children, will help to identify the position of tiotropium in future asthma guidelines and might also indicate which patients benefit most from an add-on therapy with tiotropium.