Pulmonary pharmacokinetics and safety of nebulized duramycin in healthy male volunteers.

Duramycin (Moli1901) is being developed for the treatment of reduced mucociliary clearance in cystic fibrosis. This study was conducted to estimate lung residence time and systemic exposure and to assess whether duramycin causes an inflammatory response. Six volunteers were administered a single dose (7.5 mg) of nebulized duramycin and underwent bronchoscopies to obtain a composite data set for pharmacokinetic analysis; duramycin was measured in the cellular fraction of bronchoalveolar lavage fluid (BALF) (mainly alveolar macrophages) and brush biopsies (bronchial epithelial cells). The estimated t(1/2) of duramycin was approximately 5 days in brush biopsies and 25 to 91 days in BALF cells. Levels of duramycin in BALF (C (max) 800 ng/mg) exceeded those in brush biopsies by approximately 20-fold. Duramycin was absent from plasma and did not cause any detectable inflammatory response in pulmonary tissue as judged from the BALF profile of 14 relevant cytokines. Our data suggest that duramycin qualifies for intrapulmonary administration in cystic fibrosis (CF) patients.

Ultra-sensitive determination of Formoterol in human serum by high performance liquid chromatography and electrospray tandem mass spectrometry.

An analytical method was developed and validated to determine Formoterol in human serum in the range from 0.40 to 100.24 pg/mL by high performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS) due to the lack of efficient methods to determine very low levels of Formoterol in serum and plasma. Serum was diluted by water and mixed with the internal standard (d6-Formoterol). Formoterol and internal standard were extracted using a cation-exchange solid phase column (SCX-3). After eliminating endogenous serum constituents through washing steps with water and methanol, elution took place using methanol/ammonia. After evaporation of the elution liquid the residue was redissolved and analyzed by HPLC-MS/MS with electrospray ionisation (ESI) in positive mode. A gradient between 10 mM ammonium formate and acetonitrile was used. The inter-batch precision of the calibration standards ranged from 1.55% to 9.01%. The inter-batch accuracy of the calibration standards ranged from 93.37% to 107.30%. The lower limit of quantitation (LLOQ, 0.40 pg/mL) had a precision of 19.67% and an accuracy of 96.78%. Comparable results were obtained for quality control samples. Stability in human serum was given over three freeze/thaw cycles and 2h at room temperature. Formoterol in human serum was stable for at least 6 months below -20 degrees C. This method has been used widely for quantifying Formoterol after inhalation of 9-36 microg of the drug by volunteers. A cross validation with human plasma versus serum was performed after this method was successfully validated in human serum.