Pharmacokinetics and safety of olodaterol administered with the Respimat Soft Mist inhaler in subjects with impaired hepatic or renal function.

PURPOSE: In two trials, the influences of hepatic and renal impairment on the pharmacokinetics of olodaterol, a novel long-acting inhaled ß2-agonist for treatment of COPD, were investigated. SUBJECTS AND METHODS: The first trial included eight subjects with mild hepatic function impairment (Child-Pugh A), eight subjects with moderate impairment (Child-Pugh B), and 16 matched healthy subjects with normal hepatic function. The second trial included eight subjects with severe renal impairment (creatinine clearance <30 mL·min(-1)) and 14 matched healthy subjects with normal renal function. Subjects received single doses of 20 or 30 µg olodaterol administered with the Respimat Soft Mist inhaler. RESULTS: Olodaterol was well tolerated in all subjects. The geometric mean ratios and 90% confidence intervals of dose-normalized area under the plasma concentration-time curve from time zero to 4 hours (AUC0-4) for subjects with mild and moderate hepatic impairment compared to healthy subjects were 97% (75%-125%) and 105% (79%-140%), respectively. Corresponding values for dose-normalized maximum concentration (C max) were 112% (84%-151%) (mild impairment) and 99% (73%-135%) (moderate impairment). The geometric mean ratio (90% confidence interval) of AUC0-4 for subjects with severe renal impairment compared to healthy subjects was 135% (94%-195%), and for C max was 137% (84%-222%). There was no significant relationship between creatinine clearance and AUC0-4 or C max. Renal clearance of olodaterol was reduced to 20% of normal in severe renal impairment. CONCLUSION: Mild to moderate hepatic function impairment or severe renal function impairment did not result in a clinically relevant increase of olodaterol systemic exposure after a single inhaled dose.

European Bioanalysis Forum: recommendation on dealing with hemolyzed and hyperlipidemic matrices.

Recent guidelines on bioanalytical method validation have recommended to investigate matrix effects in special matrices such as hemolytic and hyperlipidemic plasma. However, these guidelines were not clear on how to implement these recommendations. The European Bioanalysis Forum has discussed this topic in depth and has asked for feedback from member companies. Those discussions have resulted in more specific guidance on how to define hemolytic and hyperlipidemic plasma, how to validate bioanalytical methods for these matrices and how to deal with hemolytic and hyperlipidemic study samples. These recommendations are presented in this manuscript.

Effects of strong CYP2D6 and 3A4 inhibitors, paroxetine and ketoconazole, on the pharmacokinetics and cardiovascular safety of tamsulosin.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: Tamsulosin metabolism involves both CYP2D6 and 3A4. However, data on potential drug-drug interactions between tamsulosin and inhibitors of CYP2D6 and 3A4 are limited and information on potential pharmacodynamic consequences of such pharmacokinetic interactions is missing. WHAT THIS STUDY ADDS: This study provides information on the drug-drug interactions of tamsulosin with strong CYP2D6 and strong CYP3A4 inhibitors after single dose administration in healthy subjects. AIM: To determine the effect of the strong CYP2D6 inhibitor paroxetine and strong CYP3A4 inhibitor ketoconazole on the pharmacokinetics and safety (orthostatic challenge) of tamsulosin. METHODS: Two open-label, randomized, two-way crossover studies were conducted in healthy male volunteers (extensive CYP2D6 metabolizers). RESULTS: Co-administration of multiple oral doses of 20 mg paroxetine once daily with a single oral dose of the 0.4 mg tamsulosin HCl capsule increased the adjusted geometric mean (gMean) values of C(max) and AUC(0,∞) of tamsulosin by factors of 1.34 (90% CI 1.21, 1.49) and 1.64 (90% CI 1.44, 1.85), respectively, and increased the terminal half-life (t(1/2) ) of tamsulosin HCl from 11.4 h to 15.3 h. Co-administration of multiple oral doses of 400 mg ketoconazole once daily with a single oral dose of the 0.4 mg tamsulosin increased the gMean values of C(max) and AUC(0,∞) of tamsulosin by a factor of 2.20 (90% CI 1.96, 2.45) and 2.80 (90% CI 2.56, 3.07), respectively. The terminal half-life was slightly increased from 10.5 h to 11.8 h. These pharmacokinetic changes were not accompanied by clinically significant alterations of haemodynamic responses during orthostatic stress testing. CONCLUSION: The exposure to tamsulosin is increased upon co-administration of strong CYP2D6 inhibitors and even more so of strong 3A4 inhibitors, but neither PK alteration was accompanied by clinically significant haemodynamic changes during orthostatic stress testing.

Isolation, cloning and expression of a multifunctional O-methyltransferase capable of forming 2,5-dimethyl-4-methoxy-3(2H)-furanone, one of the key aroma compounds in strawberry fruits.

Strawberry fruits contain an uncommon group of key aroma compounds with a 2,5-dimethyl-3(2H)-furanone structure. Here, we report on the methylation of 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) to 2,5-dimethyl-4-methoxy-3(2H)-furanone (DMMF) by a S-adenosyl-L-methionine dependent O-methyltransferase, the cloning of the corresponding cDNA and characterization of the encoded protein. Northern-hybridization indicated that the Strawberry-OMT specific transcripts accumulated during ripening in strawberry fruits and were absent in root, petiole, leaf and flower. The protein was functionally expressed in E. coli and exhibited a substrate specificity for catechol, caffeic acid, protocatechuic aldehyde, caffeoyl CoA and DMHF. A common structural feature of the accepted substrates was a o-diphenolic structure also present in DMHF in its dienolic tautomer. FaOMT is active as a homodimer and the native enzyme shows optimum activity at pH 8.5 and 37 degrees C. It does not require a cofactor for enzymatic activity. Due to the expression pattern of FaOMT and the enzymatic activity in the different stages of fruit ripening we suppose that FaOMT is involved in lignification of the achenes and the vascular bundles in the expanding fruit. In addition, it is concluded that the Strawberry-OMT plays an important role in the biosynthesis of strawberry volatiles such as vanillin and DMMF.