Safety and Pharmacokinetics of Bendamustine Rapid-Infusion Formulation.

Bendamustine hydrochloride (BDM) is approved in the United States to treat chronic lymphocytic leukemia and relapsed indolent B-cell non-Hodgkin lymphoma. The first formulation marketed in the United States (original BDM) was a lyophilized product requiring reconstitution prior to dilution to the final admixture. A liquid formulation of BDM was subsequently introduced that did not require reconstitution before dilution. Both formulations are administered as a 500 mL admixture with a recommended infusion time of 30 or 60 minutes for chronic lymphocytic leukemia and indolent B-cell non-Hodgkin lymphoma, respectively. A newer liquid BDM formulation (rapid BDM) is a ready-to-dilute solution not requiring reconstitution that dilutes into an admixture of only 50 mL and can be safely administered in a shorter infusion time (10 minutes). Rapid BDM admixture also has longer stability at room temperature than both lyophilized and liquid BDM formulations (6 vs 2 to 3 hours). This phase 1, open-label, randomized, crossover (3-period, partially replicated) study, conducted in "end-of-life" cancer patients at 10 oncology centers in the United States, demonstrates that rapid BDM is bioequivalent to original BDM as determined by area under the curve. Expected differences in maximum plasma concentration and time to maximum plasma concentration were observed between study treatments, given the substantially shorter infusion time of rapid BDM. No clinically relevant differences in other evaluated pharmacokinetic parameters were found. Rapid BDM infusions were safe and tolerable for cancer patients in this study. The overall safety profiles of the 2 BDM formulations were comparable, with no new safety signals identified and no differences in infusion-related adverse events.

Discovery of a rapidly metabolized, long-acting ß(2) adrenergic receptor agonist with a short onset time incorporating a sulfone group suitable for once-daily dosing.

A series of novel, potent, and selective human ß2 adrenoceptor agonists incorporating a sulfone moiety on the terminal right-hand-side phenyl ring of (R)-salmeterol is presented. Sulfone 10b had salmeterol-like potency and selectivity profile, long duration of action on guinea pig trachea, and longer than salmeterol duration of action in vivo, suitable for once-daily dosing. It had lower than salmeterol oral absorption in rat, lower bioavailability in rat and dog, and a high turnover in human hepatocytes. It was metabolized in human hepatocytes by hydroxylation, oxidation, cleavage, and conjugation; most of the metabolites would be expected to have reduced or no ß2 activity. The 4-biphenylsulfonic acid was identified as a crystalline, non-hygroscopic salt of 10b, suitable for inhaled delivery. Furthermore, it was free of any genetic toxicity issues and was considered as a backup to vilanterol.

The discovery of long-acting saligenin ß2 adrenergic receptor agonists incorporating hydantoin or uracil rings.

A series of novel, potent and selective human ß(2) adrenoceptor agonists incorporating a hydantoin or a uracil ring on the right-hand side phenyl ring of (R)-salmeterol is presented. Hydantoin 12a had long duration of action in vitro on guinea pig trachea, and 12h in guinea pigs in vivo at its EC(90) 25 µM. It had lower oral absorption than salmeterol in rats, and lower bioavailability than salmeterol in vivo in both rats and dogs (2% and 5%, respectively). An improved method for measuring the absorbed fraction of analogues dosed to rats, which considers the glucuronidated fraction is presented. Compound 12a was metabolised in human liver microsomes and hepatocytes to the active hydantoic acid 12m.

Synthesis and structure-activity relationships of long-acting beta2 adrenergic receptor agonists incorporating metabolic inactivation: an antedrug approach.

A series of saligenin beta(2) adrenoceptor agonist antedrugs having high clearance were prepared by reacting a protected saligenin oxazolidinone with protected hydroxyethoxyalkoxyalkyl bromides, followed by removal of the hydroxy-protecting group, alkylation, and final deprotection. The compounds were screened for beta(2), beta(1), and beta(3) agonist activity in CHO cells. The onset and duration of action in vitro of selected compounds were assessed on isolated superfused guinea pig trachea. Compound 13f had high potency, selectivity, fast onset, and long duration of action in vitro and was found to have long duration in vivo, low oral bioavailability in the rat, and to be rapidly metabolized. Crystalline salts of 13f (vilanterol) were identified that had suitable properties for inhaled administration. A proposed binding mode for 13f to the beta(2)-receptor is presented.

Synthesis and structure-activity relationships of long-acting beta2 adrenergic receptor agonists incorporating arylsulfonamide groups.

A series of saligenin alkoxyalkylphenylsulfonamide beta(2) adrenoceptor agonists were prepared by reacting a protected saligenin oxazolidinone with alkynyloxyalkyl bromides, followed by Sonogashira reaction, hydrogenation, and deprotection. The meta-substituted primary sulfonamide was more potent than the para- and the ortho-analogues. Primary sulfonamides were more potent than the secondary and tertiary analogues. The onset and duration of action in vitro of selected compounds was assessed on isolated superfused guinea pig trachea. Sulfonamide 29b had the best profile of potency, selectivity, onset, and duration of action on both guinea pig trachea and human bronchus. Furthermore, 29b was found to have low oral bioavailability in rat and dog and also to have long duration of action in an in vivo model of bronchodilation. Crystalline salts of 29b were identified that had suitable properties for inhaled administration. A proposed binding mode for 29b to the beta(2)-receptor is presented.