Pharmacokinetics of Cromolyn and Ibuprofen in Healthy Elderly Volunteers

Background and Objectives The combination of cromolyn and ibuprofen is being investigated as a treatment for early Alzheimer's disease (AD). This study investigated the pharmacokinetics, safety, and tolerability of cromolyn and ibuprofen co-administration in healthy elderly adult volunteers. Methods In this open-labeled study, 26 subjects, aged 55-75 years, received co-administration of inhaled cromolyn (single dose 17.1 mg; double dose 34.2 mg total) and oral ibuprofen (single dose 10 mg; double dose 20 mg total). Blood sampling was performed for 6 h after co-administration in all subjects; cerebrospinal fluid (CSF) was collected in three to four subjects per cohort for 4 h following co-administration. Safety parameters, including adverse events (AEs), were monitored throughout the study. Results For cromolyn, the mean (+/- SD) maximum observed concentration (C-max) in plasma was 46.69 +/- 32.97 and 96.75 +/- 46.22 ng/ml after single- and double-dose inhalation, respectively [time to C-max (t(max)) similar to 22 min for each; terminal elimination half-life (t(1/2)) similar to 1.8 h for each]. For ibuprofen, the plasma C-max was 1090.98 +/- 474.64 ng/ml and 2062.96 +/- 655.13 ng/ml after single- and double-dose oral administration, respectively (t(max) similar to 1.6-1.8 h; t(1/2) similar to 1.9 h for each). For cromolyn, the CSF C-max was 0.24 +/- 0.08 ng/ml at 3.72 +/- 0.70 h after single-dose administration and 0.34 +/- 0.17 ng/ml at 3.45 +/- 0.95 h after double-dose administration, and for ibuprofen, the CSF C-max was 3.94 +/- 1.29 ng/ml at 2.55 +/- 0.96 h after single-dose administration and 8.93 +/- 3.29 ng/ml at 3.15 +/- 1.05 h after double-dose administration. Three (12%) subjects reported mild or moderate AEs which were unlikely to be related to study drug. Conclusions The combination of cromolyn and ibuprofen was safe and well tolerated. The concentrations of cromolyn and ibuprofen observed in the CSF are considered sufficient to titrate the estimated daily amyloid production and the associated inflammatory response in patients with AD.