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Roflumilast is an oral phosphodiesterase 4 (PDE4) inhibitor for the treatment of chronic obstructive pulmonary disease (COPD). It is metabolized by CYP1A2 and CYP3A4 to its primary metabolite, roflumilast N-oxide, through which >90% total PDE4 inhibitory activity (tPDE4i) is mediated. Fluoroquinolones, of which enoxacin is the most potent CYP1A2 inhibitor, are used to treat COPD exacerbations. This phase I, open, nonrandomized, fixed-sequence, 2-period study evaluated the effects of steady-state enoxacin on the single-dose pharmacokinetics of roflumilast and roflumilast N-oxide. Twenty healthy participants received roflumilast, 500 µg once daily, on days 1 and 12, and enoxacin, 400 mg twice daily, on days 7 to 18. Pharmacokinetic profiles were obtained for days 1 to 6 and 12 to 19. The safety and tolerability of all treatments were also assessed. In 19 evaluable participants, coadministration led to 56% higher mean systemic exposure, 20% higher mean peak concentrations, and 36% lower mean apparent oral clearance compared with roflumilast alone. For roflumilast N-oxide, 23% higher mean systemic exposure and 14% lower mean peak concentrations were seen after coadministration. Roflumilast was well tolerated both alone and in combination with enoxacin. A weak interaction was shown between roflumilast and enoxacin, as mean tPDE4i increased by 25%, but is unlikely to have clinical relevance. [ABSTRACT FROM PUBLISHER]

The objectives of the 3 phase I studies described herein were (1) to compare the pharmacokinetics of gabapentin delivered from a novel gastric-retentive dosage form vs an immediate-release formulation, (2) to assess the dose proportionality of the gastric-retentive extended-release formulation, and (3) to determine the effect of food on the pharmacokinetics of gabapentin delivered from this formulation. The time to reach maximum plasma concentration (tmax) was extended for gabapentin delivered from the gastric-retentive extended-release formulation compared with the immediate-release formulation. A dose-related increase in both the maximum plasma concentration (Cmax) and the area under the plasma concentration—time curve (AUC) was observed as the gabapentin dose increased from 600 to 2400 mg. Fed status and increased fat content delayed tmax and enhanced Cmax and AUC in proportion to the fat content. The pharmacokinetics of gabapentin delivered from this extended-release formulation allows a reduced dosing frequency while maintaining bioavailability and possibly diminishing the occurrence of adverse events attributable to a slower increase to the peak concentration compared with the immediate-release dosage form. [ABSTRACT FROM PUBLISHER]