This study investigates the effect of the co-administration of verapamil on the steady-state pharmacokinetics (PK) of solifenacin succinate and tamsulosin given as a combination tablet, EC905.

The effect of the co-administration of verapamil on the steady state PK of solifenacin succinate and tamsulosin HCl OCAS (Oral Controlled Absorption System) is evaluated in this study.

Verapamil has been chosen to represent the effect of moderate CYP3A4 inhibitors on the combined administration of solifenacin and tamsulosin given as combination tablet EC905.

Subjects are admitted to the clinic on Day -1. From Days 1-10, they receive one daily dose of EC905 to obtain steady state, followed by 20 days (Days 11-30) combined dosing of EC905 and verapamil.

On Day 10 a 24-hour PK profile is obtained for solifenacin/tamsulosin. After the last dosing on Day 30, a post-dose 24-hour PK profile for solifenacin/tamsulosin and verapamil is obtained.

Additionally, vital signs, safety ECG (Electrocardiogram) measurements, safety laboratory assessments, adverse events and concomitant medications are monitored throughout the investigational period.

Subjects return for an ESV (End of Study Visit) 10 days after the last dosing.

Inclusion Criteria:

• Body Mass Index between 18.5 and 30.0 kg/m2, inclusive

Exclusion Criteria:

• Known or suspected hypersensitivity to EC905 or any of the components of the formulation used
• Known or suspected hypersensitivity to verapamil or any of the components of the formulation used
• Regular use of any inducer of liver metabolism (e.g. barbiturates, rifampin) in the 3 months prior to admission to the Clinical Unit