Codeine Phosphate/Guaifenesin ER Tablet 30 mg/600 mg Steady State Clinical Study

This study will be a single-center, Two-site open-label, randomized, multiple-dose, two-treatment, two-period crossover design. During the course of the study, thirty eight (38) healthy adult volunteers will receive multiple doses of Codeine Phosphate/ Guaifenesin extended-release tablet 30 mg/600 mg and multiple doses of an IR Codeine Phosphate/ Guaifenesin immediate-release tablet 20 mg/400 mg tablet in two separate treatment periods. Volunteers will enter the clinic the day prior \[approximately 12 hours\] to each dosing and will be confined in the clinic for 7 nights for each treatment period. The extended release tablet (test) will be administered as two tablets two times a day, 12 hours apart, and the immediate release tablet (reference) will be administered as one tablet six times a day, 4 hours apart. Pre-dose blood samples will be collected prior to morning dose on Days 1, 2, 3, 4, 5, 6 and 7. On Day 7, Two extended release tablets will be given once in the morning and the immediate release tablet will be given three times, in the morning and 4 and 8 hours later. Serial blood samples will be collected on Day 7 for up to 12 hours post morning dose. On Day 7 volunteers will be released from the study site after the 12-hour blood collection if clinically appropriate and will return to the study site to start the next treatment after a minimum of 7 days of wash-out period, which begins the morning after the last dose taken of the previous Period.