The objective of this open-label, randomized, two-period, crossover study was to evaluate the oral bioavailability of the Mallinckrodt extended release test capsule formulation of chlorpheniramine polistirex/hydrocodone polistirex compared to an equivalent oral dose of a commercially available extended release oral suspension of chlorpheniramine polistirex/hydrocodone polistirex (Tussionex® Pennkinetic® Extended Release Oral Suspension, Celltech Pharmaceuticals, Inc.) in a test group of healthy subjects under fasting conditions.

Inclusion Criteria:

1. Males or non-pregnant, non-lactating females, 18 years of age or older.

2. Female subjects must be postmenopausal for at least one year, or surgically sterile, or practicing adequate non-hormonal contraception for at least 3 months prior to and for the duration of study participation. All female subjects will undergo a pregnancy test at screening and at check-in to the clinical study site for every dosing period. The results of the test must be negative for continued participation.

3. Weight must be within 15% of the ideal weight for height and frame, as adopted by the Metropolitan Life Insurance Co., 1993.

4. Qualifying subjects must be in good health and physical condition as determined by a screening medical history obtained within 30 days prior to study start. Subjects should not present with a history of significant past illness expected to affect the investigation.

5. The normal status of subjects will be confirmed by the following procedures:

   1. Laboratory tests (chemistry, hematology, urinalysis)
   2. Human immunodeficiency virus (HIV), hepatitis, alcohol, and "drugs of abuse" testing will be done for screening purposes only. Results of the HIV, hepatitis, and "drugs of abuse" tests must be negative or non-reactive for subjects to qualify for the study.
   3. Electrocardiogram: A 12-lead electrocardiogram (ECG) will be obtained for all subjects. This ECG must be interpreted by appropriately trained and experienced medical personnel. A subject with an ECG that is not within normal range does not qualify, unless specifically accepted (with comment) by the investigator.

6. Subjects must be able to provide written consent and agree to abide by the study requirements.

Exclusion Criteria:

1. History of chronic alcohol, drug, or narcotic abuse.
2. Chronic use of tranquilizers, sedatives, aspirin, antibiotics, or other medications.
3. History or presence of major organ dysfunction.
4. History of malignancy, stroke, or diabetes; cardiac, renal, liver, pulmonary, or severe gastrointestinal disease; or other serious illness.
5. History of anxiety, tension, severe agitation, psychosis, or mental depression.
6. Family history or diagnosis of epilepsy or other seizure disorder.
7. History of glaucoma.
8. History of acute abdominal conditions.
9. History of conditions which might contraindicate or require caution be used in the administration of chlorpheniramine/hydrocodone, including: history of renal impairment, hepatic or biliary tract disease, inflammatory bowel disease, ulcerative colitis, constipation, diarrhea, gastrointestinal obstruction or ileus, cardiac disease, hypertension, bladder obstruction, pain or difficulty passing urine, systemic lupus erythematosus, head trauma, increased intracranial pressure, pulmonary disease, asthma, or history of hypersensitivity to any opiate agonists or antihistamines.
10. Administration of any other investigational drug during the 30 days prior to enrollment into the study.
11. Subjects who smoke or have a history of smoking, or use nicotine-containing products.
12. Subjects who have donated blood within 30 days prior to study entry, including that withdrawn during the conduct of any other clinical study.
13. Subjects presenting with acute illness.
14. Subjects who must wear contact lenses during the study.
15. Subjects who have taken prescription drugs within 14 days or over-the-counter medications (including herbal preparations) within 7 days prior to dosing except for standard daily dose multivitamins.