Bioequivalence Study of Morphine Sulfate 60 mg Extended-Release Tablets Under Fed Conditions

Inclusion Criteria:

For inclusion into the trial, subjects were required to fulfill all of the following criteria:

1. Healthy subjects at least 18 years of age.
2. Willingness to provide written informed consent after being informed of the nature of the study.
3. Body mass index (BMI) between 18 and 30 and a weight of at least 110 pounds.
4. Good health as determined by a lack of clinically significant abnormalities in health assessments performed at Screening, as judged by the physician.

Exclusion Criteria:

ny of the following was regarding as a criterion for excluding subjects from the trial:

1. Hypersensitivity to morphine sulfate (MS Contin®), naltrexone (ReVia®), or related compounds.
2. Conditions that affected the absorption, metabolism, or passage of drugs out of the body (eg, sprue, celiac disease, Crohn's disease, colitis, liver, kidney, or thyroid conditions).
3. Recent history (within 1 year) of mental illness, drug addiction, drug abuse, or alcoholism.
4. A hematocrit value of ≤ 33.0% for females and ≤ 37.0% for males.
5. Donation of > 500 mL of blood in the past 8 weeks prior to study drug dosing or difficulty in donating blood.
6. Receipt of an investigational drug within the 4 weeks prior to study drug dosing.

7. Current use of any systemic prescription medications, except for oral/cutaneous/vaginal/injectable hormone contraceptives, within the 7 days prior to study drug dosing or over-the-counter (OTC) medication within 3 days of study drug dosing.

   This prohibition did not include vitamins or herbal preparations taken as nutritional supplements for non-therapeutic indications, as judged by the attending physician.

   Any nonprescription medication consumption reported was to be reviewed by the investigator prior to dosing. At the discretion of the investigator, these volunteers could be enrolled if the medication was not anticipated to alter study integrity or the safety of the subject.

8. Regular smoking of more than 5 cigarettes weekly or the regular daily use of nicotine containing products beginning 3 months before study drug administration through the final evaluation.

   Subjects had to be able to refrain from smoking while confined in the clinic.

9. Female subjects who were lactating or had a positive pregnancy test at Screening and prior to each of the treatment periods.

   Females were to use a medically acceptable method of contraception throughout the entire study period and for 1 week after study completion. Medically acceptable methods of contraception that could have been used by the subject and/or her partner were oral contraceptives/patches, progestin injection or implants, condom with spermicide, diaphragm with spermicide, intrauterine device (IUD), vaginal spermicidal or hormonal suppository, surgical sterilization of themselves or their partner(s), or abstinence. Females using contraceptive medications/devices must have used them consistently for at least 3 months prior to receiving study drug.

10. Alcohol, grapefruit beverages or foods, caffeine, or xanthine beverages or foods beginning 48 hours before each study drug administration through the last pharmacokinetic (PK) sample of each treatment period.

    Such restricted items included coffee, tea, iced tea, Coke®, Pepsi®, Mountain Dew®, chocolate, brownies, etc.

11. Regular use of any drugs known to induce or inhibit hepatic drug metabolism (examples include barbiturates, carbamazepine, rifampin, phenylhydantoins, phenothiazines, cimetidine, omeprazole, macrolides, imidazoles, fluoroquinolones) within 30 days prior to study drug administration.
12. Positive test results for human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg), and hepatitis C antibody at Screening.
13. Positive test results for drugs of abuse or pregnancy at Screening and prior to each study drug dosing period.
14. Subjects having emesis after either dose of naltrexone administered prior to the study drug were not to be continued in the study.