Single dose pharmacokinetic equivalence study of two gabapentin preparations in healthy subjects

• Published in: Drug design, development and therapy Vol. 8; no. default; pp. 1249 - 1255
• Main Authors: Tjandrawinata, Raymond, Setiawati, Effi, Putri, Ratih S.I., Yunaidi, Danang A., Amalia, Fawzia, Susanto, Liana W.
• Format: Journal Article
• Language: English
• Published: New Zealand Dove Medical Press Limited 01.01.2014; Taylor & Francis Ltd; Dove Press; Dove Medical Press
• Subjects: Adult; Amines - administration & dosage; Amines - pharmacokinetics; antiepilepsy; Bioavailability; bioequivalence; Clinical medicine; Confidence intervals; Convulsions & seizures; Cross-Over Studies; Cyclohexanecarboxylic Acids - administration & dosage; Cyclohexanecarboxylic Acids - pharmacokinetics; Dosage; Dosage and administration; Dose-Response Relationship, Drug; Drug dosages; FDA approval; Female; Food; Gabapentin; gamma-Aminobutyric Acid - administration & dosage; gamma-Aminobutyric Acid - pharmacokinetics; Headache; Healthy Volunteers; Hematology; Hepatitis; High performance liquid chromatography; HIV; Human immunodeficiency virus; Humans; International conferences; Laboratories; Liquid chromatography; Male; Middle Aged; Nausea; Original Research; Pharmacokinetics; Pharmacology; Phosphatase; Single-Blind Method; Statistical analysis; Statistical methods; Therapeutic Equivalency; Urine; Young Adult; Indonesia; Jakarta Indonesia; bioavailability; antiepilepsy; bioequivalence
• ISSN: 1177-8881; 1177-8881
• DOI: 10.2147/DDDT.S69326

The current study was conducted to find out whether two oral preparations of 300 mg gabapentin (the test and reference capsules) were bioequivalent. This was a randomized, single-blind, crossover study under fasting condition, with a 7-day washout period, which included 37 healthy adult male and female subjects. After an overnight fast, subjects were given, orally, one capsule of the test drug or of the reference drug. Blood samples were drawn immediately before taking the drug, then at 20 and 40 minutes, and 1, 1.5, 2, 2.5, 3, 4, 5, 6, 8, 10, 12, 15, and 24 hours after dosing, to evaluate pharmacokinetic parameters of the single dose administration, ie, the area under the plasma concentration-time curve (AUC) from time zero to 24 hours (AUCt), AUC from time zero to infinity (AUC(inf)), the peak plasma concentration of the drug (Cmax), time needed to achieve Cmax (tmax), and the elimination half-life (t1/2). The plasma concentrations of gabapentin were determined using validated high-performance liquid chromatography with ultraviolet detection. The geometric mean ratios (90% confidence interval) of the test drug/reference drug for gabapentin were 103.15% (90.38%-117.72%) for AUCt, 103.53% (90.78%-118.07%) for AUC(inf), and 108.06% (96.32%-121.24%) for Cmax. The differences in tmax and t1/2 values between the test and reference drug products for gabapentin were not statistically significant. Light-headedness, nausea, and headache were encountered during the study, but they were all mild and well tolerated. The 90% confidence intervals of the test/reference AUC ratio and Cmax ratio of gabapentin were within the acceptance range for bioequivalence. The two preparations of gabapentin 300 mg capsule were bioequivalent, thus both can be used interchangeably in the clinical setting.