The Bioequivalence Study of Lamotrigine Dispersible/Chewable Tablets 5mg×5 Compared With Lamotrigine Compressed Tablet 25mg in Chinese Healthy Male Subjects

This is a single dose, open-label, randomized, two-period crossover study to demonstrate the bioequivalence of lamotrigine dispersible/chewable tablets (5mg×5) and lamotrigine compressed tablets (25mg) in healthy Chinese male subjects in fasting conditions. 24 healthy Chinese male subjects will be enrolled to provide data from at least 22 evaluable subjects . In Period 1, subjects will be randomized in equal numbers to be dosed with either lamotrigine dispersible/chewable 5mg×5 tablets or lamotrigine compressed tablet 25mg×1. Following a washout of at least 14 days, subjects will be crossed over in Period 2 to receive the treatment that they did not receive in Period 1.

Pharmacokinetic blood samples will be collected over 168 hours post dose. Venous blood (2 ml each) is taken immediately before dosing (pre-dose) and 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 24, 36, 48, 72, 96, 120, 144 and 168 hours post dose to determine the lamotrigine concentration in serum. Drug concentration in serum at different time points will be determined for each subject with a validated bioanalytical method using LC/MS/MS method. The main pharmacokinetic parameters such as Cmax, tmax, AUC(0-inf), AUC(0-t), t1/2, λz, CL/F and Vd/F are calculated for subjects using non-compartment analysis method.

Physical examination, electrocardiogram and clinical laboratory tests are conducted at screening and 168 hours after administration of each dose; vital signs are measured at scheduled time; adverse events are recorded throughout the study. Clinically relevant safety measurement values are tabulated to evaluate the safety and tolerability of lamotrigine dispersible/chewable tablet. Safety evaluation lasts up to 168 hours after the second oral administration.

Inclusion criteria

• Healthy male non-smoker, based on medical history and physical examination.
• 18-40 years old, inclusive.
• Body weight >50 kg, and result of BMI is between 18.0 and 24.0 kg/m2, inclusive.
• Capable of returning to study site for follow-up according to the requirement of protocol and willing to comply with the policy, procedure and restriction of the study.
• Capable of reading and understanding the information listed in the consent form. Signing the informed consent prior to any study related procedure.
• Results of laboratory tests within the range of reference normal range, or slight abnormality which judged as not clinically significant by investigator.
• AST, ALT, alkaline phosphatase and total bilirubin =<1.5 x ULN ((total bilirubin >1.5 x ULN alone is acceptable if direct bilirubin <35% of total bilirubin).
• Normal blood pressure (systolic blood pressure 90-140 mmHg, diastolic blood pressure < 90mmHg) and pulse rate (60-100/min).
• No clinically significant abnormality on 12-lead ECG.
• Corrected QT interval < 450 ms; or corrected QT interval < 480 ms for subjects with bundle-branch block.
• Male subjects with female partners of child-bearing potential must agree to use contraceptive method after first dose of study treatment and until two weeks after the completion of the study.

Exclusion criteria

• Current or chronic history of cardiovascular, respiratory, gastrointestinal, endocrine, hepatic, hematological, psychical or nervous system diseases, use of drug that can change the absorption, metabolism or elimination of study drug, or result in danger or other drugs or diseases that interfere with the interpretation of study data.
• Personal or familial history of hypersensitivity to lamotrigine or drug with similar chemical composition.
• Participation in other clinical trial within 30 days prior to enrollment in the study.
• Use of prescription or non-prescription drugs, including monoamine oxidase inhibitor or herbal drug within 14 days prior to the screening; excluding use of lubricating oil or contraceptive barrier device containing spermicidal agents, and other contraception device.
• History of abnormality of liver function, abnormal hepatic or biliary system, or positive hepatitis B surface antigen (HBsAg), or positive hepatitis C surface antibody (HCAb) or ALT ≥ 2x upper limit of normal (ULN). Having Gilbert syndrome.
• Positive serum HIV antibody.
• Alcohol abuser, defined as alcohol consumption exceeding 3 units/day or 21 units/week. A unit equal to about 240 ml beer, 25 ml spirits or 125 ml wine.
• Positive drug monitoring at screening.
• Evidence for obviously active disease of hematological system, or obvious blood loss within 3 months.
• Blood donation 3 months prior to study.
• Current or past history of nervous-psychiatric disorder, as assessed by Columbia Suicide Severity Rating Scale-baseline evaluation or in the opinion of investigator that the subject is at risk of suicide or with history of suicide behavior/attempt.
• Unsuitable for participating in the study according to the law.
• Unsuitable for participating in the study in the opinion the investigator.