The purpose of this study is to evaluate the relative drug concentrations achieved with different formulations of GSK1838262 in healthy volunteers.

This is an open-label, randomized, single-dose, five-period, crossover study to evaluate the relative drug concentrations with different formulations of GSK1838262 in healthy volunteers. Four new formulations will be tested against the current formulation to identify the most promising new formulations for further development. Each subject will participate in five dosing periods and each period will be separated by at least seven days. Blood and urine samples will be collected over the 36 hour period following each dose administration to measure the drug concentrations.

Inclusion Criteria:

• healthy, male and female subjects aged between 18 and 65 years old.
• normal body weight.
• normal ECG, vital signs and lab tests.
• normal kidney function
• agree to use acceptable contraceptive methods required.
• capable of giving written informed consent.

Exclusion Criteria:

• positive blood alcohol or urine drug test.
• positive hepatitis B/C and HIV
• donation of more than 450 mL blood within the 56 days.
• sensitivity to gabapentin
• pregnant or lactating females
• smoker
• certain medical conditions including heart disease, psychiatric disease, gastrointestinal disease, kidney or liver dysfunction
• history of seizure