METHOD: The effects of organic modifiers in mobile phase, protein precipitation agent to plasma sample ratio, and light on montelukast stability in unprocessed and processed human plasma, were evaluated. Validation was conducted in accordance with European Medicines Agency Guideline on bioanalytical method validation.

RESULTS: No interference peak was observed when acetonitrile was used as an organic modifier. Acetonitrile to plasma ratio of 4:1 produced clean plasma sample. Approximately 3 % of cis isomer was detected in unprocessed plasma samples while 21 % of cis isomer was detected in processed plasma samples after exposing to fluorescent light for 24h. The standard calibration curve was linear over 3.00-1200.00 ng/mL. All method validation parameters were within the acceptance criteria.

Methods: Twenty-four adult male Balb/C mice were divided into six groups: i) normal diet; ii) positive control diet; iii) negative control diet; and iv) HFD with SCGO at 12.5 mg/kg body weight (mg/kg BW); v) HFD with SCGO at 25 mg/kg BW, vi) HFD with SCGO at 50 mg/kg BW. Liver weight and morphology, spleen weight, serum levels of superoxide dismutase (SOD) and tumour necrosis factor α (TNF-α), TNF-α expression in the aorta and lipid profiles were assessed at the end of the experimental period.

Results: SCGO treatment was associated with significant decreases in liver and spleen weight as well as amelioration of hepatic steatosis. SCGO treatment also decreased TNF-α levels and expression. Serum levels of SOD in the SCGO groups were significantly increased compared with the negative control group. Lipid profiles were improved in the SCGO treatment groups compared with the negative control group.