AIM: To develop a sensitive and selective liquid-chromatographic method for the determination of histamine in microdialysis samples from guinea pig skin following allergenic provocation. METHODS: The novel fluorescence derivatization method is based on an intramolecular excimer-forming reaction between 2 amino moieties of histamine and 2 molecules of 4-(1-pyrene)butanoyl chloride (PBC) yielding the corresponding dipyrene-labeled derivative. RESULTS: The PBC derivative of histamine was separated within 20 min, and the detection limit (signal-to-noise ratio = 3) of histamine was 0.6 fmol/20 μl volume injected. The basal extracellular levels of histamine in guinea pig skin microdialysates were 20.6 ± 1.7 fmol/10 μl. Subcutaneous administration of histamine liberator compound 48/80 (3 mg/kg) increased the extracellular histamine levels in the skin dialysates by about 860%, whereas ovalbumin challenge (2 mg/kg i.v.) in the sensitized guinea pigs increased the extracellular histamine levels by about 3,030%. CONCLUSION: The novel technique for histamine determination in microdialysis samples from the guinea pig skin may be utilized in preclinical research of antihistaminergic drugs and evaluation of allergenic properties of various dermal preparations such as transdermal drug delivery systems.
AIM: To develop a sensitive and selective liquid-chromatographic method for the determination of histamine in microdialysis samples from guinea pig skin following allergenic provocation. METHODS: The novel fluorescence derivatization method is based on an intramolecular excimer-forming reaction between 2 amino moieties of histamine and 2 molecules of 4-(1-pyrene)butanoyl chloride (PBC) yielding the corresponding dipyrene-labeled derivative. RESULTS: The PBC derivative of histamine was separated within 20 min, and the detection limit (signal-to-noise ratio = 3) of histamine was 0.6 fmol/20 μl volume injected. The basal extracellular levels of histamine in guinea pig skin microdialysates were 20.6 ± 1.7 fmol/10 μl. Subcutaneous administration of histamine liberator compound 48/80 (3 mg/kg) increased the extracellular histamine levels in the skin dialysates by about 860%, whereas ovalbumin challenge (2 mg/kg i.v.) in the sensitized guinea pigs increased the extracellular histamine levels by about 3,030%. CONCLUSION: The novel technique for histamine determination in microdialysis samples from the guinea pig skin may be utilized in preclinical research of antihistaminergic drugs and evaluation of allergenic properties of various dermal preparations such as transdermal drug delivery systems.