Enhancement of ampicillin partition behavior.

Area of Science:

• Analytical Chemistry
• Pharmaceutical Sciences

Background:

• Ampicillin's partition behavior is crucial for extraction and analysis.
• Optimizing ampicillin extraction from complex matrices like plasma is challenging.

Purpose of the Study:

• To identify and evaluate additives that enhance ampicillin's partition behavior.
• To develop efficient methods for ampicillin extraction from aqueous solutions and plasma.

Main Methods:

• Evaluation of ion-pair and adduct forming additives.
• Measurement of ampicillin aqueous-octanol partition coefficients at different pH values.
• Extraction of ampicillin from plasma using optimized additive concentrations.
• Quantitation of ampicillin using Thin-Layer Chromatography (TLC).

Main Results:

• Picric acid and trichloroacetic acid increased ampicillin partition coefficient 250 and 30 times at pH 3.
• Quaternary compounds significantly increased partition coefficient at pH 7, reaching 2.28 with benzalkonium chloride.
• Efficient ampicillin extraction from aqueous solutions was achieved with equimolar quaternary agents.
• High recovery (93%) of ampicillin from spiked plasma was obtained using a 1000-fold molar excess of tetraheptylammonium chloride.

Conclusions:

• Ion-pair and adduct forming additives effectively enhance ampicillin's partition behavior.
• Quaternary compounds are particularly effective for ampicillin extraction at neutral pH.
• Optimized additive concentrations allow for efficient ampicillin extraction from biological samples like plasma.