Selective solid-phase extraction of amoxicillin and cephalexin from urine samples using a molecularly imprinted...

Area of Science:

• Analytical Chemistry
• Materials Science
• Pharmaceutical Analysis

Background:

• Accurate quantification of antibiotics like amoxicillin (AMX) in biological samples is crucial for therapeutic drug monitoring and pharmacokinetic studies.
• Existing extraction methods may lack the specificity required for complex matrices like urine, leading to interference and reduced accuracy.

Purpose of the Study:

• To synthesize and characterize a novel noncovalent molecularly imprinted polymer (MIP) for the selective extraction of amoxicillin (AMX).
• To evaluate the performance of the MIP in molecularly imprinted solid-phase extraction (MISPE) for AMX and a related antibiotic, cephalexin (CPX), from aqueous and urine samples.

Main Methods:

• A noncovalent molecular imprinting approach was used to synthesize the MIP targeting amoxicillin.
• The synthesized MIP was employed as a selective sorbent in an off-line molecularly imprinted solid-phase extraction (MISPE) protocol.
• The MIP's performance was assessed using spiked water and human urine samples, with subsequent analysis and comparison against commercial SPE cartridges.

Main Results:

• The MIP demonstrated selective extraction of AMX and exhibited cross-selectivity for cephalexin (CPX).
• MISPE using the MIP achieved good recoveries (75-78%) for AMX and CPX from spiked water samples (10 mg/L).
• Slightly lower but still effective recoveries (63-65%) were obtained from spiked human urine samples (20 mg/L), with significantly cleaner extracts compared to commercial SPE cartridges.

Conclusions:

• The developed noncovalent MIP is effective for the selective extraction of amoxicillin and cephalexin from both synthetic and real biological samples.
• MISPE utilizing this MIP offers an improved analytical method with enhanced selectivity and cleaner extracts, outperforming commercially available SPE cartridges for these antibiotics.