Detection of aminophylline in serum using an immunochromatographic strip test

Aminophylline (AMP), a bronchodilator drug, is a modified form of theophylline (the pharmacological active ingredient). AMP is often given to treat respiratory diseases, including bronchial asthma, blocked emphysema, panting bronchitis, and cardiogenic asthma. In this study, we developed a rapid and sensitive method to determine AMP concentration in mouse serum. A sensitive monoclonal antibody against AMP was produced by immunizing BALB/c mice with a well-characterized AMP2-keyhole limpet hemocyanin and coating antigen (hapten-AMP1-OVA). The coating antigen and goat anti-mouse IgG antibody were sprayed onto a nitrocellulose membrane representing the test and control lines, respectively. Under optimized conditions, the cut-off limits of the test strip were 50 ng/mL in 0.01 M phosphate buffered saline (pH 7.4) and 250 ng/mL in serum. The results were obtained within 10 min and revealed that this immunochromatographic strip test is a sensitive, rapid, and simple tool for the detection of AMP in serum.