부산대학교 도서관

Purpose: The purpose of this study was to develop methods to allow evaluation of the binding characteristics for a series of α1 antagonists to biologically-derived melanin. Methods: Fresh bovine globes were used to obtain iridai and choroid/retinal pigment epithelial (CRPE) derived melanin. Binding characteristics of chloroquine, tamsulosin and doxazosin were then evaluated in vitro using tandem mass spectroscopy. Results: Tandem mass spectrometry-based assays were developed for three α1 antagonists that provided linear assay ranges which spanned (minimally) 0.01-10 μg/mL, while exhibiting excellent inter-assay precision and accuracy. When applied to the evaluation of binding characteristics for iridai melanin, mean chloroquine and tamsulosin fractions were found to be 41.9 ± 14.2 pmoles mg-1 and 25.34 ± 6.186 pmoles mg-1, respectively. Mean iridai doxazosin binding was found to be 6.36 ±2.19 pmoles mg-1. Interestingly, mean levels of tamsulosin, but not doxazosin found bound to choroid/CRPE derived melanin approached that of chloroquine (27.91 μg/mL, 25.68 μg/mL and 5.94 μg/mL for chloroquine, tamsulosin and doxazosin, respectively). One way ANOVA for binding affinity for chloroquine, tamsulosin and doxazosin was statistically significant for both iridai and CRPE-derived melanin (p = 0.0012 and 0.0023), respectively. A Bonferroni post-hoc analysis demonstrated a statistically significant difference in the amount of binding between tamsulosin, doxazosin and chloroquine to iridai but not CRPE derived melanin (p <0.05). Conclusions: Tamsulosin appears to demonstrate melanin binding affinity which approaches chloroquine and exceeds doxazosin for both iridai and CRPE-derived bovine melanin. [ABSTRACT FROM AUTHOR]