Quantitation ofIn Vitroα-1 Adrenergic Receptor Antagonist Binding Capacity to Biologic Melanin Using Tandem Mass Spectrometry

Abstract

Tamsulosin appears to demonstrate melanin binding affinity which approaches chloroquine and exceeds doxazosin for both iridal and CRPE-derived bovine melanin.

The Effect of Systemic Tamsulosin Hydrochloride on Choroidal Thickness Measured by Enhanced Depth Imaging Spectral Domain Optical Coherence Tomography

“…Gaynes et al also speculated that the affinity of tamsulosin to melanin may result in the deposition of the drug in the pigmented tissues of the eye. 2 We propose that affinity of tamsulosin to melanin leads to sequestration in the vascular-rich choroid tissue and as stated by Sari et al, its α 1A adrenoreceptor-blocking activity may lead to increase in choroidal thickness. Gaynes et al think that this may explain the occurrence of floppy iris syndrome long after the discontinuation of tamsulosin.…”

“…Gaynes et al think that this may explain the occurrence of floppy iris syndrome long after the discontinuation of tamsulosin. 2 We think that this finding may also be applicable to choroidal tissue, and an increase in choroidal thickness may not reverse to normal levels after discontinuation of tamsulosin for a period. This effect should be kept in mind when evaluating the choroidal thickness in patients with a history of tamsulosin treatment.…”

“…In a study, Gaynes et al investigated in vitro α 1 adrenergic receptor binding capacity of tamsulosin to the biologic melanin. 2 Their results showed that tamsulosin has a high binding affinity to the iris and choroid/retinal pigment epithelial-derived melanin. Gaynes et al also speculated that the affinity of tamsulosin to melanin may result in the deposition of the drug in the pigmented tissues of the eye.…”

A combination treatment based on drug repurposing demonstrates mutation-agnostic efficacy in pre-clinical retinopathy models

“…In samples collected in the middle of the active period (12 a.m.), the doses of T and M in the serum were 12.8 ± 2.33 ng/ml and 2361 ± 614 ng/ml (mean ± SD), respectively. The concentrations of T and M in eye cups were much higher than those in the serum, suggesting melanin-binding and drug retention in the melanin-rich eye 34 , 35 . Detection of T and M levels in serum was also used as a readout to test the utility and uniformity of the dietary drug-administration strategy.…”