Preclinical photodynamic therapy in Spain 1: Chemical and photophysical studies on porphycenes and other photosensitizers

Abstract

Photosensitizers approved for clinical useTo date only five drugs have been approved for PDT: porfimer sodium, 5-aminolevulinic acid (ALA) and its methyl ester, temoporfin, and verteporfin (Chart 1).ABSTRACT: Photodynamic therapy (PDT) is a rapidly expanding alternative to the treatment of solid tumors and other highly-proliferative diseases due to its many attractive features: high selectivity, repeatability, and lack of serious adverse effects. The five drugs approved for use in PDT to date suffer from different problems that limit their efficacy and safety. Current understanding of cell death mechanisms offers an opportunity for the development of new, more efficient and safer drugs. This highlight describes the efforts of our research group in the PDT field: chemical development of porphycenes as PDT photosensitizers, photophysical screening of new families of potential PDT agents, and development of spectroscopic techniques for directly monitoring singlet oxygen and thus better understand the production, diffusion, and reactivity of this primary cytotoxic species in cells.

Dual fluorescence in 9-amino-2,7,12,17-tetraphenylporphycene

“…3 Our group has focused on 2,7,12,17-tetraphenylporphycenes (TPPos) 4 that are endowed with excellent in vitro PDT photosensitizing properties. 5 In order to improve the biological compatibility and selectivity of the parental TPPo, some combinatorial approaches 6 and 9-regioselective insertions of functionalities 7 have been achieved. Our previous works showed that the fluorescence quantum yield and the ability to produce singlet oxygen were substantially decreased in 9-amino-2,7,12,17tetraphenylporphycene (9-ATPPo), but not in 9-acetoxy or 9-nitro derivatives.…”

Preparação e avaliação de nanoesferas de PLGA (50:50) contendo porfirinas anfifílicas para uso em terapia fotodinâmica

“…indicativo da alta taxa de decaimento radioativo. Alem disso, são caracterizados por ser muito eficiente nos processos de conversão interna, um processo que ainda não é totalmente compreendido 78 .…”