2‐[1‐hexyloxyethyl]‐2‐devinyl pyropheophorbide‐a (HPPH) in a nude rat glioma model: Implications for photodynamic therapy

Abstract

Twenty-four hours after injection of 0.5 mg/kg HPPH, tumor-to-brain drug ratios ranged from 5:1 to 15:1. Enhanced survival was observed in each of the HPPH/PDT-treated animal groups. These data suggest that HPPH may be a useful adjuvant for the treatment of malignant gliomas.

Determination of fluence rate and temperature distributions in the rat brain; implications for photodynamic therapy

“…[1][2][3][4] PDT is a local treatment involving the administration of a tumor-localizing photosensitizing drug 5 and has several features that make it a potentially attractive adjuvant local therapy for brain tumors. The treatment volume is limited by the attenuation of light in brain tissues, and repeated application is an option due to low long-term morbidity.…”

Nature: A rich source for developing multifunctional agents. tumor‐imaging and photodynamic therapy

“…Endogenous chromophores (molecules that also absorb light) such as NADH, collagen, lipo-pigments, and flavins exist in the body and also compete for absorption. Therefore, during therapeutic applications for maximum penetration, it is best to use red light excitation near 800 nm [16,17]. The probability per unit path length of a photon being absorbed by an endogenous chromophore such as water, hemoglobin, deoxyhemoglobin, and melanin (wavelength shorter than 630 nm), decreases with increasing wavelengths ( > 660 nm).…”

“…At the longer treatment wavelengths, the majority of these endogenous chromophores will not absorb light, allowing the photosensitizer to be the strong absorber. Therefore, the depth of penetration is much greater at longer wavelengths-two to three times greater for infrared lasers than at 630 nm [16,17].…”

Photodynamic diagnosis of gastric cancer using HPPH-CD

“…15 At present, particular attention is focused on photosensitizers with absorption and emission spectra in the near-infrared (NIR) range (700-900 nm), because scattering of the excitation light and tissue autouorescence within this spectral range is minimal, resulting in facilitated deep tissue imaging. 16,17 Over the past few years, a number of NIR uorophores with excellent photophysical properties, variable stabilities, and ease of synthesis have been developed, 18 among which cyanine dyes (CDs) in general have shown great potential for uorescence imaging. In particular, IR820, a NIR CD, is of great interest because of its inherent desirable photophysical characteristics, namely, excitation and emission in the NIR region beyond 750 nM, where light can penetrate deep into the biological tissues; however, the tumor uptake of IR820 is known to be low, limiting its use in uorescence imaging for tumor diagnosis.…”