Dendrimers
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Research on phototherapy published by A. Casas et al
2009 JUN 29 - (NewsRx.com) -- "The use of endogenous protoporphyrin IX (PpIX) after administration of 5-aminolaevulinic acid (ALA) has led to many applications in photodynamic therapy (PDT). However the efficacy of ALA-PDT is sub-optimal for thicker tumours and improved ALA delivery and therapeutic response are required," scientists in London, the United Kingdom report. "We have investigated the conjugation of ALA to a second-generation dxcendrimer for enhancing porphyrin synthesis in vitro and in vivo in a murine tumour model using systemic i.p. administration. In vitro, the dendrimer was more efficient than ALA for porphyrin synthesis at low concentrations in good correlation with higher cellular ALA dendrimer accumulation. In vivo, the porphyrin kinetics from ALA exhibited an early peak between 3 and 4 h in most tissues, whereas the dendrimer induced sustained porphyrin production for Over 24 h and basal values were not reached until 48 h after administration. Integrated porphyrin accumulation from the dendrimer and ALA, at equivalent molar ratios, was comparable showing that the majority of ALA residues were liberated from the dendrimer. The porphyrin kinetics appear to be governed by the rate of enzymatic cleavage of ALA from the dendrimer, which is consistent with in vitro results," wrote A. Casas and colleagues. The researchers concluded: "ALA dendrimers may be useful for metronomic PDT, and Multiple low-dose ALA-PDT treatments." Casas and colleagues published their study in the Journal of Controlled Release (Sustained and efficient porphyrin generation in vivo using dendrimer conjugates of 5-ALA for photodynamic therapy. Journal of Controlled Release, 2009;135(2):136-143). For additional information, contact A. Casas, UCL, National Med Laser Center, School Medical, Charles Bell House, 67-73 Riding House St., London W1W 7EJ, UK. The publisher's contact information for the Journal of Controlled Release is: Elsevier Science BV, PO Box 211, 1000 AE Amsterdam, Netherlands. Keywords: United Kingdom, London, Biotechnology, Controlled Release, Photodynamics, Phototherapy, Therapy, Treatment. This article was prepared by Anti-Infectives Week editors from staff and other reports. Copyright 2009, Anti-Infectives Week via NewsRx.com.
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