scispace - formally typeset
Search or ask a question
Book

Chemical Aspects of Photodynamic Therapy

07 Aug 2000-
TL;DR: The chemistry of Haematoporphyrin Derivative (HpD) and second generation photosensitisers are discussed in this paper, as well as other examples of photodynamic therapy.
Abstract: 1. Introduction, 2. Physical Matters, 3. Singlet Oxygen, 4. Photodynamic Action, 5. Some Other Examples of Photodynamic Therapy, 6. The Chemistry of Haematoporphyrin Derivative (HpD), 7. Second Generation Photosensitisers, 8. Porphyrin Photosensitisers, 9. Chlorins and Bascteriochlorins, 10. Phthalocyanines and Napthalocyanines, 11. Other Photosynthesises, 12. Photobleaching, 13. Biological Aspects, 14. Clinical and Commercial Developments
Citations
More filters
Journal ArticleDOI
TL;DR: The challenges to bringing PDT into mainstream cancer therapy are summarized, the chemical and photophysical solutions that transition metal complexes offer are considered, and the multidisciplinary effort needed to bring a new drug to clinical trial is put into context.
Abstract: Transition metal complexes are of increasing interest as photosensitizers in photodynamic therapy (PDT) and, more recently, for photochemotherapy (PCT). In recent years, Ru(II) polypyridyl complexes have emerged as promising systems for both PDT and PCT. Their rich photochemical and photophysical properties derive from a variety of excited-state electronic configurations accessible with visible and near-infrared light, and these properties can be exploited for both energy- and electron-transfer processes that can yield highly potent oxygen-dependent and/or oxygen-independent photobiological activity. Selected examples highlight the use of rational design in coordination chemistry to control the lowest-energy triplet excited-state configurations for eliciting a particular type of photoreactivity for PDT and/or PCT effects. These principles are also discussed in the context of the development of TLD1433, the first Ru(II)-based photosensitizer for PDT to enter a human clinical trial. The design of TLD1433 arose from a tumor-centered approach, as part of a complete PDT package that includes the light component and the protocol for treating non-muscle invasive bladder cancer. Briefly, this review summarizes the challenges to bringing PDT into mainstream cancer therapy. It considers the chemical and photophysical solutions that transition metal complexes offer, and it puts into context the multidisciplinary effort needed to bring a new drug to clinical trial.

740 citations

Journal ArticleDOI
TL;DR: A thorough survey of the photophysical and chemical properties of the developed tetrapyrrolic photosensitizers for PDT, with special attention to the singlet-oxygen yield (PhiDelta) of each photoensitizer, because it is one of the most important photodynamic parameters in PDT.
Abstract: Photodynamic therapy (PDT) is a promising new treatment modality for several diseases, most notably cancer. In PDT, light, O2, and a photosensitizing drug are combined to produce a selective therapeutic effect. Lately, there has been active research on new photosensitizer candidates, because the most commonly used porphyrin photosensitizers are far from ideal with respect to PDT. Finding a suitable photosensitizer is crucial in improving the efficacy of PDT. Recent synthetic activity has created such a great number of potential photosensitizers for PDT that it is difficult to decide which ones are suitable for which pathological conditions, such as various cancer species. To facilitate the choice of photosensitizer, this review presents a thorough survey of the photophysical and chemical properties of the developed tetrapyrrolic photosensitizers. Special attention is paid to the singlet-oxygen yield (ΦΔ) of each photosensitizer, because it is one of the most important photodynamic parameters in PDT. Also, in the survey, emphasis is placed on those photosensitizers that can easily be prepared by partial syntheses starting from the abundant natural precursors, protoheme and the chlorophylls. Such emphasis is justified by economical and environmental reasons. Several of the most promising photosensitizer candidates are chlorins or bacteriochlorins. Consequently, chlorophyll-related chlorins, whose ΦΔ have been determined, are discussed in detail as potential photosensitizers for PDT. Finally, PDT is briefly discussed as a treatment modality, including its clinical aspects, light sources, targeting of the photosensitizer, and opportunities.

643 citations

Journal ArticleDOI
TL;DR: In this article, the photochemical and photophysical properties of metallophthalocyanine complexes containing main group metals (Zn, Al, Ge, Si, Sn, Ga and In) were reviewed.

627 citations


Cites background from "Chemical Aspects of Photodynamic Th..."

  • ...Mixed-sulfonated aluminium phthalocyanine (AlPcSmix) commercially known as Photosens has been developed as a PDT drug with a fair measure of success [28]....

    [...]

  • ...The excited triplet state of the MPc can also interact with ground state molecular oxygen or substrate molecule, generating radical ions, superoxide and hydroperoxyl radicals, which subsequently afford oxidation of the substrate by Type I mechanism [28], [41] and [42]....

    [...]

  • ...Most notable among the uses of Pcs is as photosensitizers in oncology, particularly in photodynamic therapy (PDT) [22], [23], [24], [25], [26], [27], [28] and [29]....

    [...]

Journal ArticleDOI
TL;DR: Insight is provided into the dynamics of diffusion in cells, which is pertinent to drug delivery, cell signalling and intracellular mass transport, and the effect of this viscosity increase is observed directly in the diffusion-dependent kinetics of the photosensitized formation and decay of a key cytotoxic agent.
Abstract: Diffusion-mediated cellular processes, such as metabolism, signalling and transport, depend on the hydrodynamic properties of the intracellular matrix. Photodynamic therapy, used in the treatment of cancer, relies on the generation of short-lived cytotoxic agents within a cell on irradiation of a drug. The efficacy of this treatment depends on the viscosity of the medium through which the cytotoxic agent must diffuse. Here, spectrally resolved fluorescence measurements of a porphyrin-dimer-based molecular rotor are used to quantify intracellular viscosity changes in single cells. We show that there is a dramatic increase in the viscosity of the immediate environment of the rotor on photoinduced cell death. The effect of this viscosity increase is observed directly in the diffusion-dependent kinetics of the photosensitized formation and decay of a key cytotoxic agent, singlet molecular oxygen. Using these tools, we provide insight into the dynamics of diffusion in cells, which is pertinent to drug delivery, cell signalling and intracellular mass transport.

522 citations

Journal ArticleDOI
TL;DR: Basic aspects of PDT, PDT and photodynamic diagnosis for digestive cancer from the point of view of a clinical doctor, and, finally, future trends are focused on.
Abstract: One of the long-standing goals of both researchers and oncologists is to establish a framework for the complete cure of cancer with less toxic adverse effect and improved quality of life (QOL) for patients. PDT (photodynamic therapy) has much attracted as less invasive method for treating cancer. The therapeutic properties of light have been known for thousands of years, but it was only in the last century that PDT was developed. The field on PDT is now so large. Here, we will focus on a few basic aspects such as porphyrinoid photosensitizers, non-porphyrinoid photosensitizers, 5-aminolevulinic acid and its derivatives, fullerenes as efficient photosensitizers, and, PDT and photodynamic diagnosis (PDD) for digestive cancer from the point of view of a clinical doctor, and, finally, future trends.

446 citations