Specifically Meso-Substituted Porphyrins and Chlorins for Photodynamic Therapy

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This patent describes a new class of specifically meso-substituted porphyrins and chlorins, which are biologically active compounds designed to function as highly effective photosensitizers for photodynamic therapy. These compounds are synthetically tailored with particular chemical side groups to improve their water solubility, membrane affinity, and pharmacokinetic properties, aiming to enhance diagnostic and therapeutic outcomes in light-based medical treatments like cancer therapy, infection control, and diagnosis of various diseases. The patent also covers advanced methods for their synthesis, purification, and pharmaceutical formulation, including liposomal, nanoparticle, and polymer-based carriers.

Use CasesContent extracted from patent full text and abstract with AI.

• Photodynamic therapy (PDT) of various types of cancer and solid tumors
• PDT treatment of bacterial, viral, and fungal infections
• Treatment of non-tumorous hyperproliferative diseases such as arthritis and inflammatory conditions
• Diagnostic imaging and fluorescence-based identification of tumor tissues and inflammatory disease sites
• Ophthalmological disorders requiring light-activated therapeutics or diagnostics
• Urological disease treatments using photodynamic approaches
• Topical administration for dermatological disorders (e.g., psoriasis, acne, or skin cancers)
• Use in MRI imaging via fluorinated compounds for real-time in vivo tracking of disease progression and drug distribution
• Targeted delivery via conjugation with antibodies or peptides for selective accumulation in diseased tissue

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• Stronger absorption in the red and near-infrared spectral regions, allowing for deeper tissue penetration in therapy
• Enhanced selectivity for diseased tissue due to tailored amphiphilicity and membrane affinity, minimizing damage to healthy cells
• Greater water solubility and improved formulation options (e.g., liposomes, nanoparticles), increasing clinical applicability and patient compliance
• Improved pharmacokinetics leading to more predictable dosing and reduced side effects such as precipitation or delayed action
• Versatile synthesis routes enabling specific isomer production, increasing reproducibility, quality, and efficacy of the photosensitizers
• Compatibility with state-of-the-art drug delivery systems (e.g., PLGA, human serum albumin nanoparticles), enabling injectable and oral formulations
• Fluorinated variants allow complementary detection by magnetic resonance imaging (MRI)
• Low dark toxicity and high phototoxicity, offering safety before light activation while maximizing therapeutic effect upon irradiation
• Potential for conjugation with targeting agents (antibodies, peptides) to further improve disease/tissue specificity

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Patent Abstract

Biologically active compounds that can be used as photosensitizers for diagnostic and therapeutic applications, particularly for PDT of cancer, infections and other hyperproliferative diseases, fluorescence diagnosis and PDT treatment of a non-tumorous indication such as arthritis, inflammatory diseases, viral or bacterial infections, dermatological, opthamological or urological disorders are provided as well as providing methods to obtain them in pharmaceutical quality. One embodiment consists of a method to synthesize a porphyrin with a defined arrangement of meso-substituents and then converting this porphyrin system to a chlorin system by dihydroxylation or reduction, and if more than one isomer is formed separate them by chromatography either on normal or reversed phase silica. In another embodiment the substituents on the porphyrin are selected to direct the reduction or dihydroxylation to the chlorin so that a certain isomer is selectively formed. Another embodiment is to provide amphiphilic compounds with a higher membrane affinity and increased PDT-efficacy. In other embodiments the nucleophilic substitution on pentafluorophenyl-substituted tetrapyrroles is used to obtain compounds with a high PDT-efficacy. In another embodiment substituents are identified that via their steric and/or electronic influence direct the dihydroxylation or reduction with diimine so that one isomer is favored. Another embodiment consists of formulating the desired tetrapyrrole photosensitizer into a pharmaceutical formulation to be injected into the body avoiding undesirable effects like solubility problems or delayed pharmacokinetics of the tetrapyrrole systems.