A phase Ι study to evaluate the application of photocyanine using pharmacokinetic and pharmacodynamic analysis in patients with malignancy

Innovative Design Strategies Advance Biomedical Applications of Phthalocyanines

Owing to their long absorption wavelengths, high molar absorptivity, and tunable photosensitivity, phthalocyanines have been widely used in photodynamic therapy (PDT). However, phthalocyanines still face the drawbacks of poor targeting, "always-on" photosensitizing properties, and unsatisfactory therapeutic efficiency, which limit their wide applications in biomedical fields. Thus, new design strategies such as modification of targeting molecules, formation of nanoparticles, and activating photosensitizers are developed to improve the above defects. Notably, recent studies have shown that novel phthalocyanines are not only used in fluorescence imaging and PDT, but also in photoacoustic imaging, photothermal imaging, sonodynamic therapy, and photothermal therapy. This review focuses on recent design strategies, applications in biomedicine, and clinical development of phthalocyanines, providing ideas and references for the design and application of phthalocyanine, so as to promote their future transformation into clinical applications.

A new class of quaternary ammonium compounds as potent and environmental friendly disinfectants

Quaternary ammonium compounds (QACs) are inexpensive and readily available disinfectants, and have been widely used, especially since the COVID-19 outbreak. The toxicity of QACs to humans has raised increasing concerns in recent years. Here, a new type of QACs was synthesized by replacing the alkyl chain with zinc phthalocyanine (ZnPc), which consists of a large aromatic ring and is hydrophobic in nature, similar to the alkyl chain of QACs. Three ZnPc-containing disinfectants were synthesized and fully characterized. These compounds showed 15-16 fold higher antimicrobial effect against Gram-negative bacteria than the well-known QACs with half-maximal inhibitory (IC50) values of 1.43 μM, 2.70 μM, and 1.31 μM, respectively. With the assistance of 680 nm light, compounds 4 and 6 had much higher bactericidal toxicities at nanomolar concentrations. Compound 6 had a bactericidal efficacy of close to 6 logs (99.9999% kill rate) at 1 μM to Gram-positive bacteria, including MRSA, under light illumination. Besides, these compounds were safe for mammalian cells. In a mouse model, compound 6 was effective in healing wound infection. Importantly, compound 6 was easily degraded at working concentrations under sunlight illumination, and is environmentally friendly. Thus, compound 6 is a novel and promising disinfectant.

Potent inhibition of Severe Acute Respiratory Syndrome Coronavirus 2 by photosensitizers compounds

The ongoing pandemic of coronavirus disease 2019 (COVID-19) posed a major challenge to the public health. Currently, no proven antiviral treatment for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection is available. Here we report compounds pentalysine β-carbonylphthalocyanine zinc (ZnPc5K) and chlorin e6 (ce6) potently inhibited the viral infection and replication in vitro with EC₅₀ values at nanomolar level. These compounds were first identified by screening a panel of photosensitizers for photodynamic viral inactivation. Such viral inactivation strategy is implementable, and has unique advantages, including resistance to virus mutations, affordability compared to the monoclonal antibodies, and lack of long-term toxicity.

Blood distribution and plasma protein binding of PHOTOCYANINE: a promising phthalocyanine photosensitizer inphaseⅡ clinical trials

Blood distribution and plasma protein binding are the important properties that can influence pharmacokinetics and ultimately the anticancer efficacy of photosensitizers in clinical photodynamic therapy. As a novel and promising phthalocyanine photosensitizer under clinical phase Ⅱ investigation in China, the superiority of PHOCYANINE is speculated on its attribution to its binding with plasma proteins. To verify this hypothesis, explore the targeting mechanism and further apply foundation for its clinical trial evaluation, we further study its in vitro and in vivo human blood distribution, in vitro plasma protein and lipoprotein binding in detail. PHOTOCYANINE was found to be mainly distributed in plasma with low K_BP and K_EP values. Moreover, its high binding rates to plasma proteins among various species (mouse, rat, dog, monkey, and human) were then determined. Among these plasma proteins, human serum albumin and α1-acid-glycoprotein were found to bind PHOTOCYANINE highly, and low-density lipoproteins have the highest percentage of PHOTOCYANINE over other lipoproteins. This study is expected to provide some guidance for PDT clinical evaluations and for further molecular design and development of photosensitizers.