9.7.1.3 The applications of OCAs in vivo and in vi...
Currently，OCAs have not been used in clinic，but they have broad prospects for improving laser therapy.Studies on light transparency of skin tissues are mainly in vitro experiments，and few in vivo experiments（animal experiments）.Due to the safety and biocompatibility of OCAs and the different drug metabolism between in vitro and in vivo tissues，their application in the human body is limited.In vitro experiments，the method of administration is usually in vitro tissue immersion，while in vivo experiments，the methods of administration are usually surface painting and subcutaneous injection.The solution of glycerin，sugar，polyethylene glycol，propylene glycol or acetic acid has a reversible clearing effect on tissues and can be used in vivo.However，the concentration should not be too high to avoid tissue damage and necrosis.Glycerin is often used in vivo experiments.When its concentration is more than 30％，it can cause skin edema and other adverse reactions.The effect of thiazone and OmnipaqueTMin vivo was better without obvious side effect.Many studies have shown that the application of OCAs can improve the OC effect of skin in vivo and in vitro，increasing the detection depth of molecular optical imaging.There have been few studies on the combine application of OCAs and lasers；however，it has been reported that the combination of OCA（a mixture of polypropylene glycol and polyethylene glycol）and lasers is more effective and less damaging in the treatment of human skin tattoos than in the control group.Yet，the case number is small and further study is needed.There are many challenges in the application of OCAs in the human body.Development of a kind of OCAs with low toxicity，good biocompatibility，direct applying to the skin and rapid metabolism，is of great significance for laser cosmetology.(https://www.daowen.com)