Research on perfluorocarbons (PFCs) began before World War II but it was the 1942 Manhattan Project in the United States to develop the atomic bomb that led to methods of producing PFCs other than reacting fluorine with hydrocarbon. As a result, PFCs have been adapted for a number of industries. For example, Leland Clark, PhD, a biochemist known for his Clark electrode invention, worked extensively with PFCs. Although his vision was to produce a blood substitute, he developed a liquid breathing material based on Oxycytea, a third-generation PFC with the chemical name perfluoro(t-butyl cyclohexane) (FtBu) designed to enhance the delivery of oxygen to damaged tissues, which was successfully breathed by mice as a replacement for oxygenb.
PFCs are stable molecules that resist heat transfer and reactivity, according to Aharon Grossman, vice president of topical products at Oxygen Biotherapeutics Inc.—the company originally founded by Clark that produces the Oxycyte brand oxygen carrier. A few years ago, the company moved away from the blood substitute application to explore other uses for the material’s solid stability and interesting gas-carrying properties.
Uses such as treatment for traumatic brain injury, sickle cell crisis pain, trauma, wound care, decompression sickness, acute respiratory distress syndrome, stroke, myocardial infarction, surgery, diabetes and cosmetics were investigated. “We were looking for areas that could benefit from the delivery of oxygen,” said Grossman, who added, in reference to cosmetics, that “human skin needs oxygen for all of its metabolic processes, and it is known that aged or damaged skin is not well-oxygenated.”
FtBu in Skin Care
According to Grossman, humans receive a percentage of respirated oxygen through the skin, which makeup can inhibit. The company therefore focused on the gas-carrying ability of FtBu to develop a topical gel that delivers oxygen into the skin. By employing Oxycyte, the gel reportedly has six times the oxygen solubility of water, allowing it to readily absorb atmospheric oxygen. “When the gel is absorbed, it brings the oxygen into the skin with it,” said Grossman.
From an antioxidant approach, this delivery of oxygen could inadvertentently be equated with the absorption of oxygen free radicals, but these species are not what the gel helps to deliver. Rather, the gel delivers atmospheric oxygen, which is in the stable O2 form. “This stable form of oxygen is what the skin needs for metabolism,” said Grossman. “Free radicals are produced by the body, and when the skin is exposed to a large amount of free radicals, skin cells are damaged.”
While he cannot disclose the composition of the gel, Grossman maintains it is a simple combination of surfactants and water with the maximum use level of FtBu. A gel form was chosen for the product due to its absorption ability, and Grossman notes that the size of the FtBu molecule does not inhibit its absorption. “Oxycyte is a small and dense molecule, so it absorbs quickly into the skin. It is [also] non-volatile, so it doesn’t evaporate like alcohol.”
Aside from its oxygen delivery benefits, the gel is said to moisturize, reduce the appearance of fine lines and promote healthy-looking skin. Grossman adds that users of the gel should experience uniform oxygen absorption regardless of their global location, since atmospheric oxygen is 21% of the air that humans breathe.
Other Uses for FtBu
As noted, the use of FtBu in a topical gel is but one of many. Its gas-carrying ability can be used to treat decompression sickness. “In decompression sickness, Oxycyte is used to dissolve nitrogen [that is] bubbled in the blood to carry it harmlessly to the lungs where it can safely be dispelled.” The company also is in the second phase of clinical trials in Switzerland and Israel to examine the use of intravenous FtBu as an emergency treatment for traumatic brain injuries. “In the case of traumatic brain injury, Oxycyte carries the oxygen to the location in the brain that isn’t receiving oxygen, saving the tissue from necrosis,” said Grossman, who added that the FtBu molecule is much smaller than red blood cells yet has a higher gas-carrying ability than hemoglobin, thus allowing it to deliver oxygen to areas of the body where red blood cells cannot enter.
Clark’s work on the FtBu as a liquid breathing material suggests its use to transfer oxygen into the lungs, which has led to research exploring its use for the treatment of premature babies who do not have enough surfactant in their lungs to successfully breathe on their own.
While other applications are under investigation, the topical gel currently is the only product commercially available and Grossman finds FtBu to supersede all other materials in its ability to carry oxygen.