Discomes are a type of niosomes with advantages similar to polyhedral niosomes. By contrast, discomes consisting of low cholesterol concentration less than 30% mol/mol are prepared by incubating the preformed spherical niosomes in cholesteryl poly-24-oxyethylene ether (Solulan C24) at 75◦C for 1h, achieving the formation of large (11-60μm) and multifaceted vesicular systems. The inherent large size is considered to prevent discomes from being rapidly washed out by tear dynamics. Also, their nonuniform spherical structure can render a better fit on the ocular surface. For instance, discomes have achieved higher encapsulation efficiency (EE%) and ocular bioavailability. These discomes are reported as enhanced and controlled ocular delivery systems. There have been reports on discomes acting as an ocular delivery system for timolol maleate. The prepared discomes have a relatively large quantity of timolol and enhance the ocular bioavailability compared to timolol maleate solution. One possible reason for such scarcity is the necessity for a relatively high temperature during discome preparation that might influence the chemical stability of some thermolabile therapeutic agents. On the contrary, spherical niosomes have been found to have more stable membranes than polyhedral ones due to the presence of cholesterol.
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