TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The gel is an organogel or a hydrogel. The gel film consists essentially of graphene or chemically converted graphene, and water. The available surface area of graphene or chemically converted graphene is at least 1000 m2/mg. The dispersion medium (which is water or an organic liquid) comprises a drug. The dispersion medium includes at least one additive (which is added to the gel film once the gel film has been separated from the surface). Preferred Method: The method further includes: applying a conductive layer onto the surface before the step of contacting the surface with the dispersion medium comprising sheets of graphene or chemically converted graphene; separating the gel film from the surface; and increasing the temperature of the dispersion medium comprising sheets of graphene or chemically converted graphene. The temperature is increased (to 90, 95, 100, 125 or 150 degrees C): to control the resultant inter-sheet spacing in the gel film that forms on the surface; to result in gel film that permits passage of particles having an average diameter but does not permit passage of particles having a diameter larger than the first average diameter; and before the step of contacting the surface. The dispersion medium comprising sheets of graphene or chemically converted graphene dispersed is cooled before the step of contacting the surface. The surface is a filter, and dispersion medium is removed from the surface by passage through the filter, where filtration is performed under vacuum. EXAMPLE - Chemically converted graphene (CCG) was prepared by using graphene, water, hydrazine and ammonia solution. CCG was dispersed in water to a concentration of 0.37 mg/ml. The liquid comprising graphene sheets dispersed was filtered through a mixed cellulose esters filter membrane (47 mm in diameter, 0.05 mu m pore size) by vacuum suction. During the vacuum filtration, a uniform layer of black CCG was immediately formed on the filter membrane, with constant concentration of CCG during the filtration-process. The concentrations of the dispersion solution were monitored using UV-visible spectroscopy. The filtration was finished when there was no visible CCG dispersion left on the filter membrane. Relatively thick films (greater than 65 mu m) were carefully peeled off from the filter membrane using tweezers. The resultant gel film was immediately transferred to a Petri dish and immersed in water overnight to remove the remaining ammonia and unreacted hydrazine. The films were stored in water prior to use and were cut into required sizes for various tests using scissors.