Patent ID: 8343514

Claim:
A sol-gel nanostructured titania reservoir in the form of a xerogel comprising silica, titania and silica-titania, obtained by the method comprising the steps of: i) putting in a three-necked flask a mixture consisting of 36 ml of deionized water; from 0 to 50 ml of ethylene diamine tetraacetic acid (EDTA) and 190 ml of tert-butanol; ii) adding HNO 3 to the solution in a dropwise manner in order to adjust the pH to 2 when a basic drug is to be occluded within the interior of the reservoir; and adding ammonium hydroxide in a dropwise manner to the solution to adjust the pH to 12 when an acidic drug is to be occluded within the interior of the reservoir; and refluxing the solution; iii) adding 87 ml of titanium n-butoxide and 21.5 ml of tetraethoxysilane to the solution being refluxed to obtain a colloidal suspension; iv) refluxing the colloidal suspension for an additional period of 24 hours; v) drying the samples under vacuum conditions at 104 mm Hg in order to remove excess water and alcohol; and vi) drying the samples at 30° C. for 72 hours using an inert atmosphere furnace, increasing the temperature at a rate of 0.25° C/min in order to reach the final drying temperature of 30° C., wherein the pH is verified continually by means of a potentiometer during said refluxing; said reservoir having, if it comprises a drug, a constant rate of drug release over periods of 6 months to 3 years.