A method for preparing a sol-gel derived SiO 2 - monolith, with a minimum diameter of ≥ 0.5 mm, - coating, with a thickness of < 0.5 mm, or - particle, with a maximum diameter of ≤ 100 μm, comprising a specific percentage or percentages of a biologically active agent or agents other than the SiO 2 itself with or without protective agent or agents for said biologically active agent or agents, wherein method a sol-gel derived SiO 2 is prepared from a sol comprising water, an alkoxide or inorganic silicate and a lower alcohol, i.e. an alcohol with ≤ 4 carbons, using a mineral acid or a base as a catalyst, preferably a mineral acid, and said sol is aged and dried characterised in that a) in the sol the starting i) pH is from 0.05 to 2.5, preferably 1.5 to 2.5, most preferably 2.0, ii) molar ratio of water to the alkoxide or inorganic silicate is 0.5 to 2.5; preferably 1.5 to 2.5, iii) molar ratio of alcohol to the alkoxide or inorganic silicate is ≥ 0.5, preferably ≥ 1.0; and b) either, i) without induced changes of sol composition, - gelation of the sol is done by spray-drying or freeze-drying of the sol, or ii) a change or changes of sol composition, selected from the group consisting of adding water, adding the alkoxide or inorganic silicate, adding the alcohol or the catalyst, adjusting pH by adding an acid, base or buffer or adding said biologically active agent or agents, are induced after sol ageing but before gel formation, and the ratio t/t gel is ≥ 0.005, preferably ≥ 0.1, most preferably ≥ 0.9, wherein t is the ageing time of the sol, i.e. time from preparation of said sol to the induced changes, and t gel is the time point where the sol would have turned to a gel without the induced changes; and spray-drying or freeze-drying of the sol is carried out or initiated within a time of ≤ 30 minutes, preferably ≤ 15 minutes, most preferably ≤ 5 minutes, from said induced change or changes. - monolith, with a minimum diameter of ≥ 0.5 mm, - coating, with a thickness of < 0.5 mm, or - particle, with a maximum diameter of ≤ 100 μm, a) in the sol the starting i) pH is from 0.05 to 2.5, preferably 1.5 to 2.5, most preferably 2.0, ii) molar ratio of water to the alkoxide or inorganic silicate is 0.5 to 2.5; preferably 1.5 to 2.5, iii) molar ratio of alcohol to the alkoxide or inorganic silicate is ≥ 0.5, preferably ≥ 1.0; and i) pH is from 0.05 to 2.5, preferably 1.5 to 2.5, most preferably 2.0, ii) molar ratio of water to the alkoxide or inorganic silicate is 0.5 to 2.5; preferably 1.5 to 2.5, iii) molar ratio of alcohol to the alkoxide or inorganic silicate is ≥ 0.5, preferably ≥ 1.0; and b) either, i) without induced changes of sol composition, - gelation of the sol is done by spray-drying or freeze-drying of the sol, or ii) a change or changes of sol composition, selected from the group consisting of adding water, adding the alkoxide or inorganic silicate, adding the alcohol or the catalyst, adjusting pH by adding an acid, base or buffer or adding said biologically active agent or agents, are induced after sol ageing but before gel formation, and the ratio t/t gel is ≥ 0.005, preferably ≥ 0.1, most preferably ≥ 0.9, wherein t is the ageing time of the sol, i.e. time from preparation of said sol to the induced changes, and t gel is the time point where the sol would have turned to a gel without the induced changes; and i) without induced changes of sol composition, - gelation of the sol is done by spray-drying or freeze-drying of the sol, or - gelation of the sol is done by spray-drying or freeze-drying of the sol, or ii) a change or changes of sol composition, selected from the group consisting of adding water, adding the alkoxide or inorganic silicate, adding the alcohol or the catalyst, adjusting pH by adding an acid, base or buffer or adding said biologically active agent or agents, are induced after sol ageing but before gel formation, and the ratio t/t gel is ≥ 0.005, preferably ≥ 0.1, most preferably ≥ 0.9, wherein t is the ageing time of the sol, i.e. time from preparation of said sol to the induced changes, and t gel is the time point where the sol would have turned to a gel without the induced changes; and the ratio t/t gel is ≥ 0.005, preferably ≥ 0.1, most preferably ≥ 0.9, wherein t is the ageing time of the sol, i.e. time from preparation of said sol to the induced changes, and t gel is the time point where the sol would have turned to a gel without the induced changes; and