An implantable device, comprising a device substrate and an active drug, wherein the device substrate is pure zinc or a medical zinc-based alloy, wherein the device substrate contains 0.1 to 100 percent of zinc and the active drug comprises an anti-allergic drug, characterized in that the implantable device further comprises a zinc complexing agent, wherein the zinc complexing agent and the pure zinc or the medical zinc-based alloy in the device substrate form a complex in the body fluid, wherein the zinc complexing agent contains at least one coordination group selected from the group consisting of hydroxyl-on-polycyclic aromatic hydrocarbon, sulfydryl, amino, an aromatic heterocyclic group, nitroso, carbonyl, sulpho, a phosphate group and an organic phosphorus group, wherein the hydroxyl on the polycyclic aromatic hydrocarbon is a phenolic hydroxyl and the aromatic heterocyclic group is selected from the group consisting of furyl, pyrryl, imidazolyl, triazolyl, thienyl, thiazolyl, pyridyl, a pyridone group, pyranyl, a pyrone group, pyrimidyl, pyridazinyl, pyrazinyl, quinolyl, isoquinolyl, phthalazinyl, pteridyl, indolyl, purinyl and a phenanthroline group, and wherein the zinc complexing agent is selected from the group consisting of: a hydroxyl-on-polycyclic aromatic hydrocarbon-containing polydentate ligand including 8-hydroxyquinoline, 8-hydroxyquinaldine, 4,5-dioxybenzene-1,3-sodium disulfonate, 4-[3,5-bis-hydroxyphenyl-1H-1,2,4-triazole]-benzoic acid and 1-(2-pyridine azo)-2-naphthol; a sulfydryl-containing complexing agent including 8-mercaptoquinoline, mercaptoacetic acid, propyl disulfide and 5-methyl-2-mercapto mercaptobenzoate; an amido-containing complexing agent including ethidene diamine, triethylene tetramine, ethylenediamine tetraacetic acid, ethylene diamine tetraacetic acid tetrasodium, triethylene tetramine and N-(2-ethoxyl)ethidene diamine-N,N',N'-triacetic acid or N'-[5-[[4-[[5-(acetyl hydroxylamine)amyl]ammonia]-1,4-dioxobutyl]hydroxylamine]amyl]-N-(5-amido amyl)-N-hydroxyl succinamide; an aromatic heterocyclic group-containing complexing agent including phenanthroline, dipyridyl, porphyrin, porphin, chlorophyll, hemoglobin or 1,2-dimethyl-3-hydroxyl-4-pyridone; a nitroso-containing polydentate ligand including 1-nitroso-2-naphthol or 1-nitroso-2-naphthol-6-sodium sulfonate; a sulpho-containing polydentate ligand including sulfosalicylic acid and 8-hydroxyquinoline-5-sulphonic acid; a phosphate group-containing polydentate ligand including pyrophosphoric acid, tripolyphosphoric acid, hexametaphosphoric acid, polyphosphoric acid, sodium pyrophosphate, sodium hexametaphosphate or ammonium polyphosphate; an organic phosphorus-containing complexing agent including potassium diethylenetriamine pentamethylene phosphonate or sodium ethylenediamine tetramethylene phosphonate; a carbonyl-containing ligand including carboxylic acid and salt thereof, anhydride, ester, amide, polycarboxylic acid or polyanhydride, and further the carbonyl-containing ligand including gluconic acid, oxalic acid, tartaric acid, malic acid, oxaloacetic acid, fumaric acid, maleic acid, citric acid, nitrilotriacetic acid, diethylene triamine pentacarboxylic acid, alginic acid, glutamic acid, aspartic acid, ornithine, lysine, 1,2-diaminocyctohexane-N,N,N',N'-tetraacetic acid, potassium citrate, calcium citrate, monoglyceride citrate, acetylsalicylic acid, sulpho salicylamide, polyaspartic acid, polyglutamic acid, poly-ornithine, polylysine or polymaleic anhydride.