A drug-loaded microbead composition comprising: microbeads comprising a water-swellable polymer material; and a complex comprising a carrier and a therapeutic agent chemically bonded to the carrier, wherein: the complex is embedded within the polymer material; the drug-loaded microbead composition has a water content of less than 1% by weight, based on the total weight of the drug-loaded microbead composition the water-swellable polymer material is a biodegradable polymer material chosen from poly(4-hydroxybutyrate), methacrylated hyaluronic acids, chitosan-alginate, poly( N -isopropylacrylamide) copolymers, poly( N -isopropylacrylamide)-alginates, poly( N -isopropylacrylamide)-peptides, poly( N -isopropylacrylamide)-a-acryloyloxy-β,β-dimethyl-γ-butyrolactone-hydrophilic Jeffamine, poly( N -isopropylacrylamide)-poly(ethylene glycol) diacrylate-pentaerythritol tetrakis(3-mercaptopropionate), or combinations of any of the foregoing; and the therapeutic agent is chosen from doxorubicin, sorafenib, vandetanib, nivolumab, ipilimumab, regorafenib, irinotecan, epirubicin, pirarubicin, 5-fluorouracil, cisplatin, floxuridine, mitomycin C, therapeutically acceptable salts of any of the foregoing, or combinations of any of the foregoing. microbeads comprising a water-swellable polymer material; and a complex comprising a carrier and a therapeutic agent chemically bonded to the carrier, wherein: the complex is embedded within the polymer material; the drug-loaded microbead composition has a water content of less than 1% by weight, based on the total weight of the drug-loaded microbead composition the water-swellable polymer material is a biodegradable polymer material chosen from poly(4-hydroxybutyrate), methacrylated hyaluronic acids, chitosan-alginate, poly( N -isopropylacrylamide) copolymers, poly( N -isopropylacrylamide)-alginates, poly( N -isopropylacrylamide)-peptides, poly( N -isopropylacrylamide)-a-acryloyloxy-β,β-dimethyl-γ-butyrolactone-hydrophilic Jeffamine, poly( N -isopropylacrylamide)-poly(ethylene glycol) diacrylate-pentaerythritol tetrakis(3-mercaptopropionate), or combinations of any of the foregoing; and the therapeutic agent is chosen from doxorubicin, sorafenib, vandetanib, nivolumab, ipilimumab, regorafenib, irinotecan, epirubicin, pirarubicin, 5-fluorouracil, cisplatin, floxuridine, mitomycin C, therapeutically acceptable salts of any of the foregoing, or combinations of any of the foregoing. the complex is embedded within the polymer material; the drug-loaded microbead composition has a water content of less than 1% by weight, based on the total weight of the drug-loaded microbead composition the water-swellable polymer material is a biodegradable polymer material chosen from poly(4-hydroxybutyrate), methacrylated hyaluronic acids, chitosan-alginate, poly( N -isopropylacrylamide) copolymers, poly( N -isopropylacrylamide)-alginates, poly( N -isopropylacrylamide)-peptides, poly( N -isopropylacrylamide)-a-acryloyloxy-β,β-dimethyl-γ-butyrolactone-hydrophilic Jeffamine, poly( N -isopropylacrylamide)-poly(ethylene glycol) diacrylate-pentaerythritol tetrakis(3-mercaptopropionate), or combinations of any of the foregoing; and the therapeutic agent is chosen from doxorubicin, sorafenib, vandetanib, nivolumab, ipilimumab, regorafenib, irinotecan, epirubicin, pirarubicin, 5-fluorouracil, cisplatin, floxuridine, mitomycin C, therapeutically acceptable salts of any of the foregoing, or combinations of any of the foregoing. based on the total weight of the drug-loaded microbead composition the water-swellable polymer material is a biodegradable polymer material chosen from poly(4-hydroxybutyrate), methacrylated hyaluronic acids, chitosan-alginate, poly( N -isopropylacrylamide) copolymers, poly( N -isopropylacrylamide)-alginates, poly( N -isopropylacrylamide)-peptides, poly( N -isopropylacrylamide)-a-acryloyloxy-β,β-dimethyl-γ-butyrolactone-hydrophilic Jeffamine, poly( N -isopropylacrylamide)-poly(ethylene glycol) diacrylate-pentaerythritol tetrakis(3-mercaptopropionate), or combinations of any of the foregoing; and the therapeutic agent is chosen from doxorubicin, sorafenib, vandetanib, nivolumab, ipilimumab, regorafenib, irinotecan, epirubicin, pirarubicin, 5-fluorouracil, cisplatin, floxuridine, mitomycin C, therapeutically acceptable salts of any of the foregoing, or combinations of any of the foregoing.