3D printing processes in precise drug delivery for personalized medicine Haisheng Peng, Bo Han, Tianjian Tong, Xin Jin, Yanbo Peng, Meitong Guo, Bian Li, Jiaxin Ding, Qingfei Kong, Qun Wang Abstract: With the advent of personalized medicine, the drug delivery system will be significantly changed. The development of personalized medicine requires the support of many technologies, among which three-dimensional printing (3DP) technology is a novel formulation-preparing process that creates 3D objects by depositing printing materials layer-by-layer based on the computer-aided design method. Compared with traditional pharmaceutical processes, 3DP produces complex drug combinations, personalized dosage, and flexible shape and structure of dosage forms (DFs) on demand. In the future, personalized 3DP drugs may supplement and even replace their traditional counterpart. We systematically introduce the applications of 3DP technologies in the pharmaceutical industry and summarize the virtues and shortcomings of each technique. The release behaviors and control mechanisms of the pharmaceutical DFs with desired structures are also analyzed. Finally, the benefits, challenges, and prospects of 3DP technology to the pharmaceutical industry are discussed. Keywords: personalized medicine; 3D printing; dosage form; precise drug delivery Introduction: Drug delivery is a process or method by which a drug is administered to an animal or person to achieve a desired therapeutic effect. A drug delivery system (DDS) is a device or formulation that delivers active pharmaceutical agents (APIs) into the body. It enhances their efficacy and safety by tuning the drug release rate, time, and location. The ultimate goal of DDS is to realize predefined drug release patterns that ensure optimized drug absorption and tissue distribution to improve clinical outcomes and patient compliance by providing safer, more effective, and more convenient delivery modes. Drugs can enter the body through various routes using gastrointestinal, parenteral, transmucosal, transdermal, and pulmonary DDSs. They can produce systemic effects or realize target delivery to specific organs or diseases. The main factors in choosing the route of drug delivery are disease, the expected effects, and available medicine. Traditional formulations follow a 'one-size-fits-all' principle, which means adapting the patient to the drug rather than the other way around, resulting in a greater probability of side effects, most of which are dose-dependent and occur at therapeutic doses. The traditional formulations can not achieve precise drug delivery according to patients' unique requirements, especially for children and the aged, which may lead to poor patient compliance. Therefore, due to the spates of adverse reactions associated with 'standard' drugs, customized drugs and dosages have received increasing attention. At the beginning of the era of personalized medicine in medical practice, patients will be guided to select the most effective and safest therapeutic regimen based on the results of genetic tests and proteomics and metabolomics analysis. Personalized medicine will direct patients to take the right medicine in the correct dose and schedule. Scientists3D printing processes in precise drug delivery for personalized medicine Haisheng Peng, Bo Han, Tianjian Tong, Xin Jin, Yanbo Peng, Meitong Guo, Bian Li, Jiaxin Ding, Qingfei Kong, Qun Wang Abstract: With the advent of personalized medicine, the drug delivery system will be significantly changed. The development of personalized medicine requires the support of many technologies, among which three-dimensional printing (3DP) technology is a novel formulation-preparing process that creates 3D objects by depositing printing materials layer-by-layer based on the computer-aided design method. Compared with traditional pharmaceutical processes, 3DP produces complex drug combinations, personalized dosage, and flexible shape and structure of dosage forms (DFs) on demand. In the future, personalized 3DP drugs may supplement and even replace their traditional counterpart. We systematically introduce the applications of 3DP technologies in the pharmaceutical industry and summarize the virtues and shortcomings of each technique. The release behaviors and control mechanisms of the pharmaceutical DFs with desired structures are also analyzed. Finally, the benefits, challenges, and prospects of 3DP technology to the pharmaceutical industry are discussed. Keywords: personalized medicine; 3D printing; dosage form; precise drug delivery Introduction: Drug delivery is a process or method by which a drug is administered to an animal or person to achieve a desired therapeutic effect. A drug delivery system (DDS) is a device or formulation that delivers active pharmaceutical agents (APIs) into the body. It enhances their efficacy and safety by tuning the drug release rate, time, and location. The ultimate goal of DDS is to realize predefined drug release patterns that ensure optimized drug absorption and tissue distribution to improve clinical outcomes and patient compliance by providing safer, more effective, and more convenient delivery modes. Drugs can enter the body through various routes using gastrointestinal, parenteral, transmucosal, transdermal, and pulmonary DDSs. They can produce systemic effects or realize target delivery to specific organs or diseases. The main factors in choosing the route of drug delivery are disease, the expected effects, and available medicine. Traditional formulations follow a 'one-size-fits-all' principle, which means adapting the patient to the drug rather than the other way around, resulting in a greater probability of side effects, most of which are dose-dependent and occur at therapeutic doses. The traditional formulations can not achieve precise drug delivery according to patients' unique requirements, especially for children and the aged, which may lead to poor patient compliance. Therefore, due to the spates of adverse reactions associated with 'standard' drugs, customized drugs and dosages have received increasing attention. At the beginning of the era of personalized medicine in medical practice, patients will be guided to select the most effective and safest therapeutic regimen based on the results of genetic tests and proteomics and metabolomics analysis. Personalized medicine will direct patients to take the right medicine in the correct dose and schedule. Scientists