Lakhasly

Abstract: Background: Personalized medicines are becoming more popular as they enable the use of patient’s genomics and hence help in better drug design with fewer side effects. In fact, several doses can be combined into one dosage form which suits the patient’s demography. 3 Dimensional (3D) printing technology for personalized medicine is a modern day treatment method based on genomics of patient.
Methods: 3D printing technology uses digitally controlled devices for formulating API and excipients in a layer by layer pattern for developing a suitable personalized drug delivery system as per the need of patient. It includes various techniques like inkjet printing, fused deposition modelling which can further be classified into continuous inkjet system and drop on demand. In order to formulate such dosage forms, scientists have used various poly- mers to enhance their acceptance as well as therapeutic efficacy. Polymers like polyvinyl alcohol, poly (lactic acid) (PLA), poly (caprolactone) (PCL) etc can be used during manufacturing.
Results: Varying number of dosage forms can be produced using 3D printing technology including immediate release tablets, pulsatile release tablets, and transdermal dosage forms etc. The 3D printing technology can be explored successfully to develop personalized medicines which could play a vital role in the treatment of life- threatening diseases. Particularly, for patients taking multiple medicines, 3D printing method could be explored to design a single dosage in which various drugs can be incorporated. Further 3D printing based personalized drug delivery system could also be investigated in chemotherapy of cancer patients with the added advantage of the reduction in adverse effects.
Conclusion: In this article, we have reviewed 3D printing technology and its uses in personalized medicine. Further, we also discussed the different techniques and materials used in drug delivery based on 3D printing along with various applications of the technology.
Keywords: 3D printing, personalized medicine, polymers, dosage forms, patient’s genomics, personalized drug delivery system.

1. INTRODUCTION
   Drug development sector has seen a vast change and growth in treatment option which provide more efficient and safe medica- tions. One of the renowned growth seen is personalized medicine (PM). PM has potential to provide treatment with best responses and highest safety margins. This reduces side effects and ensure better patient safety [1, 2]. PM aims to join different wave of ‘om- ics’ that tends to alter drug choices, dosages, and interventions to the biology of individual patients. Its goals are to target better healthcare, facilitate research and discovery of diagnostics and therapies, as well as to predict individual predispositions to diseases or conditions [3, 4]. Herceptin for breast cancer failed in Phase III trials in 1997 as the drug was found ineffective in overall popula- tions but after careful review it was found that women who tested positive for HER2 overexpression showed significantly better re- sponse. Thus in 1998, FDA was presented clinical trial data HER2- positive group, defined by a diagnostic test, would benefit from the drug, and they approved the drug/diagnostic combination [5]. In Europe, Amgen’s colon cancer drug, Vectibix [6] was rejected and marked unapproved by regulators for marketing because it does not found to be applicable to wide range of patients. The company per- formed overall assessment of data and discovered that Vectibix performed better in patients whose tumor lacked KRAS gene muta- tion. The drug was then granted permission for those patients only [7].
   *Address correspondence to this author at the Centre of Pharmaceutics, School of Pharmaceutical Sciences, Delhi Pharmaceutical Sciences and Research University (DPSRU), New Delhi - 110017, India;
   E-mail: [email protected]
   Physician can therefore use profile of a patient’s gene variations which helps in selection of drug and therapeutic options that re- duces side effects giving successful outcomes. Moreover the indi- vidual’s susceptibility to certain diseases could be recognized be- fore the occurrence and hence PM could be used as prophylaxis to prevention of diseases in susceptible individuals. With the help of PM, physicians can now go beyond the one-size-fits-all model of prescribing medications to make more effective clinical decisions for each patient since due to patient inherited variations in their gene results in different responses of gene towards particular drugs which could vary from individual-to-individual. Therefore PM as a new technology has procreated a new discipline named pharmaco- genomics which find out the appropriate gene affecting the result of medications [1, 2, 8]. In order to develop personalized medicine different strategies are being explored by scientists, one of which is 3D printing which we have discussed in the next part of this article.