Drug delivery refers to approaches, formulations, manufacturing techniques, storage systems, and technologies involved in transporting a pharmaceutical compound to its target site to achieve a desired therapeutic effect. Principles related to drug preparation, route of administration, site-specific targeting, metabolism, and toxicity are used to optimize efficacy and safety, and to improve patient convenience and compliance. Drug delivery is aimed at altering a drug's pharmacokinetics and specificity by formulating it with different excipients, drug carriers, and medical devices. There is additional emphasis on increasing the bioavailability and duration of action of a drug to improve therapeutic outcomes. Some research has also been focused on improving safety for the person administering the medication. For example, several types of microneedle patches have been developed for administering vaccines and other medications to reduce the risk of needlestick injury.
Drug delivery is a concept heavily integrated with dosage form and route of administration, the latter sometimes being considered part of the definition. While route of administration is often used interchangeably with drug delivery, the two are separate concepts. Route of administration refers to the path a drug takes to enter the body, whereas drug delivery also encompasses the engineering of delivery systems and can include different dose forms and devices used to deliver a drug through the same route. Common routes of administration include oral, parenteral (injected), sublingual, topical, transdermal, inhaled, rectal, and vaginal, however drug delivery is not limited to these routes and there may be several ways to deliver medications through each route.
Since the approval of the first controlled-release formulation in the 1950s, research into new delivery systems has been progressing, as opposed to new drug development which has been declining. Several factors may be contributing to this shift in focus. One of the driving factors is the high cost of developing new drugs. A 2013 review found the cost of developing a delivery system was only 10% of the cost of developing a new pharmaceutical. A more recent study found the median cost of bringing a new drug to market was $985 million in 2020, but did not look at the cost of developing drug delivery systems. Other factors that have potentially influenced the increase in drug delivery system development may include the increasing prevalence of both chronic and infectious diseases, as well as a general increased understanding of the pharmacology, pharmacokinetics, and pharmacodynamics of many drugs.
Current efforts in drug delivery are vast and include topics such as controlled-release formulations, targeted delivery, nanomedicine, drug carriers, 3D printing, and the delivery of biologic drugs.
Targeted drug delivery is the delivery of a drug to its target site without having an effect on other tissues. Interest in targeted drug delivery has grown drastically due to its potential implications in the treatment of cancers and other chronic diseases. In order to achieve efficient targeted delivery, the designed system must avoid the host's defense mechanisms and circulate to its intended site of action. A number of drug carriers have been studied to effectively target specific tissues, including liposomes, nanogels, and other nanotechnologies.
Controlled or modified-release formulations alter the rate and timing at which a drug is liberated, in order to produce adequate or sustained drug concentrations. The first controlled-release (CR) formulation that was developed was Dexedrine in the 1950s. This period of time saw more drugs being formulated as CR, as well as the introduction of transdermal patches to allow drugs to slowly absorb through the skin. Since then, countless other CR products have been developed to account for the physiochemical properties of different drugs, such as depot injections for antipsychotics and sex hormones that require dosing once every few months.
Delivery of biologic drugs
Pharmaceutical preparations containing peptides, proteins, antibodies, genes, or other biologic components often face absorption issues due to their large sizes or electrostatic charges, and may be susceptible to enzymatic degradation once they have entered the body. For these reasons, recent efforts in drug delivery have been focused on methods to avoid these issues through the use of liposomes, nanoparticles, fusion proteins, and many others.
- Acoustic targeted drug delivery
- Asymmetric membrane capsule
- Bovine submaxillary mucin coatings
- Chemotactic drug-targeting
- Drug delivery to the brain
- Drug carrier
- Magnetic drug delivery
- Neural drug delivery systems
- Retrometabolic drug design
- Self-microemulsifying drug delivery system
- Thin film drug delivery
- "Drug Delivery Systems (definition)". www.reference.md. Retrieved 2021-04-20.
- Rayaprolu, Bindhu Madhavi; Strawser, Jonathan J.; Anyarambhatla, Gopal (2018-10-03). "Excipients in parenteral formulations: selection considerations and effective utilization with small molecules and biologics". Drug Development and Industrial Pharmacy. 44 (10): 1565–1571. doi:10.1080/03639045.2018.1483392. ISSN 0363-9045. PMID 29863908. S2CID 46934375.
- Tiwari, Gaurav; Tiwari, Ruchi; Sriwastawa, Birendra; Bhati, L; Pandey, S; Pandey, P; Bannerjee, Saurabh K (2012). "Drug delivery systems: An updated review". International Journal of Pharmaceutical Investigation. 2 (1): 2–11. doi:10.4103/2230-973X.96920. ISSN 2230-973X. PMC 3465154. PMID 23071954.
- Li, Junwei; Zeng, Mingtao; Shan, Hu; Tong, Chunyi (2017-08-23). "Microneedle Patches as Drug and Vaccine Delivery Platform". Current Medicinal Chemistry. 24 (22): 2413–2422. doi:10.2174/0929867324666170526124053. PMID 28552053.
- editor., Tekade, Rakesh K. (30 November 2018). Basic fundamentals of drug delivery. ISBN 978-0-12-817910-9. OCLC 1078149382.CS1 maint: extra text: authors list (link)
- Allen, T. M. (2004-03-19). "Drug Delivery Systems: Entering the Mainstream". Science. 303 (5665): 1818–1822. Bibcode:2004Sci...303.1818A. doi:10.1126/science.1095833. ISSN 0036-8075. PMID 15031496. S2CID 39013016.
- Singh, Akhand Pratap; Biswas, Arpan; Shukla, Aparna; Maiti, Pralay (2019-08-30). "Targeted therapy in chronic diseases using nanomaterial-based drug delivery vehicles". Signal Transduction and Targeted Therapy. 4 (1): 33. doi:10.1038/s41392-019-0068-3. ISSN 2059-3635. PMC 6799838. PMID 31637012.
- Kim, Yeu-Chun; Park, Jung-Hwan; Prausnitz, Mark R. (November 2012). "Microneedles for drug and vaccine delivery". Advanced Drug Delivery Reviews. 64 (14): 1547–1568. doi:10.1016/j.addr.2012.04.005. PMC 3419303. PMID 22575858.
- Nahler, Gerhard (2017). Dictionary of Pharmaceutical Medicine. Springer, Cham. p. 96. doi:10.1007/978-3-319-50669-2_4. ISBN 978-3-319-50669-2.
- "route of administration - definition of route of administration in the Medical dictionary - by the Free Online Medical Dictionary, Thesaurus and Encyclopedia". 2011-06-12. Archived from the original on 2011-06-12. Retrieved 2021-04-20.
- Jain, Kewal K. (2020), Jain, Kewal K. (ed.), "An Overview of Drug Delivery Systems", Drug Delivery Systems, Methods in Molecular Biology, New York, NY: Springer New York, 2059, pp. 1–54, doi:10.1007/978-1-4939-9798-5_1, ISBN 978-1-4939-9797-8, PMID 31435914, retrieved 2021-04-20
- "COMMON ROUTES OF DRUG ADMINISTRATION". media.lanecc.edu. Retrieved 2021-04-20.
- Park, Kinam (September 2014). "Controlled drug delivery systems: Past forward and future back". Journal of Controlled Release. 190: 3–8. doi:10.1016/j.jconrel.2014.03.054. PMC 4142099. PMID 24794901.
- Scannell, Jack W.; Blanckley, Alex; Boldon, Helen; Warrington, Brian (March 2012). "Diagnosing the decline in pharmaceutical R&D efficiency". Nature Reviews Drug Discovery. 11 (3): 191–200. doi:10.1038/nrd3681. ISSN 1474-1776. PMID 22378269. S2CID 3344476.
- ltd, Research and Markets. "Pharmaceutical Drug Delivery Market Forecast to 2027 - COVID-19 Impact and Global Analysis by Route of Administration; Application; End User, and Geography". www.researchandmarkets.com. Retrieved 2021-04-24.
- He, Huining; Liang, Qiuling; Shin, Meong Cheol; Lee, Kyuri; Gong, Junbo; Ye, Junxiao; Liu, Quan; Wang, Jingkang; Yang, Victor (2013-12-01). "Significance and strategies in developing delivery systems for bio-macromolecular drugs". Frontiers of Chemical Science and Engineering. 7 (4): 496–507. doi:10.1007/s11705-013-1362-1. ISSN 2095-0187. S2CID 97347142.
- Wouters, Olivier J.; McKee, Martin; Luyten, Jeroen (2020-03-03). "Estimated Research and Development Investment Needed to Bring a New Medicine to Market, 2009-2018". JAMA. 323 (9): 844–853. doi:10.1001/jama.2020.1166. ISSN 0098-7484. PMC 7054832. PMID 32125404.
- PricewaterhouseCoopers. "Chronic diseases and conditions are on the rise". PwC. Retrieved 2021-04-25.
- Li, Chong; Wang, Jiancheng; Wang, Yiguang; Gao, Huile; Wei, Gang; Huang, Yongzhuo; Yu, Haijun; Gan, Yong; Wang, Yongjun; Mei, Lin; Chen, Huabing; Hu, Haiyan; Zhang, Zhiping; Jin, Yiguang (2019-11-01). "Recent progress in drug delivery". Acta Pharmaceutica Sinica B. 9 (6): 1145–1162. doi:10.1016/j.apsb.2019.08.003. ISSN 2211-3835. PMC 6900554. PMID 31867161.
- "Drug Delivery Systems". www.nibib.nih.gov. Retrieved 2021-04-25.
- Tekade, Rakesh K.; Maheshwari, Rahul; Soni, Namrata; Tekade, Muktika; Chougule, Mahavir B. (2017-01-01). "Nanotechnology for the Development of Nanomedicine". Nanotechnology-Based Approaches for Targeting and Delivery of Drugs and Genes: 3–61. doi:10.1016/B978-0-12-809717-5.00001-4. ISBN 9780128097175.
- Madhusudana Rao, Kummara; Krishna Rao, Kummari S.V.; Ha, Chang-Sik (2018-01-01). "Functional stimuli-responsive polymeric network nanogels as cargo systems for targeted drug delivery and gene delivery in cancer cells". Design of Nanostructures for Theranostics Applications: 243–275. doi:10.1016/B978-0-12-813669-0.00006-3. ISBN 9780128136690.
- Patra, Jayanta Kumar; Das, Gitishree; Fraceto, Leonardo Fernandes; Campos, Estefania Vangelie Ramos; Rodriguez-Torres, Maria del Pilar; Acosta-Torres, Laura Susana; Diaz-Torres, Luis Armando; Grillo, Renato; Swamy, Mallappa Kumara; Sharma, Shivesh; Habtemariam, Solomon (December 2018). "Nano based drug delivery systems: recent developments and future prospects". Journal of Nanobiotechnology. 16 (1): 71. doi:10.1186/s12951-018-0392-8. ISSN 1477-3155. PMC 6145203. PMID 30231877.
- Amidon, Seth; Brown, Jack E.; Dave, Vivek S. (August 2015). "Colon-Targeted Oral Drug Delivery Systems: Design Trends and Approaches". AAPS PharmSciTech. 16 (4): 731–741. doi:10.1208/s12249-015-0350-9. ISSN 1530-9932. PMC 4508299. PMID 26070545.
- Bertrand, Nicolas; Leroux, Jean-Christophe (2012-07-20). "The journey of a drug-carrier in the body: An anatomo-physiological perspective". Journal of Controlled Release. 161 (2): 152–163. doi:10.1016/j.jconrel.2011.09.098. ISSN 0168-3659. PMID 22001607.
- Rudokas, Mindaugas; Najlah, Mohammad; Alhnan, Mohamed Albed; Elhissi, Abdelbary (2016). "Liposome Delivery Systems for Inhalation: A Critical Review Highlighting Formulation Issues and Anticancer Applications". Medical Principles and Practice. 25 (2): 60–72. doi:10.1159/000445116. ISSN 1011-7571. PMC 5588529. PMID 26938856.
- Perrie, Yvonne (2012). Pharmaceutics- Drug Delivery and Targeting. FASTtrack. pp. 1–19. ISBN 978-0-85711-059-6.
- Yun, Yeon Hee; Lee, Byung Kook; Park, Kinam (December 2015). "Controlled Drug Delivery: Historical perspective for the next generation". Journal of Controlled Release. 219: 2–7. doi:10.1016/j.jconrel.2015.10.005. PMC 4656096. PMID 26456749.
- Lindenmayer, Jean-Pierre; Glick, Ira D.; Talreja, Hiteshkumar; Underriner, Michael (July 2020). "Persistent Barriers to the Use of Long-Acting Injectable Antipsychotics for the Treatment of Schizophrenia". Journal of Clinical Psychopharmacology. 40 (4): 346–349. doi:10.1097/JCP.0000000000001225. ISSN 1533-712X. PMID 32639287.
- Mishell, D. R. (May 1996). "Pharmacokinetics of depot medroxyprogesterone acetate contraception". The Journal of Reproductive Medicine. 41 (5 Suppl): 381–390. ISSN 0024-7758. PMID 8725700.
- Strohl, William R. (January 2018). "Current progress in innovative engineered antibodies". Protein & Cell. 9 (1): 86–120. doi:10.1007/s13238-017-0457-8. ISSN 1674-800X. PMC 5777977. PMID 28822103.
- Marschall, Andrea L J; Frenzel, André; Schirrmann, Thomas; Schüngel, Manuela; Dübel, Stefan (2011). "Targeting antibodies to the cytoplasm". mAbs. 3 (1): 3–16. doi:10.4161/mabs.3.1.14110. ISSN 1942-0862. PMC 3038006. PMID 21099369.