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Drug Delivery And Targeting Pdf

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Nanoparticle diagram attributed to W. Long, Y. Yi, S.

Drug Delivery Systems

Targeted drug delivery , sometimes called smart drug delivery , [1] is a method of delivering medication to a patient in a manner that increases the concentration of the medication in some parts of the body relative to others. This means of delivery is largely founded on nanomedicine, which plans to employ nanoparticle -mediated drug delivery in order to combat the downfalls of conventional drug delivery.

These nanoparticles would be loaded with drugs and targeted to specific parts of the body where there is solely diseased tissue, thereby avoiding interaction with healthy tissue. The goal of a targeted drug delivery system is to prolong, localize, target and have a protected drug interaction with the diseased tissue. The conventional drug delivery system is the absorption of the drug across a biological membrane , whereas the targeted release system releases the drug in a dosage form.

The advantages to the targeted release system is the reduction in the frequency of the dosages taken by the patient, having a more uniform effect of the drug, reduction of drug side-effects , and reduced fluctuation in circulating drug levels.

The disadvantage of the system is high cost, which makes productivity more difficult and the reduced ability to adjust the dosages. Targeted drug delivery systems have been developed to optimize regenerative techniques. The system is based on a method that delivers a certain amount of a therapeutic agent for a prolonged period of time to a targeted diseased area within the body.

This helps maintain the required plasma and tissue drug levels in the body, thereby preventing any damage to the healthy tissue via the drug. The drug delivery system is highly integrated and requires various disciplines, such as chemists, biologists, and engineers, to join forces to optimize this system.

In traditional drug delivery systems such as oral ingestion or intravascular injection, the medication is distributed throughout the body through the systemic blood circulation. For example, by avoiding the host's defense mechanisms and inhibiting non-specific distribution in the liver and spleen, [4] a system can reach the intended site of action in higher concentrations.

Targeted delivery is believed to improve efficacy while reducing side-effects. When implementing a targeted release system, the following design criteria for the system must be taken into account: the drug properties, side-effects of the drugs, the route taken for the delivery of the drug, the targeted site, and the disease.

Increasing developments to novel treatments requires a controlled microenvironment that is accomplished only through the implementation of therapeutic agents whose side-effects can be avoided with targeted drug delivery. Advances in the field of targeted drug delivery to cardiac tissue will be an integral component to regenerate cardiac tissue.

There are two kinds of targeted drug delivery: active targeted drug delivery, such as some antibody medications, and passive targeted drug delivery, such as the enhanced permeability and retention effect EPR-effect. This ability for nanoparticles to concentrate in areas of solely diseased tissue is accomplished through either one or both means of targeting: passive or active. In passive targeting, the drug's success is directly related to circulation time.

Several substances can achieve this, with one of them being polyethylene glycol PEG. By adding PEG to the surface of the nanoparticle, it is rendered hydrophilic, thus allowing water molecules to bind to the oxygen molecules on PEG via hydrogen bonding. The result of this bond is a film of hydration around the nanoparticle which makes the substance antiphagocytic.

The particles obtain this property due to the hydrophobic interactions that are natural to the reticuloendothelial system RES , thus the drug-loaded nanoparticle is able to stay in circulation for a longer period of time.

Active targeting of drug-loaded nanoparticles enhances the effects of passive targeting to make the nanoparticle more specific to a target site. There are several ways that active targeting can be accomplished. One way to actively target solely diseased tissue in the body is to know the nature of a receptor on the cell for which the drug will be targeted to.

This form of active targeting was found to be successful when utilizing transferrin as the cell-specific ligand. This means of targeting was found to increase uptake, as opposed to non-conjugated nanoparticles. Active targeting can also be achieved by utilizing magnetoliposomes, which usually serves as a contrast agent in magnetic resonance imaging.

Furthermore, a nanoparticle could possess the capability to be activated by a trigger that is specific to the target site, such as utilizing materials that are pH responsive. However, some areas of the body are naturally more acidic than others, and, thus, nanoparticles can take advantage of this ability by releasing the drug when it encounters a specific pH.

One of the side effects of tumors is hypoxia , which alters the redox potential in the vicinity of the tumor. By modifying the redox potential that triggers the payload release the vesicles can be selective to different types of tumors.

By utilizing both passive and active targeting, a drug-loaded nanoparticle has a heightened advantage over a conventional drug. It is able to circulate throughout the body for an extended period of time until it is successfully attracted to its target through the use of cell-specific ligands, magnetic positioning, or pH responsive materials.

Because of these advantages, side effects from conventional drugs will be largely reduced as a result of the drug-loaded nanoparticles affecting only diseased tissue. There are different types of drug delivery vehicles, such as polymeric micelles, liposomes, lipoprotein-based drug carriers, nano-particle drug carriers, dendrimers, etc.

An ideal drug delivery vehicle must be non-toxic, biocompatible, non-immunogenic, biodegradable, [5] and must avoid recognition by the host's defense mechanisms [3]. The most common vehicle currently used for targeted drug delivery is the liposome. The only problem to using liposomes in vivo is their immediate uptake and clearance by the RES system and their relatively low stability in vitro.

To combat this, polyethylene glycol PEG can be added to the surface of the liposomes. PEGylation of the liposomal nanocarrier elongates the half-life of the construct while maintaining the passive targeting mechanism that is commonly conferred to lipid-based nanocarriers.

This nanocarrier system is commonly used in anti-cancer treatments as the acidity of the tumour mass caused by an over-reliance on glycolysis triggers drug release. Another type of drug delivery vehicle used is polymeric micelles. They are prepared from certain amphiphilic co-polymers consisting of both hydrophilic and hydrophobic monomer units. This method offers little in the terms of size control or function malleability.

Techniques that utilize reactive polymers along with a hydrophobic additive to produce a larger micelle that create a range of sizes have been developed. Dendrimers are also polymer-based delivery vehicles. They have a core that branches out in regular intervals to form a small, spherical, and very dense nanocarrier. Biodegradable particles have the ability to target diseased tissue as well as deliver their payload as a controlled-release therapy.

The success of DNA nanotechnology in constructing artificially designed nanostructures out of nucleic acids such as DNA , combined with the demonstration of systems for DNA computing , has led to speculation that artificial nucleic acid nanodevices can be used to target drug delivery based upon directly sensing its environment. These methods make use of DNA solely as a structural material and a chemical, and do not make use of its biological role as the carrier of genetic information. Nucleic acid logic circuits that could potentially be used as the core of a system that releases a drug only in response to a stimulus such as a specific mRNA have been demonstrated.

This structure could encapsulate a drug in its closed state, and open to release it only in response to a desired stimulus. Targeted drug delivery can be used to treat many diseases, such as the cardiovascular diseases and diabetes. However, the most important application of targeted drug delivery is to treat cancerous tumors.

In doing so, the passive method of targeting tumors takes advantage of the enhanced permeability and retention EPR effect.

This is a situation specific to tumors that results from rapidly forming blood vessels and poor lymphatic drainage. When the blood vessels form so rapidly, large fenestrae result that are to nanometers in size, which allows enhanced nanoparticle entry. Further, the poor lymphatic drainage means that the large influx of nanoparticles are rarely leaving, thus, the tumor retains more nanoparticles for successful treatment to take place.

The American Heart Association rates cardiovascular disease as the number one cause of death in the United States. Each year 1. Therefore, there is a need to come up with an optimum recovery system. The key to solving this problem lies in the effective use of pharmaceutical drugs that can be targeted directly to the diseased tissue.

This technique can help develop many more regenerative techniques to cure various diseases. The development of a number of regenerative strategies in recent years for curing heart disease represents a paradigm shift away from conventional approaches that aim to manage heart disease. Developments in targeted drug delivery to tumors have provided the groundwork for the burgeoning field of targeted drug delivery to cardiac tissue.

Liposomes can be used as drug delivery for the treatment of tuberculosis. The traditional treatment for TB is skin to chemotherapy which is not overly effective, which may be due to the failure of chemotherapy to make a high enough concentration at the infection site. The liposome delivery system allows for better microphage penetration and better builds a concentration at the infection site.

Oral intake is not advised because the liposomes break down in the Gastrointestinal System. By printing a plastic 3D shape of the tumor and filling it with the drugs used in the treatment the flow of the liquid can be observed allowing the modification of the doses and targeting location of the drugs. From Wikipedia, the free encyclopedia. Journal of Biotechnology. Mark; Torchilin, Vladimir P.

McGraw-Hill Companies. MIT Tech Talk. Journal of Controlled Release. Expert Opinion on Drug Delivery. Drug Delivery: A Nanomedicine Approach. Australian Biochemist. ACS Publications. Life Sci. Drug Delivery and Nanoparticles: Applications and Hazards. The National Center for Biotechnology Information. Seminars in Oncology. Journal of Clinical Oncology.

American Journal of Clinical Oncology. Chemical Engineering Science. Pharmaceutical Particles and Processing. Clinical Cancer Research. Archived from the original on Physica D: Nonlinear Phenomena. London: Reuters. Topics in medicinal chemistry. Categories : Pharmacokinetics Medicinal chemistry Drug discovery. Namespaces Article Talk. Views Read Edit View history.

Nanosized Drug Delivery Systems: Colloids and Gels for Site Specific Targeting

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Advanced Drug Delivery Reviews

This authoritative volume explores the fundamental concepts and numerous applications of targeted delivery of drugs to the body. Together, the twenty-three chapters cover a wide range of topics in the field, including tumor and hepatic targeting, polymer-drug conjugates, nanoemulsion, physical and biophysical characteristics of nanoparticles, and in vivo imaging techniques, among others. The book also examines advanced characterization techniques, regulatory hurdles and toxicity-related issues that are key features for successful commercialization of targeted drug delivery system products. Targeted Drug Delivery is a comprehensive reference guide for drug delivery researchers, both beginners and those already working in the field. Padma V.

Drugs have long been used to improve health and extend lives. The practice of drug delivery has changed dramatically in the past few decades and even greater changes are anticipated in the near future. Biomedical engineers have contributed substantially to our understanding of the physiological barriers to efficient drug delivery, such as transport in the circulatory system and drug movement through cells and tissues; they have also contributed to the development several new modes of drug delivery that have entered clinical practice. Yet, with all of this progress, many drugs, even those discovered using the most advanced molecular biology strategies, have unacceptable side effects due to the drug interacting with healthy tissues that are not the target of the drug. Side effects limit our ability to design optimal medications for many diseases such as cancer, neurodegenerative diseases, and infectious diseases.

Kumar Bishwajit Sutradhar, Md. Nanoparticles are rapidly being developed and trialed to overcome several limitations of traditional drug delivery systems and are coming up as a distinct therapeutics for cancer treatment. Conventional chemotherapeutics possess some serious side effects including damage of the immune system and other organs with rapidly proliferating cells due to nonspecific targeting, lack of solubility, and inability to enter the core of the tumors resulting in impaired treatment with reduced dose and with low survival rate. Nanotechnology has provided the opportunity to get direct access of the cancerous cells selectively with increased drug localization and cellular uptake.

Targeted drug delivery , sometimes called smart drug delivery , [1] is a method of delivering medication to a patient in a manner that increases the concentration of the medication in some parts of the body relative to others. This means of delivery is largely founded on nanomedicine, which plans to employ nanoparticle -mediated drug delivery in order to combat the downfalls of conventional drug delivery. These nanoparticles would be loaded with drugs and targeted to specific parts of the body where there is solely diseased tissue, thereby avoiding interaction with healthy tissue.

Nanotechnology in Cancer Drug Delivery and Selective Targeting

In recent years, nanosized materials have provided new hope for developing effective therapies for a variety of different diseases, allowing targeted administration of new and traditional drugs, thus increasing efficacy and limiting side effects. Research advances in nanotechnology have offered the Research advances in nanotechnology have offered the possibility of altering the biodistribution of therapeutic agents, enhancing their accumulation in the pathological sites. Nanosized drug delivery systems generally focus on loading or conjugating bioactive molecules in biocompatible colloidal nanocarriers such as nanoparticles, polymer nanotherapeutics, liposomes, etc.

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 - Ты отлично понимаешь, что это за собой влечет - полный доступ АНБ к любой информации.  - Сирена заглушала его слова, но Хейл старался ее перекричать.  - Ты считаешь, что мы готовы взять на себя такую ответственность. Ты считаешь, что кто-нибудь готов. Это же крайне недальновидно.


PDF | Targeted drug delivery system as the name suggests is a science of specifying the drug moiety to targeted area. This type of delivery system is at | Find.


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Targeted Drug Delivery : Concepts and Design

1 Comments

Argentino F. 09.05.2021 at 20:08

PDF | Drug delivery to the body can be divided into two broad groups: (I) Local (II) systemic. The local delivery of drugs is available only for the.

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