Drug delivery refers to approaches for transporting pharmaceutical compounds in the body to achieve therapeutic effects safely. Traditional drug delivery distributes medication throughout the body, but targeted delivery aims to concentrate medication in specific organs. Common drug delivery vehicles include liposomes, polymeric micelles, dendrimers, and biodegradable nanoparticles, which must be non-toxic and avoid immune responses. Liposomes are frequently used and can carry both hydrophobic and hydrophilic drugs by encapsulating an aqueous core within a lipid bilayer membrane.

1. Presented by :-

2. Definition:
 Drug delivery refers to approaches, formulations, technologies, and systems
for transporting a pharmaceutical compound in the body as needed to safely
achieve its desired therapeuticpeutic effect.
 Drugs have long been used to improve health & extend lives.
 There are many success stories concerning the use of drugs and vaccines in
the in the treatment, prevention and in some cases even eradication of
diseases (e.g.smallpox)

3.  It is necessary to develop suitable dosage forms or drug delivery systems to
allow the effective, safe and reliable application of these bioactive
compounds to the patient.
 Indeed the drug delivery system employed plays a vital role in controlling
the pharmacological effect of the drug as it can influence the rate of drug
release, the site and duration of drug action and subsequently the side-effect
profile. An optimal drug delivery system ensure that the active drug is
available at the site of action for the correct time and duration.

4.  In traditional drug delivery systems such as oral ingestion or intravascular
injection, the medication is distributed throughout the body through the
systems blood circulation for most therapeutic agents, only a small portion of
the medication reaches the organ to be affected.
 Targeted drug delivery, sometimes called smart drug delivery or intelligent
drug delivery, 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.
 The conventional drug delivery system is the absorption of the drug across a
biological membranes, whereas the targeted release system release the drug
in a dosage form.

5.  There are different types of drug delivery vehicle, such as liposomes, polymeric
micelles, lipoprotein-based drug carriers, nano-particle drug carriers, dendrimers, etc.
An ideal drug delivery vehicle must be non-toxic, biocompatible, non-immunogenic,
biodegradable, and must avoid recognition by the host’s defense mechanisms.

6.  The most common vehicle currently used for targeted drug delivery is the liposomes. A
liposome is a spherical vesicle having at least one lipid bilayer. The liposomes. A
liposome can be used as a vehicle for administration of pharmaceutical drugs. A
liposome has an aqueous solution core surrounded by a hydrophobic membrane, in
the form of a lipid bilayer. Hydrophilic solutes dissolved in the core cannot readily pass
through the bilayer. Hence a liposome can be loaded with hydrophobic and/or and
hydrophilic molecules.
 Liposomes are non-toxic, non-hemolytic, and non- immunogenic.

8.  A liposome is a lipoidal bilayer which encapsulates a region of aqueous solution
inside a hydrophobic membrane, dissolved hydrophilic solutes cannot readily pass
through the lipids. Hydrophobic chemicals can be dissolved into the membrane, and
in this way liposome can carry both hydrophobic and hydrophilic molecules. To
deliver the molecules to sites of action, the lipid bilayer can fuse with other bilayer
such as the cell membrane, thus delivering the liposome contents.

9.  Another type of drug delivery vehicle used is polymeric micelles. Micelles are
approximately spherical in shape. Micelles are usually formed by single-chain lipids. A
micelle is an aggregate of surfectant molecules dispersed in a liquid colloidal. In a
micelle, the hydrophobic tails of several surfactant molecules assemble into an oil-like
core.
 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.
Dendrimers are highly branched, three-dimensional features that resemble the
architecture of a tree.

10.  Two strategies are used for the application of dendrimers to drug delivery; drug
encapsulation by dendritic structure and drug conjugation to dendrimers. Firstly, the
drug molecules can be physically entrapped inside the dendrimers; secondly, the drug
molecules can be covalently attached onto the surface or other functional gp. Various
functional moieties based on dendrimers provide miscellaneous biomedical
applications of these promising materials, such as cancer targeting therapy.

11.  Biodegradable particles have the ability to target diseased tissue as well as deliver their
drugs as controlled-release therapy. Biodegradable particles bearing ligands to P-
selectin, endothelial selectin (E-selectin) and ICAM-1 (All are receptors) have been
found to adhere to inflamed endothelium (heart muscle). Therefore, the use of
biodegradable particles loaded with drugs can also be used for cardiac tissue repair.

12.  The success of DNA nanotechnology in constructing artificially designed
nanostructures out of nucleic acids such as DAN, 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 releases a drug only in response to a
stimulus such as a specific mRNA, have been demonstrated.

13.  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 cancer tumors.
 Liposomes can be used as drug delivery for the treatment of tuberculosis. The
traditional treatment for TB is only chemotherapy which is not very 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 he infection site. The delivery of the drugs works
intravenously and by inhalation. Oral intake is not advised because the liposomes break
down in the Gastrointestinal System.

14.  Medications can be taken in a variety of ways-by mouth, by inhalation, by absorption
through the skin, or by intravenous injection. Each method has advantages and
disadvantages, and not all methods can be used for every medication. Improving current
delivery methods or designing new ones can enhance the use of existing medications.
 Microneedle arrays are one example of a new method to deliver medications
through the skin. In thses arrays, dozens of microscopic needles, each far thinner than a
strand of hair, can be coated or filled with a medicine. The needles are so small that,
although they penetrate the skin, they don’t reach nerves in the skin, thus delivering
medications painlessly.