Novel drug delivery systems refer to approaches for transporting pharmaceutical compounds in the body to achieve therapeutic effects safely. They are classified as implants, films/strips, liposomes, controlled delivery modules, erythrocytes, nanoparticles, and prodrugs. Implants are placed under the skin to release drugs over time. Films and strips are meant for topical application of slow drug release. Liposomes can transport both hydrophilic and hydrophobic drugs. Controlled delivery modules release drugs slowly from a polymeric matrix. Erythrocytes allow drugs to circulate in the body for prolonged release. Nanoparticles are colloidal systems that deposit drugs at target sites. Prodrugs undergo biotransformation before showing pharmacological activity

1. NOVEL DRUG DELIVERY SYSTEMS
Somesh Chandra
Assistant Professor
Om Sadashiva College of Pharmacy

2. ● NOVEL DRUG DELIVERY SYSTEM
It refers to approaches,formulations,technologies and
systems for transporting a pharmaceutical compound
in the body as needed to safely achieve its desired
therapeutic effects.
NDDS is classified as follows:
● 1. Implants
● 2. Films and strips
● 3. Liposome drug carriers
● 4. Controlled drug delivery modules
● 5. Erythrocytes
● 6. Nanoparticles
● 7. Prodrugs.

3. ● (IMPLANTS
● The hypodermic tablets are placed under the skin by a minor surgery
● in order to release drugs over prolonged periods of time.
● Now the magnetically controlled implants have been developed which can
be opened or closed at will in order to release or stop the drug.
● The implants which are in capsule form, consist of a body and a cap. It can
be opened by placing a magnet on the skin and moving it in the desired
direction.
● These implants are placed in the upper thigh at a depth of 5 mm. These
implants are useful in hormone therapy.
● When AlNicoi rod magnet is taped over the skin immediately above the
capsule, it will remain open and release the medicament but the capsule
gets closed as soon as the magnet is removed.

4. ● FILMS AND STRIPS
● These are meant for topical application for slow release of drug over
● predetermined period of time.
● The films and strips which are becoming popular these days are:
● 1. Zero order release films
● 2. Buccal strips
● 3. Spray bandages
● Zero Order Release Films
● These films are called "laminates", and are meant for topical applications.
Nitroglycerin laminates are prepared by mixing propylene glycol with
about 1% carbopol resin. The mixture is neutralised with sodium
hydroxide solution and then 0.1% of nitroglycerin is added. It is then
placed between polythene sheets 5 x 5 cm and its edges are sealed by heat.
It is then placed on a pressure sensitive adhesive sheet of 5.5 x 5.5 cm so
that it can be properly adhesive to the skin. Such laminates release the
drug (nitroglycerin) slowly into circulation for about 12 hours.
● Similarly pilocarpine films are prepared from acrylates and methacrylates.

5. ● Buccal Strips
● The buccal and sublingual tablets are now replaced with buccal
● strips. These strips consist of a thin absorbent base of fabrics, filter
● paper and cotton etc. The buccal strips are prepared by immersing a
● long piece of fabric made from polyamide fibres into a molten mixture
of carbowaxes and dissolved or dispersed drug (around 20%). The
fabric is then cooled and cut into small pieces (ideal dimension is 2 x
1cm). The buccal strip is made in contact with buccal mucosa for
about 15 minutes and then it is removed and discarded.

6. ● Spray Bandages
● These bandages.are prepared by spraying the solution of
drug in polylactide (polymer of lactic acid anhydride). A
2% solution of purified lactide polymer is made in
chloroform and the drug in the concen tration of 0.01% to
90% is dissolved or dispersed in it. Such solution is then
packed in an aerosol container having a suitable
propellant, such as, CF2C12(Dichloro-difluro methane).
When this solution is sprayed, it will be a comfortable
bandage which can be simply washed off with warm water.

7. ● LIPOSOME DRUG CARRIERS
● There are several carriers in our body which transport bio-chemicals
● from one part of the body to an other e.g. proteins, enzymes etc.
Liposomes are phospholipids which can transport both hydrophilic and
hydrophobic drugs. Large -multilamellar vesicles (LMV), small
● unilamellar vesicles (SUV) and large unilamellar vesicles (LUV) are
● some of the liposomes which are known today. By modifying the
● method of preparation, it is possible to prepare different liposomes. The
small drug molecules get trapped in liposomes, whereas large drug
molecules can also make hydrophobic or electrostatic bonding with it.
● Liposomes are sometimes mixed with cholesterol or ergosterol to
change the permeability of liposomes to solute molecules.

8. ● Applications Liposomal drugs have wide therapeutic
applications,
● some of which are as follows:
● 1. Used in diseases caused by intracellular parasites e.g. malaria,
● tuberculosis and amoebiasis.
● 2. Liposome entrapped insulin is active orally and can be replaced
● by intramuscu. lar administration of insulin.
● 3. Liposomes can be used to transport functional DNA/RNA
molecules into cells.
● 4. Liposomes can be used to transport radio-pharmaceuticals and
● immunological products. I
● 5. Liposomal daunomycin has longer duration of action than free
● daunomycin which is used in the treatment of neoplasia. I
● 6. Liposome entrapped actinomycin-D and nitrogen mustard are
● more effective than the parent drug.

9. ● CONTROLLED DRUG DELIVERY MODULES (CDDM)
● Controlled drug delivery modules are devices which are formed by
● embedding the drug within a polymeric matrix so that it gets released
slowly to the body over a very long period of time. The polymeric
matrices used to hold the drug reversibly are polyethylenes, silicone
elastomers and cellulose esters. The drug-polymer complex may be
formulated into tablet, capsule or any other suitable formulation. These
controlled drug delivery modules are punctured before administration
with laser beam to make a small orifice of a few microns in diameter for
the release of the drug. The drug is released from these modules by
diffusion, osmosis or chemical reaction.
● Controlled drug delivery modules can be applied to the skin, implanted
subcutaneously or inserted into various body cavities. The CDDM has
an advantage because there is an unattended drug delivery without any
patient intervention.

10. ● ERYTHROCYTES
● Erythrocytes have also been tried in order to achieve controlled
● release of drugs.
● The life span of an erythrocyte is about 120 days. Erythrocytes can
allow a drug to circulate in the body for a long time
● which helps in the slow release of drug in serum. When the drug is
encapsulated in eryhthrocytes, the drug gets leaked out of its cell
over to prolonged period of time. Moreover, it can be sent to the
specified sites.
● Resealed erythrocytes are prepared by putting them into a
hypotonic medium, so that they can be swollen.
● The aqueous solution of the drug is added to the medium so that
the drug gets into erythrocytes through the open pores. When the
isotonicity is adjusted the erythrocytes shrink,
● thus encapsulating the drug within them.

11. ● These erythrocytes may be suspended in normal saline solution
for preparing injections. Resealed erythrocytes technique as
drug carrier is very promising but it is difficult to arrange a large
quantity of these erythrocytes. The
● techniques can be used on commercial scale only if erythrocytes
are made available in test tubes.
● Applications
● 1. Resealed erythrocytes of urease have been used in kidney
failure to degrade serum urea.
● 2. Resealed erythrocytes of asparaginase have shown good
results in asparaginase dependent leukaemia.
● 3. Resealed erythrocytes of methotrexate and adrianycin have
been tried in cancer therapy. It has shown good results.
● 4. Resealed erythrocytes of prednisolone have shown good
results to prolong the antiinflammatory action.

12. ● NANOPARTICLES
● It is based on colloidal drug delivery system. The particle size of
● this system is in nanometer range i.e. 200-500 mm. That is why they
are called nanoparticles. The system consists of a drug and a carrier to
deposit the drug at the target site. The carriers used are naturally
occurring macromolecules like human serum albumin, bovine serum
albumin and other substances like gelatin, casein and ethylcellulose.
● The method of preparation of nanoparticles is similar to coacervation
phase separation used in microencapsulation except that it is in quite
controlled manner. An aqueous solution of natural macromolecules is
prepared and drug is mixed in it. In case the drug is hydrophobic, it is
dissolved in a small quantity of organic solvents and mixed with the

13. ● carrier, taking precautions that the drug may not be precipitated.
The system is then desolvated in controlled manner by adding a
solvent competing solute like sodium sulphate or alcohol. This
results in the formation of colloidal particles in nanometer range.
These nanoparticles
● may be hardened, isolated and dried for storage. Nanoparticles
can be dispersed in aqueous system.
● Applications
● l. Flourescein isothiocyanate (FITC) nanoparticles have been used
to incorporate cytotoxic agents into tumour cells in cancer
chemotherapy.
● 2. Nanoparticles along with biological maker like
immunoglobulins can be used to target the drugs to very specific
sites.
● 3. In nuclear medicine 99 m Technitium nanoparticles are used to
study the morphology, blood flow and functions of various
● organs of the body.

14. ● PRODRUGS
● The compounds which undergo biotransformation before showing
desired pharmacological activity are called prodrugs or proagents.
● Prodrugs are generally the esters or amides of parent drugs. The
● prodrugs are useful in improving the solubility, stability,
bioavailability of drugs, masking the unpleasant taste and odour of
the parent drug and reducing the drug toxicity.
● Applications
● 1. Chloramphenicol palmitate, the prodrug of chloramphenicol is
used in the preparation of paediatric suspension because it has no
bitter taste.

15. ● 2. Procaine-penicillin G and Benzathine-penicillin
G are prodrugs of penicillin G which shows
resistance to hydrolysis as compared to the parent
drug.
● 3. Testosterone cypionate the prodrug of testosterone
is long-acting in comparison to the parent drugs when
injected in an oil base.
● 4. Clindamycin 2-palmitate the prodrug of clindamycin
has no
● bitter taste of the parent drug.
● 5. Cliaidamycin 2-phosphate the prodrug of
clindamycin cause little
● pain and irritation at the site of injection when given
by i/m route as compared to its parent drug.

16. ADVANTAGES OF NDDS:
1)Accurate dosing.
2)Ease of Administration.
3)Enhanced efficacy and safety.
4)Stable and delivery maintained under
various physiological variables.
5)Controlled drug delivery.
6)Increases bioavailability.
7) Improves drug potency.
8) Protection from physical and chemical
degradation.

17. CHALLENGES OF NDDS:
1)Expensive.
2) There is reduced potential for dose adjustments.
3)In case of failure of dosage form, the risk of dose
dumping is present.
4)It can alter the pharmacokinetics and dynamics
of a drug.