About Drug Delivery

1. THE RISE AND RISE OF
DRUG DELIVERY

2. ORAL ROUTE
 Released drug is absorbed in small intestine.
 Advantages: - patient acceptance
- convenient
 Disadvantages: - poor uptake — rapidly metabolized
- chemical instability in GI tract
 Traditional: Tablets, capsules

3. Tablets:
A tablet is a hard, compressed medication in
round, oval or square shape.
Types of tablets:
1- Disintegrating tablet (conventional or
plain tablet)
 Disintegrating tablet is the most common type
of tablets that is intended to be swallowed.

4. Types of Tablets (Cont.)
Single layer tablet

5. Types of Tablets (Cont.)
2- Chewable tablets
 Chewable tablets are to be chewed and thus
mechanically disintegrated in the mouth.
 Advantages of chewable tablets:
- Provide quick and complete disintegration of the tablet
and thus obtain a rapid drug effect
- Easy administration, especially for infants and elderly
people.

6. Types of Tablets (Cont.)

7. Types of Tablets (Cont.)
3- Effervescent tablets
- Effervescent tablets are dropped into a
glass of water before administration
during which CO2 is liberated.

8. Types of Tablets (Cont.)
 Advantages of effervescent tablets:
1- To obtain rapid drug action, for example analgesics
and antacids.

9. Types of Tablets (Cont.)

10. Types of Tablets (Cont.)
2- To facilitate drug intake, for example vitamins

11. Types of Tablets (Cont.)
4- Sublingual and Buccal tablets
 They are used for drug release in mouth followed by
systemic uptake of the drug.
 A rapid systemic drug effect can thus be obtained
without first-path liver metabolism.
 Sublingual tablets are placed under the tongue.

12. Types of Tablets (Cont.)

13. Types of Tablets (Cont.)
 Buccal tablets are placed in the side of the check for
absorption through oral mucosa.

14. Types of Tablets (Cont.)
5- Lozenges
 They are tablets that dissolve slowly in the mouth and
so release the drug dissolved in the saliva.
 Lozenges used for
- Local medications in the mouth or throat, e.g. local
anaesthetics, antiseptics and antibiotics.

15. Types of Tablets (Cont.)
 Hard candy lozenges , e.g. Halls®

16. Capsules:
 A capsule is a medication in a gelatin container.
1- Hard gelatin capsules
- The capsule consists of two halves and filled with powder.

17. Capsules:
2 Soft gelatin capsules:
 The capsule consists of one part and used for oils and
for active ingredients that are dissolved or suspended in
oil.
chewable soft gelatin capsules of omega-3

18. Novel oral delivery
systems:
1- Fast dissolving oral film:
-It consists of a very thin polymeric film strip incorporating
and delivering pharmaceutical active ingredients (alone or in
combination).
-It has the size of a stamp and – once placed in the mouth –
dissolves in a few seconds and is swallowed with the saliva
without the need of taking water.

19. Novel oral delivery
systems:

20. Advances in Controlled /
Sustained Release Drug Delivery
System:
 Benefits of modified drug delivery system:
- Decreased in dosing frequency
- Sustained & Consistent blood level within the therapeutic
window.
- Enhanced bioavailability
- Reduced side effects
- Improved patient compliance

21. Advances in Controlled /
Sustained Release Drug Delivery
System:
 Some technologies of modified release drug delivery
system:
I. Osmotic Drug Delivery Devices:
They fall in two categories
1- Implantable
E.g. Implantable Miniosmotic pump


22. Osmotic Drug Delivery
Devices:
2- Oral osmotic
Pump
Single chamber Multi chamber
Specific types
osmotic pump osmotic pump
E.g. Push pull osmotic pump
E.g. Elementary osmotic pump E.g. Elementary osmotic pum
E.g. Osmotic pump with non
expanding second chamber

23. Novel oral delivery
systems:
2- Controlled drug delivery systems
I. The osmotic-controlled release oral delivery
system, OROS:
- It is an advanced drug delivery technology that uses
osmotic pressure as the driving force to deliver
pharmacotherapy, usually once-daily, in several
therapeutic areas.

24. Novel oral delivery
systems:
A- The elementary osmotic pump

25. Novel oral delivery
systems:
 Following ingestion, water is absorbed into the
system, dissolving the drug, and the resulting
drug solution is delivered at the same rate as
the water entering the tablet.
 Disadvantage:
It is only suitable for the delivery of water-soluble
drugs.

26. Novel oral delivery
systems:
B- The two-layer osmotic push–pull tablet
- The polymeric expanding compartment (push layer) provides additional force on the
drug layer to ensure that the drug is delivered through the delivery orifice at the
target rate.

27. The osmotic push– pull tablet

28. Novel oral delivery
systems:
C- The advanced longitudinally compressed tablet
multilayer formulation
- It consists of an osmotic push layer and can be
configured to contain several drug layers.
- The option of multiple drug layers provides increased
flexibility and control over the pattern of release of
medication from the system.

29. The advanced longitudinally
compressed tablet multilayer
formulation

30. Novel oral delivery
systems:
D- The L-OROS system
- provide controlled delivery of liquid drug formulations in
a capsule form.
- This system consists of a semipermeable membrane
coating that encloses a liquid drug layer and osmotic
push layer.

31. Novel oral delivery
systems:

32. Novel oral delivery
systems:
E- Sandwiched Osmotic Tablets (SOTS)
- It is composed of polymeric push layer sandwiched
between two drug layers with two delivery orifices.
- When placed in the aqueous environment the middle
push layer containing the swelling agents swells and the
drug is released from the two orifices situated on
opposite sides of the tablet and thus SOTS can be
suitable for drugs prone to cause local irritation of the
gastric mucosa.

33. Sandwiched Osmotic Tablets

34. Novel oral delivery
systems:
F- OROS-CT
- OROS-CT is used as a once or twice a day formulation
for targeted delivery of drugs to the colon.
- The OROS-CT can be a single osmotic agent or it can be
comprise of as many as five to six push pull osmotic unit
filled in a hard gelatin capsule.

35. OROS-CT

36. Novel oral delivery
systems:
II. pH sensitive systems

38. Transdermal Route
 Transdermal patch is a medicated
adhesive patch that is placed on the
skin to deliver a specific dose of medication
through the skin and into the bloodstream.
 Transdermal drug delivery offers an attractive alternative
to the conventional drug delivery methods of oral
administration and injection.
38

40. Transdermal Route
 Advantages of Transdermal drug delivery
system over Conventional Dosage Forms:
-Avoids vagaries associated with gastrointestinal
absorption due to pH, enzymatic activity, drug-food
interactions etc.
-Substitutes oral administration when the route is
unsuitable as in case of vomiting, diarrhea.
- Avoids hepatic “first pass” effect.
- Avoids the risks and inconveniences of parenteral
therapy.

41. Transdermal Route
- Reduces daily dosing, thus, improving patient compliance.
- Rapid termination of drug effect by removal of drug
application from the surface of the skin.
- Suitability for self-administration.

42. Transdermal Route
 Limitations of Transdermal drug delivery:
- The drug must have some desirable physicochemical
properties for penetration through stratum corneum.
- Skin irritation or contact dermatitis due to the drug,
excipients and enhancers of the drug used to increase
percutaneous absorption is another limitation.
- The barrier function of the skin changes from one site to
another on the same person, from person to person
and with age.

43. Transdermal Route
(Cont.)
 Traditional : controlled release patches

44. Transdermal Route
(Cont.)
Device Designs
A-membrane based : Release rate constant (rate-limited by
diffusion through membrane)
laminated layers:

45. Transdermal Route
(Cont.)
B- monolithic patch
- C0 >> Cs drug dissolution in polymer matrix controls
release rate.
⇒

46. Transdermal Route
(Cont.)
The Latest Approaches for Enhancing
Transdermal Drug Delivery
-Various technologies have been developed to bypass or
modulate the barrier function of the skin.
I. Iontophoresis:
Iontophoresis is an effective and painless method of delivering
medication to a localized tissue area by applying electrical
current to a solution of the medication.

47. Transdermal Route
(Cont.)
 The diagram below illustrates the basic mechanism.
Like electrical charges repel. Therefore, application of a
positive current will drive positively charged drug
molecules away from the electrode and into the tissues;
similarly, a negative current will drive negatively charge
ions into the tissues.

48. What is iontophoresis ?

49. Iontophoretic Patches

50. Iontophoretic Patches

51. Iontophoresis & Beauty
• Iontophoresis, a widely
used method in the fields
of dermatologist, emits
feeble electric current to
the skin to lower the skin
barriers, and used electical
repulsion to deliver the
nutrients of cosmetics to
deep under the skin

52. Transdermal Route
(Cont.)
II. Reverse iontophoresis:
 Iontophoresis can be used in reverse to remove
molecules from the circulation.
 One example, the GlucoWatch, a needleless means of
monitoring blood glucose levels in diabetic patients, uses
an electrical signal that is proportional to the amount of
glucose in the extracellular fluid.

53. GlucoWatch & principle

54. Transdermal Route
(Cont.)
II. Electroporation:
This process, in which brief, intense electric charges
create small pores in the phospholipid bilayer of cell
membranes, can assist in the transdermal delivery of
drugs.
Electroporation appears to reversibly disrupt the lipid
bilayers in the stratum corneum, and the channels it
creates are said to promote the passage of
hydrophilic drugs through the skin.

55. Electroporation
ii) When the electric field is
applied, the ions move
according to their charge.
iii) Pathways are formed
across the cell membrane
allowing DNA to enter.
iv) When the electric field is
deactivated, the
membrane heals.

56. Electroporation

57. Transdermal Route
(Cont.)
III.Phonophoresis (sonophoresis) :
- The use of ultrasound of a suitable frequency to
enhance skin permeability seems to be a useful
alternative technique for delivering drugs through the
skin and can be applied to vaccination and gene
therapy.

58. Mechanism of action of
phonophoresis:
Enhanced Transdermal Permeation by Cavitation upon application of Ultrasound

59. Phonophoresis
(sonophoresis)

60. Transdermal Route
(Cont.)
IV. Microneedles (Microporation):
- patches coated with hundreds of microscopic needles (microneedles) that
pierce only the stratum corneum.
- They are generally one micron in diameter and range from 1-100 microns
in length.
- The microneedles are usually drug-coated projections of solid silicon or
hollow, drug-filled metal needles.
- They can deliver proteins, nanoparticles, and both small and large
molecules through the skin.
- Because the nerves located deeper in the skin are not stimulated, the
patient does not experience pain or discomfort.
- Instead, patients feel the texture of sandpaper or a cat's tongue.

61. Microneedles
An array of stainless silicon microneedles An array of stainless steel microneedles

62. Microneedles
Microscope image shows an array of hollow microneedles
next to a hypodermic needle typical of those now used to
inject drugs and vaccines

63. Patch Microneedles

64. Transdermal Route
(Cont.)
V. Needleless Jet Injectors:
- Needleless jet injectors combine the advantages of
transdermal and parenteral drug delivery methods.
- It fires fine, solid particles through the stratum corneum
using high-pressure helium gas or uses nitrogen gas to
propel liquid drug formulations through the skin.
- The high velocity jet stream pierces the skin and the
drug disperses into the subcutaneous adipose tissue.

65. Transdermal Route
(Cont.)
- Drug delivery is painless because the
injectors use particles that are too small
to trigger pain receptors.

66. Needleless Jet Injectors:

67. Transdermal Route
(Cont.)
VI. Medicated Tattoos:
- modified the temporary tattoo popular with children and
young adults to contain an active drug for transdermal
delivery