Introduction Classification along with example of Parental Implants

1. Royal College Of Pharmaceutical Education & Research
Sayne Khurd Malegaon ( 423203 )
MOHAMMED AWAIS IQBAL
(B PHARMACY)
UNDER THE GUIDANCE OF
SHAKEEB AKHTAR
M-PHARM
(PHARMACEUTICS)
SUBJECT ADVANCED DRUG DELIVERY SYSTEM
By

2. Content
• Introduction
• Type of Polymers
• Classification
• Advantages and Disadvantages of Implants
• Evaluation
• Examples of Parenteral Implants Drugs
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3. Introduction
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Implants are small sterile solid masses consisting of a highly
purified drug made by compression or molding or extrusion.
 Parental Implants are drug delivery systems which provide
controlled delivery of drug at the site of implantation.
Implants are developed with a view to provide continuous
release of the drug into the blood stream over long periods of
time without the repeated insertion of needles.
Therefore the base material for implant are required to be
biocompatible.

4. Type of Polymers
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1. Biodegradable
2. NonBiodegradable
1. Biodegradable
• In this inert polymers, used that are eventually absorbed or excreted by the
body.
• No need for surgical removal of the implant after the conclusion of therapy.
• Drug is dispersed in to a biodegradable polymer matrix like poly vinyl
methyl ether and is coated with immobilized urease in a neutral PH.
• In the presence of urea, ammonia is released causing increase in PH at which
polymer degrades leading to drug release.
• These are prepared by using commonly degradable polymers
like polyglycolic acid(PGA), Polyhydroxy butyrate (PHB), poly vinyl methyl
ether etc.

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Non Biodegradable
• In this nodegradable polymer are used as these are not adsorbed or
excreted by body
• Due to this reason the minor surgery is necessary for the removal of
implant from the body.
• There is also a possibility that membrane rupture will
• potentially lead to “drug dumping” during therapy.
• Dose dumping is a phenomenon of drug metabolism in which
environmental factors can cause the premature and exaggerated release of
a drug. This can greatly increase the concentration of a drug in the body
and thereby produce adverse effects or even drug-induced toxicity
• Nonbiodegradable implants are commonly prepared using polymers such
as silicones, poly(urethanes) etc.

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CLASSIFICATION
Controlled drug
release by
Diffusion
Controlled drug
release by
Activation
Controlled drug
release by Feedback
regulated
mechanism
1. Membrane permeation.
Control release system
2. Polymetric Matrix diffusion
control release system
3. Membrane matrix
hybrid type control release
system
4. Micro reservoir dissolution
control release system
I. Physical activation:
1. Osmotic pressure (e.g. Alzet
pump)
2. Vapor pressure(e.g.Infusaid
pump)
3. Phonophoresis
4. Magnetically activated
II.Chemical activation:
1.Hydrolysis (e.g. controlled
release of levonorgestrel)
2.Hydration (e.g. Hydron Implant
1. Bioerosion.
2. Bioresponsive

7. Controlled drug release by Diffusion
1. Membrane permeation Control release system:
• Drug reservoir is encapsulated within a spherical compartment that
is enclosed by a rate controlling polymeric membrane.
• Drug reservoir : solid particle/dispersion of solid particles in a
liquid or solid dispersion medium.
• Polymer membrane: nonporous/microporous/semipermeable
• Example
Norplant subdermal implant.
Progestasert IUD.
Ocusert system. 7

8. Controlled drug release by Diffusion
2. Polymetric Matrix diffusion control release system:
• Drug reservoir is prepared by homogeneously dispersing drug
particles at a rate controlling polymeric matrix fabricated from either
a lipophilic or hydrophilic polymer.
3. Membrane matrix hybrid type control release system:
• It is a hybrid of Membrane permeation controlled drug delivery
system and Matrix diffusion controlled drug delivery system.
• It minimizes the risk of dose dumping associated with membrane
permeation controlled drug delivery system.
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9. Controlled drug release by Activation
Approach Mechanism Examples
Osmotic Pressure Drug reservoir solution or
semisolid placed within
semipermeable housing with
controlled water permeability
Alzer osmatic pump
Vapour Pressure Drug reservoir placed inside
infusate chamber
Infusaid Pump
Magnetically Activated Magnetic wave triggering
mechanism is incorporate into
drug delivery device
-
Hydrolysis Activated Solid drug is homogenously
dispersed throughout polymer
matrix of bioerodible or
biodegradable polymer
Levonorgestrel
Hydration Activated Solid drug is coated by
hydrophilic polymer
Hydron implant
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Advantages and Disadvantages of Implants
Advantages Disadvantages
Controlled drug delivery for over a long
time.
Mini-surgery is needed which is painful
Improve patient compliance Difficult to discontinue the therapy
Targeted drug delivery Discomfort at the site of implantation
Bypass first pass metabolism Costly as compared to conventional
dosage form
Decrease side effects
Improved stability of drugs
Improve availability of drugs

11. Evaluation
Photographic Imaging: Photograph of drug loaded implants are
taken using digital camera. Surface morphology greatly
influence the release kinetics of implants. The kinetics of drug
release is greatly dependent on the morphology character of
Implants.
• Weight Variation of implants
• Measurement of implants thickness
• Test for free formaldehyde
• Invitro drug release studies
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12. Evaluation
The flow through cell (USPApparatus 4) may be used
for release testing of implant formulation. The
implants may be held in the flow through cell with
special holder . The standard tablet cell 12.0 and 22.6
mm may be used without the tablet clip when the unit
is operated in the closed-system configuration or in the
open configuration. Approprate flow rates can be
selected depending on the formulation and application
The temperature can be maintained at 37 +2 -2 0C. For
accelated testing higher temperatures can be used. A
set of 6 cells is used for test
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13. Examples of Parenteral Implants Drugs
1. Buprenorphine implants “Probuphine®”
• It consists of a small, solid implant made from a
mixture of ethylene vinyl acetate (EVA) and a drug
substance.
• It is placed subcutaneously, normally in the upper
arm.
• Each implant contains the equivalent of 80 mg of
buprenorphine.
• Uses
- It is indicated for the treatment of opioid addiction
in patients.
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14. Examples of Parenteral Implants Drugs
2. Naltrexone implants “Earope”
• Naltrexone implants are small medication pellets that get
inserted under the skin and slowly release the medication
over varying lengths of time.
• Naltrexone is a drug belonging to a class of drugs called
opioid antagonists.
• Uses
- Naltrexone can help reduce the desire for drugs such as:
Heroin, Morphine, Codeine. But naltrexone doesn’t treat
the withdrawal symptoms that opioid users may experience,
including: Anxiety, Sleep disturbances, Sweating, Abdominal
pain.
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ThankYou