Injectable Depot Preparations by Izharahemad Ansari From Smt. Kashibai Navale College of Pharmacy, Pune.

1. INJECTABLE DEPOT PREPARATIONS
Guided By
Dr.(Mrs) Jyotsana R. Madan
(M. Pharm., Ph.D.)
Presented By
Mr. Izharahemad N. Ansari
(F. Y. M. Pharm.)
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2. Contents
 Introduction
 Definition
 Advantages
 Disadvantages
 Requirements
 Reasons for development
 Polymers used
 Routes of administration
 Classification
 Examples
 Conclusion
 References
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3. INTRODUCTION
DEFINITION
Depot is a drug reservoir that releases the drug molecule
continuously at a rate determined to a large extent leading
to prolong absorption drug molecule from formulation.
The release can either be continuous or pulsatile
depending on the structure of the device and the polymer
characteristics.
Depot is aqueous or oleaginous suspension (or)
oleaginous solution administered by parenteral route.
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4. Continue….
A depot injection is usually a SC or IM product which
release its active compound continuously over a certain
period of time.
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5. Advantages
Improved patient convenience and compliance
Prolonged steady state drug plasma concentration
Maximum utilization of drug
Less frequency of dosing
Reduction in health care cost through improved
therapy
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6. Disadvantages
Decreased systemic availability
Poor invitro- invivo co-relation
Possibility of dose dumping
Retrieval of drug is difficult in case of toxicity,
poisoning or hypersensitivity reactions
Reduced potential for dosage adjustments
Higher cost of formulations
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7. Requirements
The ingredients used for depot formulation should be
 Sterile
 Pyrogen free
 Non-irritating
 Non-toxic
 Bio-degradable
 Bio-compatible
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8. Reasons for development
 Parenteral depot preparations are long acting
formulations ideally provide a slow, constant,
sustained and prolonged action.
 No surgical removal of depleted system is
required.
 Metabolic byproducts of depot products are
non-toxic.
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9. Polymers used in Depot Preparations
Generally, Biodegradable polymers are used as it
get degraded in the body.
 Natural- albumin, starch, dextran, gelatin,
fibrinogen, hemoglobin.
 Synthetic- poly amides, poly acryl amides, poly
amino acid, poly urethane.
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10. Routes of Administration
 Sub-cutaneous route for well absorbed and
water soluble drugs with limited injection
volume i.e. 0.5-1.5 ml.
 Intramuscular route is suitable for slightly
soluble drugs with injection volume upto
2ml.
 Intravenous route is for liposomes,
nanoparticles, microspheres and niosomes.
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11. Who can and cannot use
But usually cannot use this injectable if:
Most women can safely use this
injectable
• Breastfeeding
6 weeks
or less
• Very high blood
pressure • May be
pregnant
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12. Classification of depot preparations12
• Dissolution-Controlled Depot preparations : In this
the drug absorption is controlled by slow
dissolution of drug particles in the formulation. Eg.
Formation of salt or complexes with low aqueous
solubility, Suspension of Macrocrystals.
• Adsorption-type Depot preparations : In this the
drug absorption is based on the amount of drug
unbounded. Eg. Vaccine Preparation.

13. Continue..13
• Encapsulation-type Depot preparations : In this the
rate of drug release is controlled by the rate of
permeation across the permeation barrier. Eg.
Naltrexone pamoate- releasing biodegradable
microcapsule.
• Esterification-type depot preparations : The rate of
drug absorption is controlled by the interfacial
partitioning of drug ester from the reservoir. Eg.
Fluphenazine enenthate

14. DISSOLUTION CONTROLLED DEPOT
In this depot formulation the rate of absorption is controlled by the
slow dissolution of drug particles in the tissue fluid surrounding the
formulation or in the formulation.
The rate of dissolution (Q/t) d is defined by :
Q/t = SDC/h
Where, S = surface area of the drug particles.
D = diffusion coefficient of drug molecules in the medium.
C = saturation solubility of the drug in the medium.
H = thickness of the hydrodynamic diffusion layer.
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15. Eg: Aqueous suspension of testosterone isobutyrate
for intramuscular administration.
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16. ADSORPTION TYPE DEPOT
This type of depot preparation is formed by the binding of
drug molecule to adsorbents
In this only the unbound , free species of the drug is
available for absorption as soon as the unbound drug
molecules are absorbed a fraction of the bound drug
molecule is released to maintain equilibrium .
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17. Eg: Prolongation of insulin activity was made by complexing
insulin with protamine. Protamine-insulin complex releases upto 24
hrs on subcutaneous injection. Protamine –Zn – insulin complex
when given subcutaneous releases upto 36 hrs but it has slow onset
of action 4 to 8 hrs.
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18. ENCAPSULATION TYPE DEPOT
This type of depot formulation is prepared by
encapsulating drug solids within a permeation barrier or
dispersing drug particles in a diffusion matrix. Both
permeation barrier and diffusion matrix are fabricated
from biodegrable or bioabsorbable macromolecules such
as gelatin, dextran, polylactate and long chain fatty acids
and glycerides.
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19. Eg: Naltrexone palmoate releasing biodegradable
microcapsules, liposomes
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20. ESTERFICATION TYPE DEPOT
This depot preparation is produced by esterifying a drug to form
bioconvertable pro drug type ester and then formulating it in a
inject able formulation this formulation forms a drug reservoir at
the site of injection.
Eg: fluphenazine enanthate testosterone 17 cypionate in oleagenous
solution.
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21. Examples of few Injectable controlled release
formulations
1. Long-acting Penicillin Preparations
2. Long-acting Vitamin B12 preparations
3. Long-acting Adreno corticotropic Hormone Preparations
4. Long-acting Steroid preparations
5. Long-acting Antipsychotic Preparations
6. Long-acting Antinarcotics Preparations
7. Long-acting Contraceptive Preparations
8. Long-acting Insulin Preparations
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22. Long-acting Contraceptive Preparations
Types :
Long acting reversible contraceptives.
Long acting hormonal contraceptives.
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23.  LARC is defined as contraceptive methods that require
administration less than once per cycle or month.
Examples of LARC are:
 Progestogen-only intrauterine systems.
 Progestogen-only injectable contraceptives.
 Progestogen-only subdermal implants.
 Progesterone Vaginal Ring (PVR).
 Copper intrauterine Device.
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24. Progestogen-only intrauterine systems
Is a levonorgestrel-releasing intrauterine device
Is T-shaped with reservoir on the vertical arm
Releases progestin levonorgetsrel 20ug daily
Has 2 monfilament string attached to the vertical arm.
Life span is 5years
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25. Mechanism of action
Thickening of cervical mucus impeding sperm accent.
Alteration in uterotubal fluid that interferes with sperm migration.
Anovulation in 10-15% of cycles.
Thinning of endometrium to reduce likelihood of implantation.
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26. Progestogen-only injectable contraceptives
Types:
 Depo Medroxy Progesterone Acetate (DMPA) 150 mg
- Microcrystalline suspension
- 3 monthly
 Norethisterone Enanthate (Net-En) 200 mg
- In oil
- 2 monthly
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27. Mechanism of action
Inhibition of ovulation by suppressing gonadotropinns.
Thickening of cervical mucus.
Thinning of the .endometrium
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28. Advantages
The risk of ectopic pregnancy is significantly lower among
users compared to women who do not use contraception.
The risk of endometrial cancer is reduced by as much as
80%, an effect that is long term and increases with
duration of use.
Some women with endometriosis have improvement of
symptoms with use of DMPA.
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29. Disadvantages
Decrease in bone mineral density, hence, encourage
calcium intake.
 Irregular bleeding & prolonged menstrual flow
 Mood swing & Depression.
 Weight gain, about 5Ib (2.2kg) in 1 year of use.
 Delayed return to fertility when discontinued, ≥10
months.
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30. Case Study
Objectives - The Risk of Deep Venous Thrombosis
Associated With Injectable Depot–Medroxyprogesterone
Acetate Contraceptives or a Levonorgestrel Intrauterine
Device.
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31. Methods and Results –
 Analyses were performed in the Multiple Environmental
and Genetic Assessment study, a large case-control study
on risk factors for venous thrombosis. For the current
analyses, they selected premenopausal women, aged 18 to
50 years, who were not pregnant nor within 4 weeks
postpartum and were not using oral contraceptives; 446
patients and 1146 controls were included.
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32. Injectable depot–medroxyprogesterone acetate
contraceptives were associated and increased risk of
venous thrombosis compared with nonusers of hormonal
contraceptives. The use of a levonorgestrel intrauterine
device was not associated with an increased risk.
Unfortunately, the few women using a contraceptive patch
or an implant prevented a reliable estimate of the risk of
thrombosis.
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33. Conclusion of case study-
The risk of venous thrombosis was increased for injectable
depot–medroxyprogesterone acetate contraceptive users,
while we were able to reliably exclude an increased risk
associated with levonorgestrel intrauterine device use.
Therefore, the latter seems to be the safest option
regarding the risk of venous thrombosis.
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34. Conclusion
Injectable depot preparation is designed to achieve a desired
pharmacological response in a sustained manner at a selected
site without undesirable interactions at the other sites. Other
injectable products are complex dosage forms, requiring
careful development of test methods and acceptance criteria
for the specifications
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35. References
M. Kalyani, P. Surendra, V. Sirisha. Parenteral Controlled
Drug Delivery System. International Journal of Research
in Pharmaceutical and Nano Sciences. 2013 May 02; 573-
74.
Agrawal M, Limbachiya M, Patel G, Sapariya A. A
Review on Parenteral Controlled Drug Delivery System.
International Journal Of Pharmaceutical Sciences and
Research. 2012 Sep; 3(10); 3657-59.
S.D. Sanghai, V.S. Kadam, S.B. Jadhav, Md. Jameeruddin,
V.B. Bharkad. A Review On Parenteral Drug Delivery
System. Indo American Journal of Pharmaceutical
Research. 2014 Mar 17; 1542-44.
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36. Rajeevini K, Mahalakshmi K, Dr. Uma V. Implantable
Drug Delivery Systems: A Review On Parenteral
Implants. International Journal of Innovative
Pharmaceutical Sciences and Research. 2015 Sep; 1407-
08.
Hitesh B. A Prolonged Release Parenteral Drug Delivery
System-An Overview. International Journal of
Pharmaceutical Sciences Review and Research. 2010 Aug;
3(1); 1-9.
Parenteral-injectable-implantable-controlled-drug-
delivery-systems/article/www.authorstream.com/
A,Vlieg, Frans M., F. Rosendaal. The Risk of Deep
Venous Thrombosis . 2010 Aug;2297.
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