Vaccines are a cornerstone of preventive healthcare, and the evolution of vaccine drug delivery systems (VDDS) has significantly enhanced their effectiveness, stability, and accessibility. This presentation provides a comprehensive overview of the current and emerging delivery technologies used in vaccine administration. The content delves into traditional methods such as intramuscular and subcutaneous injections, as well as next-gen systems like microneedle patches, nanoparticle carriers, liposomes, viral vectors, and mucosal (nasal/oral) delivery systems. Special attention is given to cold chain challenges, dose-sparing strategies, and targeted delivery methods that improve patient compliance and immune response. The presentation also explores biotechnological advancements enabling needle-free and thermostable vaccines, their role in combating global pandemics, and the regulatory considerations involved in VDDS development. Through case studies and real-world examples (e.g., mRNA COVID-19 vaccines), it highlights how formulation science, nanotechnology, and novel excipients are shaping the future of immunization. Whether you are a student, researcher, or industry professional, this resource offers insightful perspectives on how innovative delivery mechanisms are revolutionizing vaccinology and enhancing public health outcomes across the globe.

1. Name- Lubdha Prashant Badgujar
PRN -24054482817002
Department- Pharmaceutics
Date of Presentation -4th
April 2025
Title: Vaccine Drug Delivery Systems

2. Content –
 Introduction
 What are vaccine?
 History of vaccine
 Ideal properties of vaccines.
 Mechanism of vaccine
 Types of vaccine
 Uptake of antigen
 Single shot vaccine
 Mucosal delivery vaccine
 Transdermal delivery vaccine
 References

3. What are Vaccines?
1 Biological
Preparation
Stimulates the body's
immune response
against infectious
diseases.
2 Key Function
Trains the immune
system to recognize
and fight pathogens.
3 Importance
Controls diseases, reduces
mortality, and creates herd
immunity.
Understanding Vaccines
This presentation will cover the importance of
vaccines. We will explore their history and how they
work. We will also discuss ideal properties and
mechanisms.

4. Definition of Vaccines
A vaccine is a biological preparation designed to
stimulate the body's immune response against a
specific infectious disease. It typically contains:
 A weakened or inactivated form of a pathogen
(virus/bacteria).
 Toxins or subunit antigens derived from the
pathogen.
 mRNA/DNA sequences that instruct cells to
produce an immune-activating protein.
Key Function:
Vaccines train the immune system to recognize and
fight pathogens without causing the disease itself.

5. Successful Vaccines
Smallpox Vaccine
Eradicated smallpox by 1980.
Polio Vaccine
Reduced polio cases worldwide.
COVID-19 Vaccine
mRNA technology saved millions of lives.

6. History of Vaccination
1 1796: Jenner's Vaccine
Foundation for modern immunology.
2 1885: Pasteur's Vaccine
Revolutionized disease prevention.
3 20th Century
Clasical Vaccines.
4 21st Century
Cutting-Edge Innovations.
mRNA Vaccines (2020-Present)
Nanoparticle-Based Vaccines
Microneedle & Transdermal Vaccine Delivery

8. Safety & Stability
 Minimal side effects
 No severe reaction
 Low Reactogenicity
Easy Administration
 Intramuscular Injection
 Oral vaccines
 Nasal spray vaccines
Low Cost & Mass Production
Challenges Solution
R&D Costs RecomandationDNA
Cold Chains Logistics mRNA Vaccines
Production Capacity Public-Private
Partnership

10. 1]Live-Attenuated Vaccines
Contain a weakened (attenuated) version of the pathogen that replicates but does not cause disease
in healthy individuals.
Mechanism: Mimics natural infection, triggering strong B-cell (antibody) and T-cell (cell-
mediated) immunity.
Benefits: Strong, long-lasting immunity; requires fewer doses.
Examples: MMR (Measles, Mumps, Rubella), Varicella (Chickenpox), BCG (Tuberculosis)
2] Inactivated (Killed) Vaccines
Contain dead pathogens that cannot replicate but still stimulate an immune response.
Mechanism: Stimulates B cells to produce antibodies,but requires boosters for prolonged
immunity.
Benefits: Safe for immunocompromised individuals; stable at room temperature
Examples: Inactivated Polio (IPV), Hepatitis A, Rabies
.

11. 5] mRNA & DNA Vaccines – Next-Gen Technology
Use genetic instructions (mRNA or DNA) to instruct human cells to produce the pathogen’s antigen, triggering
an immune response.
✔ Mechanism: Cells temporarily produce the antigen, leading to robust B & T cell immunity.
✔ Benefits: Rapid development; highly effective; no risk of infection.
4] Toxoid Vaccines
Designed to neutralize bacterial toxins rather than the bacteria itself.
✔ Mechanism: Uses inactivated bacterial toxins (toxoids) to stimulate immunity.
✔ Benefits: Highly effective against toxin-related diseases; very safe.
3] Subunit, Recombinant, & Conjugate Vaccines
Contain only specific fragments (proteins, polysaccharides) of a pathogen, ensuring safety without using the
whole virus.
✔ Mechanism: Triggers antibody production with minimal side effects.
✔ Types & Examples:
•Subunit Vaccines: Contain pathogen fragments (HPV vaccine).
•Recombinant Vaccines: Genetically engineered antigens (Hepatitis B).
•Conjugate Vaccines: Enhances weak antigens (Pneumococcal vaccine).

12. Immune System Activation
Dendritic Cells
Process antigens and
present them using
MHC(Major
Histocompatible Complex)
proteins.
Macrophages
Engulf pathogens and
release inflammatory
signals.
Helper T Cells
Recognize antigens and
activate other immune
cells.

13. B & T Cell Response
1 B Cell Response
Antibody
production to
neutralize
pathogens.
2 T Cell Response
Killing infected
cells to stop virus
multiplication.
3 Memory Cells
Store information for future encounters.
Memory B and T cells stay in
bloodstream.
Faster Response
Stronger immune
response upon
reinfection.
Memory Cells
Long-Term Protection

14. Types of Vaccines
Live-Attenuated
Weakened pathogen,
strong immunity.
Inactivated
Killed pathogen, requires
boosters.
Subunit
Specific parts of pathogen, very safe.

15. mRNA & DNA Vaccines
Genetic Instructions
Cells produce harmless antigen version.
Immune Response
Body recognizes protein as foreign.
No Infection Risk
Only delivers genetic material.

16. Conventional Delivery Methods
Intramuscular
Subcutaneous
Intradermal
Advanced Delivery Approaches
Nanoparticles
Enhance antigen delivery.
Microneedles
Painless, self-
administered.

17. 1] Nanoparticle-Based Vaccine Delivery Systems
✔ Definition: Nanoparticles (NPs) are tiny carriers (~1-100 nm) that enhance antigen delivery and immune response.
✔ Types of Nanoparticles Used in Vaccines:
 Lipid Nanoparticles (LNPs): Used in mRNA vaccines (Pfizer & Moderna COVID-19 vaccines).
 Polymeric Nanoparticles: Biodegradable carriers made of PLGA (Poly-Lactic-Co-Glycolic Acid).
 Gold Nanoparticles: Stabilize antigens and improve immune activation.
🔹 Advantages:
✅ Protects vaccine antigens from degradation.
✅ Enhances uptake by immune cells (APCs).
✅ Allows controlled and sustained antigen release.
📌 Example: Pfizer and Moderna COVID-19 vaccines use Lipid Nanoparticles (LNPs) to encapsulate mRNA and protect it from
degradation.
Advanced Vaccine Delivery Approaches
Traditional needle-based delivery methods have several limitations, such as pain, storage
requirements, and compliance issues. To overcome these challenges, advanced vaccine
delivery methods have been developed, including nanoparticles, liposomes, and
microneedles.

18. 2)Liposome-Based Vaccine Carriers
✔ Definition: Liposomes are phospholipid vesicles that encapsulate antigens, improving stability and
delivery.
✔ Mechanism: Liposomes merge with cell membranes, allowing antigen release inside the cells.
✔ Advantages:
✅ Protects antigens from enzymatic degradation.
✅ Enhances antigen uptake and immune response.
✅ Suitable for oral and nasal vaccines.
Example: Epaxal® (Hepatitis A vaccine) uses a liposome-based formulation.
3)Microneedle-Based Vaccine Patches
✔ Definition: Microneedle patches contain hundreds of microscopic, dissolvable needles that deliver the
vaccine painlessly into the skin.
✔ Mechanism: The microneedles pierce the outer skin layers, releasing the vaccine into the dendritic
cell-rich dermis.
✔ Advantages:
✅ Painless & Self-Administered – No need for injections.
✅ No Cold Storage Required – Increases vaccine stability.
✅ Cost-Effective – Reduces the need for trained healthcare professionals.
📌 Example: Flu vaccine microneedle patch is being developed for painless influenza vaccination.

19. Innovations in Vaccine Delivery
Systems
Exploring advanced methods for vaccine administration,
enhancing effectiveness, accessibility, and patient compliance.
Single-Shot Vaccine Technology
1 Reduces Doses
Less need for boosters.
2 Better Compliance
Ensures higher
vaccination rates.
3 Remote Areas
Useful where multiple
doses are challenging.

20. Introduction
•Single-shot vaccines are designed to prevent multiple diseases (4 to 6) with just one
injection, enhancing patient convenience and compliance.
•Traditional vaccines often require multiple doses, leading to higher costs, logistical
challenges, and patient non-compliance.
•To overcome these limitations, single-shot vaccines have been developed, offering protection
with a single administration.
Definition: A single-shot vaccine is a combination product comprising:
• A prime component antigen,
• A microsphere-based delivery system,
• Suitable adjuvants,
• An encapsulated antigen enabling delayed release, ensuring booster immunization
over time.
This approach ensures efficient, cost-effective, and long-lasting immunity with a simplified
vaccination regimen.
EXAMPLES-
 Johnson & Johnson (Janssen) COVID-19 Vaccine – A viral vector vaccine that provides protection against COVID-19 with a
single dose.
 Yellow Fever Vaccine (Stamaril, YF-VAX) – A live attenuated vaccine providing lifelong immunity with one dose.

21. Adjuvants in Single-Shot Vaccines
Vaccine Adjuvants
•Adjuvants are substances added to vaccines to enhance their effectiveness.
•They work by stimulating the immune system, making it more responsive to
the vaccine.
Need for Adjuvants
✔ Enhance therapeutic efficacy by improving immune response.
✔ Form an antigen depot at the inoculation site, enabling slow and sustained
antigen release.
✔ Improve vaccine performance by effectively targeting the antigen-
presenting cells (APCs) for an optimal immune response.
The inclusion of adjuvants in single-shot vaccines ensures long-lasting
immunity with a single dose, reducing the need for multiple booster shots.

22. Types of Adjuvants
1. Gel-Based Adjuvants
✔ Examples: Aluminum hydroxide, Calcium phosphate
Function: Act as a depot, allowing slow antigen release and prolonged
✔
immune response.
2. Oil Emulsion & Particulate-Based
Adjuvants
✔ Examples: Liposomes, Biodegradable microspheres
Function: Improve antigen stability and enhance immune stimulation
✔ .
3. Virosomes
✔ Virosomes mimic viruses but are non-infectious.
They incorporate
✔ antigens and proteins on their surface to trigger an
immune response.
They
✔ do not contain genetic material, eliminating the risk of
infection.
Mechanism of Action
✔ Immune cells recognize and engulf particulate adjuvants.
These are then
✔ presented to the immune system, initiating a
protective immune response.
By utilizing different types of adjuvants, single-shot vaccines can
achieve enhanced immunogenicity, prolonged antigen exposure, and
improved vaccine efficacy
Biodegradable Polymers
✔ Definition:
Biodegradable polymers are macromolecules composed of
monomers linked by functional groups. They contain unstable
bonds in the backbone, making them susceptible to degradation.
✔ Biodegradation Process:
These polymers break down into biologically acceptable
molecules, which are metabolized and eliminated through
natural physiological pathways.
✔ Significance in Drug Delivery:
•Sustained drug release for prolonged therapeutic effects.
•Reduced toxicity due to natural degradation.
•Biocompatibility, making them ideal for medical applications.

23. Important determinants for single shot vaccine
development

24. Microsphere Component of Single-Shot Vaccine
🔹 OctoVAX Microsphere Technology
Utilizes cross-linked modified dextran polymers for controlled drug delivery.
🔹 Dextrans as Biocompatible Polymers
•Ideal for hydrogel formation.
•Microspheres prepared without organic solvents.
•No pH drop during degradation, maintaining stability.
🔹Hydrogel Formation with Dextran-Based Polymers
•Various dextran derivatives have been developed.
•DexHEMA (Hydroxy-Ethyl Methacrylate-Dextran) is one such derivative.
🔹 Enhanced Biodegradation
•Incorporation of hydrolytically sensitive carbonate ester groups.
•Ensures biodegradation under physiological conditions for safe vaccine
delivery.

26. Mucosal Vaccine Delivery
Nasal
Spray vaccines for
respiratory viruses.
Oral
Vaccines stimulate
gut immunity.
Rectal
Administer vaccines through
mucous membranes.
Definition
Mucosal vaccine delivery targets the mucosal immune system (found
in mucous membranes of the nose, mouth, and rectum), providing
immunity at the site of infection. This delivery route is crucial for
vaccines that prevent infections in mucosal areas, such as respiratory,
gastrointestinal, and urogenital infections.
Advantages:
 No Needles: Mucosal vaccines are non-invasive and eliminate the need
for syringes, which increases patient acceptance.
 Enhanced Immune Response: Mucosal vaccines stimulate local IgA
(Immunoglobulin A) responses at the site of infection. IgA is vital in
preventing pathogens from entering the body through mucosal surfaces.
Potential for Wider Distribution: Easier self-administration at home and
in low-resource settings, making them ideal for mass vaccination campaigns.
Examples
Nasal Spray Vaccines: FluMist (Influenza)
Oral Vaccines: Oral Polio Vaccine (OPV)

27. Design & Strategies for Mucosal Delivery
1. Emulsion-type delivery
2. Liposome-based delivery
3. Polymeric nanoparticles
4. Virosomes
5. Melt-in-mouth strips

28. Transdermal Vaccine Delivery
Microneedles
Small needles
penetrate skin.
Patches
Easy,
self-administration.
Dermis
Releases vaccine
into dermis.
Transdermal vaccination involves delivering the vaccine across the skin layers. This method
utilises microneedles (small needles that painlessly penetrate the skin) or patches to deliver
vaccines. It provides a new frontier in vaccine administration, offering advantages over
traditional injection methods.

30. Vaccine Delivery Systems
Intramuscular
Injection
Well-established,
strong immune
response
Requires trained
personnel, can be painful
Oral Vaccines Easy to administer,
mucosal immunity
Stability issues, may need
multiple doses
Microneedles
Painless, self-
administration,
no cold storage
Limited skin penetration,
still in development

31. Future Scope
DNA
Next-generation vaccines.
AI
Personalized therapies.
Smart
Wearable vaccine patches.
The future of vaccine drug delivery is bright and dynamic, with cutting-edge technologies aimed at
enhancing the effectiveness, accessibility, and patient compliance of vaccines. These advancements will
significantly impact global health and disease prevention.

32. References
• N.K. Jain TEXTBOOK OF PHARMACEUTICAL MICROBIOLOGY.
• Garg Neeraj, Mangal Sharad, Khambete Hemant."Recent patents on drug delivery & formulation"; Mucosal
Delivery of Vaccines: Role of Mucoadhesive/Biodegradable Polymers 2010;4,114-128.
• Saroja CH, Lakshmi PK"Recent trends in vaccine delivery systems": A Review International J pharm investig
2011 apr-jun;1(2):64-74
• Advances In Vaccination: A Review By Swarnali Dasa', Rohitas Deshmukh, International Journal Applied
Pharmaceutics Vol 1 Issue 1, 2009
• Mucosal delivery of vaccines: a review zara sheikh", nishat jahan, rejaul karim Zara Sheikh*et al.
International Journal of Pharmacy & Technology
• Recent advances in vaccine delivery by Soni Khyati J., Patel Rakesh P., Asari Vaishnavi M. and Prajapati
Bhupendra G Journal of Applied Pharmaceutical Science 01 (01); 2011: 30-37
• Bernard KW., Mallonee J., Wright JC. Pre exposure immunization with intraderma human diploid cell rabies
vaccine, Risks and benefits of primary and booster vaccination. The Journal of the American Medi Asso.2005;
257(8): 1059-1063.A