CUTTING EDGE TECHNOLOGIES FOR DRUG DELIVERY
NANOMEDICINES
Clinical needs and advanced drug delivery challenges ...........................................................................3
Clinical needs ..................................................................................................................................3
Challenges.......................................................................................................................................3
From small drugs to bio-therapeutics ....................................................................................................6
History .............................................................................................................................................7
Scientific findings supporting the belief ........................................................................................... 10
Breakthrough ................................................................................................................................. 13
Future perspectives ........................................................................................................................... 14
Believers and non-believers ............................................................................................................ 14
Importance of correct science communication to society ................................................................. 14
Directions: hard to predict – in depth academic research.................................................................. 14
Simplicity ....................................................................................................................................... 14
Intracellular delivery of bio-therapeutics ............................................................................................. 15
Administration of nucleic acids ....................................................................................................... 15
Challenges..................................................................................................................................... 16
Delivery for ocular therapies ............................................................................................................... 19
Challenges in ophthalmology .......................................................................................................... 19
Delivery routes ............................................................................................................................... 20
Delivery vehicles ............................................................................................................................ 24
Extracellular vesicles for advanced drug delivery ................................................................................. 28
Production – isolation – characterization ......................................................................................... 29
Loading – engineering ..................................................................................................................... 30
Clinical translation ......................................................................................................................... 31
Delivery and endosomal escape of macromolecular drugs ................................................................... 34
1
, Intracellular delivery of macromolecules ......................................................................................... 34
Types of non-viral delivery carriers ................................................................................................... 34
Interaction with cell membranes and intracellular processing........................................................... 34
Toxicity of endosomal escape ......................................................................................................... 35
Endosomal escape mechanisms ..................................................................................................... 36
Methods to evaluate endosomal escape .......................................................................................... 39
Delivery for vaccination ...................................................................................................................... 41
Humoral and cellular immune responses ........................................................................................ 41
mRNA nanovaccines (LNP): what’s inside ........................................................................................ 41
mRNA LNPs for infectious diseases ................................................................................................. 43
mRNA LNPs for cancer immunotherapy ........................................................................................... 43
Future perspectives ........................................................................................................................ 44
2
,CLINICAL NEEDS AND ADVANCED DRUG DELIVERY CHALLENGES
! ideal = magic bullet: only reach target tissue without affecting healthy tissue
CLINICAL NEEDS
DRUG FORMULATION
− Conventional drug administration
• Distribution: delivery of active compounds at certain please xyz in complex physiology
• Extravasation: molecules in bloodstream are uncontrolled as to where they go
= only a small amount arrives at the target + a lot of side effects in non-targets
CHALLENGES
DRUG TARGETING
− Microbubble-based delivery
• Concept
o Macromolecular gas-filled microbubbles
o Exposure to ultrasound waves (high and low-pressure <2 cm): shrinkage + expanding
! increasing energy: energy collapses bubble = cavitation
= reduced systemic toxicity
• Application
o Encapsulate contrasting agent in capillaries for high quality images
o Encapsulate chemo drugs in microbubbles to set free at site of ultrasound waves
o Delivery of drugs into bubble
- Electrostatic loading
- Shell composition
- Drug dissolved in inner oil layer
- Attaching multiple reservoirs
ANTIBIOTICS DELIVERY
− Problems
• Antimicrobial resistance (AMR): lobal major threat to human health
o Reduce required antibiotic doses
o Improve treatment efficiency
o Slow resistance development
• Difficulties to penetrate biofilm and kill bacteria that chronically infect an implant
− Gold nanoparticles dispersion
• Concept
o Au: 50-70 nm – small enough to enter
o Low-intensity pulsed laser light: Au able to enter structures
high-intensity short-pulsed (<10 ns) laser: Au vibrates in biofilm
• Application: antibiotica penetrates more effectively into the biofilm: lower dose required
3
, VACCINE DELIVERY
− Problem: multiple shot vaccination = boosts
• Vaccination programs strongly depend on healthcare infrastructure
• Difficulties to implement multiple shot vaccination in low-resource settings
= people die from infections for which vaccinations exist already
o DTP (diphtheria – tetanus – pertussis) coverage:
= 85% - 14 million children under/not vaccinated (<3 dosages)
Single-shot vaccination
• Concept
o Self-exploding microcapsules
- Degradable DEX-HEMA microgel core + semi-permeable membrane
= layer-by-layer membrane: polyanion + polycation
▪ Permeable for H2O: increase swelling
▪ Impermeable for degradation products + entrapped drugs
e.g. poly(lactic-co-glycolic acid) degrades into lactic and glycolic acid
• Application
o Water diffused into the microgel core which degrades
o Swelling pressure increases until membrane ruptures
o Release of particle infused in core
= multiple types that combust at different times
− Problem: vaccination IV containing pathogens
➔ DC take up antigen more specific delivery required
➔ migration + maturation to lymph nodes but drain away to other parts
➔ presentation to T and B-cells
➔ cytotoxic T-cells and antibody production
Advanced presentation to DC
o Naked antigens
- Direct uptake by DC – often inefficient
o Microcapsules: naked antigen (nanometer) + capsule (micrometer)
- Better uptake by DC of antigens and transport to lymph nodes
- Pandemics: given amount of vaccine can immunize larger population
MUCOSAL VACCINATION
− Route of infection = route of delivery
• Concept
o Less infrastructure: cheaper to ‘vaccinate’ mucosal immunity through activation
o Easier mass vaccination
• Application: mucosal surfaces = extensive lymphoid tissue (GALT – NALT)
o Contains M-cells: ‘transport’ particles to lymphocytes and macrophages
o Mucosal vaccination = mucosal activation = immunity
! in nose: very high concentration of T-cells and antibodies
e.g. oral Polio vaccine – rotavirus – salmonella – cholera
4
NANOMEDICINES
Clinical needs and advanced drug delivery challenges ...........................................................................3
Clinical needs ..................................................................................................................................3
Challenges.......................................................................................................................................3
From small drugs to bio-therapeutics ....................................................................................................6
History .............................................................................................................................................7
Scientific findings supporting the belief ........................................................................................... 10
Breakthrough ................................................................................................................................. 13
Future perspectives ........................................................................................................................... 14
Believers and non-believers ............................................................................................................ 14
Importance of correct science communication to society ................................................................. 14
Directions: hard to predict – in depth academic research.................................................................. 14
Simplicity ....................................................................................................................................... 14
Intracellular delivery of bio-therapeutics ............................................................................................. 15
Administration of nucleic acids ....................................................................................................... 15
Challenges..................................................................................................................................... 16
Delivery for ocular therapies ............................................................................................................... 19
Challenges in ophthalmology .......................................................................................................... 19
Delivery routes ............................................................................................................................... 20
Delivery vehicles ............................................................................................................................ 24
Extracellular vesicles for advanced drug delivery ................................................................................. 28
Production – isolation – characterization ......................................................................................... 29
Loading – engineering ..................................................................................................................... 30
Clinical translation ......................................................................................................................... 31
Delivery and endosomal escape of macromolecular drugs ................................................................... 34
1
, Intracellular delivery of macromolecules ......................................................................................... 34
Types of non-viral delivery carriers ................................................................................................... 34
Interaction with cell membranes and intracellular processing........................................................... 34
Toxicity of endosomal escape ......................................................................................................... 35
Endosomal escape mechanisms ..................................................................................................... 36
Methods to evaluate endosomal escape .......................................................................................... 39
Delivery for vaccination ...................................................................................................................... 41
Humoral and cellular immune responses ........................................................................................ 41
mRNA nanovaccines (LNP): what’s inside ........................................................................................ 41
mRNA LNPs for infectious diseases ................................................................................................. 43
mRNA LNPs for cancer immunotherapy ........................................................................................... 43
Future perspectives ........................................................................................................................ 44
2
,CLINICAL NEEDS AND ADVANCED DRUG DELIVERY CHALLENGES
! ideal = magic bullet: only reach target tissue without affecting healthy tissue
CLINICAL NEEDS
DRUG FORMULATION
− Conventional drug administration
• Distribution: delivery of active compounds at certain please xyz in complex physiology
• Extravasation: molecules in bloodstream are uncontrolled as to where they go
= only a small amount arrives at the target + a lot of side effects in non-targets
CHALLENGES
DRUG TARGETING
− Microbubble-based delivery
• Concept
o Macromolecular gas-filled microbubbles
o Exposure to ultrasound waves (high and low-pressure <2 cm): shrinkage + expanding
! increasing energy: energy collapses bubble = cavitation
= reduced systemic toxicity
• Application
o Encapsulate contrasting agent in capillaries for high quality images
o Encapsulate chemo drugs in microbubbles to set free at site of ultrasound waves
o Delivery of drugs into bubble
- Electrostatic loading
- Shell composition
- Drug dissolved in inner oil layer
- Attaching multiple reservoirs
ANTIBIOTICS DELIVERY
− Problems
• Antimicrobial resistance (AMR): lobal major threat to human health
o Reduce required antibiotic doses
o Improve treatment efficiency
o Slow resistance development
• Difficulties to penetrate biofilm and kill bacteria that chronically infect an implant
− Gold nanoparticles dispersion
• Concept
o Au: 50-70 nm – small enough to enter
o Low-intensity pulsed laser light: Au able to enter structures
high-intensity short-pulsed (<10 ns) laser: Au vibrates in biofilm
• Application: antibiotica penetrates more effectively into the biofilm: lower dose required
3
, VACCINE DELIVERY
− Problem: multiple shot vaccination = boosts
• Vaccination programs strongly depend on healthcare infrastructure
• Difficulties to implement multiple shot vaccination in low-resource settings
= people die from infections for which vaccinations exist already
o DTP (diphtheria – tetanus – pertussis) coverage:
= 85% - 14 million children under/not vaccinated (<3 dosages)
Single-shot vaccination
• Concept
o Self-exploding microcapsules
- Degradable DEX-HEMA microgel core + semi-permeable membrane
= layer-by-layer membrane: polyanion + polycation
▪ Permeable for H2O: increase swelling
▪ Impermeable for degradation products + entrapped drugs
e.g. poly(lactic-co-glycolic acid) degrades into lactic and glycolic acid
• Application
o Water diffused into the microgel core which degrades
o Swelling pressure increases until membrane ruptures
o Release of particle infused in core
= multiple types that combust at different times
− Problem: vaccination IV containing pathogens
➔ DC take up antigen more specific delivery required
➔ migration + maturation to lymph nodes but drain away to other parts
➔ presentation to T and B-cells
➔ cytotoxic T-cells and antibody production
Advanced presentation to DC
o Naked antigens
- Direct uptake by DC – often inefficient
o Microcapsules: naked antigen (nanometer) + capsule (micrometer)
- Better uptake by DC of antigens and transport to lymph nodes
- Pandemics: given amount of vaccine can immunize larger population
MUCOSAL VACCINATION
− Route of infection = route of delivery
• Concept
o Less infrastructure: cheaper to ‘vaccinate’ mucosal immunity through activation
o Easier mass vaccination
• Application: mucosal surfaces = extensive lymphoid tissue (GALT – NALT)
o Contains M-cells: ‘transport’ particles to lymphocytes and macrophages
o Mucosal vaccination = mucosal activation = immunity
! in nose: very high concentration of T-cells and antibodies
e.g. oral Polio vaccine – rotavirus – salmonella – cholera
4
