1. Centre of Polymer Systems
Novel pH sensitive chitosan -grafted- star shaped polylactide nanoparticles for sustained and controlled release application
Antonio Di Martino, Pavel Kucharczyk , Vladimir Sedlarik
Centre of Polymer Systems
Czech Republic

2. Drug Delivery Systems (DDS)
DDS: approaches, formulations, technologies for the targeted delivery and/or controlled release of therapeutic agents
Safe
Perform therapeutic function
Convenient administration
Ease of manufacturing

3. Why Polysaccharides?
Considered one of the most promising materials for drug delivery
Various sources : Algae, Microbial, Plants and Animals
Abundant
Low cost
Large number of reactive groups
Chemical composition
Wide range od Mw
Biocompatible
Biodegradable
Low Immunogenicity
Non-Toxic

4. Polysaccharides Based Nanoparticles
Hyaluronic Acid
Dextran
Heparin
Pectic Acid
Cyclodextrin
Chondroitin Sulfate
Chitosan

5. Bioactive Molecules Antibiotics Steroids Antineoplastics Amoxicillin
Antibiotics
Amoxicillin
Sultamicillin
Methicillin
Steroids
Progesterone
Testosterone
Estradiol
Antineoplastics
Vincristine
Paclitaxel
Doxorubicin

6. Large amount of drug released immediately upon placement in the media
Burst Effect
Large amount of drug released immediately upon placement in the media
Advantages
Wound treatment
Targeted delivery (triggered burst release)
Pulsatile release
Disadvantages
Local or systemic toxicity
In vivo short t1/2
Waste of drug
Short release profile
Frequent administration
Difficult to predict intensity
Journal of Controlled Release 73 (2001) 121 –136

7. Burst Effect Causes How to reduce…. Process conditions
Surface characteristics
Morphology
Carrier-Drug interactions
Causes
How to reduce….
Surface extraction
Drug loading distribution
Surface modification
Polymer morphology and composition
preparation steps
cost

8. Aim of the work
CS modification by grafting Star Shaped carboxy-terminated
Poly Lactic Acid (SSPLA)
Reduction of TMZ Burst Intensity

9. Chitosan (CS) Biocompatibility Biodegradability Non-toxic
Not immunogenic
Chemical modification
Soluble in mildly acidic aqueous media
Well-known behaviour

10. Bioactive molecule Temozolomide (TMZ) Alkylating agent
Anaplastic astrocytoma
Glioblastoma multiforme
Why Use a Carrier for TMZ ?
Short half-life
Intrinsic tumor resistance
Limited access to brain tumors
Poor response

11. Methods

12. SSPLA & CS-SSPLA synthesis & characterization
SSPLA : Star Shaped carboxy-terminated Poly Lactic Acid
Polycondensation reaction
Pentetic Acid as core molecule
MSA as catalyst
GPC
FTIR-ATR
1H-NMR
Characterization
CS-SSPLA : Chitosan – g –Star Shaped carboxy-terminated Poly Lactic Acid CS
FTIR-ATR
1H-NMR +
EDC, NHS
48h , RT
SSPLA
CS-SSPLA

13. Nanoparticles preparation
PolyElectrolytes Complexation method
Fast
Low cost
Solvent-free
NPs size related topolymers w/w
Dextran sulfate (DS, Mw 40 kDa)
CS-SSPLA / DS (w/w): 2
1 mg TMZ
I. Add DS + TMZ solution DS +
II. 30 min stirring , RT DS
CS-SSPLA
TMZ
CS-SSPLA
TMZ

14. Nanoparticles characterization
Dynamic Light Scattering (DLS)
z-potential (mV)
Transmission Electron Microscopy (TEM)
Swelling in different media
Average dimension (nm)
Stability over time
Morphology
Dimension

15. TMZ Encapsulation & Release
Dt = amount of TMZ added (mg/ml)
Df = amount of TMZ free after encapsulation (mg/ml)
Simulated Intestinal Fluid (SIF) : pH 6.8 – Pancreatin free
Preparation Media (PM) : pH 5.5
Simulated Gastric Fluid (SGF): pH 1.8 – Pepsin free
Temperature : 37 ˚C
180 rpm shake
Release conditions
Encapsulation and Release were evaluated by UV-Vis at 325 nm

17. SSPLA and CS-SSPLA SSPLA CS-SSPLA Mn = 1900 g/mol Mw = 4000 g/mol GPC
Mw/Mn = 2.4
GPC
1H- NMR (-COOH/-OH ratio) = I 5.01/ I 4.2 = 3.45
CCOOH = mmol/g
CS-SSPLA
FTIR-ATR = presence of amide bond
1H-NMR

18. Nanoparticles dimension & charge
CS = 120 nm ± 10 nm
CS-SSPLA = 170 nm ± 24 nm
Average dimension (DLS):
CS = 38 ± 0.5
CS-SSPLA = 23 ± 1
z-potential (mV) :
TMZ does NOT INFLUENCE NPs dimension and z-potential
CS-SSPLA CS
Preparation media (pH 5.5)
Room Temperature

19. Encapsulation Efficiency (EE)
TMZ was encapsulated during preparation
Encapsulation
Efficiency (%)
CS = 250 ± 3 mg TMZ / mg carrier
CS-SSPLA = 266 ± 5 mg TMZ / mg carrier

20. Release studies I CS CS-SSPLA prolonged release pH Swelling SSPLA
Release rate
SSPLA
Does not significantly
influence the swelling

21. Release studies II : BurstCS
CS-SSPLA
Increases or decreases release intensity at the initial time pH
SSPLA
Reduces burst intensity

22. Conclusions Nanoparticles dimension < 200 nm
Nanoparticles are stable up to 1 month at room temperature
mg TMZ / mg of carrier
Prolonged release up to 10 days
More than 60% reduction of the initial burst in presence of SSPLA

23. Future Perspectives Multi-drug encapsulation
Combination of hydrophilic and hydrophobic drugs
Peptides or proteins
Preparation of tablets for oral administration

24. Acknowledgements This work was financially supported by
the Czech Science Foundation (Grant No Y)
the Ministry of Education, Youth and Sports of the Czech Republic – NPU I Programme (LO1504) and EUPRO (LE12002)
the Internal Grant Agency of TBU in Zlin –Czech Republic (Grant No. IGA/CPS/2015/003)