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Novel PLA-Chitosan nanocomplexes for controlled and sustained release of DNA-Alkylating drugsA. Di Martino,
Centre of Polymer Systems, University Institute, Tomas Bata University in Zln, tr. T. Bati 5678, 76001, Zlin, Czech Republic
approaches, formulations, technologies for the targeted delivery and/or controlled release of therapeutic agentsSafePerform therapeutic functionConvenient administrationSimple to manufactureDrug Delivery Systems (DDS)
1950 1980 : 1st generation Basics of controlled release
1980 2010 : 2nd generation Smart delivery
2010 2040 : 3rd generation Modulated delivery
- Zero order- Smart polymers and hydrogels- Peptide and protein- Nanoparticles
- Targeted delivery- Long term delivery systems - Minimal burst- In vitro-in vivo correlation (IVIVC)
Park. Journal of Controlled Release 190 (2014) 38
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Development of DDS : an overview
Park. Journal of Controlled Release 190 (2014) 38
Nanoparticles as DDSWhy use Nanoparticles?
Dispersion or solid form Various morphologies nanospheres, nanocapsules. Drug(s) can be dissolved, entrapped, encapsulated or attached High Encapsulation and Loading Efficiency Protection Controlled and sustained release Side effects reduction
Polysaccharides Various sources : Algae, Microbial, Plants and animals
Abundant
Wide range of Mw
Chemical composition
Large number of reactive groups
Biocompatible and biodegradable
Low immunogenicity
Not toxic
Why polysaccharides?
Polysaccharides in Drug delivery
Hyaluronic acidAlginate
Pectic acid
Dextran sulfate
Cyclodextrins
Chondroitin sulfate
Chitosan
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Small molecules Proteins PeptidesCyclodextrinesPolysaccharidesDrugsChitosan and derivativesSynthetic PolymersLMW, MMW,HMW
-C3-OH-C6- OH-NH2D-GlucosamineN-Acetyl -D-Glucosamine
GoalsPreparation of a set of amphiphilic carriers
Single and Multiple Encapsulation of DNA alkylating drugs
Improve drug release performance
Reduction of burst effect
Increase drug cytotoxicity
Polylactic acid (PLA)Linear PLA (LPLA)Carboxy enriched PLA (CPLA)Branched PLA (BPLA)Amphiphilic polymerChitosan
Low molecular weight
D.D. 75-85 %Hydrophilic backbone
Hydrophobic side chain
Chitosan-PLA synthesis and characterization
FTIR-ATR
1H-NMRSynthesisCharacterizationDi Martino et al. Int.J.Pharm. 2015 Dec 30;496(2):912-21Di Martino & Sedlarik . Int.J.Pharm. 2014 Oct 20;474(1-2):134-45
CS-PLA based nanoparticles Polyelectrolytes Complexation (PEC)
Ionotropic Gelation (IG) Fast and simple Solvent free Not needs special equipment Dimension and surface charge control Low P.D.I. Good reproducibility
PECPolyions- Natural- Semi synthetic- Synthetic
+ charges / - chargesMwConcentration
IGSmall molecules
Nanoparticles dimension Core structure Stability Encapsulation efficiency Release ratePEC or IGWhat are we looking for ?
+ charges / - chargesConcentration
Drug LoadingPost preparation
Low encapsulation efficiency
Surface localization
Burst effect Preparation
High encapsulation
Protection from external environment
Sustained release
Burst effect reductionParameters Carrier structure Drug structure Method pH Temperature Ionic strength Drug to carrier weight ratio
Carrier Drug interactions
Anticancer drugs
Suicide inhibitor Inhibition of thymidylate synthase AntimetaboliteDoxorubicinTemozolomide5-Fluorouracil Alkylate/methylate DNA N-7 or O6 guanine Resistance mechanism DNA intercalation Inhibits topoisomerase II Block the DNA replicationSIDE EFFECTSHYDROLYSIS CIRCULATION TIME
SIDE EFFECTSADMINISTRATION ROUTE
Why use nanocarriers ?
Nanocomplexes characterization
- Single loading not influence average dimension - Simultaneous loading increase average dimension
PLA side chain structure direct influences nanoparticles size Increase in dimension up to 50 %Average dimension is around 150nm
Encapsulation Efficiency- single loadingCarrier structure-Drug structure-Environment conditions
Environment Presence of side chain (-COOH, branched) Drug structureInfluence encapsulation efficiency
Encapsulation efficiency-multiple loading
DOX containing formulations are better encapsulatedFurther investigations
Release kinetic models Statistical methods Model dependent methods Model independent methods exploratory data analysis method repeated measures design multivariate approach Zero & first order, Higuchi model, Korsmeyer-Peppas model, Hixson Crowell, Baker-Lonsdale model, Weibull model .difference factor (f1) and similarity factor (f2) to compare dissolution profiles
Reduction of burst effectLarge amount of drug released immediately upon placement in the mediaAdvantagesWound treatmentTargeted delivery (triggered burst release)Pulsatile release
DisadvantagesLocal or systemic toxicityIn vivo short t1/2Waste of drugShort release profileFrequent administrationDifficult to predict intensity
Journal of Controlled Release 73 (2001) 121 136What is burst effect?
Release rate - Individual
DOX, TMZ and 5-FU loaded individuallyPhysiological solution (pH 7.4)T : 37 C
No initial burst effect is observed in all formulationsRelease begin after 5 hoursSustained release
tlag
Release rate - Simultaneous
No interactions among drugsNo initial burst effect is observed in all formulationsRelease begin after 4 hoursSustained release
tlag
DOX, TMZ and 5-FU loaded simultaneouslyPhysiological solution (pH 7.4)T : 37 C
Cell tests Cytotoxicity evaluation of free and loaded drugs
MEF, NIH/3T3 cell-linesCS-BPLACS-BPLA+ 5FUCS-BPLA + TMZCS BPLA + DOX
CS-LPLACS-BPLA
Presence of PLA side chain increase drug cytotoxicity!!!24h24h24h24h
Conclusions Nanocomplexes based on chitosan and a set of different PLA were prepared
Dimension up to 200 nm and good stability in various simulated physiological fluid
PLA side chain directs influence the nanocomplex properties
Presence of COOH groups and branched PLA structure increase encapsulation efficiency
Reduction of burst effect BPLA > CPLA > LPLA
Branched PLA prolongs the release of all tested drugs
Cell cytotoxicity tests demonstrate an increase in drug toxicity after loading in CS-PLA based formulations
Acknowledgements
grant No. 15-08287Ygrant No. LO1504