Drug Delivery systems : Drug Delivery systems Nanoparticles
Alahliyya Amman university- Jordan Slide 2: Carrier systems are promising strategy to overcome many problems of drug administration. The in vivo fate of drug is no longer determines by the properties of the itself but the carrier system which should permit a controlled and localized release of drug according to the need of therapy. Advantages of nanosizing : Advantages of nanosizing Improving solubility.
Adhesion to tissues.
Developing of nanoparticle is a part of nanoparticulate system. Nanoparticles NP: : Nanoparticles NP: Nanoparticles are submicron carrier composed of natural or synthetic polymers.
Or ; they are polymeric particles made of natural or synthetic polymers ranging from 10-1000 nm in which drug may be bound in solid solution or dispersion, adsorbed or chemically attached. Slide 5: Advantages of NP:
1-Improved stability of drug in biological environment.
Eg: protein and peptides orally.
Eg: insulin in polycyanoacrylamide.
Increase stability against digestive enzymes.
Eg;doxorubicine loaded on polysorbate 80 coated nanoparticles(experimental)
Full mechanism by which NP enter the brain preferably is not clearly understood. Slide 6: Suggested mechanism is endocytosis of heavily coated NP with polysorbate 80.
Lymph targeting was achieved through highly lipophilic NP that accumulate in lymph nodes.
Oral vaccination. Slide 7: 3- Mucoadhesive properties:
To prolong residence of poorly absorbable drugs.
Eg: oral antibiotics.
4- controlled release of drug:
Oral : hormones, replacement therapy. eg: calcitonin.
Ocular: diabetic retinopathy, chronic inf. Slide 8: 5- Protection of GIT from drug irritation (NSAI)
Eg; indomethacine in isobutylcyanoacrylate.
6- Transdermal delivery:
It was found that “reasonable absorption” gave systemic action.
Eg: Leutinizing hormone analogus peptide. Methods of preparation : Methods of preparation NP may be prepared by three methods:
1- Solvent evaporation method:
Suitable for Biodegradable NP made of hydrophobic polymers like: PLA .
2- Polymerization of monomers: polyalkylcyanoacrylate NP were produced by this method, in which the polymer is prepared from monomer with the drug and other materials as surfactants , stabilizers. Upon purification we get the NP loaded with the drug. Slide 10: The properties of NP such as particle size, surface potential hydrophilic- hydrophobic balance are determined by method of preparation.
Drug loading: Successful NP system is the one which has high loading efficiency to reduce quantity of carrier required for administration.
Drug loading into the NP is achieved by:
1- The incorporation of drug at time of production.
2- Adsorbing the drug after the formation of NP by incubation in a drug solution.
We may need substances like Surface active materials and stabilizers. Eg: cyclodextrin and sodium oleate. Drug Release : Drug Release Drug release from NP is achieved by:
3- Mixed mechanism.
Surface modification of biodegradable NP with blood compatible materials in order to prolong their circulation period in the plasma by increasing their stability against Slide 12: Phagocytosis and plasma protein adsorption.
NP surface modification can be achieved by:
A- coating with hydrophilic polymers or surfactant.(polysorbate 80)
B- Development of biodegradable copolymers with hydrophilic segments. Mechanism of NP absorption enhancement of Peptide: : Mechanism of NP absorption enhancement of Peptide: 1-Mucoadhesion of NP in GIT which increase drug conc. On the epithelium.( electrostatic forces)
2- Increase stability against GI degradation Slide 15: Magnetic nonoparticles
Diagnosis, cancer therapy Nanocapsules : Nanocapsules Slide 18: About 100 Ao (10 nm) to 2000 Ao shell like polymeric particles belongs to reservoir system in which drug is contained as oily solution or dispersion.
To distinguish between NP and NC, we subject them to centrifugation. NP form sediment while NC form upper layer due to oily drplet.
NP NC Slide 19: Method of preparation:
1- condensation polymerization.
3-Microemulsification (new method)
- small size, improve absorption.
- accumulation related to small size with ability of targeting.