Nanoparticles for protein drug delivery

1. A method of treating obesity in a subject in need thereof comprising identifying a subject in need of treatment for obesity and administering bioactive nanoparticles to said subject, wherein said nanoparticles consist of positively charged chitosan, a negatively charged substrate, and at least one appetite-suppressing agent, wherein a shell portion of said nanoparticles is dominated by said positively charged chitosan, and wherein said negatively charged substrate is at least partially neutralized with a portion of said positively charged chitosan in the core portion of said nanoparticles.

2. The method of claim 1 , wherein the chitosan has a molecular weight about 80 kDa or less.

3. The method of claim 1 , wherein said nanoparticles have a mean particle size between about 50 and 400 nanometers.

4. The method of claim 1 , wherein the chitosan is N-trimethyl chitosan, EDTA-chitosan, low molecular weight chitosan, chitosan derivatives or combinations thereof.

5. The method of claim 1 , wherein said nanoparticles are loaded in tablets or pills.

6. The method of claim 1 , wherein said nanoparticles are encapsulated in capsules.

7. The method of claim 6 , wherein said capsules further comprise at least a solubilizer or pharmacopoeial excipients.

8. The method of claim 6 , wherein said capsules are enterically coated.

9. The method of claim 6 , wherein said capsules further comprise at least one permeation enhancer.

10. The method of claim 9 , wherein said permeation enhancer is selected from the group consisting of Ca 2+ chelators, bile salts, anionic surfactants, medium-chain fatty acids, phosphate esters, chitosan, and chitosan derivatives.

11. The method of claim 1 , wherein said nanoparticles are freeze-dried, thereby said nanoparticles being in a powder form.

12. The method of claim 1 , wherein said nanoparticles are mixed with trehalose and then freeze-dried, thereby said nanoparticles being in a powder form.

13. The method of claim 1 , wherein said nanoparticles further comprise magnesium sulfate or TPP.

14. The method of claim 1 , wherein said at least one appetite-suppressing agent is appetite-suppressing peptide or peptide fraction.

15. The method of claim 1 , wherein said at least one appetite-suppressing agent is leptin.

16. The method of claim 1 , wherein said at least one appetite-suppressing agent is obestatin.

17. The method of claim 1 , wherein said at least one appetite-suppressing agent is ghrelin antagonist.

18. The method of claim 1 , wherein said at least one appetite-suppressing agent is Peptide YY.

19. The method of claim 1 , wherein said at least one appetite-suppressing agent is Urotensin-I or Urotensin II.

20. The method of claim 1 , wherein said at least one appetite-suppressing agent is cholecystokinin.