Cyclodextrins in nasal delivery of low-molecular-weight heparins: in vivo and in vitro studies.
OBJECTIVE
To test the hypothesis that cyclodextrins reversibly enhance nasal absorption of low-molecular-weight heparins (LMWHs) and to investigate the mechanisms by which cyclodextrins enhance LMWH absorption via the nose.


METHODS
Absorption of LMWHs was studied by measuring plasma anti-factor Xa activity after nasal administration of various LMWH formulations to anesthetized rats. In vivo reversibility studies were performed to investigate if the effects of cyclodextrins are reversible and diminish with time. The absorption-enhancing mechanisms of cyclodextrins were investigated in cell culture model. The transport of enoxaparin and mannitol, changes in transepithelial electrical resistance (TEER), and distribution of tight junction protein ZO-1 were investigated.


RESULTS
Formulations containing 5% dimethyl-beta-cyclodextrin (DMbetaCD) produced the highest increase in the bioavailability of LMWH preparations tested. In vivo reversibility studies with 5% DMbetaCD showed that the effect of the absorption enhancer at the site of administration diminished with time. Transport studies using 16HBE14o(-) cells demonstrated that the increase in the permeability of enoxaparin and mannitol, reduction in TEER, and the changes in the tight junction protein ZO-1 distribution produced by 5% DMbetaCD were much greater than those produced by beta-cyclodextrin (betaCD) or hydroxyl-propyl-beta-cyclodextrin (HPbetaCD).


CONCLUSIONS
Of the cyclodextrins tested, DMbetaCD was the most efficacious in enhancing absorption of LMWHs both in vivo and in vitro. The study also suggests that cyclodextrins enhance nasal drug absorption by opening of cell-cell tight junctions.
Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, Texas 79106, USA.
Tianzhi
T
Yang
Alamdar
A
Hussain
Jennifer
J
Paulson
Thomas J
TJ
Abbruscato
Fakhrul
F
Ahsan
D000281:Administration, Intranasal; D000818:Animals; D000990:Antithrombin III / Q000378:metabolism; D001682:Biological Availability; D001692:Biological Transport; D002457:Cell Extracts; D002478:Cells, Cultured; D017985:Dalteparin / Q000008:administration & dosage / Q000493:pharmacokinetics; D004553:Electric Conductivity; D017984:Enoxaparin / Q000008:administration & dosage / Q000493:pharmacokinetics; D006495:Heparin, Low-Molecular-Weight / Q000008:administration & dosage / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D008353:Mannitol / Q000493:pharmacokinetics; D008565:Membrane Proteins / Q000378:metabolism; D009297:Nasal Mucosa / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D062826:Zonula Occludens-1 Protein; D047392:beta-Cyclodextrins / Q000494:pharmacology*
D002457:Cell Extracts; D017984:Enoxaparin; D006495:Heparin, Low-Molecular-Weight; D008565:Membrane Proteins; D010750:Phosphoproteins; C569042:TJP1 protein, human; C569044:Tjp1 protein, rat; D062826:Zonula Occludens-1 Protein; D047392:beta-Cyclodextrins; D008353:Mannitol; D000990:Antithrombin III; D017985:Dalteparin