Larch arabinogalactan for dry eye protection and treatment of corneal lesions: investigations in rabbits.
OBJECTIVE
The aim of the present study was to investigate the corneal protective and healing properties of arabinogalactan (AG), a natural polysaccharide present in conifers of the genus Larix (Larch). AG was tested in comparison with other two polysaccharides possessing well-established properties in the treatment of dry eye: tamarind seed polysaccharide and hyaluronic acid.


METHODS
The AG formulation was subjected to the following investigations: rheologic measurements; evaluation of mucoadhesive properties by rheologic interaction with mucin; ferning test; and in vivo evaluation on rabbits, including treatment of an experimental dry eye; evaluation of the preocular retention; and evaluation of healing rate of experimental corneal wound.


RESULTS
AG dispersions showed a newtonian nonviscous behavior, eta = 1.6 mPa . s for 10% w/w solution; it possessed good mucoadhesive properties useful for retention on the eye surface. In fact, a prolonged time of residence in rabbit eyes was ascertained using fluorescein-labeled AG. Five percent (5.0%) w/w AG exerted a good protective effect against the appearance of corneal dry spots. It also reduced significantly the healing time of an experimental corneal lesion since 27 h after the first treatment.


CONCLUSIONS
These findings suggest that AG may be a potential therapeutic product for dry eye protection and for the treatment of corneal wounds.
Burgalassi
Susi
S
Department of Bioorganic Chemistry and Biopharmaceutics, University of Pisa, Pisa, Italy. burgal@farm.unipi.it
Nicosia
Nadia
N
Monti
Daniela
D
Falcone
Giulia
G
Boldrini
Enrico
E
Chetoni
Patrizia
P
D000818:Animals; D003316:Corneal Diseases / Q000188:drug therapy*; D004195:Disease Models, Animal; D004337:Drug Carriers / Q000737:chemistry / Q000627:therapeutic use; D004353:Drug Evaluation, Preclinical; D004361:Drug Tolerance; D015352:Dry Eye Syndromes / Q000517:prevention & control*; D005685:Galactans / Q000737:chemistry / Q000627:therapeutic use*; D006801:Humans; D006820:Hyaluronic Acid / Q000737:chemistry / Q000627:therapeutic use; D028221:Larix / Q000737:chemistry*; D008297:Male; D010316:Particle Size; D011134:Polysaccharides / Q000737:chemistry / Q000627:therapeutic use; D011817:Rabbits; D012212:Rheology; D012995:Solubility; D013499:Surface Properties; D029861:Tamarindus / Q000737:chemistry; D013997:Time Factors; D014783:Viscosity
D004337:Drug Carriers; D005685:Galactans; D011134:Polysaccharides; D006820:Hyaluronic Acid; C005653:arabinogalactan