Novel mucoadhesive polysaccharide isolated from Bletilla striata improves the intraocular penetration and efficacy of levofloxacin in the topical treatment of experimental bacterial keratitis.
OBJECTIVE
The objective of the present study was to evaluate a novel mucoadhesive polymer extracted from Bletilla striata for ocular delivery of 0.5% levofloxacin in rabbits, and to determine its improved efficacy against experimental keratitis.


METHODS
B. striata polysaccharide (BsP) was subjected to cell cytotoxicity and ferning tests. The pharmacokinetics and bioavailability of topically applied 0.5% levofloxacin-BsP eye drops was investigated and compared with 0.5% levofloxacin eye drops (Cravit). Experimental Staphylococcus aureus keratitis was induced and treated with levofloxacin or levofloxacin-BsP eye drops.


RESULTS
BsP markedly increased the proliferative capacity of a human corneal epithelial [corrected] cell line. The ferning test showed that BsP exhibited optimal performance as a tear fluid. The polysaccharides significantly increased intra-aqueous penetration and corneal accumulation in rabbits. Treatment with levofloxacin-BsP reduced the number of organisms more significantly than eye drops containing levofloxacin alone.


CONCLUSIONS
BsP appears to be a promising candidate as a vehicle for topical ophthalmic drug delivery, especially for antibiotics.
Wu
Xiang-gen
XG
Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Qingdao, PR China. wuxianggen@126.com
Xin
Meng
M
Chen
Hao
H
Yang
Li-na
LN
Jiang
Hao-ran
HR
D000042:Absorption; D000287:Administration, Topical; D000818:Animals; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D001082:Aqueous Humor / Q000187:drug effects; D058491:Bacterial Load; D001682:Biological Availability; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D003315:Cornea / Q000166:cytology / Q000187:drug effects; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000187:drug effects / Q000502:physiology; D005123:Eye / Q000166:cytology / Q000187:drug effects; D005260:Female; D006801:Humans; D007634:Keratitis / Q000188:drug therapy* / Q000382:microbiology; D064704:Levofloxacin; D008297:Male; D015242:Ofloxacin / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D009883:Ophthalmic Solutions; D029595:Orchidaceae / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D011134:Polysaccharides / Q000302:isolation & purification / Q000494:pharmacology*; D011817:Rabbits; D013203:Staphylococcal Infections / Q000188:drug therapy*; D013211:Staphylococcus aureus / Q000187:drug effects; D013666:Tears; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents; D009883:Ophthalmic Solutions; D010936:Plant Extracts; D011134:Polysaccharides; D064704:Levofloxacin; D015242:Ofloxacin