Lipid-based ophthalmic emulsion
The present invention is directed to a lipid-based ophthalmic emulsion. The emulsion has an increased amount of a mucoadhesive galactomannan polymer that promotes a long-lasting protection against desiccation and moisture retention.
1. An ophthalmic emulsion, the emulsion comprising:
water forming an aqueous phase;
oil forming an oil phase;
a hydrophilic surfactant having an HLB value from 10 to 18;
a hydrophobic surfactant having an HLB value from 1 to 6;
a charged phospholipid;
borate;
a mucoadhesive galactomannan polymer; and
a preservative;
wherein the mucoadhesive galactomannan polymer is present in the emulsion at a concentration of at least about 0.13 w/v % but no greater than 0.3 w/v %;
wherein the preservative is free of a benzalkonium chloride; and
wherein the ophthalmic emulsion has a hydration protection against desiccation of at least 10% higher than a control emulsion, wherein the control emulsion has the same composition of the ophthalmic emulsion except of containing 0.05 w/v % of the same galactomannan polymer used in the ophthalmic emulsion.
2. The emulsion as in claim 1 wherein the oil is a hydrocarbon selected from mineral oil, paraffin oil and petrolatum.
3. The emulsion as in claim 1 wherein the oil is at least 0.1 w/v % and no greater than 3 w/v % of the emulsion.
4. The emulsion as in claim 3 wherein the hydrophilic surfactant is present in the emulsion in an amount that is at least 0.08 w/v % and is no greater than about 0.8 w/v %.
5. The emulsion as in claim 4 wherein the hydrophilic surfactant is polyoxyethylene-40-stearate.
6. The emulsion as in claim 4 wherein the hydrophobic surfactant is at least about 0.01 w/v % and is no greater than 2.0 w/v %.
7. The emulsion as in claim 6 wherein the hydrophobic surfactant is a sorbitan tristearate.
8. The emulsion as in claim 1 wherein the mucoadhesive galactomannan polymer is selected from the group consisting of guar and hydroxypropyl guar.
9. The emulsion as in claim 8 wherein the charged phospholipid is an anionic phospholipid named dimyristoyl phosphatidylglycerol.
10. The emulsion as in claim 1 further comprising a borate/polyol buffer system.
11. The emulsion as in claim 10 wherein the preservative is a polymeric quaternary ammonium compound.
12. The emulsion as in claim 1 , wherein:
i. the oil phase is in droplets within the aqueous phase and the droplets have a D 90 diameter that is no greater than about 700 nm but is at least 10 nm; and
ii. the borate and galactomannan polymer cooperatively act to form a gel upon instillation of the emulsion in an eye of an individual.
13. The emulsion as in claim 12 , wherein the oil phase is in droplets within the aqueous phase and the droplets have a D 90 diameter that is no greater than about 500 nm but is at least 30 nm.
14. The emulsion as in claim 13 , wherein the oil phase is in droplets within the aqueous phase and the droplets have a D 90 diameter that is no greater than about 300 nm but is at least 50 nm.