Spray ejector mechanisms and devices providing charge isolation and controllable droplet charge, and low dosage volume ophthalmic administration

1. A method of delivering a therapeutically effective low dosage volume medicament composition to an eye of a subject in need thereof, the method comprising:

(a) generating a directed stream of droplets including the low dosage volume medicament composition, wherein said stream of droplets is generated via a charge isolated ejector mechanism; and

(b) delivering the directed stream of droplets including the low dosage volume medicament composition to the eye of said subject,

wherein a delivered stream of droplets including the low dosage volume medicament composition is deposited on the cornea of the eye, and

wherein the charge isolated ejector mechanism comprises piezoelectric ejector mechanism comprising:

a generator plate having a plurality of openings formed between a fluid entrance side of the generator plate and a droplet exit side of the generator plate;

a piezoelectric actuator operable to directly or indirectly oscillate the generator plate upon application of a voltage;

a dielectric element; and

a first conducting ring having a bottom surface, at least a portion of the bottom surface facing the fluid entrance side of the generator plate to separate the dielectric element from the generator plate thereby charge isolating and grounding the generator plate.

2. The method of claim 1 , wherein the delivered stream of droplets including the therapeutically effective low dosage volume medicament composition is deposited on the cornea in a volume of about 18 ul or less than ¾ of the volume of that of a standard eyedropper.

3. The method of claim 1 , wherein the delivered stream of droplets including the therapeutically effective low dosage volume medicament composition is deposited on the cornea in a volume of about 12 ul or less than ½ of the volume of that of a standard eyedropper.

4. The method of claim 1 , wherein the delivered stream of droplets including the therapeutically effective low dosage volume medicament composition is deposited on the cornea in a volume of about 6 ul or less than ¼ of the volume of that of a standard eyedropper.

5. The method of claim 1 , wherein the directed stream of droplets is generated such that at least about 75% of the mass of the droplets deposit on the cornea of said subject.

6. The method of claim 1 , wherein the directed stream of droplets has an average droplet diameter in the range of 20 to 400 microns.

7. The method of claim 1 , wherein the directed stream of droplets has an average initial velocity in the range of 0.5 m/s to 10 m/s.

8. The method of claim 1 , wherein said medicament is a glaucoma medicament.

9. The method of claim 1 , wherein said medicament is selected from the group consisting of travoprost, latanoprost, bimatoprost, dorzolamide HCl, timolol maleate, brimonidine tartrate, brinzolamide, dorzolamide HCl, and BAK-free latanoprost.

10. The method of claim 1 , wherein delivering the directed stream of droplet is for the treatment, amelioration, or prevention of an eye disease, condition, discomfort, infection, or disorder in a subject in need thereof.

11. The method of claim 10 , wherein said eye disease, condition, discomfort, infection, or disorder is glaucoma.

12. The method of claim 1 , wherein the charge isolated ejector mechanism further comprises a flexible printed circuit comprising a laminate structure including the generator plate, the piezoelectric actuator, the first conducting ring, and the dielectric layer,

wherein the laminate structure further comprises a second conducting ring, wherein the second conducting ring has a top surface opposite a bottom surface, and wherein the first conducting ring has a top surface that is opposite the bottom surface, and wherein the dielectric layer has a top surface opposite a bottom surface, and

wherein at least a portion of the top surface of the second conducting ring faces the piezoelectric actuator and at least a portion of the bottom surface of the second conducting ring faces at least a portion of the top surface of the dielectric layer to separate the piezoelectric actuator from the dielectric layer, and

wherein at least a portion of the bottom surface of the dielectric layer faces the top surface of the first conducting ring to separate the second conducting ring from the first conducting ring.

13. The method of claim 12 , wherein the ejector mechanism further comprises an ejector plate coupled to the generator plate, and the piezoelectric actuator being operable to oscillate the ejector plate, and thereby the generator plate, and the first conducting ring separating the ejector plate from the dielectric layer.

14. The method of claim 13 , wherein the ejector plate has a central open region aligned with the generator plate, and the piezoelectric actuator is coupled to a peripheral region of the ejector plate so as to not obstruct the plurality of openings of the generator plate.

15. The method of claim 14 , wherein the plurality of openings of the generator plate are disposed in a center region of the generator plate that is uncovered by the piezoelectric actuator and aligned with the central open region of the ejector plate.

16. The method of claim 14 , wherein the generator plate has a reduced size relative to the ejector plate, and the size of the generator plate is determined, at least in part, by the area occupied by the center region and the arrangement of the plurality of openings.

17. The method of claim 13 , further comprising one or more adhesive layers.

18. The method of claim 13 , further comprising at least one additional metalized layer.