Drop-dispensing

The container must be sealed by a closure. If air is allowed to enter and interact with the essential oil, the chemical reaction of oxidation can occur. Oxidation in this case can be considered the addition of oxygen to an oil constituent to form a new compound. New compounds formed will alter the composition of the oil. Water vapour may also enter from the air. An open or incompletely sealed container will allow essential oil components to escape as vapours, and this will change the balance of constituents. The best choice of closure for a bottle is a screw cap fitted with a wad or washer. Ideally bottles are fitted with childproof tops and drop dispensers to control amounts dispensed. 

Opticare produce eye drop dispensers that make instilling eye drops easier. These eye drop dispensers hold the plastic eye dropper bottles used by manufacturers and make them easier to squeeze, with only slight pressure needed to dispense a single drop. For patients with impaired manual dexterity or arthritis the Opticare Arthro model has extended arms, making the process of squeezing the bottle effortless. 

Both styles of eye drop dispenser are fitted with an orbit-shaped eye piece designed to ensure that the drop goes into the eye rather than down the cheek. The design of the eye piece also ensures that the bottle cannot touch the eye, preventing contamination. These compliance aids can be prescribed on the NHS. 

Electrowetting, Applications, Fig. 4 Drop dispensing or metering from a reservoir using static electrowetting schemes (From Ref. [9])... 

Robert de Saint Vincent M, Delville JP (2012) Thermocapillary migration in small-scale temperature gradients application to optofluidic drop dispensing. Phys Rev E 85 026310... 

A method of quantization and analysis of droplets ejected from an inkjet device has been described that overcomes the limitations described above. The method is comprised of depositing one or more drops of a first solvent from an inkjet dispensing device into a cuvette containing a predetermined amount of a second solvent. Then these compoimds are mixed, and the UV-absorption spectra of the resulting solution are recorded. In this way, the mass of the drops dispensed by the inkjet dispensing device can be calculated using a predetermined calibration curve (4). 

Parkkari M, Latvala T, Ropo A (2010) Handling test of eye drop dispenser - comparison of unit-dose pipettes with conventional eye drop bottles. J Ocul Pharmacol Ther 26 273-6... 

For liquids that are best weighed droplet-wise, vials with a drop dispenser (dropper) are suitable. By varying the position of the vial, the droplet size can be easily adjusted. 

Fig. 28.3 Deposition of MOX sol onto a microheater using the drop dispenser technique (Idea from Spannhake et al. 2009)...

Suh et al. also reported a direct method for molding of PEG polymers [40], which involves the placement of a patterned PDMS mold on top of a drop-dispensed or spin-coated PEG solution typically dissolved in water or ethanol, leaving behind a polymer replica after solvent evaporation followed by mold removal. In comparison with qCP, the technique generates features varying in height with precise control over cell migration and interconnection of cell arrays. 

---