Dropper insert

If a preparation is dosed in drops rather than millilitres, the bottle has to be equipped with a pipette, or a dropper cap, or a dropper insert, or a spout cap. The Ph. Eur. describes requirements with regards to the dose and the reproducibility... 

The dropping pipette gives a more reproducible drop size than the dropper insert. 

A dropper insert is a dropping mechanism in the neck of the bottle (see Fig. 24.13). Many dropper inserts turn out not to meet the requirements of the Ph. Eur. the dropping speed is too high or they don t provide drops at all. The reproducibility of the drop weight is often poor. The drop size appears to depend for example on the angle at which the bottle is held and on the amount of fluid in the bottle. 

Drops for oral use + Dropper or pipette cap, dropper insert... 

Carefully remove the dropper insert by rolling/twisting it off the botde. 

Do not insert droppers into reagent bottles. Pour a small amount of the chemical into a beaker. 

Figure 3-5 Modification of polycarbonate spectacle lenses to facilitate drop instillation. After a hole is drilled through the center of each lens, the patient inserts the dropper tip into the hole, gazes superiorly, and squeezes the bottle.

Figure 3-6 Commercial eyedrop assistance device. (A) Insertion of dropper bottle into device. (B) Device in use.

When the reaction has ceased and practically all the magnesium has reacted, immerse the tube in a beaker containing water and ice. Add very slowly 5 ml dilute hydrochloric acid prepared by the addition of 3 ml concentrated acid to 5 g of ice. The dilute acid can be added by means of a pipette dropper, by removing the calcium chloride tube and using the opening to insert the dropper. When the decomposition of the reagent is complete, the aqueous layer should be clear. If it is milky or cloudy, or if undissolved magnesium is present, add a few drops of concentrated hydrochloric acid and allow the reaction to proceed for a few minutes. 

To decompose the addition compound, immerse the tube in ice-salt mixture and add slowly, by means of a dropper, diluted acid obtained by mixing 5 ml concentrated hydrochloric acid with 5 g of ice. Add only sufficient hydrochloric acid to dissolve the precipitate which forms. Allow to stand until all the residual magnesium has reacted with the acid. The ether layer should have a volume of at least 10-12 ml. If it is le.ss, add ordinary ether to make up this volume. Insert the separatory stopper and remove the aqueous layer. Dry the ether layer by adding 0.5-1 g of anhydrous calcium sulfate. Care must be taken to drj the ether thoroughly, since the carbinol forms an azeotropic mixture with water. Transfer the dry ether mixture to an eight-inch distilling tube, and distill from a water bath until the temperature rises to 70°. Remove the water bath and heat over a small smoky flame. The fraction which boils at 77-84° is collected. 

Fill a 100-mL graduated cylinder exactly to the 50.0-mL mark with water that has been tinted with food coloring. Use a dropper to adjust the volume. Insert a thermometer and read the temperature of the water. Remove the thermometer. 

Insert the dropper with prescribed medication deep into the ear canal and instill drops. 

The dropper should be held over the ear canal when instilling eardrops. Inserting the dropper deep into the ear could cause injury to the ear. 

Insert a medicine dropper (or short glass tube) into a 0 1-hole rubber stopper (b) if you are using a measuring tube in FIGURE 12.1 or into a 00 1-hole rubber stopper if you are using a buret in FIGURE 12.1. 

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