Volume of ONE drop

[Mr Pharm S]

Any one know the volume of one drop when calculating quantities of eye drop bottle to supply?

You know the situation where our hospital collegues write scripts with minimal information on.

ie, Xalatan nocte R+L 2/12

Obviously it will depend on all kinds of factors, dropper bottle design, viscosity of liquid etc

I have always used the volume of one drop as 0.1ml therefore

0.1ml daily in both eyes = 0.2ml daily

0.2ml x 56days = 11.2ml

11.2ml/2.5ml bottle = 4.48 bottles

so gave 5 x 2.5ml bottles of Xalatan

How would you have worked it out and how many bottles would you have given?

Cheers

[tinx25388]

I always understood it to be 20 drops/ml therefore making a drop 0.05ml

1 drop into each eye = 0.1ml daily
0.1ml x 56 = 5.6ml
= 2.24 bottles

But I could be wrong!

(Also are you having trouble getting hold of Xalatan at the moment? I would love to see 5 bottles!)

[Nik]

I also thought the amount equivalent to 1 drop was 0.05ml. There is another thread on this forum about this.

[johnep]

Yes subject discussed exhaustively before. Concensus was that 2.5ml should last a month at one drop daily. I would give one bottle per eye per month.
johnep

[Mr Pharm S]

Ok, nice one. Back order of Xalatan came this morning. 25 bottles came in, 25 bottles went out to owings. Hope some more come in the morning. Any links for previous posts, I searched before posting and couldnt find anything.

[Fleegle]

Jeez lads..that's fierce technical! I just give them a bottle and tell them to come back for another one if it runs out. Half of it ends up running down their cheeks anyway..

Fleeg.

A Happy New Year to one and all by the way!

[laurabuk]

We use 0.05ml therefore 100 drops in 5ml - so 2 drops a day for 28 days would be 56 drops thus 2 x 2.5ml bottles would be supplied.

I don't understand why Xalatan comes in those ridiculously small bottles compared to other eye drops - but I do like their new livery. Xalatan/Xalacom is a common error.

[Fleegle]

Oh come on!

The supply of eyedrops always has been, and always will be, dynamic. There is no such thing as 'volume of ONE drop'. A bit of advice on correct storage and usage is certainly in order, but that's about it. Whatever happened to supply 'QS' anyway? I used to love pulling the GPs up over that one.

Fleeg.

[bobbin]

I don't understand why Xalatan comes in those ridiculously small bottles compared to other eye drops

Apparently, the droplet volume is small. According to Pfizer, one bottle of 2.5ml should release about 80 drops.

In the scenario above, I would supply two bottles.