Question

RESTASIS Ophthalmic Emulsion contains 0.05% w/v cyclosporin. If a dose of one drop measures 28 μL, how many micrograms of cyclosporin are present?

What if the RESTASIS Ophthalmic Emulsion contains 50% w/v cyclosporin?

Answer 1

• 28 microlitres of RESTASIS Ophthalmic Emulsion contains 28000 micrograms of cyclosporin.(Since number of microgram [water] in 1 microliter = 1000.)

• If RESTASIS Ophthalmic Emulsion contains 50% w/v cyclosporin, then it contains 28000 microlitres or 28000000 micrograms of cyclosporin

(Given 0.05% w/v cyclosporin RESTASIS Ophthalmic Emulsion contains 28 microlitres or 28000 micrograms of cyclosporin
Therefore 1% w/v cyclosporin RESTASIS Ophthalmic Emulsion contains 560 microlitres or 560000 micrograms of cyclosporin
Hence 50% w/v cyclosporin RESTASIS Ophthalmic Emulsion contains 28000 microlitres or 28000000 micrograms of cyclosporin)
0.05% w/v cyclosporin -28 microlitres
1% w/v cyclosporin   -28/0.05=560 microlitres
50% w/v cyclosporin   -560*50=28000 microlitres