High-precision piezo-ejection ocular microdosing: Phase II study on local and systemic effects of topical phenylephrine

Tsontcho Ianchulev, Robert Weinreb, James C. Tsai, Shan Lin, Louis R. Pasquale

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Aim: Conventional eyedropper-delivered volumes (25-50 μl) exceed the eye's usual tear-film volume (7 μl) and precorneal reservoir capacity, risking overflow and ocular/systemic complications. Piezoelectric high-precision microdosing may circumvent these limitations. Results & methodology: In this masked, nonrandomized, cross-over study, subjects (n = 12) underwent pupil dilation with topical phenylephrine (PE) administered by 32-μl eyedropper (2.5% or 10% formulation) and 8-μl electronic microdosing (10% formulation). Microdosing with PE-10% achieved comparable peak dilation as 10% eyedropper-delivery and superior dilation to 2.5% eyedropper-delivery (p = 0.009) at 75 min. Microdosing significantly reduced 20-min plasma PE levels versus PE10% eyedropper; neither treatment altered heart rate/blood pressure. Eye irritation occurred significantly less frequently with microdosing than PE10% eyedrops. Conclusion: Piezo-ejection PE microdosing achieves comparable biological effect as eyedropper dosing; reduced systemic absorption may decrease risk of systemic side effects.

Original languageEnglish
Pages (from-to)17-27
Number of pages11
JournalTherapeutic Delivery
Issue number1
StatePublished - Jan 2018
Externally publishedYes


  • adverse events
  • microdosing
  • ocular drug delivery
  • ocular medication
  • phenylephrine
  • piezo-ejection system
  • pupil dilation
  • systemic absorption


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