title: Differential flow rate of commercially available triamcinolone with and without preservative through small-gauge needles.
abstract: OBJECTIVE
  To compare the flow rate through different gauge needles of triamcinolone acetonide with benzyl alcohol (TABA) versus preservative-free triamcinolone acetonide injectable suspension (TAIS).
  
  
  METHODS
  Experimental injections of 1 mL of TABA or TAIS were performed through a 27-, 30-, or 32-gauge needle. A piezoelectric pressure transducer connected to a personal computer was placed between the syringe and needle to record the force-time relationship and assess the flow rate (mL/s). Measurements were performed in triplicate.
  
  
  RESULTS
  Flow rates were similar between preparations using a 27-gauge needle. Using a 30-gauge needle, the flow rate was 0.058 mL/s for TABA and 0.178 mL/s for TAIS. Using a 32-gauge needle, no flow was sustained by TABA, whereas the flow rate of TAIS was 0.114 mL/s (P < .05).
  
  
  CONCLUSIONS
  TAIS can be injected through a 32-gauge needle without the risk of obstruction. Occlusions were seen with TABA using the 30- and 32-gauge needles.
authors.forename: Mariana
authors.initials: M
authors.lastname: Cabrera
authors.forename: Alex
authors.initials: A
authors.lastname: Gonzalez
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Albini
authors.forename: Cornelis
authors.initials: C
authors.lastname: Rowaan
authors.forename: Mariela
authors.initials: M
authors.lastname: Aguilar
authors.forename: William
authors.initials: W
authors.lastname: Lee
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Fortun
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Moshfeghi
authors.forename: Harry W
authors.initials: HW
authors.lastname: Flynn
authors.forename: Jean-Marie A
authors.initials: JM
authors.lastname: Parel
mesh_terms: D019905:Benzyl Alcohol / Q000737:chemistry*; D055598:Chemical Phenomena; D005938:Glucocorticoids / Q000737:chemistry*; D009339:Needles; D009883:Ophthalmic Solutions; D011310:Preservatives, Pharmaceutical / Q000737:chemistry*; D014160:Transducers, Pressure; D014222:Triamcinolone Acetonide / Q000737:chemistry*; D014783:Viscosity
chemical_list: D005938:Glucocorticoids; D009883:Ophthalmic Solutions; D011310:Preservatives, Pharmaceutical; D014222:Triamcinolone Acetonide; D019905:Benzyl Alcohol