title: Buffering capacity of bovine vitreous.
abstract: OBJECTIVE
  To measure the buffering capacity of bovine vitreous to HCl, NaOH, and triamcinolone acetonide.
  
  
  METHODS
  Vitreous was dissected from 10 bovine globes, homogenized, and divided into 5.0-mL aliquots. The carbonate/bicarbonate buffer of the vitreous was maintained by performing all subsequent titrations under an atmosphere of 5% CO2/95% air. The pH was monitored during the addition of 0.1 N HCl, 0.1 N NaOH, or 40 mg/mL triamcinolone acetonide to the vitreous sample; 0.9% NaCl was used as control.
  
  
  RESULTS
  The buffering capacity of bovine vitreous to HCl was 10 times greater than that of 0.9% NaCl. The buffering capacity of vitreous to NaOH was four times greater than that of 0.9% NaCl. Bovine vitreous was able to resist pH changes from addition of triamcinolone acetonide at levels 20 times greater than commonly injected intravitreally.
  
  
  CONCLUSIONS
  Vitreous had a greater buffering capacity than 0.9% NaCl, indicating a greater capacity to remain stable when acidic or alkaline pharmaceuticals are injected in microliter amounts.
authors.affiliation: Department of Ophthalmology, Tulane University Health Sciences Center, New Orleans, Louisiana, USA. ccole@eyes.arizona.edu
authors.forename: Mandi D
authors.initials: MD
authors.lastname: Conway
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Jermak
authors.forename: Gholam A
authors.initials: GA
authors.lastname: Peyman
authors.forename: Harvey T
authors.initials: HT
authors.lastname: Swanson
authors.forename: Diane A
authors.initials: DA
authors.lastname: Blake
mesh_terms: D000818:Animals; D002021:Buffers; D002417:Cattle; D006851:Hydrochloric Acid / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D012972:Sodium Hydroxide / Q000737:chemistry; D014222:Triamcinolone Acetonide / Q000737:chemistry; D014822:Vitreous Body / Q000737:chemistry*
chemical_list: D002021:Buffers; D012972:Sodium Hydroxide; D014222:Triamcinolone Acetonide; D006851:Hydrochloric Acid