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Updated: Nov 12, 2025
Use of Rabbit Eyes in Pharmacokinetic Studies of Intraocular Drugs
Published on: July 23, 2016
UPLC-MS/MS assay of Tedizolid in rabbit aqueous humor: Application to ocular pharmacokinetic study
Mohd Abul Kalam1, Muzaffar Iqbal2, Abdullah Alshememry1
1Nanobiotechnology Unit, Department of Pharmaceutics, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia; Department of Pharmaceutics, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia.
Abstract:
Tedizolid phosphate (TZP) a prodrug of Tedizolid (TDZ) is a novel oxazolidinone antibiotic, used for the treatment of acute bacterial skin, skin structure infections and other serious gram positive and MRSA infections. In the present study, a sensitive UPLC-MS/MS analytical method was developed and validated for the quantification of TDZ in rabbit's aqueous humor (AqH) by using linezolid as internal standard (IS). Both TDZ and IS were separated on an Acquity™ HILIC column using an isocratic mobile phase comprising of acetonitrile: 20 mM ammonium acetate (85:15, v/v), eluted at 0.3mLmin-1 flow rate with total run time of 3 min. The AqH samples were processed by protein precipitation method by using acetonitrile as precipitating agent. TDZ and IS were detected in positive mode using electrospray ionization source. The precursor to product ion transitions at m/z 371.15 to 343.17 for TDZ and m/z 338.18 to 296.22 for IS were used for the quantification in multiple reaction monitoring mode. The calibration curve was linear in the concentration range of 4.98-1000ngmL-1 and the lower limit of detection was 1.97ngmL-1 only. The method was validated following US-FDA-guidelines and the results of validation parameter were found within the set limits. The developed UPLC-MS/MS method was fast, sensitive and reliable for the quantification of TDZ in the rabbit AqH and was successfully employed for ocular pharmacokinetic study of TDZ in AqH after topical ocular application of TZP-containing formulations in rabbit eyes.
Insights
A new UPLC-MS/MS method accurately quantifies tedizolid (TDZ) in rabbit aqueous humor. This validated assay is crucial for understanding TDZ
Area of Science:
- Analytical Chemistry
- Pharmacokinetics
- Ophthalmology
Background:
- Tedizolid phosphate (TZP) is a prodrug of tedizolid (TDZ), a novel oxazolidinone antibiotic effective against serious Gram-positive and MRSA infections.
- Accurate quantification of TDZ in ocular tissues is essential for pharmacokinetic studies, particularly after topical administration.
Purpose of the Study:
- To develop and validate a sensitive Ultra-Performance Liquid Chromatography-tandem Mass Spectrometry (UPLC-MS/MS) method for quantifying TDZ in rabbit aqueous humor (AqH).
- To apply the validated method to investigate the ocular pharmacokinetics of TDZ following topical application of TZP.
Main Methods:
- A HILIC column was used with an isocratic mobile phase (acetonitrile: 20 mM ammonium acetate, 85:15 v/v) for separation.
- Sample preparation involved protein precipitation using acetonitrile.
- Quantification was performed using UPLC-MS/MS in positive mode with linezolid as the internal standard.
Main Results:
- The UPLC-MS/MS method demonstrated linearity over a concentration range of 4.98-1000 ng/mL, with a lower limit of detection of 1.97 ng/mL.
- Method validation, following US-FDA guidelines, confirmed its sensitivity, reliability, and speed.
- The method was successfully applied to quantify TDZ in rabbit AqH for pharmacokinetic analysis.
Conclusions:
- A fast, sensitive, and reliable UPLC-MS/MS method for TDZ quantification in rabbit AqH has been successfully developed and validated.
- This method is suitable for ocular pharmacokinetic studies of TDZ, aiding in the development of effective topical ophthalmic formulations.
