STUDY OF OFLOXACIN ENANTIOMERS DISSOLUTION FROM SELECTED SOLID DOSAGE FORMS USING HIGH PERFORMANCE CAPILLARY...

Area of Science:

• Pharmaceutical Sciences
• Drug Delivery and Formulation

Background:

• Ofloxacin is a fluoroquinolone antibiotic available as a racemic mixture or as the active S-(-)-isomer, levofloxacin.
• Understanding the dissolution kinetics of optical isomers from different oral dosage forms is crucial for predicting in vivo performance and therapeutic efficacy.
• Commercially available ofloxacin formulations (racemic and enantiopure) were selected for comparative dissolution analysis.

Purpose of the Study:

• To investigate and compare the dissolution rate kinetics of ofloxacin optical isomers (S-(-)- and R-(+)-ofloxacin) from various solid oral dosage forms.
• To evaluate the influence of dissolution media (0.1 M/L HCl and phosphate buffer pH 6.8) on the release profiles of ofloxacin enantiomers.
• To identify potential formulation-dependent differences in the dissolution behavior of ofloxacin isomers.

Main Methods:

• Utilized the flow-through cell method (USP 4) to assess drug release from coated tablets.
• Employed a validated high-performance capillary electrophoresis (HPCE) method for accurate quantification of ofloxacin enantiomers in dissolution samples.
• Calculated the fraction of the average dose released for individual optical isomers under different pH conditions.

Main Results:

• Ofloxacin-Ratiopharm and Tavanic demonstrated near-complete (approx. 100%) dissolution of both isomers within 30 minutes in 0.1 M/L HCl.
• Tarivid showed approximately 50% dissolution in 0.1 M/L HCl, while OfloHexal exhibited varied dissolution (14-44%) in phosphate buffer pH 6.8.
• No significant differences in dissolution kinetics were observed between S-(-)- and R-(+)-ofloxacin within the same formulation, but significant inter-formulation differences were noted.

Conclusions:

• Significant variations exist in the dissolution profiles of ofloxacin optical isomers among different commercially available oral dosage forms.
• Formulation plays a critical role in the dissolution rate of ofloxacin enantiomers, impacting potential bioavailability.
• The study highlights the importance of enantioselective dissolution testing for chiral drugs like ofloxacin.