Advantages of liposome-based delivery system

1. Advantages of liposome-based delivery system • Boost efficiency of ocular drug delivery • Delivery of hydrophilic or lipophilic drugs • Delivery of DNA/peptide/protein • Liposome encapsulation may reduce ocular irritation

2. Criteria set forth by Lippomix • Within ocular pH range (6.8-7.6) • Isotonic • Stable over the long term • Projection of Commercial Shelf Life • Pharmaceutically Elegant

3. Formulation development • Formulation prototypes (44) -Buffered (24) -Unbuffered (20) • Formulations which meet criteria (11) • Short term stability data (1 month @ RT) • Summary • Conclusions

4. Unbuffered Formulations 0.9% NaCl Phosphatidylcholine (PC) Diclofenac Benzalkonium or Benzethonium chloride Buffered Formulations Boric acid, pH 7.2 Phosphatidylcholine (PC) Diclofenac Benzalkonium or Benzethonium chloride Formulation prototypes

5. Liposomal formulation (placebo) • 0.1% (w/v) PC • 0.9% (w/v) NaCl

6. Benzethonium chloride FDA approved for ophthalmic use Does not contain mercury Maximum concentration of 0.01% (w/v) Benzalkonium chloride Commonly used, FDA approved preservative for multiple-use ophthalmic products Does not contain mercury Maximum concentration of 0.013% (w/v) Anti-microbial agents

7. Unbuffered Formulations: 0.9% NaCl (24)

8. Recommended formulations: Unbuffered (6)

9. pH Stability- Unbuffered formulations • No change in pH over a period of 30 days • pH of all six samples was between 6.5-7.0

10. Particle size stability: Unbuffered formulations • No change in sample containing 0.3% PC and 0.1% diclofenac up to 20 days. • Five formulations increase in size after processing, but remain constant in size up to 20 days.

11. Buffered Formulations: 0.3 M Boric acid, pH 7.2 (20)

12. Recommended formulations:Buffered (5)

13. pH Stability: Buffered Formulations • No change in pH over a 20 day period. • pH of all five formulations ranges from 7.2-7.3.

14. Particle size stability: Buffered Formulations • During cooling of sample, all formulations shifted to a size ~3 m. • Microscopic estimates put the liposomes between 1-5 m. • The larger-sized particles appear to maintain their size over the short term. • Once a sample equilibrates, there is no change in particle size.

15. Summary of findings • Formulations may be made buffered (boric acid) or unbuffered (NaCl). • PC concentrations within 0.05-0.3% (w/v) produce formulations with greatest clarity. • Diclofenac may be added at 0.02-0.1%. • Benzethonium chloride at 0.01% is the more suitable anti-microbial agent, with regard to formulation clarity. • pH of recommended formulations is constant over the short term (~30 days). • Most formulations shift to a larger particle size after processing, but remain stable once equilibrated.

16. Formulation Criteria • Formulation clarity • Free of ethanol/organic solvents • Ability to include an anti-microbial agent • Within ocular pH range (6.8-7.6) • Isotonic • Stable over the long term (1 month to date) • Projection of Commercial Shelf Life • Pharmaceutically Elegant

17. Conclusion • We can produce several liposome-based ophthalmic formulations of diclofenac. • All formulations are sterile, contain an anti-microbial agent, no organic solvents, and are within ocular pH and tonicity. • Furthermore, these formulations are stable with respect to clarity and pH .

18. Future developments Additional product opportunities: • Hydrophilic drugs • Lipophilic drugs • DNA/Proteins/Peptides • Other disease states (glaucoma, seasonal allergic or bacterial conjunctivitis, dry eye, etc…)

19. pH Stability-Unbuffered Formulations

20. pH Stability-Buffered Formulations