AAPS PharmSciTech

, Volume 8, Issue 1, pp E1–E12 | Cite as

Liposomes as an ocular delivery system for acetazolamide: In vitro and in vivo studies

  • Rania M. Hathout
  • Samar Mansour
  • Nahed D. Mortada
  • Ahmed S. Guinedi


The purpose of this study was to formulate topically effective controlled release ophthalmic acetazolamide liposomal formulations. Reverse-phase evaporation and lipid film hydration methods were used for the preparation of reversephase evaporation (REVs) and multilamellar (MLVs) acetazolamide liposomes consisting of egg phosphatidylcholine (PC) and cholesterol (CH) in the molar ratios of (7∶2), (7∶4), (7∶6), and (7∶7) with or without stearylamine (SA) or dicetyl phosphate (DP) as positive and negative charge inducers, respectively. The prepared liposomes were evaluated for their entrapment efficiency and in vitro release. Multilamellar liposomes entrapped greater amounts of drug than REVs liposomes. Drug loading was increased by increasing CH content as well as by inclusion of SA. Drug release rate showed an order of negatively charged > neutral > positively charged liposomes, which is the reverse of the data of drug loading efficiency. Physical stability study indicated that approximately 89%, 77%, and 69% of acetazolamide was retained in positive, negative, and neutral MLVs liposomal formulations up to a period of 3 months at 4°C. The intraocular pressure (IOP)-lowering activity of selected acetazolamide liposomal formulations was determined and compared with that of plain liposomes and acetazolamide solution. Multilamellar acetazolamide liposomes revealed more prolonged effect than REVs liposomes. The positively charged and neutral liposomes exhibited greater lowering in IOP and a more prolonged effect than the negatively charged ones. The positive multilamellar liposomes composed of PC:CH:SA (7:4:1) molar ratio showed the maximal response, which reached a value of −7.8±1.04 mmHg after 3 hours of topical administration.


Acetazolamide multilamellar liposomes reverse-phase evaporation liposomes 


  1. 1.
    Kaur IP, Garg A, Singla AK, et al. Vesicular systems in ocular delivery: an overview.Int J Pharm. 2004;269:1–14.CrossRefGoogle Scholar
  2. 2.
    Kaur IP, Smitha R, Aggarwal D, et al. Acetazolamide: future perspective in topical glaucoma therapeutics.Int J Pharm. 2002;248:1–14.CrossRefGoogle Scholar
  3. 3.
    Duffel MW, Ing IS, Segarra TM, et al. N-substituted sulfonamide carbonic anhydrase inhibitors with topical effects on intraocular pressure.J Med Chem. 1986;29:1488–1494.CrossRefGoogle Scholar
  4. 4.
    Friedman Z, Allen RC, Steven MR Topical acetazolamide and methazolamide delivered by contact lenses.Arch Ophthalmol. 1985;103:936–966.Google Scholar
  5. 5.
    Tous SS, Nasser KAE. Acetazolamide topical formulation and ocular effect.STP Pharm Sci. 1992;2:125–131.Google Scholar
  6. 6.
    Loftsson T, Fridriksdottir H, Thorisdottir S, et al. Topically effective ocular hypotensive acetazolamide and ethoxyzolamide formulation in rabbits.J Pharm Pharmacol. 1994;46:503–504.Google Scholar
  7. 7.
    Kaur IP, Singh M, Kanwar M. Formulation and evaluation of ophthalmic preparation of acetazolamide.Int J Pharm. 2000;199:119–127.CrossRefGoogle Scholar
  8. 8.
    Kaur IP, Smitha R. Penetration enhancers and ocular bioadhesives: two new avenues for ophthalmic drug delivery.Drug Dev Ind Pharm. 2002;28:473–493.CrossRefGoogle Scholar
  9. 9.
    Guinedi AS, Mortada ND, Mansour S, et al. Preparation and evaluation of reverse-phase evaporation and multilamellar niosomes as ophthalmic carriers of acetazolamide.Int J Pharm. 2005;306:71–82.CrossRefGoogle Scholar
  10. 10.
    El-Gazayerly ON, Hikal AK. Preparation and evaluation of acetazolamide liposomes as an ocular delivery system.Int J Pharm. 1997;158:121–127.CrossRefGoogle Scholar
  11. 11.
    Szoka F, Papahodjopoulos D. Procedure for preparation of liposomes with large internal aqueous space and high capture by reverse-phase evaporation.Proc Natl Acad Sci USA. 1978;75:4194–4198.CrossRefGoogle Scholar
  12. 12.
    Arrowsmith M, Hadgraft J, Kellaway IW. The in vitro release of steroids from liposomes.Int J Pharm. 1983;14:191–208.CrossRefGoogle Scholar
  13. 13.
    Law SL, Shih CL. Characterization of calcitonin-containing liposomes formulations for intranasal delivery.J Microencapsul. 2001;18:211–221.CrossRefGoogle Scholar
  14. 14.
    Gulati M, Grover M, Singh M, Singh S. Study of azathioprine encapsulation into liposomes.J Microencapsul. 1998;15:485–494.CrossRefGoogle Scholar
  15. 15.
    Perugini P, Pavanetto F. Liposomes containing boronophenylalanine for boron neutron capture therapy.J Microencapsul. 1998;15:473–483.CrossRefGoogle Scholar
  16. 16.
    Winum J, Casini A, Mincione F, et al. Carbonic anhydrase inhibitors: N-(p-sulfamoyl phenyl)-α-D-glycopyranosylamines as topically acting antiglaucoma agents in hypertensive rabbits.Bioorg Med Chem Lett. 2004;14:225–229.CrossRefGoogle Scholar
  17. 17.
    Monem AS, Ali FM, Ismail MW. Prolonged effect of liposomes encapsulating pilocarpine HCl in normal and glaucomatous rabbits.Int J Pharm. 2000;198:29–38.CrossRefGoogle Scholar
  18. 18.
    du Plessis J, Ramachandran C, Weiner N, Muller DG. The influence of lipid composition and lamellarity of liposomes on the physical stability of liposomes upon storage.Int J Pharm. 1996;127:273–278.CrossRefGoogle Scholar
  19. 19.
    Morilla MJ, Benavidez P, Lopez MO, Bakas L, Romero EL. Development and in vitro characterization of a benznidazole liposomal formulation.Int J Pharm. 2002;249:89–99.CrossRefGoogle Scholar
  20. 20.
    Law SL, Hung HY. Properties of acyclovir-containing liposomes for potential ocular delivery.Int J Pharm. 1998;161:253–259.CrossRefGoogle Scholar
  21. 21.
    Srinath P, Vyas SP, Prakash VD. Preparation and pharmacodynamic evaluation of liposomes of indomethacin.Drug Dev Ind Pharm. 2000;26:313–321.CrossRefGoogle Scholar
  22. 22.
    Nagarsenker MS, Londhe VY, Nadkarni GD. Preparation and evaluation of liposomal formulations of tropicamide for ocular delivery.Int J Pharm. 1999;190:63–71.CrossRefGoogle Scholar
  23. 23.
    Gruner SM. Materials properties of liposomal bilayers. In: Ostro MJ, ed.Liposomes From Biophysics to Therapeutics. New York, NY: Marcel Dekker; 1997:1–38.Google Scholar
  24. 24.
    Nagarsenker MS, Londhe VY. Preparation and evaluation of a liposomal formulation of sodium cromoglicate.Int J Pharm. 2003;251:49–56.CrossRefGoogle Scholar
  25. 25.
    Peschka R, Dennehy C, Szoka FCL. A simple in vitro model to study the release kinetics of liposome encapsulated material.J Control Release. 1998;56:41–51.CrossRefGoogle Scholar
  26. 26.
    Stuhne-Sekalec L, Stancev NZ. Liposomes as carriers of cyclosporine A.J Microencapsul. 1991;8:441–446.CrossRefGoogle Scholar
  27. 27.
    Finkelestein MC, Weismann G. Enzyme replacement via liposomes: variation in lipid composition determined liposomal integrity in biological fluid.Biochim Biophys Acta. 1979;587:202–216.Google Scholar
  28. 28.
    Alpar OH, Bamford JB, Walters V. The in vitro incorporation and release of hydroxocobalamin by liposomes.Int J Pharm. 1981;7:349–351.CrossRefGoogle Scholar
  29. 29.
    Juliano RL, Stamp D. Pharmacokinetics of liposome-encapsulated antitumor drugs.Biochem Pharmacol. 1978;27:21–27.CrossRefGoogle Scholar
  30. 30.
    Arica B, Ozer AY, Ercan MT, et al. Characterization and in vitro studies on primaquine diphosphate liposomes.J Microencapsul. 1995;12:469–485.CrossRefGoogle Scholar
  31. 31.
    al-Muhammad J, Ozer AY, Hincal AA. Studies on the formulation and in vitro release of ophthalmic liposomes containing dexamethasone sodium phosphate.J Microencapsul. 1996;13:123–130.CrossRefGoogle Scholar
  32. 32.
    Glavas-Dodov M, Goracinova K, Mladenovska K, et al. Release profile of lidocaine HCl from topical liposomal gel formulation.Int J Pharm. 2002;242:381–384.CrossRefGoogle Scholar
  33. 33.
    Nagarsenker MS, Joshi AA. Preparation, characterization and evaluation of liposomal dispersions of lidocaine.Drug Dev Ind Pharm. 1997;23:1159–1165.CrossRefGoogle Scholar
  34. 34.
    Armengol X, Estelrich J. Physical stability of different liposome compositions obtained by extrusion method.J Microencapsul. 1995;12:525–535.CrossRefGoogle Scholar
  35. 35.
    Pietzyk B, Henschke K. Degradation of phosphatidylcholine in liposomes containing carboplatin in dependence on composition and storage conditions.Int J Pharm. 2000;196:215–218.CrossRefGoogle Scholar
  36. 36.
    Velpandian T, Gupta SK, Gupta YK, Biswas NR, Agarwal HC. Ocular drug targeting by liposomes and their corneal interactions.J Microencapsul. 1999;16:243–250.CrossRefGoogle Scholar

Copyright information

© American Association of Pharmaceutical Scientists 2007

Authors and Affiliations

  • Rania M. Hathout
    • 1
  • Samar Mansour
    • 1
  • Nahed D. Mortada
    • 1
  • Ahmed S. Guinedi
    • 1
  1. 1.Department of Pharmaceutics, Faculty of PharmacyAin Shams UniversityCairoEgypt

Personalised recommendations