Amino acids as cryoprotectants for liposomal delivery systems

Afzal R. Mohammed, Allan G.A. Coombes, Yvonne Perrie

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Liposomes provide an efficient delivery system for solubilisation and delivery of both small and macro molecules. However, they suffer from the disadvantage of instability when stored as aqueous dispersions. Cryoprotection of the liposomal systems provides an effective approach to overcome poor stability whilst maintaining formulation characteristics, although, the formulation of a freeze-dried product requires the consideration of not only the selection of an appropriate cryoprotectant, but also needs careful consideration of the processing parameters including pre-freezing conditions, primary and secondary drying protocols along with optimisation of cryoprotectant concentration. This current work investigates the application of amino acids as potential cryoprotectants for the stabilisation of liposomes, and results indicate that amino acids show biphasic nature of stabilisation with 4 mol of cryoprotectant per mole of the lipid exhibiting optimum cryoprotection. The investigations of process parameters showed that the pre-freezing temperatures below the glass transition of the amino acids followed by drying for over 6h resulted in stable formulations. Studies investigating the efficiency of drug retention showed that the cryoprotection offered by lysine was similar to that shown by trehalose, suggesting that amino acids act as effective stabilizers. ESEM analysis was carried out to monitor morphology of the rehydrated liposomes.

LanguageEnglish
Pages406-413
Number of pages8
JournalEuropean Journal of Pharmaceutical Sciences
Volume30
Issue number5
DOIs
Publication statusPublished - Apr 2007

Fingerprint

Liposomes
Amino Acids
Freezing
Trehalose
Lysine
Glass
Lipids
Temperature
Pharmaceutical Preparations

Keywords

  • amino acids
  • arginine
  • pharmaceutical chemistry
  • cholesterol
  • cryoprotective agents
  • drug carriers
  • drug compounding
  • freeze drying
  • histidine
  • ibuprofen
  • lipids
  • liposomes
  • lysine
  • particle size
  • phosphatidylcholines
  • solubility
  • pharmaceutical technology
  • temperature
  • time factors
  • trehalose
  • viscosity
  • water

Cite this

Mohammed, Afzal R. ; Coombes, Allan G.A. ; Perrie, Yvonne. / Amino acids as cryoprotectants for liposomal delivery systems. In: European Journal of Pharmaceutical Sciences. 2007 ; Vol. 30, No. 5. pp. 406-413.
@article{ff0eaccfbb6c4b3684a2f0ba893eb0d3,
title = "Amino acids as cryoprotectants for liposomal delivery systems",
abstract = "Liposomes provide an efficient delivery system for solubilisation and delivery of both small and macro molecules. However, they suffer from the disadvantage of instability when stored as aqueous dispersions. Cryoprotection of the liposomal systems provides an effective approach to overcome poor stability whilst maintaining formulation characteristics, although, the formulation of a freeze-dried product requires the consideration of not only the selection of an appropriate cryoprotectant, but also needs careful consideration of the processing parameters including pre-freezing conditions, primary and secondary drying protocols along with optimisation of cryoprotectant concentration. This current work investigates the application of amino acids as potential cryoprotectants for the stabilisation of liposomes, and results indicate that amino acids show biphasic nature of stabilisation with 4 mol of cryoprotectant per mole of the lipid exhibiting optimum cryoprotection. The investigations of process parameters showed that the pre-freezing temperatures below the glass transition of the amino acids followed by drying for over 6h resulted in stable formulations. Studies investigating the efficiency of drug retention showed that the cryoprotection offered by lysine was similar to that shown by trehalose, suggesting that amino acids act as effective stabilizers. ESEM analysis was carried out to monitor morphology of the rehydrated liposomes.",
keywords = "amino acids, arginine, pharmaceutical chemistry, cholesterol, cryoprotective agents, drug carriers, drug compounding, freeze drying, histidine, ibuprofen, lipids, liposomes, lysine, particle size, phosphatidylcholines, solubility, pharmaceutical technology, temperature, time factors, trehalose, viscosity, water",
author = "Mohammed, {Afzal R.} and Coombes, {Allan G.A.} and Yvonne Perrie",
year = "2007",
month = "4",
doi = "10.1016/j.ejps.2007.01.001",
language = "English",
volume = "30",
pages = "406--413",
journal = "European Journal of Pharmaceutical Sciences",
issn = "0928-0987",
number = "5",

}

Amino acids as cryoprotectants for liposomal delivery systems. / Mohammed, Afzal R.; Coombes, Allan G.A.; Perrie, Yvonne.

In: European Journal of Pharmaceutical Sciences, Vol. 30, No. 5, 04.2007, p. 406-413.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Amino acids as cryoprotectants for liposomal delivery systems

AU - Mohammed, Afzal R.

AU - Coombes, Allan G.A.

AU - Perrie, Yvonne

PY - 2007/4

Y1 - 2007/4

N2 - Liposomes provide an efficient delivery system for solubilisation and delivery of both small and macro molecules. However, they suffer from the disadvantage of instability when stored as aqueous dispersions. Cryoprotection of the liposomal systems provides an effective approach to overcome poor stability whilst maintaining formulation characteristics, although, the formulation of a freeze-dried product requires the consideration of not only the selection of an appropriate cryoprotectant, but also needs careful consideration of the processing parameters including pre-freezing conditions, primary and secondary drying protocols along with optimisation of cryoprotectant concentration. This current work investigates the application of amino acids as potential cryoprotectants for the stabilisation of liposomes, and results indicate that amino acids show biphasic nature of stabilisation with 4 mol of cryoprotectant per mole of the lipid exhibiting optimum cryoprotection. The investigations of process parameters showed that the pre-freezing temperatures below the glass transition of the amino acids followed by drying for over 6h resulted in stable formulations. Studies investigating the efficiency of drug retention showed that the cryoprotection offered by lysine was similar to that shown by trehalose, suggesting that amino acids act as effective stabilizers. ESEM analysis was carried out to monitor morphology of the rehydrated liposomes.

AB - Liposomes provide an efficient delivery system for solubilisation and delivery of both small and macro molecules. However, they suffer from the disadvantage of instability when stored as aqueous dispersions. Cryoprotection of the liposomal systems provides an effective approach to overcome poor stability whilst maintaining formulation characteristics, although, the formulation of a freeze-dried product requires the consideration of not only the selection of an appropriate cryoprotectant, but also needs careful consideration of the processing parameters including pre-freezing conditions, primary and secondary drying protocols along with optimisation of cryoprotectant concentration. This current work investigates the application of amino acids as potential cryoprotectants for the stabilisation of liposomes, and results indicate that amino acids show biphasic nature of stabilisation with 4 mol of cryoprotectant per mole of the lipid exhibiting optimum cryoprotection. The investigations of process parameters showed that the pre-freezing temperatures below the glass transition of the amino acids followed by drying for over 6h resulted in stable formulations. Studies investigating the efficiency of drug retention showed that the cryoprotection offered by lysine was similar to that shown by trehalose, suggesting that amino acids act as effective stabilizers. ESEM analysis was carried out to monitor morphology of the rehydrated liposomes.

KW - amino acids

KW - arginine

KW - pharmaceutical chemistry

KW - cholesterol

KW - cryoprotective agents

KW - drug carriers

KW - drug compounding

KW - freeze drying

KW - histidine

KW - ibuprofen

KW - lipids

KW - liposomes

KW - lysine

KW - particle size

KW - phosphatidylcholines

KW - solubility

KW - pharmaceutical technology

KW - temperature

KW - time factors

KW - trehalose

KW - viscosity

KW - water

U2 - 10.1016/j.ejps.2007.01.001

DO - 10.1016/j.ejps.2007.01.001

M3 - Article

VL - 30

SP - 406

EP - 413

JO - European Journal of Pharmaceutical Sciences

T2 - European Journal of Pharmaceutical Sciences

JF - European Journal of Pharmaceutical Sciences

SN - 0928-0987

IS - 5

ER -