Phospholipid based liposomes using proliposome technology were developed for the encapsulation and delivery of micronutrients such as iron. The phospholipid used was based on a composition containing primarily phosphatidylcholine with small quantities of charged lipids. Liposomal formulations were prepared by varying the concentration of phospholipid from 1.5 to 3.0%. Ferrous-sulphate (FeSO4. 7H2O) as the iron source and ascorbic acid as the anti-oxidant were chosen for encapsulation in the liposomes. A range of 15- 45% of ferrous-sulphate and 10-30% of ascorbic acid was used for encapsulation. The preparation of liposomes was optimised by varying different parameters such as concentration of the lipid, concentration of ferrous-sulphate/ascorbic acid, time and type of stirring employed. Both the placebo and ferrous sulphate/ ascorbic acid loaded liposomes were characterised by the particle size distribution analysis and the electron-microscopy studies. The amount of the entrapped ferrous-sulphate in the liposomes was analysed by atomic-absorption spectroscopy. The particle size of liposomes prepared using 1.5% concentration of phospholipid were found to be the lowest when compared to the formulations with 2.25 and 3.0 % of phospholipid. The volume median diameter of 50% of particles of placebo and ferrous- sulphate loaded liposomes prepared using 1.5% of phospholipid concentration was around 0.7μm and 5 μm respectively. The electron microscopic characterisation revealed the multilamellar nature of the formed liposomes with wider size distribution. The maximum entrapment efficiency of ferrous-sulphate achieved was around 11% for the liposomal formulation prepared using 15% of ferrous-sulphate as the initial loading concentration.
展开▼
