Thin film hydration method

Figure 1 Cryo-TEM microscopy of DSPC DSPG CHOL liposomes obtained by thin-film hydration method and extruded through 0.2-pm polycarbonate membranes. Abbreviations. DSPC, l,2-distearoyl-s -glycerol-3-phosphocholine DSPG, 2,2-distearoyl-5 -glycerol-3[phosphor-rac-(l-glycerol)] CHOL, cholesterol.

Liposomes are mostly prepared by the thin film hydration method in which a thin fihn is produced by dissolving the phospholipids in suitable organic solvent... 

Pluronic poloxamers can be suitable carrier materials for this purpose due to their capacity to enhance the absorption of water-insoluble compounds by formation of micelles in aqueous environment that can host such hydrophobic compounds. Different authors have described the formation of quercetin-loaded Pluronic micelles by thin-film hydration methods and have shown that the resulting micelles enhanced the solubilization of the active compound. Ghanem et al. described the encapsulation of quercetin in Pluronic F127 via spray drying. ... 

Sathali et al. formulated a topical gel containing clobetasol propionate niosomes to prolong the duration of action and prevent side effects. The clobetasol propionate niosomes were prepared by altering the ratio of various non-ionic surfectants (Span 40,60, and 80) to cholesterol by the thin film hydration method. The in vivo results showed that the niosomal gel had a sustained as well as a prolonged action. 

There are many methods to prepare liposomes. This review will discuss only some of the commonly used methods. These include liposomes made by thin film hydration, reverse phase evaporation, freeze-drying, and proliposome methods. 

FTIR spectroscopy is a more accurate method for a quick analysis of the phosphorus in thin films. However, the P205 peak in FTIR is seriously affected if the thin film becomes hydrated. Some loss of sensitivity is caused by the movement of part of the peak from the P205 region to the P205 H20 region upon hydration of the thin film (Figure 3). This shift affects the measured phosphorus content of a thin film. Also, the lack of a significant... 

Ormosil spin-coated thin films obtained from vinyltriethoxysilane and doped with jS-di-ketonates have been recently investigated by H. Wang and collaborators. Both hydrated chelates and temaiy complexes with phen and tppo were doped at a concentration of 5 mol% (relative to Si) by a multi step sol-gel method. Out of the 12 compounds tested, [Nd(tta)3(tppo)2] yielded the best results but no quantitative luminescence data are given, preventing comparison with materials of known properties (Wang et al., 2005). 

Sampling methods used for IR analysis of clathrate hydrate compounds, which are largely composed of highly absorbing water molecules, were limited to mulls, thin films prepared by vapor co-deposition methods (the resulting amorphous deposit is warmed in a vacuum to the crystallization temperature" ), or adamantane pellets... 

ZnSe thin films were also deposited on glass substrates by the chemical hath deposition (CBD) method using method using zinc sulfate, sodiumselenosulfate, hydrazine hydrate, ammonia as precursors. The slow release of zinc ions (Zn ) and selenide ions (Se ) in the reaction solution facilitated the condensation of the ions on the substrate. The films were composed of spherical particles with a zinc blende phase. The particle size was influenced by the hydrazine hydrate concentration or zinc sulfate concentration. The electrochemical atomic layer deposition (EC-ALD) method was used to deposit ZnSe nanometer films on a multicarbon nanotubes/polyvinyl alcohol (CNTs/PVA) membrane. The morphology of the films varied with the ratio of the zinc to selenium. 

Zhang and Zhu [60] have combined two methods in preparing liposomes, by hydrating particulate-based proliposomes followed by freeze-drying. This approach has been reported to enhance the entrapment of amikacin compared to the same vesicles before freeze-drying or vesicles prepared by the thin film method. 

---