Stabilisers delivery

One of the primary objectives of production operations is to deliver product at the required rate and quality. Therefore the product quality specification and any agreed contract terms will drive the activities of the production operations department, and will be a starting point for determining the preferred mode of operation. The specifications, such as delivery of stabilised crude with a BS W of less than 0.5%, and a salinity of 70 g/m, ... 

Hong, K., Zheng, W., Baker, A., Papahadjopoulos, D. (1997). Stabilisation of cationic liposome/DNA complexes by polyamines and polyethylenglycol-phospholipid conjugates for efficient in vivo gene delivery. FEBS Lett., 414, 187-192. 

Semenova M.G., Belyakova, L.E., Polikarpov, Yu.N., Antipova, A.S., Anokhina, M.S. (2008). Utilization of sodium caseinate nanoparticles as molecular nanocontainers for delivery of bioactive lipids to food systems relationship to the retention and controlled release of phospholipids in the simulated digestion conditions. In Williams, P.A., Phillips, G.O. (Eds). Gums and Stabilisers for the Food Industry 14, Cambridge, UK Royal Society of Chemistry, pp. 326-333. 

There has been considerable recent interest in the self - assembly and surface activity of amphiphilic polymers and copolymers. Their interfacial and bulk solution properties have shown a rich pattern of behavior, and the ability to tailor their properties offers a wide range of potential applications. Their bulk aggregation behavior make them candidates, for example, for dye transportation and drug delivery whereas their surface properties make them useful as colloid stabilisers, anti -foaming agents and emulsifiers. This behavior can be illustrated in Fig. 3.24. 

The combination of a metal carbonyl compound and a guanylate cyclase stimulant (e.g. YC-1) or stabiliser for the therapeutic delivery of carbon monoxide [240]... 

Kantaria, S., Rees, G. D., and Lawrence, M. J. (1999), Gelatin-stabilised microemulsion-based organogels Rheology and application in iontophoretic transdermal drug delivery, /. Controlled Release, 60(2-3), 355-365. 

Fig. 3.3. Tentative mechanism of reduction of dioxygen. The scheme shows some of the more significant reaction steps at the haem iron-Cug centre of cytochrome oxidase. The reaction may be initiated by delivery of dioxygen to the reduced enzyme (in anaerobiosis top of figure). An initially formed oxy intermediate is normally extremely short-lived, but can be stabilised and identified in artificial conditions (see Refs. 92, 99,129, 134). Concerted transfer of two electrons from Fe and Cu to bound dioxygen yields a peroxy intermediate. This, or its electronic analogue, is stabilised in the absence of electron donors (ferrocytochrome a and/or reduced Cu ), and has been termed Compound C [129,130,132). It may also be observed at room temperature, and is then probably generated from the oxidised state by partial oxidation of water in the active site, in an energy-linked reversed electron transfer reaction [29] (see also Refs. 92, 99). Also the ferryl intermediate [92,99,100] has been tentatively observed in such conditions [29]. In aerobic steady states the reaction is thought to involve the cycle of intermediates in the centre of the figure (dark frames). The irreversible step is probably the conversion of g = 6 (see Refs. 98, 133) to peroxy .

Flatley RHM, Blair JA. Stabilisation and delivery of labile materials by amorphous carbohydrates and their derivatives. ] Mol Cat B 1999 7 11-19. 

Few studies have been carried out on nonaqueous emulsions, but these can be useful as topical vehicles or reservoirs for the delivery of hydrolytically unstable dmgs. Systems such as castor oil or propylene glycol in silicone oil can be formulated using silicone surfactants the HLB number clearly does not help in the formulation, especially if the continuous phase has low polarity. The key to stabilisation lies in the sufficient solubility of the emulsifier in the continuous phase. 

Aqueous foams are formed from a three-dimensional network of surfactant films in air. Foams can be used as formulations for the delivery of enemas and topical products. Foams which develop in production of liquids or in ampoules are troublesome hence there is an interest in breaking foams and preventing foam formation. The breaking and prevention of liquid foams is less well understood than the stabilisation of foams, it is recognised, however, that small quantities of specific agents can reduce foam stability markedly. There are two types of such agent ... 

Oupicky D, Ogris M, Howard KA, Dash PR, Ulhrich K, Seymour LW. Importance of lateral and steric stabilisation of polyelectrolyte gene delivery vectors for extended systemic circulation. Molecul Therap 2002 5 463—472. 

Gelatin stabilised microemulsion based organogels Isopropyl myristate Cyclosporin A Safe and effective delivery through topical application [111]... 

There have been attempts to develop aquasomes as an alternative to liposomes for drug delivery. They consist of porous nanoparticles, specially prepared by sonication of precipitated calcium phosphates such as hydroxyapatite or dicalcium phosphate. These particles are then coated with oligomeric molecules containing -OH groups which can anchor an outer layer of drug molecules or other bioactive species. The outer layer of molecules becomes immobilised or stabilised during transportation to the required site for action. Aquasomes may serve to construct anti-viral decoys which act as vaccines. 

Figure 3.8 Electrostatic interactions of cationic polymers with anionic genes can be used to form polyplexes for the stabilisation and delivery of DNA...

---