Water-soluble pouches

EP 1319706 06/2003 Ramcharen et al.l Unilever Dispersed sohd in a hquid detergent in a water-soluble pouch... 

Polyvinyl alcohol is produced by hydrolysis of polyvinyl acetate, since the vinyl alcohol monomer is unstable. The degree of solubility can be controlled by modifying the extent of hydrolysis and the molecular weight of the polymer. Films can be produced which are readily soluble in water of any temperature or soluble in hot water only. Applications include hospital laundry bags and soluble pouches for chemicals and detergents. Most applications require the pouch to be contained in an outer barrier package to prevent moisture from reaching the material prematurely. 

Water soluble polymers are also now finding application in the area of packaging. For example polyvinyl alcohol pouches are used to dispense liquid detergent formulations. The pouch is placed in the washing machine and the polyvinyl alcohol slowly dissolves to release the liquid. The emphasis nowadays is to use natural polymers, both polysaccharides and proteins, as packing materials because of their ability to biodegrade and recent advances in this area are covered in Chapter 10. 

Absorption of normally non-absorbed or poorly absorbed water soluble drugs from a Thomas gastric fundic pouch of the dog is greatly increased by certain surfactants [83]. Vitamin B12 absorption from both stomach and intact gastrointestinal tract of the rat is similarly enhanced [84]. As might be anticipated, while blood levels of cephaloridine are elevated several fold when surfactant is added to the ligated stomach, their influence in the intact GI tract is diminished and... 

For determination of disulfide bond formation and changes in protdn solubility of MSSM and MSCM in sodium dodecyl sulfate (SDS) (Sigma Chemical Company, St. Louis, MO), samples were heated in sealed polythene pouches in a controlled water bath over 40 min at temperatures ranging from 40 to 99°C or at 80°C over a 60 min period. 

Edible films are stand-alone thin layers of biopolymer materials. Films are generally used to determine the film properties, such as water vapor and gas barrier, mechanical properties, solubility, optical and other properties. Edible films are formed with less than 0.3 nun of thickness, while at higher thickness are called sheets. The films can also be placed on or between food components as a wrapper (McHugh, 2000) and they can be potentially formed as capsules, pouches, casings, and bags (Krochta, 2002). 

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