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Film coating problems

Figure 4 Common examples of film-coating problems that trigger troubleshooting... Figure 4 Common examples of film-coating problems that trigger troubleshooting...
Designed experimentation, involving mostly some type or modification of factorial design, has been used to study many different types of formulation problems. These include a pharmaceutical suspension [21], a controlled-release tablet formulation [22], and a tabletcoating operation [23]. In the latter case, Dincer and Ozdurmus studied an enteric film coating and utilized the steepest descent graphic method to select the optimum. [Pg.620]

One of the elements of film coating that attracts much attention at technical symposia is that dealing with troubleshooting. This very fact is a clear indication of how poorly the matters described here are considered. While it is certainly important to understand the issues that can potentially lead to problems, and explore recovery options, the very idea that troubleshooting needs to be considered is clearly an admission of failure during... [Pg.442]

The hydrodynamic factors that influence the plasma polymerization process pose a complicated problem and are of importance in the application of plasma for thin film coatings. When two reaction chambers with different shapes or sizes are used and when plasma polymerization of the same monomer is operated under the same operational conditions of RF power, monomer flow rate, pressure in the reaction chamber etc., the two plasma polymers formed in the two reaction chambers are never identical because of the differences in the hydrodynamic factors. In this sense, plasma polymerization is a reactor-dependent process. Yasuda and Hirotsu [22] systematically investigated the effects of hydrodynamic factors on the plasma polymerization process. They studied the effect of the monomer flow pattern on the polymer deposition rate in a tubular reactor. The polymer deposition rate is a function of the location in the chamber. The distribution of the polymer deposition rate is mainly determined by the distance from the plasma zone and the... [Pg.176]

The samples without defensive film coat were studied by the method of concentration pulses (MCP) at pressure 0.2 Torr within the range of temperatures 370 -596 °C in order to determine the hydrogen permeability parameters of stainless steel (12X18H10T). The knowledge of these parameters allowed to simplify the problem of parameter identification for titanium nitride. The samples with titanium nitride covering were studied by method of permeability at pressures 0.5-249 Torr and the temperatures 380-670 °C. [Pg.672]

Two of the substances detected, pentamethyl heptene and tetramethyloctene were considered as substances known to contribute to the odour of extrusion film coatings. The fact that these substances could transfer from the film to the gas phase supported the potential for these substances to give rise to odour problems in foodstuffs. They also impregnated a filter paper with octanal and placed it in the test cell in contact with paperboard laminated to various films including PE, PP, poly(ethylene terephthalate) (PET) and aluminium/PE (Al/PE) (with PE on the outer surface). They monitored transfer of octanal across the material held at 30 °C for 8-10 hours. Transfer was most rapid through uncoated paperboard. Octanal was shown to transfer across PE film laminated to the paperboard within ten minutes. There was no transfer of octanal through PP, Al/PE and PET over ten hours. [Pg.401]

Film-coating was developed early in the 1950s to help resolve many of the problems associated with sugar-coating. It involves the application of a film-forming polymer onto the surface of a substrate (such as tablets, granules, and capsules). In addition to the polymer, the film contains plasticizers and colorants, which are needed to achieve the desired properties in the final dosage form. [Pg.665]

Enzyme DNA hybridization assays with electrochemical detection can offer enhanced sensitivity and reduced instrumentation costs in comparison with their optical counterparts. Efforts to prevent non-specific binding of the codissolved enzyme and to avoid fouling problems by selecting conditions suitable to amplify the electrode response have been reported by Heller and co-workers [107]. A disposable electrochemical sensor based on an ion-exchange film-coated screen-printed electrode was described by Limoges and co-workers for an enzyme nucleic acid hybridization assay using alkaline phosphatase [108] or horseradish peroxidase [109]. In another methodology to improve sensitivity, a carbon paste electrode with an immobilized nucleotide on the electrode surface and methylene blue as hybridization indicator was coupled, by Mascini and co-workers [110], with PGR amplification of DNA extracted from human blood for the electrochemical detection of virus. [Pg.401]

PROBLEMS OF POLYMERIC FILM COATING Physical Aging... [Pg.405]


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See also in sourсe #XX -- [ Pg.430 , Pg.431 ]




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