Capsule cooling

Complex Coacervation. This process occurs ia aqueous media and is used primarily to encapsulate water-iminiscible Hquids or water-iasoluble soHds (7). In the complex coacervation of gelatin with gum arabic (Eig. 2), a water-iasoluble core material is dispersed to a desired drop size ia a warm gelatin solution. After gum arabic and water are added to this emulsion, pH of the aqueous phase is typically adjusted to pH 4.0—4.5. This causes a Hquid complex coacervate of gelatin, gum arabic, and water to form. When the coacervate adsorbs on the surface of the core material, a Hquid complex coacervate film surrounds the dispersed core material thereby forming embryo microcapsules. The system is cooled, often below 10°C, ia order to gel the Hquid coacervate sheU. Glutaraldehyde is added and allowed to chemically cross-link the capsule sheU. After treatment with glutaraldehyde, the capsules are either coated onto a substrate or dried to a free-flow powder. 

Erk [20] described a spectrophotometric method for the simultaneous determination of metronidazole and miconazole nitrate in ovules. Five capsules were melted together in a steam bath, the product was cooled and weighed, and the equivalent of one capsule was dissolved to 100 mL in methanol this solution was then diluted 500-fold with methanol. In the first method, the two drugs were determined from their measure d%/dk values at 328.6 and 230.8 nm, respectively, in the first derivative spectrum. The calibration graphs were linear for 6.2—17.5 pg/mL of metronidazole and 0.7—13.5 pg/mL of miconazole nitrate. In the second (absorbance ratio) method, the absorbance was measured at 310.4 nm for metronidazole, at 272 nm for miconazole nitrate and at 280.6 nm (isoabsorptive point). The calibration graphs were linear over the same ranges as in the first method. 

Byeon et al. [23] described a fluorimetric method for (z>)-penicillamine using 9-fluorenylmethyl pentafluorophenyl carbonate and acetonitrile. Capsules containing penicillamine were extracted with water and then filtered. The solution was incubated at 70 °C for 40 min with borate buffer solution. After cooling, the mixture was extracted with diethyl ether and the fluorescence of the aqueous phase measured at (excitation = 260 nm, emission = 313 nm). The calibration graph was linear for 0.4-5.0 pM of penicillamine with a coefficient of variation of 0.4%. 

Assay preparation. Transfer not less than 20 Capsules to a blender jar or other container, and add about 150 mL of methylene chloride, and cool in a solid carbon dioxide acetone mixture until the contents have solidified. If necessary, transfer the mixture of capsules and methylene chloride to a blender jar, and blend with high-speed blender until all the solids are reduced to fine particles. Transfer the mixture to a 500-mL volumetric flask, add n-heptane to volume, mix, and allow solids to settle. Transfer an accurately measured volume of this solution, equivalent to 250 mg of valproic acid, to a 100 mL volumetric flask, dilute with w-heptane to volume, and mix. Transfer 5.0 mL to a container equipped with a closure. Add 2.0 mL of the internal standard solution, close the container, and mix. 

Assay preparation. Transfer an accurately measured volume of syrup, equivalent to about 250 mg of valproic acid, to a separator. Add 40 mL of water and 2.0 mL of hydrochloric acid not less than 20 capsules to a blender jar or other container, and add about 150 mL of methylene chloride, and cool in a solid... 

In the belt apparatus, the sample is contained in a noble metal capsule (a BN or MgO container is used for chalcogenides) and surrounded by pyrophyllite and a graphite sleeve, the latter serving as an internal heater. In a typical high-pressure run, the sample is loaded, the pressure raised to the desired value and then the temperature increased. After holding the pressure for about 30 minutes, the sample is quenched (400 K s ) while still under pressure. The pressure is then released after the sample has cooled to room temperature. 

Herbal pills, tablets or capsules should generally be taken with warm water. However, an exception is made to these two principles if the patient suffers from an excess heat syndrome in which the heat is so strong that it is impossible to accept any warm drinks. In this case, since the administration of warm fluids may cause vomiting, herbal medicines can be taken cool. 

The results shown in Fig. 24 indicate that this assumption is correct. The photoelectric emission of a platinum surface at X = 265.5 mg diminishes after the N2O capsule, still cooled with liquid air, has been smashed (F in Fig. 2). The emission current becomes entirely unmeasure-able after removal of the cooling medium. This corresponds to a considerable increase of the work function in the presence of N2O. 

More easily to be understood are the effects observed when ir electrons are present in the adsorbed molecule. Figure 28 shows the change of the photoelectric emission of a platinum surface covered with benzene (76). The benzene was contained in a capsule, which could be smashed magnetically (see F in Fig. 2). The tube, G in Fig. 2, was cooled by liquid air. At the points of the curve marked with arrows, the cooling of G was interrupted for 1 or 2 min., so that a small quantity of benzene molecules might be adsorbed at the platinum surface. The sensitivity increased (Fig. 28) at first and then decreased after passing a maximum, which was reached in the vicinity of the monomolecular covering (B, C in Fig. 28). 

The above techniques are not satisfactory for solid sample containing light fractions that will be lost if exposed to ambient conditions of pressure and temperature. Samples like these can best be handled by cooling the sample and encapsulating them in small sealed metal—fusible alloy—containers (capsules) or glass capillaries. The metal must have a low melting point. 

Even more recent has been the introduction of cncapsiilaiion/exirusion. which also permits conversion of Havorants. such as essential oils, into solid form. Spray drying is nut required. In the encapsulation process, the flavor substance is "enrobed." A viscous carbohydrate, with less than ]O f water, is created by heating, after which an emulsifier and acid flavoring ingredients are added. The ingredients are reacted under pressure in a cool alcohol bath, and then the product is extruded to fornt filaments, Thus, the final easy-to-handle product contains the flavor within a small capsule. 

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