Tableting materials

The relative content varies by nearly 1% due to inhomogeneities in the tablet material and machine tolerances. 

Tableting machine simulators [41-48] have been developed in order to mimic tablet production systems with a very small amount of powder. Similar to eccentric tableting machines, tableting machine simulators use one pair of punches. Working only with a single pair of punches reduces the consumption of tableting materials and facilitates instrumentation for displacement measurement.

Force, displacement, and time are the three most important parameters to characterize the compaction cycles of tableting materials. Even when Hoblitzell and Rhodes postulated a linear relationship between force-time and force-displacement data [145], this could not been exactly proved until today. Thus it is important to analyze these three measured data together. 

The systems to control weight uniformity are not able to control uniformity of the mixture. When during filling of the die the tableted material demixes, tablet weight... 

Picker, K. M. (2000), Three-dimensional modeling to determine properties of tableting materials on rotary machines using a rotary tableting machine simulator, Ear. J. Pharm. Biopharm., 50(2), 293-300. 

Taking into account the effect of the tablet material on the stress distribution on tooling to aid tool design... 

Tabletting materials can be prepared by a number of different methods as outlined below.

A wide variety of types of sample may be expected by the forensic scientist. These inclnde powdered drug material, tabletted material and items likely to have traces of the drug samples present. From these items, the appropriate samples shonld be taken, described and subsequently forwarded for analysis. 

For tabletted materials, homogenization is more problematic since if the tablet was homogenized, it would also be destroyed. For this reason, a sample is taken from the tablet and gently scraped from the dose form, away from any ballistic features which are likely to be of use in subsequent examinations. The powder is then thoroughly homogenized prior to testing. 

In order to achieve this, a full physical description of the materials should first be carried out. It is sometimes possible, following this process, to feed the information obtained into relevant databases to identify the drug(s) present in the dose form. The identification process then becomes a simple matter of confirmation. If the dose form is not included in the databases, however, a full chemical analysis, including drug extraction from the tabletted material, presumptive testing, thin layer chromatography and a confirmatory technique must be undertaken. 

High-temperature pressing, 160-170 °C, for aminoplasts calls for an even higher temperature of preliminary heating in the case of tabletted materials (about 140 °C). 

The relative standard deviation of the determination was found to be 0,5% (photometer) resp, 0.7% (HPLC ) for samples and references. The relative content varies by nearly 1% due to inhomogeneities in the tablet material and machine tolerances. 

Punches usually have a longer lifetime than dies if they are made from the same material that is why manufacturers often choose different steel qualities. The surface of a die bore can become smoother or rougher during its use. The ejection force does not— apart from the composition of the tableting material and the compaction force—necessarily depend on roughness of the die wall, but to a high degree depends on the metal type of the... 

For specific tableting tasks, the tooling manufacturer will be able to provide optimum tool properties. It may be helpful in this respect to supply him with a sample of the tableting material in question. 

Empirical evidence shows that materials with low mean yield pressures undergo plastic deformation, whereas, tableting materials with high mean yield pressure have a tendency to be brittle and consolidate via fragmentation. Based on Heckel plots and the compaction behavior of materials can be classified into three types. A, B, and C (Fig. 6) (88,89). 

Eckers, C., Hutton, K. A., de Biasi, V., East, P. B., Haskins, N. J. and Jacewicz, V. W. Determination of clavam-2-carboxylate in clavulanate potassium and tablet material by liquid chromatography-tandem mass spectrometry. ]. Chromatogr., A 686 213-218, 1994. 

Dechene et al. determined acetyl salicylic acid, phenacetin, caffeine and codeine in tablets. Acetyl salicylic acid and phenacetin were separated and determined on one packed column of DS 200 on Haloport by temperature programming, 100-180°C, whereas caffeine and codeine were separated on a packed column of SE-30 (10 %) on Chromosorb W AW by temperature programming, 195-260°C. Codeine and caffeine were extracted from the powdered tablet material with chloroform after the addition of alkali, and the chloroform solution used for the gas chromatographic assay. Results obtained with the method are listed in Table 20.4. 

Scraping Used with tablet material. In this technique, tablets submitted wfll be scraped instead of completely powdered. This is done to keep the tablet intact for any further forensic analysis, whereas powdering woifld mean that the tablet would be lost. 

Locust bean gum has been investigated for its use as superdisin-tegrant additive. An orodispersible tablet material of nimesuUde, with locust bean gum has been fabricated. It was found that a tablet formulation with 10% locust bean gum disintegrates in only 13 s (33). 

Another ambient method, called AP-DIOS-MS, was also used for the identification of amphetamines and fentanyls in forensic samples. The principle is similar to that of DIOS, but occurs at atmospheric pressure. The use of tandem mass spectrometry (MS/MS) allowed unambiguous identification of the amphetamines and fentanyls (Pihlainen et al. 2005). AP-DIOS-MS/MS was also successfully applied to the identification of authentic compounds from drug seizures. Common diluents and tablet materials did not disturb the analysis and compounds were unequivocally identified. The limits of detection (LODs) for amphetamines and fentanyls with AP-DIOS-MS/ MS were 1-3 pmol, indicating excellent sensitivity of the method (Pihlainen et al. 2005). Protein digest analysis (250 finol of bovine serum albumin) by AP-DIOS-MS was also performed... 

Gold G, Palermo BT. Hopper flow electrostatics of tableting material I. Instrumentation and acetaminophen formulations. J Pharm Sci 1965 54 310. 

The weighed sample of powdered tablet material is stirred with acetone, filtered using quantitative techniques, and titrated with perchloric acid in dioxane, using methyl red as indicator. The end point is from orange to salmon pink. 

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