Dissolution, of tablets and

IVIVC (In-Vitro, In-Vivo Correlation) module to correlate relationships between the in vitro dissolution of tablets and capsules and the in vivo dissolution in human and animal systems. 

Dorr T, Willibald-Ettle I. Evaluation of the kinetics of dissolution of tablets and lozenges consisting of saccharides and sugar substitutes. Pharm Ind 1996 58 947-952. 

In-process controls, such as the checking of weights and disintegration or dissolution of tablets, satisfactory mixing, appropriate suspension preparation, or clarity of solutions must be conducted to ensure appropriate product content uniformity and performance... 

The flow-through cell is applicable not only for the determination of the dissolution rate of tablets and sugar-coated tablets, but has also been applied to suppositories, soft-gelatin capsules, semisolids, powders, granules, and implants. A small volume cell containing the sample solution is subjected to a continuous stream of dissolution media. The dissolution... 

Shangraw, R. F.. and Demarest, D. Survey of current industrial practice in the formulation and manufacture of tablets and capsules. Pharm. Tech. 17(l) 32-44, 1993. USP 24-NF 19. United States Pharmacopoeia Convention, Inc. Rockville. MD, 2000. Piscitelli, D. A.. Bigora, S., Propst, C.. Goskonda, S., Young. D.. et al. Impact of formulation process changes on in vitro dissolution and the bioequivalence of piroxicam capsules. Phaim. Dev. Technol. 3 443 52, 1998. 

Application/spray rate The optimal application/spray rate should be determined. Spraying too fast will cause the tablets to become overwet, resulting in clumping of tablets and possible dissolution of the tablet surface. Spraying too slowly will cause the coating materials to dry... 

Our group was the first to report imaging with a diamond ATR accessory that provided a field of view of ca. 1 mm2 and the spatial resolution of ca. 15 pm without the use of an infrared microscope [18], The demonstration of the applicability of a diamond ATR accessory for FTIR imaging opened up a range of new opportunities in polymer research, from compaction of tablets [21-23] to studying phase separation in polymer blends subjected to supercritical fluids [24], This imaging approach was successfully utilised for the study of dissolution of tablets in aqueous solutions [25], We have also demonstrated macro... 

Soloman, S. Non-Destructive Identification of Tablet and Tablet Dissolution by Means of Infrared Spectroscopy. US Patent 338,909, October 21, 1997. 

Non-uniform or incomplete coverage of tablets and beads results in different dissolution patterns... 

Suzuki T, Nakagami H. Effect of crystallinity of microcrystalline cellulose on the compactability and dissolution of tablets. Eur ] Pharm Biopharm 1999 47 225—230. 

Flow calorimetry has also been used to investigate dosage forms. Dissolution of tablets under various simulated conditions has been explored, for example. Here, the tablet is presented with various solutions designed to mimic conditions in the gastro intestinal (GI) tract (pH 7 buffer) and stomach (pH 3 buffer for fasting and lipid solutions for fatty meals). The rate of dissolution can then be estimated for conditions in vivo. 

When 12 tablets were placed across the flow of 100 gpm, the chlorine concentration decreased below the detection limit (0.1 mg/L) within 5 min. It remained below the detection limit even after 60 min. In the next test, initially a flow rate of 300 gpm was maintained and 16 tablets were placed across the flow. Within 5 min the chlorine concentration decreased to below detection limit. After 10 min, the flow rate was increased to 450 gpm. At this increased flow rate, the residual chlorine concentration increased to values of 0.6-0.8 mg/L, well above the detection limit of 0.1 mg/L (which is the allowable discharge hmit in many locations), within 25 min (Fig. 3). This indicates that the flow rate of chlorinated waters can significantly impact the efficiency of dechlorination operations. Higher flow rates may not provide sufficient contact time for dissolution of tablets into the stream. After approx 40 min, the number of tablets was increased to 20. This decreased the residual concentration to below detection limit within 5 min. The increase in the number of tablets probably provided an enhanced contact area and better dissolution of the tablets into the flow, resulting in a decrease in the residual chlorine concentrations. 

The properties of all excipients present in the tablet must be considered for their possible effects on the final preparation, such as weight variation, disintegration time, dissolution characteristics and in vivo performance. The lower the proportion of the active substance present in the mixture, the more difficult it is to achieve a sufficient homogeneity. In Sects. 4.9 and 4.10, the formulation of tablets and the possibilities to process coated or modified-release tablets in capsules are discussed. 

Dissolution time and disintegration time of tablets and capsules... 

The determination of the dissolution rate of the active substance from the dosage form is relevant for solid dosage forms and dispersions, especially when the substance is poorly soluble (see Sect. 16.1.4). Only dissolved substances are available for absorption. Ph. Eur. describes in chapter 2.9.3 Dissolution test for solid dosage forms the equipment, the method of analysis and the interpretation of the determination of the dissolution rate of tablets and capsules. For suppositories it is described in Ph. Eur. chapter 2.9.42 Dissolution test for lipophilic solid dosage forms . 

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