Hard compressed tablets

Soft gelatin capsules are not an inexpensive dosage form, particularly when compared to direct compression tablets [3]. There is a more intimate contact between the shell and its liquid contents than exists with dry-filled hard gelatin capsules, which increases the possibility of interactions. For instance, chloral hydrate formulated with an oily vehicle exerts a proteolytic effect on the gelatin shell however, the effect is greatly reduced when the oily vehicle is replaced with polyethylene glycol [3]. 

The material obtained from the kneading process should be, after drying and blending, compressed to tablets. The compressing capabilities and the tablet characteristics (content uniformity, thickness, hardness, friability, weight variances, and disintegration time) should meet the finished product specification for the compressed tablets. 

Bilayer compression force (kN) First-layer compression force (kN) Tablet cylindrical height (mm) Tablet hardness (N) Tablet friability (% 500 Drops)... 

Hard shell capsules occupy a central role in drug product development and manufacture, ranking second behind compressed tablets in frequency of utilization in drug delivery. In product development, such capsules are often the first dosage form for any orally administered drug substance. Although the expectation may be that the final marketed form will be a compressed tablet, firms may consider using the capsule as the first marketed form to shorten the overall development cycle. 

As shown in Table 6.17, the hardness—compression force profile for Drug A tablets is linear across the range of compression forces studied. This linear profile is attributed to the properties inherent in the brittle and ductile excipients chosen for this formulation. In contrast, the hardness—compression force profile for Drug B shows a plateau in tablet hardness at higher compression forces (> 11 kN), as listed in Table 6.18. 

Press Speed (Tablets/h) Compression Force (kN) Tablet Hardness (N) Tablet Weight Variation (%RSD) Mean Tablet Friability at 4 rpm (%) Mean Tablet Friability at 15 rpm (%)... 

EC is an inert, hydrophobic polymer that has been studied substantially for its application as a matrix-forming material in direct compression tablets. Direct compression is the preferred method of manufacture for producing tablets intended for immediate or sustained release. There have been reports on the compressibility and compatibility of EC [307-310] and on its use as a matrix-forming material in direct compression tablets for the delivery of soluble and poorly soluble drugs [311-316]. Tablet hardness [310,314,315], the particle size of the polymer [314,315,317], and the viscosity grade [313,314] were observed to directly affect the drug release rate. It was noted that tablet hardness affected the... 

Aulton, M. E. (1981), Indentation hardness profiles across the faces of some compressed tablets, Pharm. Acta Helv., 56,133-136. 

Directly compressed tablets containing chitin or chitosan in addition to mannitol Mannitol is not a compressible material. The addition of chitin, chitosan, and MCC improves the compressibility of mannitol. The measured hardness for the tablets composed of mannitol/chitin, marmitol/chitosan, and mannitol/MCC increased with increase in the concentration of chitin, chitosan, or MCC (Fig. 2.37). Chitin, chitosan, and MCC should be added at a level >20% (w/w) to improve the compressibility of mannitol tablets. The relationship between the disintegration time of tablets and the concentration of chitin chitosan or MCC excipients added to mannitol was investigated. Results showed that all tablets... 

At present, knowledge bases for aerosols, IV injection solutions, hard gelatin capsules, and direct compression tablets have been completed. Other knowledge bases for coated forms, granules, freeze-diied formulations, and pellets are in different stages of development. Trials have demonstrated that the system proposes formulations that are acceptable to formulators, and in December 1996, the system was first introduced for field trials in a pharmaceutical company. 

Chowhan ZT. Role of binders in moisture-induced hardness increase in compressed tablets and its effect on in vitro disintegration and dissolution. / Pharm Sci 1980 69 1. ... 

Evaluating the results from development and/or scale-up batches of compressed tablets employs the use of control charting techniques, process capability analysis, and prediction intervals as described earlier. The techniques apply equally well to in-process measurements of hardness, thickness, and tablet weight, and compendial requirements such as assay, dose uniformity by content uniformity, and dissolution. 

Tablets and hard gelatin capsules form the vast majority of solid dosage forms on the market. While the actual processes involved of filling capsules and compressing tablets differ, the preparation of the powders to be processed are, in many cases, very similar.

The hardnesses of tablets obtained at constant compression force were measured. Harder tablets were obtained for lower amounts of binder, but results are satisfactory over aU the domain (figures 6.6c and 6.7c). A lubrification time of about 3 minutes appears to be the optimum (figure 6.6d). 3% humidity gave significantly harder tablets than the powder with humidity below 2%. ... 

To give some perspective as to the magnitude of the difference between hard and soft compressed tablets, typical hard detergent tablets (such as those produced for automatic dish washing) are compressed at pressures over 40,000 kN/m, whereas soft tablets use pressure as low as... 

As cyclodextrin polymer has sufficient flow properties it can be used in directly compressed tablets. Showing some binding capacity that is an increasing effect on the hardness of the tablets it can be considered a binder-disintegrant (4). Its. effectivity in different placebo formulations has been compared to other disintegrants... 

Chowhan ZT. Moisture, hardness, disintegration and dissolution interrelationships in compressed tablets prepared by the wet granulation process. Drug Dev Ind Pharm 1979 5 41 2. 

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