Tabletting Articles

Sticking occurs when granules attach themselves to the faces of tablet press punches. Picking is a more specific term that describes product sticking o­nly within the letters, logos, or designs o­n the punch faces. This article explains the causes of sticking and picking and describes the steps you can take to resolve both problems.


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Ossi Korhonen, Seppo Pohja, Soili Peltonen, Eero Suihko, Mika Vidgren, Petteri Paronen, Jarkko KetolainenAAPS PharmSciTech. 2002; 3(4): article 34.

The aim of this study is to apply 3-D modeling to data obtained from different tableting machines and for different compression wheels o­n a linear rotary tableting machine replicator. A new analysis technique to interpret these data by 3-D parameter plots is presented. Tablets were produced o­n an instrumented eccentric tableting machine and o­n a linear rotary tableting machine replicator. The materials used were dicalcium phosphate dihydrate (DCPD), spray-dried lactose, microcrystalline cellulose (MCC), hydroxypropyl methylcellulose (HPMC), and theophylline monohydrate. Tableting was performed to different maximum relative densities (ρ rel, max). Force, time, and displacement were recorded during compaction. The 3-D data plots were prepared using pressure, normalized time, and porosity according to Heckel. A twisted plane was fitted to these data according to the 3-D modeling technique. The resulting parameters were analyzed in a 3-D parameter plot.

The objective of this study is to test the hypothesis that time plasticity (parameter d from 3-D modeling) is influenced by tableting speed. Tablets were produced at different maximum relative densities (ρrel, max) o­n an instrumented eccentric tableting machine and o­n a linear rotary tableting machine replicator. Some 3-D data plots were prepared using pressure, normalized time, and porosity according to Heckel. After fitting of a twisted plane, the resulting parameters were analyzed in a 3-D parameter plot. The materials used were dicalcium phosphate dihydrate (DCPD), spray-dried lactose, microcrystalline cellulose (MCC), hydroxypropyl methylcellulose (HPMC), κ-carrageenan (CAR), and theophylline monohydrate (TheoM). The results show that tableting speed especially influences the parameter d (time plasticity) of the 3-D model for plastically and viscoelastically deforming materials such as MCC, HPMC, CAR, and TheoM.

Prions cause neurodegenerative diseases, such as scrapie in sheep, bovine spongiformencephalopathy (BSE) in cattle, Creutzfeldt-Jakob disease (CJD), Gerstmann-Straussler-Scheinker syndrome (GSS), fatal familial insomnia (FFI), kuru, and a new variant of CJD in humans. These diseases are associated with conversion of the normal cellular form of the prion protein (PrPC) to a pathogenic scrapie form (PrPSc), which is apparently the infectious agent in transmitted forms of the disease. The sequences of PrPSc and the noninfectious precursor PrPC are identical. Although both isoforms are chemically identical, they possess very different physicochemical properties. PrPC is substantially helical, but PrPSc has ~40% -sheet.

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The pace of biotechnology advancement has never been more rapid, with the number of biotech research centers, academic programs, and proposed manufacturing sites at an all-time high. Though biotechnology products are targeting a steadily widening range of therapeutic applications, their manufacture also entails levels of complexity previously unseen in the pharmaceutical industry. As a result of this complexity, manufacturers have their eyes squarely focused on two critical considerations: time and cost. As a result, any technology that promises to reduce one or both of these factors, without compromising product quality, is sure to gain the industry’s attention.

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Because direct compression is more economic and straightforward in terms of good manufacturing practice requirements than are wet granulation and dry compaction, the pharmaceutical industry is focusing increasingly on this process. Although coarse microcrystalline cellulose (MCC) grade 12 offers outstanding flow properties, the most commonly used grade for direct compression is the well-known fine grade 102. The reason for this preference is that many users expect segregation (and subsequent poor weight- and content-uniformity results) when combining fine active ingredients with coarse-grade excipients.

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A tablet press is one of the most complex machines used in the manufacturing environment. Clearly defining the basic principles in tablet press operation is essential to having a successful run. Learning key factors can help to avoid the many obstacles that can interrupt a successful run. Worldwide, more than 18 different companies make tablet presses. All tablet presses operate in the same basic way with only a few exceptions. This fact allowed the industry to define and create a standard for tablet press machines and tablet press tooling, which was published in the Tablet Specification Manual (TSM) by the American Pharmaceutical Association. The TSM can be acquired through any tooling or tablet press supplier. This article discusses how tblet press performance can be optimized by clearly distinguishing between granulation and machine issues; focusing on the importance of flow, compression, and ejection; and performing the necessary maintenance and quality control checks.

According to a 1993 survey by Shangraw and Demarest, direct compression is the preferred manufacturing process for pharmaceutical tablets (1). The major characteristics of a good, directly compressible filler are physical and chemical compatibility, compactibility, flowability, lubricity,and the ability to blend uniformly with the active pharmaceutical ingredients (APIs) and other excipients. The most commonly used fillers are lactose, microcrystalline cellulose (MCC), starch, and dibasic calcium phosphate (DCP). Various types of MCC, lactose, and DCP exist with distinct differences in their particle These differences affect the compression and tablet characteristics.

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Starch is a multipurpose excipient in tablet formulations.
It can be used as a binder, disintegrant, and filler. Natural
starches also have been pregelatinized to increase
their cold-water swellability and increase their flowability
(1). Pregelatinization can be carried out by thermal methods
(2). Although some research has been carried out on the
compressional characteristics of natural starches (3,4), little or
no research appears to have been conducted on the effect of
pregelatinization on the compressional characteristics of starches
in relation to their usefulness in tablet formulations.
Sorghum and plantain starches obtained from Sorghum bicolor
L. (poaceae) and Musa paradisiaca L. (musaceae), respectively,
have been investigated as binders and disintegrants in
tablet formulations (5,6). However, it appears that no attempt
has been made to study the effects of these starches in either