Rapid Release Granulation

National University of Singapore, Singapore Anthony Yolande and Lee Chin Chiat 

International Specialty Products (ISP) Asia Pacific Pte. Ltd., Singapore 

Solution can be defined as a mixture of at least two components forming a single phase, which is homogenous at the molecular level. The transfer rate of molecules or ions from solid state into solution is known as dissolution rate and the extent to which this proceeds under a given set of conditions is known as solubility. 

the rate of solution (dissolution rate) and the amount that can be dissolved (solubility) are two separate concepts but in practice, high solubility is usually associated with high dissolution rate (2). 

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McGinity, J.W. Koleng, J.J. Preparation and Evaluation of Rapid-Release Granules Using a Novel Hot-Melt Extrusion Technique, 1997, 2, 153. 

Rapid release granulation is expected to benefit the class of compound where absorption is highly dependent on the dissolution of the drugs in the gastrointestinal tract, termed as Class II compounds under the Biopharmaceutics Classification Scheme (Table 1). 

In contrast, some cytokines (e.g. some CSFs and EPO) appear to be expressed constitutively. In yet other instances cytokines such as PDGF and TGF-P are stored in cytoplasmic granules and can be rapidly released in response to appropriate stimuli. Other cytokines (mainly ones with growth factor activity, e.g. TGF-P, FGF and IL-1) are found bound to the extracellular matrix in connective tissue, bone and skin. These are released, bringing about a biological response upon tissue injury. 

Figure 3 Possible factors affecting the rapid release of drug in the respective steps under dry and wet granulation methods.

Sodium cyanide NaCN Poisonous by inhalation, ingestion or skin absorption Do not handle with bare hands Releases HCN slowly with water, more rapidly with acids Nonflammable white granules, fused pieces or eggs Odourless when dry slight almond odour in damp air Completely water soluble... 

These stimuli elicit a complex series of responses that result in cell functions such as chemotaxis and release of inflammatory compounds, oxidants, and proteases. Probably related to chemotaxis is a rapid, transient actin polymerization response. Inflammation results in part from the release of proteases and myeloperoxidase normally stored in granules inside the cell (5) and from oxidants produced by an NADPH-oxidase system (6) located primarily... 

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