Solid drug products, excipients used

Table 5 Common excipients used in solid drug products...

When the excipient matrix in a formulation is largely amorphous, similar XRPD methods can be used to determine the amount of crystalline drug substance present in a drug product. The principles were established in a study that included a number of solid dose forms [40],... 

Solids Solid dosage forms are the most common means for presenting the drug product for patient administration. Most APIs are in crystallized or powder forms. They are ground to predetermined sizes using mills or pulverizers. The APIs and excipients are then mixed using blenders or tumblers. 

A preservative is a substance that prevents or inhibits microbial growth and extends the shelf life of the drug products. In most pharmaceutical drug products, only a few compounds are typically selected as preservatives. For efficiency, a generic method should be developed for the types of preservatives that are more commonly used. For example, butylated hydroxytoluene (BHT) is an antioxidant commonly used in many solid dosage formulations to retard oxidative degradation of the excipients. 

To work around this concentration limitation, formulation scientists often use a solid-state formulation as a means to achieving a higher protein concentration for the final drug product. By reconstituting the solid formulation with less water than was used to initially formulate the drug, one gets an increased protein concentration in the reconstituted product, as depicted in Fig. 1. It is important for the formulation scientist to remember that, in addition to the protein, the excipients in the formulation are also increased in concentration when the solid formulation is reconstituted to a lower final volume. Care should be taken to maintain a suitable final product osmolality for injection. 

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