Hard shell capsules granulations

The dose of the drug and its solubility are important considerations in the design of the formulation. The amount and type of active ingredient influences capsule size and the nature and amount of excipients to be used in the formulation. Larger-dose drugs that must be granulated to produce tablets may be more easily direct-filled into hard shell capsules with proper choice of excipients. 

In a survey of industry practices, Heda (12) found that, as a matter of policy, 46% of the firms sampled favor direct filling of powders as a first choice over granulation prior to filling capsules. Thirty-six percent of firms allow formu-lators to make that decision at their own discretion, whereas 18% of firms favor granulation of all formulations prior to encapsulation. Yet, for half of the firms responding, only 0 10% of their hard shell capsule products are direct-fill powder formulations, and only 27% of firms reported that more than 50% of their capsules were developed as direct-fill formulations. Although some of these non-direct-fill formulations may be controlled release formulations, e.g., barrier-coated bead products, difficult powder formulation problems may, at least in part, account for this observation. 

Capsules have traditionally been used to contain powder or granule formulations but in recent years have been adapted to contain oily liquid as soft gelatin capsules. However, hard gelatin capsules, stored under the high temperature and high humidity conditions, tend to be more brittle than soft capsules because the capsule shell is thinner. 

Capsules— These are primarily intended for oral administration and are solid preparations with hard or soft shells comprised of gelatin or hydrox-ypropyl methyl cellulose and small amounts of other ingredients such as plasticizers, fillers, and coloring agents. Their contents may be powders, granules, pellets, liquids, or pastes. 

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