Compounding Hotline

Author: Martin A. Erickson III, RPh

Mr. Erickson is director of professional affairs at Gallipot Inc.


Q:

Could you please cite studies about the delivery of medication rectally using hard gelatin capsules?

A:

Gelatin capsules are dose forms used to administer medications orally. Rectal administration of gelatin powder-filled capsules is not recommended for a variety of reasons, including the tendency for the material to form a bolus, which is expelled before the patient can absorb the drug. The pharmaceutically and medically accepted method for administering medication rectally is by means of a suppository dose form. This dose form is compounded by the pharmacist or is manufactured by melting a suitable vehicle (usually either a hydrogenated vegetable oil or a polyethylene glycol wax derivative) in which the drug(s) and perhaps some excipients are dispersed. When the dose form is administered rectally, the suppository either melts or dissolves, depending upon the vehicle chosen, releasing the drug(s) evenly throughout the patient’s rectum. To reiterate, gelatin capsules are not recommended as a means by which to administer drugs rectally, although occasionally a researcher may attempt to administer a softgel capsule rectally. A literature search performed on the National Library of Medicine Web site revealed essentially no relevant citations relating to rectal administration of medication in gelatin capsules. 

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