Capsule
From Pharmpedia
Capsules equal the tablets in their popularity and usage. They are convenient means of dispensing a variety of solids, semi-solids and liquids. All capsules basically consist of soluble shells of a material like gelatin. The solid substances are dispensed in hard capsules while for dispensation of liquids and semi-solids soft capsules are preferred. Capsules are generally employed for enclosing materials meant for oral administration and are swallowed as a whole. Nowadays some capsules are administered through rectum, or vagina and are useful substitutes for the more conventional types of suppositories based on oleaginous or water soluble bases. Soft capsules can also be employed for enclosing single application of eye ointments. Here the capsules have to be pricked with needle and the contained ointment transferred to ophthalmic cavity by application of slight pressure. Capsules afford a tasteless, odourless enclosure, convenient for administration of variety o9f medicaments, which are otherwise difficult to administer. However, aqueous or hydroalcoholic liquids cannot be enclosed in capsules because they dissolve gelatin.
Gelatin capsule was first invented in 1834 by Mothes, a French pharmacy student in collaboration with a French pharmacist Dublanc. They used one piece olive shaped structures which had to be sealed after filling with a drop of concentrated gelatin solution and were counterparts of the modern day soft gelatin capsules. The inventors used the capsules to mask the tastes of obnoxious materials. Mothes first sold empty shells but later supplied only filled ones. As such other inventors tried to appear on the scene to overcome the patent of Mothes. Lehuby in 1846 invented a two piece structure which was identical with the present day hard gelatin capsules. He called them ‘mes envelopes medicamenteuse’ or medicinal envelopes. The first British patent was granted to Murdoch in 1848 who was Lehuby’s agent. Lehuby’s process for production of gelatin shells was essentially the one used today. The first large scale manufacture of gelatin capsules was undertaken by Eli Lilly & Co. in Hampshire. In U.S.A. the manufacture commenced nearly a century ago. Large scale machinery for manufacture of empty shells, which was fully automated, was designed inn 1913. Filling and sealing machinery came into being in 1950. At first the devices were semi-automatic but by 1960 fully automated versions were marketed. The availability of automated machinery has given fillip to the popularity of capsules so much that today about 10 to 15% of dosage forms are capsules of one kind or the other.
Capsules should not be used for packaging of highly water soluble materials such as ammonium chloride, potassium bromide,
potassium chloride etc., because sudden release of such compounds can cause irritation. It is also not advisable to use capsules
for very deliquescent or efflorescent materials. Deliquescent substances may draw up moisture from the capsule shell rendering it
brittle. The efflorescent materials may cause softening of the capsules.
There are two types of capsules available
Retrieved from "http://www.pharmpedia.com/Capsule"
This page has been accessed 1,772 times. This page was last modified 04:55, 25 October 2006. All content, except where otherwise noted, is licensed under a Creative Commons Attribution License.
