Thursday, May 6, 2010


In the manufacture of pharmaceuticals, encapsulation refers to a range of techniques used to enclose medicines in a relatively stable shell known as a capsule, allowing them to, for example, be taken orally or be used as suppositories. The two main types of capsules are:
  • Hard-shelled capsules, which are normally used for dry, powdered ingredients or miniature pellets (also called spheroids that are made by the process of Extrusion and Spheronization - Spheronization is a trade mark of Caleva Process Solutions) or tablets;
  • Soft-shelled capsules, primarily used for oils and for active ingredients that are dissolved or suspended in oil.
Both of these classes of capsules are made from aqueous solutions of gelling agents like:
  • Animal protein mainly gelatin;
  • Plant polysaccharides or their derivatives like carrageenans and modified forms of starch and cellulose.
Other ingredients can be added to the gelling agent solution like plasticizers such as glycerin and/or sorbitol to decrease the capsule's hardness, coloring agents, preservatives, disintegrants, lubricants and surface treatment.
Since their inception, capsules have been viewed by consumers as the most efficient method of taking medication. For this reason, producers of drugs such as OTC analgesics wanting to emphasize the strength of their product developed the "caplet" or "capsule-shaped tablet" in order to tie this positive association to more efficiently-produced tablet pills. After the 1982 Tylenol tampering murders, capsules experienced a minor fall in popularity as tablets were seen as more resistant to tampering.

 Single piece gel encapsulation:
In 1834, Mothes and Dublanc were granted a patent for a method to produce a single-piece gelatin capsule that was sealed with a drop of gelatin solution. They used individual iron moulds for their process, filling the capsules individually with a medicine dropper. Later on, methods were developed that used sets of plates with pockets to form the capsules. Although some companies still use this method, the equipment is not produced commercially any more. All modern soft-gel encapsulation uses variations of a process developed by R.P. Scherer in 1933. His innovation was to use a rotary die to produce the capsules, with the filling taking place by blow molding. This method reduced wastage, and was the first process to yield capsules with highly repeatable dosage.
The current owner of the RPScherer technology is Catalent Pharma Solutions, the world's largest manufacturer of prescription pharmaceutical softgels.
Softgels can be an effective delivery system for oral drugs, especially poorly soluble drugs. This is because the fill can contain liquid ingredients that help increase solubility or permeability of the drug across the membranes in the body. Liquid ingredients are difficult to include in any other solid dosage form such as a tablet. Softgels are also highly suited to potent drugs (for example, where the dose is <100 ug), where the highly reproducible filling process helps ensure each softgel has the same drug content, and because the operators are not exposed to any drug dust during the manufacturing process.
In 1949, the Lederle Laboratories division of the American Cyanamid Company developed the "Accogel" process, allowing powders to be accurately filled into soft gelatin capsules.

Two piece gel encapsulation:
James Murdock of London patented the two-piece telescoping gelatin capsule in 1847. The capsules are made in two parts by dipping metal rods in the gelling agent solution. The capsules are supplied as closed units to the pharmaceutical manufacturer. Before use, the two halves are separated, the capsule is filled with powder or mor normallt spheroids made by the process of spheronization (either by placing a compressed slug of powder into one half of the capsule, or by filling one half of the capsule with loose powder) and the other half of the capsule is pressed on. With the compressed slug method, weight varies less between capsules. However, the machinery required to manufacture them is more complex.
The powder or spheroids inside the capsule contains the active ingredient(s) and any excipients, such as binders, disintegrants, fillers, glidant, and preservatives.

Osmotic-controlled Release Oral delivery System (OROS):
OROS is a controlled release oral drug delivery system in the form of a consumable capsule. The capsule has a rigid water-permeable jacket with one or more small holes. As the capsule passes through the body, the osmotic pressure of water entering the capsule pushes the active drug through the opening in the capsule.
OROS is a trademarked name owned by Alza Corporation.
Multiple Choice Questions (MCQs) from Capsules in Pharmaceutics
1-  Capsule are dosage form contain ______ of drug.

a) single dosage  
b) unit dosage    
c) double dosage   
d) both b & c
2-  Basic empty capsule shell are made from a mixture of ______.

a) sugar   
b) water  
c) Galeton 
d) all of above
3-  Galeton is ______ in air when dry.

a) Unstable  
b) stable   
c) both a & b  
d) none of above
4-  Soft Galeton capsule have ______ moisture content then hard Galeton capsule.

a) low  
b) equal  
c) high   
d)  none of above
5-  The normal shell contain _____ of moisture.

a) 9-12%  
b) 15-18%  
c) 12-15%      
d) none of above
6-  Capsule are _____ to swallowed.

a) very difficult     
b) difficult    
c) both a & b   
d) easy
7-  On large scale soft Galeton capsule are prepared by_______.

a) plate process    
b) rotator die process  
c) both a & b    
d) none of above
8-  The hard Galeton capsule are produced by mechanical dipping of _______ of desire able shape and diameter.

a) pins    
b) pegs     
c) both a & b      
d) none of above
9-  Hard Galeton capsule contain ______ of moisture.

a) 9-12%  
b) 15-18%  
c) 12-15%      
d) none of above
10-  Capsule are should be stored at ____ and ____ humidity level.

a) dry , low   
b) dry , high   
c) cool , high   
d) cool , low
11-  Examples  of drug dispensed in soft Galeton capsule are ¬¬¬¬¬_______.

a) volatile drug  
b) liquid , suspension , powders e.t.c    
c) vitamin E , digoxin e.t.c   
d) all of above
Answers to Multiple Choice Questions (MCQs) from Capsules in Pharmaceutics
•    1- b
•    2- d
•    3- b
•    4- c
•    5- c
•    6- d
•    7- c
•    8- c
•    9- a
•    10- d
•    11- c

(These MCQs are helpful for the preparation of Pharmacy Exams)
Further Reading:

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