INTRODUCTION TO PHARMACEUTICAL CAPSULES:
Pharmaceutical Capsule is a versatile form of an oral solid dosage (second most popular after Tablet), which is easily consumable by humans. History indicates that capsule are invented to overcome the limitations and discomfort cased by the pharmaceutical tablets viz.
# Capsule shell can contain multiple or more than one forms of drugs including powder, granules, pellets etc, whereas, a Tablet is a solid form of a medicine.
# Capsules can act faster, as the outer shell simply dissolves in the digestive track and the medication or the active ingredients inside gets absorbed in the blood stream faster as compared to Tablets.
# Tablets can have flavored coatings, which can go away while consumption and thus can leave bad taste in mouth, whereas, capsules are tasteless.
# Some of the drugs (which are meant to be consumed orally) cannot be effectively made in the form of a Tablet, hence Capsule is the only available option for them.
TYPES AND SIZES OF CAPSULES:
Pharmaceutical Capsules are found to be of two types viz. Hard Gelatin (or Cellulose shell) Capsules and Softgel Capsules. The manufacturing process for Hard and Softgel are different, as their use is different. While Hard capsules can be used to fill drugs and active ingredients in the form of powder, pellets, tablets etc, the Softgel capsules are meant for carrying the appropriate dose of drugs and active ingredients in the form of a liquid inside.
In this post, we will focus on the Hard Gelatin capsules, which are manufactured in two parts viz body shell and cap. Later, with the help of encapsulation machine, the drugs are filled inside the capsule body and the cap is fitted back on the body shell thus sealing the drug inside.
Hard Gelatin Capsules used in Pharma Industry can be classified as under:
# Size 000: Average weight is 163 mg, with a tolerance of +/- 11 mg, and the gross volume is 1.37 ml
# Size 00: Average weight is 118 mg, with a tolerance of +/- 7 mg, and the gross volume is 0.91 ml
# Size 0: Average weight is 95 mg, with a tolerance of +/- 6 mg, and the gross volume is 0.68 ml
# Size 1: Average weight is 75 mg, with a tolerance of +/- 6 mg, and the gross volume is 0.5 ml
# Size 2: Average weight is 60 mg, with a tolerance of +/- 4 mg, and the gross volume is 0.37 ml
# Size 3: Average weight is 47 mg, with a tolerance of +/- 3 mg, and the gross volume is 0.3 ml
# Size 4: Average weight is 38 mg, with a tolerance of +/- 3 mg, and the gross volume is 0.21 ml
INTRODUCTION TO ENCAPSULATION (CAPSULE FILLING MACHINES):
Capsule filling machines can be classified as Manual, Automatic and Semi Automatic.
Encapsulation process overall essentially requires multiple action such as separating the cap from the body of the empty capsules, forming the proper and accurate slug of the feed (powder), feeding the slug in the capsule body, sealing the body with cap again and then de-dusting and cleaning if needed.
Based on the level of automation, the machine falls under either of these three categories.
MANUAL CAPSULE FILLING MACHINE:
A Manual Or Hand Operated Capsule filling machine is basically a made up of a punch type Stainless Steel structure. The capsule holding plate is made in two pars with concentric holes. Usually 300 holes machine is found to be the most common one. The 300 holes are machined in both these plates in the form of an array of 25 X 12.
The empty hard gelatin capsules are then fed to theses plates vertically and manually (such that one capsule occupies one hole). While feeding the capsules, one has to ensure that the capsule's body is facing ground and the cap is facing the sky.
A manual lever is applied, which pushes the top plate up and a gap is created between top and bottom plate. Now, the concentric holes between both these plates have a slightly different diameters. The low plate has a smaller diameter (same as the capsule body diameter), hence, the capsule bodies are held back by the lower plate, whereas, the top part of the capsule (cap) are taken away by the top plate during the lever action. The holes in the top plates are slightly bigger (same as the diameter of the cap of the capsule).
Once the top plate (with capsule caps) is removed manually, the actual powder feed is added or poured on the bottom plate and the powder is allowed to get inside and fill the capsule body. The operator manually (with the help of a metal plate) pushes and spreads the powder to get deposited in each capsule evenly and equally.
The main frame (where the bottom plate sits) has a hinged foldable arm which has an equal size plate at the end with pins on it. The utility of this arm with pinned plate is to push the material fed in the capsule bodies to get properly fed inside (and to fill the volume uniformly).
This hinged arm is then lifted again and the top plate (carrying capsule caps) is kept back on the filled capsule bodies for reunion. In order to ensure that both plates exactly coincides, there are guide-pins provided on the top plate that properly fits the bottom plates, hence, each capsule cap properly coincides with the respective capsule body.
In order to achieve the reunion of each capsule, the bottom frame is provided with one more hinged arm with a foldable plate. This plate when exercised, pushed the caps gently on the body and the telescopic nature of the cap and body ensure the capsules are sealed.
The foldable hinged plate is then lifted and once again the top plate is lifted with full capsules (body + cap + fed ingredients).
(Pic Ref: www dot jicon dot com)
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