Pharmaceutical Processes and Techniques
Construction
The body of a double cone mixer consists of two cone-shaped sections joined to a central section. The rotational axis is perpendicular to the cone axis and passes through the central section. The blender body is held by two lateral supports, one of which is fitted with the driving motor.
Working
The double cone blender is attached to the two lateral supports to prevent movement of the mixture. The materials are then loaded, and the lid of the blender is closed. The equipment is then switched on, and the blenders start rotating in three directions: clockwise, anti-clockwise, and straight. After the blending process is complete, the lid of the blender is opened, and the materials are easily discharged.
Uses
- Preparation of different products in various industries, such as pharmaceutical, chemical, and cosmetic products.
- Uniform mixing of granules or dry powders.
- Homogeneous mixing of solid-solid particles of small amounts of powders.
Maceration
In this process, solid ingredients are placed in a stoppered container with the solvent and allowed to stand for at least 3 to 7 days with frequent agitation until the soluble matter is dissolved. The mixture is then filtered, and the clarified liquid is obtained. An example is the extraction of orange peel.
Percolation
Percolation is a continuous downward displacement of solvent through a bed of crude drug to obtain an extract. In this process, the extract used is the crude drug to separate the active constituents present in the ingredient.
Classification of Powders According to IP
Pharmaceutical powders have been characterized by IP according to the size of the sieve through which they can pass. The following powders can be specified according to IP:
Coarse Powders
All particles of this powder can pass through a sieve number 10 with a mesh size of 1700 μm, but not more than 40% of the powders by weight must pass through a sieve number 44 with a mesh size of 355 μm.
Moderately Coarse Powders
All particles of this powder will pass through a sieve number 22 with a mesh size of 710 μm.
Moderately Fine Powders
All particles of this powder pass through a sieve number 44 with a mesh size of 355 μm.
Fine Powders
All particles of this powder pass through a sieve number 85 with a mesh size of 180 μm.
Very Fine Powders
All particles of this powder pass through a sieve number 120 with a mesh size of 125 μm.
Micro Fine Powders
All particles of this powder pass through a sieve number 350 with a mesh size of 75 μm.
Working
The drug is put into the cylinder of the mill and rotated. The speed of rotation is crucial. At low speeds, the balls will slide or roll over each other, resulting in negligible size reduction. At high speeds, the balls will be thrown out to the walls, and no grinding will occur. However, at about 2-3 of the speed of the ball mill, the balls are carried almost to the top of the mill and then fall in, resulting in maximum size reduction. The product is then collected.
Dye Test
The red dye is mixed with an emulsion. A drop of the emulsion is placed on a microscopic slide and covered with a cover slip. It is then examined under a microscope. If the dispersed globule appears red and the background is colorless, the emulsion is an oil-in-water emulsion. The reverse condition occurs in water-in-oil emulsions, where the dispersed globule appears colorless, and the background is red.
Conductivity Test
Water is a good conductor of electricity, whereas oil is a non-conductor. The conductivity test can be performed by dipping a pair of electrodes connected through a low-voltage bulb into the emulsion. If the bulb glows when the electric current is passed, the emulsion is an oil-in-water type. If the bulb does not glow, it is a water-in-oil type of emulsion.
Types of Suspensions
There are two types of suspensions:
- Deflocculated suspension
- Flocculated suspension
Flocculated Suspension
Flocculated suspensions are those in which the particles are loosely held together in small clusters or flocks.
Deflocculated Suspension
Deflocculated suspensions are those in which the particles are dispersed uniformly throughout the liquid.
Difference Between Deflocculated and Flocculated Suspensions
Flocculated Suspension
- Particles have undergone flocculation.
- High rate of sedimentation.
- Consists of loosely packed particles that form a hard, dense cake that cannot be easily redispersed.
- Sediment is rapidly formed.
Deflocculated Suspension
- No flocculation takes place.
- Low rate of sedimentation.
- Sediment becomes very closely packed to the liquid particles, which can be easily redispersed.
- Sediment is slowly formed.
Dry Granulation Method
Suitable for drugs that are sensitive to moisture and heat.
Wet Granulation Method
Suitable for drugs that are stable to moisture and heat.
Evaluation of Tablets
General appearance, weight variation, solubility, disintegration, dissolution test, hardness, friability
Capsules– capsules are the solid dosage form in which the drug substances is enclosed in a gelatin shell. The capsules are available in hard as well as soft gelatin capsule.
Difference between hard and soft gelatin capsule
Hard gelatin capsule
The heart gelatin capsule cell consists of two parts body and cap.
They are cylindrical in shape.
the contents of hard gelatin capsule usually contain the medicament or mixture of medicament in form of powders or granules.
Hard gelatin capsule gets sealed after the drug get enclosed so that the drug should not come out from the capsule.
Soft gelatin capsule
The soft gelatin capsule shell becomes a single unit after sealing the two halves of capsule.
They are available in round and oval shape.
The contents of soft gelatin capsule usually consist of liquid or paste like consistency.
Filling and sealing of capsules are done with the help of machines.