Powder and Granules, what do you mean by Powder and Granules?

Definition of Powder

Powders, which are finely divided solids, offer versatility in industry and everyday life through easy integration with solvents such as water, facilitating a variety of applications such as pharmaceutical formulations and industrial processes, while being tailored to specific needs and requirements. can be adjusted. This improves human health, comfort and productivity.

Powder, often understood as a finely divided solid substance, has many uses in industry and everyday life. Its versatility lies in the fact that it is easily mixed with suitable solvents such as water or liquids, making it easy to apply in a variety of forms and functions. For example, imagine a powdered drug, a common scenario in the pharmaceutical industry. This powdered drug can be dissolved in a suitable solvent, such as water, to form an orally administrable solution. Alternatively, the powder can be applied topically and used as a powder to treat skin conditions or wounds.

Additionally, the composition of the powder can be made individually depending on each need. Diluents are often added to pharmaceuticals to adjust the density and properties of the powder. For example, liquids contain small amounts of methyl paraben and propyl paraben, typically in a 2 to 3:1 ratio, which is about 0.05% to 0.10% of the total mixture. This combination is classified by the FDA as “generally recognized as safe” (GRAS) for food preservation, ensuring both effectiveness and safety of the final product.

The classification of powders goes beyond their composition to include a variety of uses. For example, powders can be classified according to their use, such as pharmaceutical powders for medical use, cosmetic powders for beauty products, and industrial powders for manufacturing processes. Each classification may have specific requirements and regulations that apply to production and use.

In essence, the definition of Powder goes beyond a simple physical state and embodies a realm of possibility where careful composition and application can lead to innovations that improve human health, comfort, and productivity.

Classification of Powder on the basis of use.

Internal Use Bulk Powder
External Use Bulk Powder
Unit dose or Divided Dose Powder

Internal Use Bulk Powder

The finely divided chemicals or drugs in dry form can be used in internal purpose [Oral Power]

Classifications:

Dry powder inhalers
Effervescent powders
Oral powder
Powder spray

External Use Bulk Powder

The finely divided chemicals or drugs in dry form can be used in External purpose [Dusting Powder] and available in multiple doses[Dusting Powder]

Classification:

Dentifrices
Dusting powders
Insufflations

Unit dose or Divided Dose Powder

The finely divided chemicals or drugs in dry form can be used in internal purpose [Oral Power] but the individual doses are separately wrapped.

Classification

Powder for injection
Effervescent powders
Douche powders

Classification of Powders based on size

Powder can be divided into several categories based on its size.

Macroscopic Powder
Microscopic Powder
Submicron Powder
Nano Powder
Ultrafine Powder

Macroscopic Powder:

These powders have particle sizes ranging from 10 μm (micrometers) to 1000 μm. They are usually visible to the naked eye and are often used in applications where physical properties are important, such as tablet or granule production.

Microscopic Powder:

The particle size of this powder varies from 0.1μm to 10μm. They are invisible to the naked eye and are widely used in pharmaceutical, cosmetics and other industries where fine particles are needed for specific properties.

Submicron Powder:

The particle size of this powder is 0.01μm to 0.1μm. They are very fine and are used in advanced materials, nanotechnology and some medical applications where precise control of particle size is essential.

Nano powder:

This powder has a particle size of less than 100 nanometers (0.1 μm). They exhibit unique properties due to their small size and high surface-to-volume ratio and have applications in fields such as electronics, catalysis, and drug delivery.

Ultrafine Powder:

These powders have particle sizes ranging from 1μm to 100μm, which are finer than macroscopic powders but larger than fine and submicron powders. They are used in a variety of industries including paint, varnish and additive industries.

Classifying powders based on size is important because it affects the properties, behavior, and uses of the powder. Different particle sizes can lead to changes in fluidity, compressibility, surface area and reactivity, among other things. Therefore, understanding and controlling particle size distribution is important in many industries to achieve desired performance and effectiveness.

Mixing of Powders

The use of double tapping technology is essential for accurate mixing of powder ingredients, especially in pharmaceutical manufacturing where precise dosing is important. Known in the pharmaceutical industry for the efficiency of geometric dilution, this technique ensures uniform distribution of ingredients in the mixture.

The process begins with carefully measuring the smallest powdered substances and placing them in a mortar. Then more powder is added to the mortar in equal amounts. After mixing the two ingredients, rub the mixture vigorously until you have a uniform mixture. This rigorous mixing process ensures that each particle of the small ingredient is distributed evenly into the larger mass, preventing potential concentration gradients or uneven dosing.

One of the key principles of geometric dilution is the concept of incremental addition. As the mixing process progresses, each time you add more powder, you actually double the amount of material in the mortar. This incremental concentration ensures consistency and uniformity of the final product by ensuring small ingredients are fully incorporated into the overall mixture.

A practical example of the application of this technology is the development of effective drugs, especially those containing hormonal components. These preparations require precise doses of the active ingredient, which is usually present in small quantities. By using geometric liquids via double tapping technology, pharmaceutical manufacturers can ensure that these powerful compounds are evenly distributed throughout the formulation, reducing the risk of dosage variation and ensuring the safety and efficacy of the final product.

Process Steps

To facilitate homogenization and to prevent stratification the particle size has to be reduced. The process steps is depicted here-

Sieving
Weighing of each ingredient
Mixing
Packaging

General method for preparation of bulk Powders: Geometric dilution

Firstly weigh the Smallest Volume[Powder X] and place into a mortar
Secondly weigh the Large Volume[Powder Y] and place into a separate labeled container
Add the same amount of Powder Y as of same amount of Powder X into the mortar
Use pestle to mix well
Now add the same amount of “Powder Y” as the same amount of Powder as of Mortar then mix with Pestle, continue this process. Every time the powder quantity will be double compare to previous quantity in mortar.

General method for preparation of Divided Powders

Weigh the Active ingredients and diluent accurately.
Arrange trituration of two powers separately before mixing.
The mix the two ingredients with spatulation method.
Place the powders in a surface ensure they are in proper quantity using block and divide method.
Arrange dividing the quantity as per requirement.
Wrap them into individual paper.
Place them into individual container and
Finally label the container.

To dilute the active ingredients of the powder, generally lactose is used to produce the required quantity due to Lactose is colorless, odorless, soluble and also harmless can easily maintain the flow property. The patient who are susceptible to Lactose then Light Kaolin may be used.

Powder calculations

If you are dealing with Powder calculation, you have to calculate at least 1% extra powder to compensate loss during compounding.Always try to take minimum quantity of active ingredients compare to dilution, then minimum weighable quantity is diluted several times.

Advantages of Powders

Powder is more stable compare to liquid dosage form
Very much useful for multiple dosage of single product
Helpful for children and senior citizen
Ensure first rate of bioavailability due to small particle size

Disadvantages of Powders

Unstable in atmospheric conditions
Uniformity dosage failure occur frequently
Not suitable for carry out from here and there.

Shelf life and storage of Internal Powders

Internal powders shelf life is 14 to 30 days
Due to protective packaging proprietary power have longer shelf life
Powder should be store in moisture proof and airtight area.

Shelf life and storage of External Powders

External powders shelf life is 30 days.
If ensure proper packaging then dry power remain stable in longer period of time.
Must be store in a cool and dry place.

Containers for Internal Powders

If powders are prepare extemporaneously then then wrapped powders are often dispensed in paperboard box.
An air tight container is preferable to store internal powder to protect from moisture.
Almost all bulk powders are packed in airtight container.

Containers for External Powders

Glass, metal or plastic containers can be used for storage of external powders. For packaging of propellant and lubricants, pressurized containers are commercially available to ensure proper safety and security.

Labels and advice for Internal Powders

Mix with suitable solvent or supplied solvent if comes with powder container itself otherwise mix indicated amount of water slowly in a divided portion and shake upon addition of divided amount. Don’t add all indicated amount of solvent at a time. Add it gradually in several portion. Bulk powder must be dilute and measure carefully. Bulk powder use for babies can be placed into mouth with a drink

Labels and advice for External Powders

For external use only.
Store in cool and dry place.
Protect from direct sunlight

Uses of Powders

The powder is uses for the following cases-
Used as counter-irritant e.g camphor starch dusting powder.
Used as antimicrobial e.g. Chlorhexidine dusting powder.
Used as antipyretic e.g. ipecacuanha and opium[Dover’s Powder]
Treatment of antacid and anti-flatulent e.g. Magnesium trisilicate
Used as antiseptics i. g. 5% of Povidone-Iodine Powder[Betadine Powder]
Treatment of juvenile arthritis i.e. Ibuprofen powder
Aluminium free baking powder e.g. Rumford
Widely use in Cosmetics and Face Powders
To relief skin burn e.g. prickly heat powders
Protect skin and nappy rashes e.g. Baby powders
Used in dyspepsia e.g. Rhubarb powder

Granules:

Granules are produced by the agglomeration of minute particle produce large free flowing particles. The particle range vary between 4 and 10 mesh size. Most of them are irregular shape but need to produce spherical shape. Granules are the intermediate form of Tablets and Capsules.

What’s the advantage of Granules over Powder?

To avoid powder separation.
To increase the flow of powder.
To increase higher porosity.
To increase the compressibility of powder.
The materials having lightly hygroscopic tendency may adhere and form cake if store in powder form.

Classification of Granules

Granules are classified into following Categories

Coated granules
Effervescent granules
Gastro-resistant granules
Modified release granules

Coated Granules

The granules are undergone single or multilayer coating process with the help of various types of excipient form coated granules use in multi dose preparations. The materials which are used to coat the granules are firstly made solutions or suspensions with suitable solvent may be Organic[Isopropyl Alcohol/Methanol/Metethelene Chloride or Inorganic[Water]. Solvents are generally evaporate during coating process.

Effervescent Granules

The uncoated granules, generally contains acid substances and hydrogen carbonate or carbonate which react instantly with water upon addition with it and release carbon-dioxide. The granules must be dispersed or dissolved with water before administration.

Gastro resistant Granules

The granules that are intended to resist the gastric fluid and release the active ingredients in intestinal fluid well known as delayed release granules. The gastro resistant properties are just attain by coating of suitable materials[Polymer Like-Hydroxypropyl methylcellulose phthalate/vinyl acetate phthalate/Cellulose acetate trimellitate/esters of aleurtic acid/Cellulose acetate phthalate etc.]

Modified release Granules

The granules contains special type of excipients or that is prepared with special procedure are both involved, and designed to altered the rate, the place or time at which the active ingredient release. The modified release granules are two types as Delayed release granules and Prolonged release granules.

Granules preparation Methods

All of the granules are made of mainly in two method

Dry Granulation Method
Wet Granulation Method

Dry Granulation Method

Dry Granulation methods are performed in two ways-

Roller Compactor
Slugging

Roller Compactor:

The dry powder passed through roller compactor then a granulating machine. A Roller compactor is also familiar as roll press, roll compactor use to process fine powder to dense sheet form by forcefully passing through two heavy rotating metal roll running counter to each other.

To attain different forms and textures the surface of the compacting rolls may contain corrugations or pocket indentation and surface of roller compactor may be smooth to do the same. The compacted powder further granulated in a mechanical granulator to get uniform particle.

Slugging

During slugging process the pressure may be difference between 8,000 to 12,000 lb to form large tablets based on the physical characteristics of powder form. The produced slug may be in flat faced in 1 inch diameter.

The resulted slugs are granulated to produce desired particle size used to produce tablets and capsule. During dry granulation, some fine particles are produced that is not agglomerated, the fines particle are collected, separated finally reprocessed.

Wet Granulation Method

In the wet granulation method the, paste prepared by moisten the powder or powder mixture then the paste passed through the specific screen of mesh size and produced desired size of granules. Granules are then placed on tray for drying and dried it by heat or air. The granules are periodically moves on the drying tray to avoid adhesion to outsized mass.

The other type of wet granulation method is known as fluid bed granulation processing (also known as agglomeration) where particles are placed on conical shape of equipment and liquid excipient spray on the particle in vigorously dispersed and suspended conditions then the product dried to form pellets of defined granules size.

How to prepare Effervescent Granules?

Here two methods followed-

Fusion method
Wet Granulation method

Fusion Method

The method, where equivalent molecule of Water and Citric Acid present[One Molecule of water in each molecule of Citric Acid] act as binding agent for Powder. First of all the Citric Acid Crystals are made powder then this powder mixed with other powder. Same sieve size to be ensure to get uniform powder mixture. The mixing equipment’s and the sieves are made of stainless steel to avoid effect of the acid

To avoid premature chemical reaction and absorption of moisture the mixing of powder performed rapidly in a low humidity area. Then the powder mixer transfer a suitable dish in an oven which temperature between 34°C to 40°C. Use heat resistant spatula to turn the powder. During this process, the heat release water of crystallization from Citric Acid which dissolve a portion of this power mixture and initiate chemical reaction produce Carbon Dioxide cause the soften of powder mass. Then the powder become to extend spongy and this spongy powder then rubbed through a sieve to produce desired size granules.

Various size of sieves are available in the market produce different size of granules e.g. No. 4 sieves use to produce large granules, No. 8 sieves use to produce medium size granules and No. 10 sieves use to produce small granules. To get best result during storage the granules are dried below 54°C and rapidly placed in container just after drying and tightly sealed.

Wet Granulation Method:

The wet granulation method is different from that of the fusion granulation method as water didn’t come from crystal stage of materials and additionally water to be added moisten the granules. Here all materials remains anhydrous until addition of water. After addition of water the prepared mass are then dried to prepare desired granules.

Shelf life and storage:

The Shelf life of the granules is 2-3 weeks. Granules should be stored in double layer polybag in airtight containers, add silica gel pouch outside the container to get proper result. Must be stored in cool and dry place and protect from direct sunlight.

In this way Powder and Granules are very essential to our day to day life. Powder and granules are consider the important part of pharmaceutical preparations. Special precaution may requires during manufacturing of powder and granules. This is all about the short brief description about Powder and Granules.