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Pharmaceutics

Tablet dosage forms- Properties and types

What is tablet dosage forms?

Tablets are solid dosage forms containing active pharmaceutical ingredients and excipients. Tablets are solid, circular, flat, and convex. Tablet dosage forms contain a quantity of a drug given as a single unit, and they are known collectively as solid unit dosage forms. 

Even in the case of sustained action preparation, which technically contains the equivalent of several regular doses of a drug. 

They vary in shape and differ significantly in size and weight, depending on the amount of medicinal substances and the intended mode of administration.

Tablets- Advantages and Disadvantages

   Advantages

  • · Tablet is a tamperproof dosage form
  • · It is a conventional unit dosage from 
  • · It having an economical cost
  • · Suitable for large scale production
  • · Tablets are more advantages because having optimum portability, required minimum storage space

Disadvantages

  • · Those drugs having poor wetting as well as slow dissolution.
  • · Bitter tasting, an objectionable odor of drugs 
  • · Some drugs having amorphous nature or flocculent having compression problem

Properties of Tablet Dosage Forms

PILLS
  • The tablet should be elegant, free from cracks, contamination, discoloration, etc.
  • · It must be release active pharmaceutical ingredient in the body in an obvious way
  • · It should have proper mechanical strength, does not fragile during transportation
  • · Does not alter or change any physical and chemical properties under any environmental condition
  • · It must have suitable chemical stability over a period of time.

Different Types of Compressed Tablet

1.   Tablets ingested orally – 

Compressed tablet– 
Person Holding Medicines

A compressed tablet, which is an uncoated tablet, contains API with pharmaceutical ingredients like diluents, binder, disintegrant, glidant, colorant, etc. 

Compressed tablets are prepared by using compression. 

Different types of methods used in the preparation of tablet, such as:  

  • Wet granulation
  • Dry granulation
  • Direct compression

Example: Paracetamol (1)

  • Multi-compressed tablet– 
    • There are two types layered tablets and compressed tablets. 
    • Both types can be either two-component or three-component systems. 
    • A multi-compressed tablet is usually prepared: to separate physically or chemically incompatible ingredients and prolonged action products. 
tablet dosage forms

Sugar coated tablet– 

  • o For test masking the bitterness of a pill, sugar coating is the most conventional way. In these processes, a sugar solution is applied to the tablet. 
  • o Different capacity pans are used for the process at an angle of 400. The most skillful laborers are used for the processing of coating. 
  • o Sugar coating is a cheap, safe patient compliance process, but it is also time-consuming and contains a high weight-gain process because of the increase in the packaging and shipping.
  • The following steps are used for the sugar coating 
    • Ø Seal coating
    • Ø Sub-coating
    • Ø Grossing/smoothing
    • Ø Coloring
    • Ø Polishing/finishing
    • Ø Printing

·        Film-coated tablet– 

  • o It is the modern technique for tablet coating in this method. Tablets are coated with a too-small layer of polymeric material. 
  • o Film coating is a single-step process in which polymeric material is sprayed on a tablet with the continuous rotation of the tablet. After coating, the tablet is dried to remove the deposited solvent. 
  • o The following raw materials are used for the film coating:
  •  Ø Polymers
  • Ø Solvents
  • Ø Plasticizers 
  • Ø Colorants

 o  Chewable tablet:-

o Tablets, which are place in the mouth and chewed, known as chewable tablets, these tablets contain a large amount of additives and excipients such as 

  • § Diluents, 
  • § Disintegrants, 
  • § Binder And Adhesive, 
  • § Lubricant, 
  • § Glidants, 
  • § Colouring Agent,
  • § Flavouring and Sweetening Agent. 

·           Delayed-release tablet or enteric-coated tablet– 

  • o Released in the small intestine. 
  • o The coating of this tablet is insoluble in low pH and easily soluble in high pH. 
  • o Enteric-coated tablets are useful to protect gastric stress optimal absorption and can be easily acted on the intestine by providing delayed-release.

2.   Tablet used in the oral cavity 

tablet
  • Buccal tablet– kept in the buccal cavity. They release their drug for absorption directly through the oral mucosa. Buccal tablets avoid the first-pass metabolism. 
  • ·           Sublingual tablet- kept below the tongue and released slowly. For the secretion of saliva, this tablet is formulated with bland excipients. If salivation increases, the drug may be swallowed and not absorbed from the cavity.
  • ·        Lozenges– are intended for local action in the mouth or throat. This is preferred in antiseptic, antibacterial, local anesthetics, astringent, and antitussive. Lozenges do not contain a disintegration agent. It dissolves slowly in the mouth. 
  • ·        Dental cone – to fill vacant space after tooth extraction, dental cones are useful in preventing bacterial growth during tooth extraction. It is helpful in slowly releasing the drug in the presence of a small amount of serum.

3.      tablet dosage forms administered by another route

tablet dosage forms
  • Vaginal tablet– These tablets have slow dissolution and drug release rate in the cavity of the vagina. Vaginal tablets are ovoid or pear-shaped. It is used for vaginal infection. 
  • Implantation tablet– also called depot tablets. The main motive of implants tablet is prolonged drug release, ranging from months to year—usually small disc-like shape not more than 8mm in length.

4. tablet dosage forms used to prepare a solution

·        Effervescent tablet– 

  • o It contains tartaric acid, citric acid, and sodium bicarbonate to give effervescence of carbon dioxide in the presence of water. 
  • o When an effervescent tablet is added to the water, a chemical reaction is started between acids and the sodium bicarbonate to form the sodium salt of the acid and produce carbon dioxide and water. 
  • o This reaction is relatively fast and completed within one minute.

·        Dispensing tablet– 

  • o It cannot be used on a routine basis with water. 
  • o Dispensing tablets are intended to be added to a given volume of water by a pharmacist to produce desired concentration. 
  • o Silver proteinate, bichloride of mercury, and quaternary ammonium compounds are added in mild quantity. 
  • o Mostly soluble components are added for better effects. 

·        Tablet triturates– 

  • o Used to increase bulk, it mixed with inert substances. 
  • o To increase the bulkiness of the potent drug is added with lactose or acacia. Mainly used for potent drugs. 
  • o Tablet triturates are usually soft and friable.
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Pharmaceutics

Rubber as a material for seals and closures

Rubbers are an excellent material for forming seals and closures. A closure is a part of the package used for closing the packaging material of the pharmaceuticals. They are substances that prevent the loss of product and help in prohibiting the entry of any foreign particle into the container. 

 rubber closure

There are two types of rubbers:

  1. Natural rubber: These are derived from naturally occurring sources. They are suitable for multiple use closures. But, natural rubber cannot be easily autoclaved as it becomes brittle. It also carries a risk of absorption of rubber into the products.
  • Synthetic rubber: These are artificial elastomers and are mainly synthesized from petroleum products. They undergo lesser absorption due to fewer additives in it. Some examples of synthetic rubber include silicone, butyl, Bromo butyl, chloro-butyl, etc.

Some popular types of rubbers used for manufacturing closures are:

Butyl rubber: It is a copolymer of isobutylene with 1-3% of isoprene or butadiene. It has low water absorption and air permeability. It is relatively cheaper than other synthetic rubbers. But, it does not have good oil and solvent resistance.

Neoprene: These are chloroprene rubber and are polymers of 1:4 chloroprene. It has good heat stability and less air and water vapor permeable.

Silicone rubber: They have high heat resistance (up to 2500°C). They have extremely low permeability and absorption of water. Due to their saturated chemical structure, they have excellent aging characteristics. But they are costly.

Read More:

As you are aware Pharmaceutical products are highly susceptible to degradation. The quality of the pharmaceutical products directly affects their response and effectiveness. Therefore it is essential to ensure that the packaging of the material is suitable. Read more: Containers: Desirable features and types

Pharmaceutical containers are made up of different types of materials. Know about Materials for containers: their merits and demerits

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Pharmaceutics

Containers: Desirable features and types

Pharmaceuticals are highly susceptible to degradation, and the quality of the pharmaceutical products directly affects their response and effectiveness. Therefore it is essential to ensure that the packaging of the material is suitable. Containers are used to store various types of Pharmaceutical products with or without physically contacting the product.

Jar, Pills, Medicine, Bottle, Medication

Pharmaceuticals packaging is vital as it provides protection, helps in identification, improves the convenience in transporting, and provides information about the content without physically interfering with the product itself.

There are many desirable properties of a container:

1) It should protect the contents from mechanical damage :

  • Every pharmaceutical product is susceptible to a mechanical hazard. A product may get damaged due to shaking during transportation (generally while transporting via land due to trucks or other vehicles).
  • Therefore containers should protect the contents from this type of vibration.
  • A container should also be capable of bearing the pressure and compressions applied to the pharmaceuticals during the handling of the contents during transportation.
  • It should be shockproof and protect from abrasions that may cause damage the product due to electrostatic damage to the materials. Also, a container should protect the contents from piercing caused by sharp objects.

2) It should protect the contents from damages caused by the environment:

  • Various environmental factors affect the quality and efficiency of Pharmaceuticals. Variability in temperatures is a major cause of damage to different pharmaceutical products.
  • A container should help maintain the temperature and not cause any increase or decrease the temperature under any conditions.
  • It should withstand high levels of humidity so that the packaging remains intact and keeps protecting the content from damage due to humidity.
  • The containers should be able to protect against particular contamination.
  • Some contents are photosensitive and get degraded on exposure to light. Special containers should be prepared for such kind of products.
  • Some products, generally of organic origin, are susceptible to microbial degradation. A container should protect the contents from microbial attacks.

3) Should be elegant and appealing:

  • Apart from the packaging material’s characteristics, the container should also have an aesthetic touch to it.
  • A more elegant look of a product makes it last more impression on the customer.
  • The pharmaceutical market is very competitive, and therefore, the product’s appearance makes the first impression on the customer before the contents. Also, it should be more feasible for the customer to handle.
  • It should be properly labeled and should provide sufficient information. An ideal container should be inert towards the material stored in it. It should withstand temperature and humidity changes. It should not chemically or physically interact with the product.
  • A container should provide stability to the contents. It should be non-toxic and should withstand wear and tear against environmental damages and general handling.

Types of containers

Containers can be classified into the following types based on their utility:

1. Airtight containers

These containers prevent the contents from dust, moisture, and air. These are also called hermetic containers. Airtight containers have air-tight sealing or closing, preventing moisture entry in the packaging. These types are commonly used for materials prone to degradation in contact with air or moisture.

2. Light resistant containers

Some materials are light sensitive. They lose their characteristics on exposure to sunlight. Such types of materials are kept in light-resistant containers. They protect the contents from direct exposure to light. Many medicines are photosensitive and are stored in light-sensitive containers.

3. Multi-dose containers

These containers are used to allow the withdrawal of multiple doses from the same container without affecting the quality, purity, or strength of the pharmaceutical dosage. Such types of containers often contain multiple doses of the product. These are generally used for injectables.

4. Single-dose containers

These are particular types of containers used for storing a single dose of the product. Parenteral products are generally stored in these types of containers. E.g., ampoules.

5. Well closed containers

These are the common types of containers to hold the products efficiently and in a well-closed environment. They protect the contents from loss during transportation, storage, handling, and sale.

6. Aerosol containers

Aerosol containers are used to store aerosols. They are made up of suitable materials to withstand the pressure required to contain aerosols.

7. Child-proof containers

These containers are used to protect the children from hampering the contents. Sometimes, the products are harmful to the children and can cause a hazardous effect. To protect such products, they are fitted with closures, besides it also protects children from accessing hazardous medicines.

Reference:

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Pharmaceutics

Materials for containers: their merits and demerits

Pharmaceuticals packaging is vital as it provides protection, helps identify, improves the convenience in transporting, and provides information about the content without physically interfering with the product itself. Pharmaceutical containers are made up of different types of materials. The containers are made from the following types of materials: Plastic, glass, and metal.

1. Plastic Material

Plastics are synthetic polymers having high molecular weight. Plastic containers are commonly used in the packaging of Pharmaceuticals.

Jar, Pills, Medicine, Bottle, Medication

There are mainly two types of plastics: Thermoplastics and thermosets.

  1. Thermoplastics: These are the types of plastics that have the property of changing their shape on heating and solidifying on cooling. They are resistant to breakage and can be produced at low costs. They are mostly used for packing large volumes of sterile materials like ophthalmic or parenteral solutions.

Eg.- polystyrene, PVC, polyethylene, polypropylene, acrylic, etc.

  • Thermosets: These are plastics that have the ability to retain their shape permanently on heating. They are rigid and do not break easily. They lose their ability to change shape, because on heating they form cross-linking between linear chains, resulting in solidification.

Eg.- Melamine, epoxy resins, polyester, etc.

Plastics are generally made up of the following main types:

  1. Polyethylene: It is a light, flexible, but tough plastic. It is resistant to chemicals and does not allow water vapors to penetrate inside. It can be sterilized by autoclaving. It is generally used for packing parenteral doses and ophthalmic preparations.
  2. PVC: Its full form is Poly Vinyl Chloride. It is heavier, less flexible ad more permeable to water vapors, but has high clarity and unaffected by sunlight. Intravenous bags are made up of PVC. Various eye ointments and tubes are packed using PVC.
  3. Polystyrene: It is used for its versatility and durability. It can be easily modified into various shapes. Syringes, bottles, cream boxes and jars are made up of polystyrene.
  4. PMMA: Poly Methyl acrylate is a light, transparent material, but is hard and strong. It is used for preparing tubes and bottles.
Merits of plastics
  • – Plastics are lightweight and durable. 
  • – They are extremely resistant to breakage. 
  • – They can be easily molded into a variety of shapes and sizes. 
  • – They are resistant to inorganic chemicals. 
  • – They can be transported easily.
Demerits
  • – Plastics are relatively expensive.
  • – They may absorb the chemical substance.
  • – They can chemically interact with contents.
  • – They are permeable to water vapor.

2. Glass Material

glass Materials for containers

Glass is a widely used material for the packaging of Pharmaceuticals. Many pharmaceutical products are used for oral and local administration. Glass bottles are usually the first packaging choice.

Glass is basically made up of silicon dioxide with altered physicochemical properties obtained by adding oxides of sodium, magnesium, and iron. There are three types of glass:
i. Type I – borosilicate glass: It is also called neutral glass. It is a highly inert type of glass and has a high melting point.
ii. Type II – treated soda-lime glass: These are made by de-alkalizing. They are used to store alkali susceptible materials.
iii. Type III – regular soda-lime glass: These are untreated regular soda-lime glass containing high amounts of alkaline oxides. They are used to store solid dosage forms.

Merits of Glass Containers 
  • – They are economical and easily available.
  • – They do not degrade with age.
  • – Have the ability to protect photosensitive pharmaceuticals from light.
  • – Available in various shapes and sizes.
  • – Do not change shape on exposure to a varied range of temperatures and maintains the temperature for a long period of time.
Demerits of Glass Containers
  • – Glass is brittle and can break easily.
  • – Can develop cracks on experiencing sudden temperature changes.
  • – It is relatively heavy than plastic.

3. Metal Material
Mainly three metals are used for making containers using metals: Aluminum, Tin, and Lead.

metal containers

Lead is poisonous and is therefore seldom used for selective purposes. Tin is the most inert material for packaging but is very costly. Aluminum is more reactive than tin but is cheap and readily available.

Reference:

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Pharmaceutics

Emulsions: O/W and W/O Types of emulsion

We all know that oil and water together, are immiscible, it means they do not mix with each other. What if we need a medication, which requires the mixing of both of these ingredients as a disperse system? Have you heard of creams and emulsions or O/W emulsion and W/O emulsion? Let’s understand about this disperse system in little details:

Emulsions are a type of disperse system, where an insoluble liquid phase is dispersed within another liquid phase. Creams are also a type of emulsion, that offer good viscosity and consistency for topical preparations. These preparations are broadly presented in two types.

  • Oil in Water emulsion (o/w): oil as dispersed phase and water as dispersion medium
  • Water in Oil emulsion (w/o): water as the dispersed phase and oil as dispersion medium

O/W emulsion and W/O emulsion

Features:

  • Emulsions are difficult to manufacture as two immiscible agents are formulated together to form a dispersed system.
  • These are thermodynamically unstable preparations, hence stabilizers should be used for pharmaceutical preparation.
  • Creams are used for external applications, emulsions may be administered through an IV, rectal or oral route as well.
  •  O/W and W/O preparations are used topically.
  • Emulsions are unstable disperse systems than suspensions, so various excipients are used to stabilize it.
  • O/W preparations: therapeutic agents that have low aqueous solubility are dissolved in the oil phase
  • Some drugs have less palatability due to bitterness. Emulsions help to administer such drugs. A flavoring agent or artificial sweetener is used to mask the taste.
  • Liquid paraffin is administered in o/w emulsion to achieve an optimum cathartic effect. The taste and odor are masked with flavoring agents.
  • Certain drugs may cause irritation if applied topically. These drugs are administered with the help of o/w formulations.
  • emulsions help patient convenience where swallowing solid dosage form is difficult.

O/W emulsion and W/O emulsion: Identification tests

  • Electrical conductivity: Oil in Water emulsion conduct electric current whereas Water in Oil emulsions do not
  • Dilution with water: Oil in Water emulsion may be diluted with water whereas Water in Oil emulsions cannot be diluted.
  • Use of dyes: oil-soluble dyes for o/w emulsion whereas water-soluble dyes for w/o emulsion.