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INDUSTRIAL PHARMACY I (BP502T) UNIT 2 (IP1)

Unit II deals with the formulation, preparation, manufacturing, and evaluation of tablets as solid dosage forms. It covers different types of tablets, tablet ingredients, and methods of manufacture such as direct compression, wet granulation, and dry granulation. The unit also includes tablet coating methods and common defects like capping, lamination, sticking, and picking. Various tablet manufacturing machines and their working principles are discussed. Finally, the unit covers evaluation tests of tablets to ensure their quality, safety, strength, and drug release.

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UNIT 2 Chapter 1 TABLETS
TABLETS • Tablet are compressed solid unit dosage form which contain medicament with or without excipients • Tablets are solid unit dosage forms that contain an active drug along with other substances (excipients). • They vary in shape, size, and weight. • Tablets are prepared by compressing powdered ingredients into a solid form. • They may be circular, flat, oval-shaped or biconvex.
➢ Advantages • Tablets are easy to administer. • Easy to transport (light in weight) • They provide a precise dose of medication. • They have a long shelf life compared to liquid dosage forms. • Cheap • Simplest oral dosage form • They are easy to take, improving patient compliance. • They can be prepared in different strengths, shapes, and sizes. • Unpleasant taste and odour can be masked by sugar or film coating. • Physically and chemically stable dosage form. • Sustain release product is possible by enteric coating.
➢ Disadvantages • Children and elderly patients may find tablets difficult to swallow. • They are not suitable for patients with vomiting or severe diarrhoea. • Not suitable for unconscious patients. • Some tablets may irritate the stomach or cause gastrointestinal discomfort. • Hygroscopic drugs are difficult to formulate as tablets. • Not used in emergency (Slow action) • Special tablets such as extended-release and enteric-coated tablets require special manufacturing techniques, making them more expensive.
➢ Ideal Characteristics of Tablets • They should be uniform, containing an accurate and consistent amount of active drug. • They should be easy to swallow and handle. • They should be free from defects such as cracks, chips, contamination, and discoloration. • They should be physically and chemically stable. • They should be hard enough to withstand handling and transportation. • They should disintegrate and dissolve at the desired rate for better drug absorption. • They should have an acceptable appearance in terms of shape, colour, and taste.
A) Tablets Inserted Orally • An oral tablet is a solid dosage form that is swallowed or chewed and then absorbed through the digestive system. ✓ Types of Oral Tablets: a) Compressed Tablets b) Multiple Compressed Tablets c) Enteric-Coated Tablets d) Sustained-Release Tablets e) Sugar-Coated Tablets f) Film-Coated Tablets g) Chewable Tablets a) Compressed Tablets • A compressed tablet is prepared by compressing powder or granules into a solid dosage form using a tablet compression machine. • No special coating • Mostly water soluble, Rapid disintegration.
b) Multiple Compressed Tablets • A multiple compressed tablet (or multilayer tablet) contains two or more layers of material compressed together into a single tablet. c) Enteric-Coated Tablets • An enteric-coated tablet has a special coating that prevents it from dissolving in the stomach. • It passes through the stomach unchanged and dissolves in the intestine. • These tablet are prepare because drug substance destroyed by gastric acid or cause gastric irritation in stomach. d) Sustained-Release Tablets • Sustained-release tablets (also called prolonged-release or sustained-action tablets) are designed to release the drug slowly over a long period, usually 8–24 hours. • This is achieved by using special formulations and technologies that control the release of the active drug.
e) Sugar-Coated Tablets • A sugar-coated tablet is a tablet covered with a layer of sugar or a sweet substance to mask the unpleasant taste or odour of the drug. f) Film-Coated Tablets • A film-coated tablet is a tablet covered with a thin layer (film). The film coating is used to: • Mask unpleasant taste and odour • Protect the tablet from moisture, light. • Improve the appearance of the tablet g) Chewable Tablets • Chewable tablets are tablets that are designed to be chewed and then swallowed, instead of being swallowed whole. • Children and elder person who may have difficulty in swallowing a tablet • Basically larger in size.
B) Tablets Used in the Oral Cavity • Tablets used in the oral cavity are designed to dissolve or disintegrate in the mouth and release the active drug to produce a therapeutic effect. Types: a) Buccal Tablets b) Sublingual Tablets c) Troches & Lozenges d) Dental Cones a) Buccal Tablets • Buccal tablets are placed between the lips and gum, where they dissolve slowly and release the medication into blood without passing GIT.
b) Sublingual Tablets • Sublingual tablets are placed under the tongue, where they dissolve quickly and release the drug into the bloodstream through the mucous membrane. • Sublingual tablets are placed under the tongue for instant melting and ultra-fast systemic absorption. c) Troches & Lozenges • Tablet which are commonly used to treat sore throat or to control coughing in common cold that dissolve slowly in the mouth to release the medication. E.g. Strepsils, Vicks. d) Dental Cones • Dental cones are used after tooth extraction. • They are placed in the empty tooth socket to prevent infection caused by pathogenic microorganisms.
C) Tablets Administered by Other Routes • These are tablets administered by routes other than the oral route. Types: a) Vaginal Tablets b) Implantable Tablets a) Implantable Tablets • Those tablet which are placed under the skin and inserted by minor surgery in a specific organ or tissue. • These tablet have slow absorption provide continuous release of drug for the month or year. • Use for administration of hormones such as testosterone steroids for contraception. b) Vaginal Tablets • Vaginal tablets are small solid dosage forms that are inserted into the vagina. • These tablet are used to release antibacterial agents to treat virginal infection.
D) Tablets Used to Prepare Solutions • These tablets are dissolved in water or another liquid to prepare a solution before use. Types: a) Effervescent Tablets b) Dispensing Tablets c) Hypodermic Tablets d) Tablet Triturates a) Effervescent Tablets • These tablet which dissolve in water and release carbon dioxide (CO₂) gas. • These tablet are prepared by compressing granular effervescent salt such as sodium bicarbonate and citric acid.
b) Dispensing Tablets • Dispensing tablets are prepared by moulding or compression. • Tablet contain large amount of highly potent API require water to make solution. c) Hypodermic Tablets • Hypodermic tablets are small solid dosage forms that are dissolved before use and the prepared solution is administered by injection (subcutaneously or intramuscularly). • Hypodermic tablets were used to quickly prepare fresh, highly stable, and fast-acting sterile injection solutions at a patient's bedside before modern pre-filled liquid vials became standard. d) Tablet Triturates • Tablet triturates are small tablet-like dosage forms that are crushed into a fine powder before administration.
❑ EXCIPIENTS • An excipients are those substance which has no therapeutic value but all added with drug in formulation for, • help in production • Improve patient acceptability • Improve stability • improve tablet performance ➢ Main Types of Excipients 1. Diluents (Fillers) 2. Binders 3. Disintegrants 4. Lubricants 5. Glidants 6. Preservatives 7. Colouring Agents 8. Flavouring Agents 9. Sweetening Agents
1. Diluents (Filler, Bulking agent) • Diluents are inactive substances added to increase the bulk (size) of tablets, making them easy to handle and consume. E.g. Lactose, Microcrystalline Cellulose (MCC), Starch, dextrose, calcium phosphate. 2. Binders • Binders are substances that hold the drug and other excipients together, giving the tablet strength and cohesion. E.g. Tragacanth, acacia, Cellulose derivatives, Starch, Gelatine. 3. Disintegrants • Disintegrants are added to tablets to help them break into smaller particles after swallowing. E.g. Bentonite, Modified Starch.
4. Lubricants • Lubricants reduce friction during tablet manufacturing and prevent the tablet material from sticking to the dies and punches. E.g. Magnesium Stearate, Stearic Acid, Talc. 5. Glidants • Glidants improve the flow properties of powders during manufacturing and prevent sticking. E.g. Colloidal Silica, Talc, Magnesium Stearate, corn starch (5-10%) 6. Preservatives • Preservatives are added to prevent microbial growth, especially in moisture-sensitive formulations. E.g. Methyl paraben, ethyl paraben, propyl paraben.
7. Colouring Agents • Colouring agents are added to give colour to tablets and improve their appearance and attractiveness. E.g. Food dyes, Pigments. 8. Sweetening Agents • Sweetening agents are added to mask the unpleasant or bitter taste of the drug and improve patient acceptability. E.g. Sucrose, Lactose, Fructose Mannitol, Saccharine. 9. Flavouring Agents • Flavouring agents are added to give tablets a pleasant taste or flavour improve patient acceptability. E.g. Natural or artificial flavours such as Spearmint and Orange.
➢ Ideal Characteristics of Excipients Used in Tablets • They should not interact with the active drug or other excipients. • They should be non-toxic and safe for human use. • They should not affect the pH of the tablet or the body. • They should not retain moisture. • They should withstand compression during tablet manufacturing. • They should be low in cost. • They should be soluble in water or other suitable solvents. • They should not affect the stability or bioavailability of the drug.
➢ Formulation of Tablets • Tablet formulation is the process of manufacturing tablets on a large scale. Also known as tablet manufacturing process. It mainly involves two methods: A. Granulation Method a) Wet Granulation b) Dry Granulation B. Direct Compression Method A. Granulation Method • Granulation is the process of converting a powder mixture into granules to improve flow properties, compressibility, and uniformity. ✓ Types of Granulation: a) Wet Granulation b) Dry Granulation
a) Wet Granulation Method • Wet granulation is a tablet manufacturing process in which powder ingredients are mixed with a liquid binder to form granules. ✓ Steps Involved in Wet Granulation 1. Weighing and Mixing of Ingredients 2. Preparation of Damp Mass 3. Wet Screening 4. Drying of Moist Granules 5. Dry Screening 6. Lubrication 7. Compression
1. Weighing and Mixing • The required quantities of drug and excipients are weighed accurately and mixed uniformly. 2. Preparation of Damp Mass • A liquid binder (such as water or another solvent) is added to the powder mixture to form a damp mass. 3. Wet Screening • The damp powder mass is passed through a 6–12 mesh screen to prepare wet granules. • This can be done manually or by using granulating equipment. 4. Drying • The wet granules are dried using a tray dryer, fluidized bed dryer, or hot air oven to remove excess moisture. • The drying temperature and time depend on the nature of the drug and the moisture content.
5. Dry Screening • The dried granules are passed through a smaller mesh screen to remove oversized and undersized particles. 6. Lubrication • A lubricant, such as magnesium stearate, is added to the granules to improve flow properties and reduce friction during tablet compression. 7. Compression • The final step is to compress the granules into tablets using a tablet compression machine (tablet press).
✓ Advantages of Wet Granulation • Improves flow properties • Increases granule density • Enhances compressibility • Provides better content uniformity ✓ Disadvantages of Wet Granulation • Longer processing time • Higher manufacturing cost • Risk of moisture-related problems (not suitable for moisture-sensitive drugs)
b) Dry Granulation Method • Dry granulation is a tablet manufacturing process in which powder is compressed without adding a liquid binder. • It is also called the Double Compression Method. Steps Involved 1. Weighing and Mixing 2. Compression into Slugs 3. Milling 4. Sieving 5. Mixing 6. Compression into Tablets
1. Weighing and Mixing • The active drug and excipients are accurately weighed and mixed uniformly in a powder mixer/blender 2. Compression to Form Slugs • The powder mixture is compressed using a slugging machine or roller compactor to form slugs (large compact tablets). • This step is also called pre-compression. 3. Milling • The slugs are broken into smaller granules using a hammer mill or other milling equipment. 4. Sieving • The milled granules are passed through a sieve to obtain uniform particle size.
5. Mixing • After sieving, lubricants and other required excipients are added and mixed to improve the flow properties. 6. Compression to Form Tablets • The mixed granules are compressed into tablets using a single-punch or rotary tablet compression machine. ✓ Advantages of Dry Granulation • Suitable for heat- and moisture-sensitive materials • Improves flow and compressibility • Cost-effective ✓ Disadvantages of Dry Granulation • Create more dust • May require additional lubrication.
B. Direct Compression Method • Direct compression is a tablet manufacturing process in which powders are compressed directly into tablets without granulation. • This method is used when the drug and excipients have good flowability and compressibility. ✓ Steps Involved 1. Material Selection • The active pharmaceutical ingredient (API) and excipients should have good flowability and compressibility. 2. Blending • The API and excipients are mixed uniformly to ensure even distribution of all ingredients. 3. Compression • The blended powder is transferred to a tablet compression machine, where it is compressed under high pressure using punches and dies to form tablets.
✓ Advantages of Direct Compression • Simple and efficient process • Cheaper • Faster dissolution rate due to high disintegration. ✓ Disadvantages • Sometime not blended uniform • Not suitable for all drugs • Not suitable for high dose drug.
❑ Tablet Compression Machines • Tablet compression machines are specialized machines used in the pharmaceutical industry to compress powders into tablets. • These machines are available in different sizes, from small laboratory machines to large industrial machines. ➢ Types of Tablet Compression Machines 1. Single Punch Tablet Machine 2. Multi Punch Tablet Machine 1. Single Punch Tablet Machine • Single Punch Tablet Machine is a tablet compression machine that produces one tablet at a time using one set of punches and dies.
✓ Key Components of a Single Station Tablet Press • Die: A cylindrical cavity that gives shape to the tablet. • Punches: Upper and lower punches that compress the granules into tablets. • Compression Cam: Controls the movement of the punches during compression. • Hopper: Supplies powder or granules to the die. • Ejection System: Removes the compressed tablet from the die. ✓ Working Mechanism of Single Station Tablet Press • The hopper (feed system) fills the die with powder or granules. • The upper punch moves down and compresses the powder. • The lower punch rises to form the tablet. • The ejection system removes the compressed tablet from the die. • The same process is repeated for each tablet.
✓ Applications • Research and Development (R&D) • Small-batch production • Educational purposes ✓ Advantages • Flexible • Cost-effective • Easy to use ✓ Disadvantages • Limited production capacity
2. Multi Punch Tablet Machine (Rotary Tablet Press) • A Multi Punch Tablet Machine (also called a Rotary Tablet Press) is an advanced tablet compression machine used for large-scale tablet production in the pharmaceutical industry. ➢ Key Components • Hopper: Holds the powder or granules and delivers them to the die. • Dies: Moulds that give shape to the tablets. It contains multiple dies. • Punches: Upper and lower punches are provided for each station. • Compression Cam: Controls the movement of the punches. • Compression Rollers: Pre-compression and main compression rollers apply pressure to compress the powder into tablets. • Ejection System: Removes the compressed tablets from the dies.
➢ Working Mechanism. • The powder blend is fed into the die stations through the hopper. • The upper punches move down and compress the powder. • The lower punches rise to form the tablets. • The ejection system removes the tablets from the dies. • The process is repeated continuously at each station. ✓ Applications • Pharmaceutical manufacturing • Food production ✓ Advantages • High production efficiency • Consistent tablet quality • Versatile (can produce different types of tablets) ✓ Disadvantages • High initial investment
➢ Defects of tablet (Compression Processing Problems in Tablets) • Compression and processing problems can affect the quality, efficacy, and safety of tablets. 1. Capping and Lamination • The upper layer of the tablet separates from the main body, causing uneven surfaces or tablet breakage. ✓ Causes • Poor flow properties of granules • High compression force (high tablet hardness, Speed) • Insufficient binder • Air is entrapped ✓ Solutions • Improve the granulation process • Adjust the amount of binder • Use proper lubrication
2. Sticking and Picking • Tablet material sticks to the punches or dies, causing tablet defects. ✓ Cause • Insufficient lubrication • Use die and punches ✓ Solution • Increase the amount of lubricant • A new set of die and punches 3. Weight Variation • Weight variation means tablets in the same batch have different weights. • This can cause dose inaccuracy. ✓ Causes • Inconsistent powder feeding • Variation in granule size
✓ Solutions • Regular calibration of the machine • Use a consistent granulation method 4. Mottling • Mottling is the uneven distribution of colour on a tablet, resulting in light or dark spots. ✓ Causes • Improper mixing of the colouring solution • Difference in the colour of the colouring agents and excipients. ✓ Solution • Use good-quality colouring agents • Change the binder system
❑ Tablet Coating • Tablet coating is the process of applying a thin, uniform layer of coating material to the surface of a tablet. • The coating material is usually applied as a solution or suspension. ➢ Advantages • Improves the taste, odour, and colour of the tablet • Makes tablets easier to swallow • Improves product stability • Protects the tablet from the gastric (stomach) environment • Provides a smooth finish • Helps in easy identification of tablets
➢ Types of Tablet Coating Tablet Coating are of mainly 3 types: 1. Sugar Coating 2. Film Coating 3. Enteric Coating 1) Sugar Coating • Sugar Coating is a type of tablet coating that involves applying a sweet, colored coating table tablet to improve its appearance. • Mask taste & protect stability. It involves following steps. a. Sealing b. Smoothing c. Polishing d. Sub coating e. Coloring
a. Sealing • Sealing is done to make the tablet waterproof and maintain its physical and chemical stability. • Materials Used: Shellac, Zein, Hydroxypropyl Cellulose. B. Sub-Coating • Sub-coating is the stage where the actual coating process begins. • A large amount of sugar coating is applied, which can increase the tablet weight by 50–100%. • Materials Used: Powdered Sucrose, Powdered Gum, Acacia. c. Smoothing • Smoothing is done to cover and fill the surface imperfections of the tablet caused during sub- coating. • It is usually done by applying a simple syrup solution.
d. Colouring • It involves multiple application of syrup solution containing the required color materials necessary to achieve desired shade. • Water soluble dyes or water insoluble pigments may be used. e. Polishing • After coloring are polished to give desired shine to the tablet. • Generally, sugar coated tablet are dull in appearance, so polishing give the surface shine and tablet elegance. • E.g. beeswax, carnauba, candelilla wax.
2) Film Coating • Film coating is the process of applying a thin polymer film around the tablet core. • The film-coating solution may be aqueous or non-aqueous. • The thickness of this coating in usually about 20-100 μm ✓ Film Coating Materials i. Film formers (Polymer) - improved appearance and protect from atmospheric condition. E.g. Hydroxypropyl methyl cellulose (HPMC), methyl hydroxyethyl cellulose, povidone. ii. Plasticizers – these are added to film coating formula to improved the flexibility and processability polymer film. E.g. Polyethylene glycol (PEG), glycerol, castor oil.
iii. Solvent- used to dissolve the polymer E.g. Water, methanol, ethanol, acetone. iv. Colourants- to improved product appearance. E.g. Sunset yellow, tartrazine, erythrosine. v. Glossants vi. Antioxidants
✓ Advantages • Protect drugs from atmospheric effect • Less time consuming because it is a single process • Good solubility in the coating solvent and GI fluids • Stable in the presence of heat, light, moisture, and air • Compatible with the drug and excipients to produce an elegant product • Non-toxic and safe for use • Not so much increase the tablet weight • Not so much affect tablet disintegration time.
3) Enteric Coating • Basically it is one type of film coating • Enteric coating is the process of applying a special coating to a tablet that protects it from the acidic environment of the stomach and allows it to disintegrate in the intestine. ➢ Purpose of Enteric Coating • Protects acid-labile drugs which easily destroyed in acidic environment. E.g. antibiotics • If drug cause irritation to the stomach • Delivers drugs for local action in the intestine E.g. Intestinal antiseptics • Provides delayed drug release
✓ Material Used • Enteric coating polymer these are PH sensitive polymer • Insoluble in acidic PH • Soluble in basic PH E.g. Hydroxypropyl methyl cellulose phthalate, Polyvinyl acetate phthalate, acrylate polymer. ✓ Ideal Characteristics of Enteric Coating Materials • Resistant to gastric fluids • Compatible with the coating solution • Non-toxic • Low cost • Easy to apply
➢ Coating Materials • This are those materials which are used for coating or applied on the surface of tablet. a) Film Coating Materials 1. Polymers • Hydroxypropyl Methylcellulose (HPMC) • Hydroxypropyl Cellulose (HPC) • Methyl Methacrylate 2. Plasticizers • Polyethylene Glycol (PEG) • Glycerin • Triacetin • Dibutyl Phthalate 3. Solvent • Water
4. Colourants • Titanium Dioxide • Iron Oxide • Natural Colours b) Enteric Coating Materials 1. Polymers • Cellulose Acetate Phthalate (CAP) • Polyvinyl Acetate Phthalate (PVAP) • Hydroxypropyl Methylcellulose Phthalate (HPMCP) 2. Plasticizers • Triethyl Citrate • Dibutyl Phthalate • Polyethylene Glycol (PEG) 3. Other Additives • Talc • Titanium Dioxide
c) Sugar Coating Materials 1. Sugars • Sucrose 2. Polymers • Acacia • Gelatine • Povidone 3. Colourants • Artificial colours • Natural colours
➢ Formulation of coating composition • The formulation of coating composition is the complete mixture of materials used to prepare the coating solution or suspension for tablet coating. Example: Film Coating (Non-Enteric) The coating composition contains: ✓ Polymers – Form the coating film. ✓ Solvents – Dissolve or disperse the polymer. ✓ Plasticizers – Increase flexibility and prevent cracking. ✓ Colouring Agents (Colourants) – Provide colour and product identification. ✓ Opacifying Agents – Improve opacity and protect from light (e.g., Titanium dioxide). ✓ Anti-tacking Agents – Prevent tablets from sticking together (e.g., Talc). ✓ Other Additives – Flavouring agents, sweeteners, surfactants, etc. (if required). Note: The functions of these ingredients are already covered under Film Coating
➢ Methods of Coating • Methods of coating are the techniques used to apply a coating layer onto tablets. ✓ Methods of Tablet Coating • Sugar Coating (already discussed) • Film Coating (already discussed) • Enteric Coating (already discussed) • Dip Coating • Brush Coating • Spray Coating • Compression Coating (Press Coating) • Vacuum Film Coating For your syllabus, the main methods are: Sugar Coating Film Coating Enteric Coating
1. Dip Coating • In this method, the core tablet is dipped into the coating solution. • The coated tablet is then removed and dried. • Used for simple coating applications. 2. Brush Coating • The coating solution is applied manually using a brush. • Requires experienced personnel. • Mainly used for small-scale or laboratory work. 3. Spray Coating • The coating solution is sprayed onto the tablets using a spray gun. • It is a fast, economical, and versatile coating method. • Suitable for tablets of different sizes and shapes. • This is the most commonly used method in pharmaceutical industries.
4. Compression Coating (Press Coating) • Also called Tablet-in-Tablet Coating. • The core tablet is placed inside another layer of coating material and compressed. Used to: • Achieve modified or delayed drug release. • Protect sensitive drugs from moisture or light. 5. Vacuum Film Coating • Vacuum film coating is a film coating method in which tablets are coated under vacuum inside a hot jacketed coating pan.
➢ Equipment Employed in Tablet Coating Most tablet coating processes use three types of equipment: a) Standard Coating Pan b) Perforated Coating Pan c) Fluidized Bed Dryer a) Standard Coating Pan • Standard coating pan is also known as a Conventional Coating Pan or Pan Coater. • It is the most commonly used coating equipment because it is: • Easy to operate • Easy to load and unload tablets due to its wide opening. ✓ Types of Standard Coating Pan 1. Pellegrini Pan System 2. Immersion Sword System 3. Immersion Tube System
✓ Construction • It consists of a circular metal pan mounted on a supporting stand. • The pan is slightly tilted at an angle of about 45° to the horizontal. • This pan is about 8-60 inches in diameter • The pan rotates with the help of a motor. • Hot air is supplied during coating to dry the tablets. ✓ Working • Tablets are loaded into the rotating pan. • The pan rotates, causing the tablets to tumble continuously. • The coating solution is sprayed or poured onto the tablets. • Hot air is supplied to evaporate the solvent and dry the coating. • The process is continued until the desired coating thickness is obtained. • Finally, the coated tablets are removed from the pan.
2. Perforated Coating Pan • A Perforated Pan System is a tablet coating equipment in which a perforated (or partially perforated) rotating drum is used for coating tablets. • It is widely used for sugar and film coating because it provides uniform coating and efficient drying. ✓ Types of Perforated Coating Pan 1. Accela-Cota System 2. Hi-Coater System 3. Glatt Coater System 4. Dria coater System
✓ Construction • It consists of a perforated or partially perforated drum. • The drum rotates on its horizontal axis inside a closed chamber. • It contains spray nozzles that atomize the coating solution into fine droplets. • Hot air is passed through the perforations to dry the coating. Working • Tablets are loaded into the perforated rotating drum. • As the drum rotates, the tablets tumble continuously. • The coating solution is sprayed through atomizing spray nozzles. • Hot air passes through the perforations, removing the solvent and drying the coating. • The process continues until a uniform film coating is obtained.
3. Fluidized Bed Coater • A Fluidized Bed Coater (Air Suspension Coater) is a highly efficient coating system in which tablets, pellets, or granules are suspended by a stream of hot air while the coating solution is sprayed onto them ✓ Construction It consists of: • Vertical cylindrical coating chamber • Support screen (air distributor) • Funnel-like modification (Wurster insert) • Air atomizing spray nozzle • Liquid feed for the nozzle • Fluidizing air supply • Exhaust air duct
✓ Working • Tablets or pellets are placed in the vertical coating chamber. • Hot fluidizing air enters through the centre of the column, causing the particles to rise in the centre (fluidization). • The coating solution is sprayed through a spray nozzle located at the bottom or top of the chamber. • The hot air evaporates the solvent, forming a uniform coating on the particles. • The coated particles fall back and the cycle repeats until the required coating is achieved.
➢ Defects in Tablet Coating • Defects in tablet coating are the problems that occur during or after the coating process, affecting the appearance and quality of coated tablets. 1. Blistering 2. Chipping 3. Filling 4. Bridging 5. Roughness 6. Blooming 7. Sticking 8. Picking 9. Colour Variation 10. cracking
1. Blistering • Formation of blisters or bubbles on the tablet surface due to separation of the coating film. • Cause: Excessive drying temperature or overheating. 2. Chipping • Chipping is a coating defect in which the film coating becomes dented or chips off from the edges of the tablet. Cause: • Decrease in pan rotation speed. • Incorrect amount of plasticizer in the coating formulation. Treatment • Adjust the proportion of plasticizer in the coating formulation. • Maintain the proper pan rotation speed during coating.
3. Filling • Filling is a coating defect in which too much coating solution fills the score line, logo, or monogram on the tablet, making it shallow or invisible. Cause: • Excessive application of coating solution, resulting in a thick coating film. Treatment • Carefully control the coating solution (fluid) application rate. • Ensure proper mixing/tumbling of tablets in the coating pan to obtain uniform coating.
4. Bridging • Bridging is a coating defect in which the coating film shrinks during drying and bridges over the score line, logo, or engraved (intaglio) markings, covering the surface depression. Cause: • Shrinkage of the coating film during drying. • Problems with the coating formulation. Treatment • Modify and maintain the coating formulation (e.g., proper polymer/plasticizer ratio). • Optimize the coating process to reduce film shrinkage.
5. Roughness • Roughness is a coating defect in which the tablet surface becomes rough or uneven due to deposition of spray-dried particles. Cause • Spray droplets dry too quickly before reaching the tablet bed. Treatment • Move the spray nozzle closer to the tablet bed. • Reduce the degree of atomization to produce appropriate droplet size.
6. Blooming • Blooming is a coating defect in which the tablet becomes dull or hazy after prolonged storage at high temperature. Cause • Excessive amount of plasticizer in the coating formulation. Treatment • Reduce the concentration of the plasticizer in the coating formulation.
7. Sticking and Picking • Sticking occurs when tablets stick to each other or to the coating pan. • Picking occurs when part of the coating film sticks to the pan, leaving a picked or damaged appearance on the tablet. Cause: • Over-wetting of tablets. • Excessive tackiness of the coating film. Treatment • Reduce the coating solution (liquid) application rate. • Increase the drying air temperature and airflow (air volume) to improve drying.
8. Colour Variation • Colour variation is a coating defect in which the colour of the coated tablets is uneven or non- uniform. Cause: • Problems with the coating formulation. • Improper processing conditions during coating. Treatment • Ensure proper mixing of the coating solution. • Use mild drying conditions to obtain uniform colour.
9. Cracking • Cracking is the formation of cracks in the tablet coating. Causes • Insufficient drying • Mechanical stress during handling Prevention • Optimize the drying conditions • Use flexible coating materials • Handle tablets gently
❑ Quality Control Tests (Tablet Evaluation Parameters) • Quality control tests are performed to evaluate the quality of tablets during manufacturing and on the finished product. These tests ensure that tablets are safe, effective, and meet pharmacopoeia standards. ➢ Tablet Evaluation Tests 1. General Appearance 2. Size and Shape 3. Thickness Test 4. Hardness Test 5. Friability Test 6. Weight Variation Test 7. Content Uniformity Test 8. Dissolution Test 9. Disintegration Test
1. General Appearance • General appearance refers to the identity and overall quality of the tablet. • It is important for consumer acceptance. Parameters Evaluated • Size • Shape • Colour • Odour • Taste • Surface texture 2. Size and Shape • Depends on the die and punch used during tablet manufacturing. • Round • Oval • Flat • Biconvex
3. Thickness Test • The Thickness Test is performed to ensure that tablets have a uniform thickness, which indicates consistent compression during manufacturing. • Ensures tablets fit correctly into blister packs and containers. • Helps maintain uniform drug dose and tablet weight. Instruments Used: • Vernier Caliper
4. Hardness Test • The Hardness Test is performed to measure the crushing strength (mechanical strength) of a tablet. • It determines the force required to break the tablet. • Ensures tablets can withstand handling, packaging, and transportation. • Ensures tablets are not too hard (delay disintegration and dissolution). • Ensures tablets are not too soft (which may break or chip easily). Instruments Used • Monsanto Hardness Tester
5. Friability Test • The Friability Test is performed to measure the resistance of tablets to abrasion, chipping, and breakage during handling, packaging, transportation, and storage. • Ensures tablets can withstand handling and transportation Procedure • Randomly select tablets and weigh them (Initial Weight = W₁). • Rotate in Roche Fibrilator at 25 rpm for 4 minutes (100 revolutions). • Remove dust and reweigh tablets (Final Weight = W₂). Formula %Friability = 𝑊1 − 𝑊2 𝑊1 × 100 Instrument Used • Roche Fibrilator Acceptance Limit • Percentage friability should not be more than 1.0%.
6. Weight Variation Test (Uniformity of Weight) • The Weight Variation Test is performed to ensure that each tablet has a uniform weight, which indicates that every tablet contains the correct amount of drug and excipients. • Confirms that each tablet contains the correct drug dose. • Ensures dose accuracy and patient safety. • Detects variation during tablet compression. • Randomly 10 tablets are selected to of these assayed individually to determine amount of API
8. Dissolution Test • The Dissolution Test is performed to measure the rate and extent of drug release from a tablet into a dissolution medium. • It checks the tablet's ability to dissolve and release the medication in the body. • Predicts the bioavailability of the drug. Apparatus • USP Apparatus I – Basket Type • USP Apparatus II – Paddle Type Test Conditions • Volume: 900 mL • Temperature: 37 ± 0.5°C • Speed: As specified in the pharmacopoeia (commonly 50–100 rpm)
➢ Procedure • Place dissolution medium in each vessel. (Water, 0.1N HCL, Phosphate buffer) • Maintain temperature at 37 ± 0.5°C. • Place tablets/caps into Basket or Paddle apparatus. • Rotate at the specified speed. • Withdraw 5–10 mL sample at specified intervals. • Replace with equal volume of fresh medium. • Analyse the sample using UV Spectrophotometer or another suitable analytical method. Acceptance Criteria • The amount of drug released should meet the pharmacopoeia specifications
9. Disintegration Test • The Disintegration Test is used to determine how quickly a tablet breaks into small particles after coming in contact with a liquid. Apparatus • Disintegration Test Apparatus It consists of: • Water bath • Basket rack assembly with 6 tubes • Stainless steel mesh at the bottom • Plastic discs Procedure • Fill the beaker with suitable medium. • Maintain temperature at 37°C. • Place one tablet in each tube. • Lower the basket into the medium. • Operate the apparatus at 30 cycles/minute. • Record the disintegration time.
UNIT 2 Chapter 2 LIQUID ORALS Presented by, Mr. Chetan S. Mali
LIQUID ORALS • Liquid orals are liquid dosage forms intended for oral administration (taken by mouth). According to the syllabus, they are of four types: 1. Syrups 2. Elixirs 3. Suspensions 4. Emulsions A) SYRUPS • Syrups are viscous (thick) liquid dosage forms containing a high concentration of sugar dissolved in water, along with the Active Pharmaceutical Ingredient (API), flavours, and colours.
➢ Types of Syrups 1. Simple Syrups 2. Medicated Syrups 3. Flavoured Syrups 1. Simple Syrup • Simple syrup is a clear, sweet liquid prepared by dissolving sugar in water, usually with heating to obtain a clear syrupy solution. 2. Medicated Syrup • A medicated syrup is a sweetened liquid preparation that contains one or more Active Pharmaceutical Ingredients (APIs) dissolved in a syrup base. 3. Flavoured Syrup • A flavoured syrup is a sweetened liquid preparation that contains natural or artificial flavours to improve taste.
➢ Common Characteristics of Syrups • Thick and viscous consistency • Sweet taste • Liquid dosage form • May contain active ingredients • Usually administered orally ➢ Preparation Methods of Syrups There are four methods of syrup preparation: a. Solution with Heat b. Agitation without Heat c. Addition of Medicated or Flavouring Liquids to Syrup d. Percolation
1. Solution with Heat • This method is suitable for heat-stable substances. • Sucrose is accurately weighed and dissolved in purified water with heating. • Heat-stable ingredients are added to the hot syrup. • The syrup is then cooled, and the final volume is adjusted with purified water. • Heat-labile or volatile substances are added after cooling to room temperature 2. Agitation Without Heat • This method is used for preparation of syrups containing volatile substances. • In this process, active substance is added in solution and agitated in a glass-stoppered bottle. • It involves the following steps: • Sucrose and other ingredients are weighed properly. • Dissolved in purified water. • Kept in a bottle of about twice the volume of the syrup, followed by continuous agitation.
3. Addition of Medicated or Flavouring Liquid to Syrup • This method is used when fluid extracts or flavouring liquids are added to the syrup. • Alcohol is used to dissolve non-aqueous substances. • Alcohol also acts as a preservative. 4. Percolation Method • The percolation method involves passing hot water through a percolator to extract active and flavouring ingredients from herbs, spices, fruits, etc. This method is commonly used to prepare: • Herbal syrups • Spiced syrups • Fruit syrups
B) ELIXIRS • Elixirs are clear, sweet, flavoured liquid preparations containing dissolved active pharmaceutical ingredients (APIs). • They are used for medicinal purposes. • They are often confused with syrups, but elixirs contain alcohol (4–40%) and usually have a higher proportion of API. ➢ Characteristics of Elixirs • Sweet and flavoured • Liquid dosage form • Higher proportion of API than syrups • Contains alcohol (4–40%) • Used as a medicinal preparation
➢ Method of Preparation of Elixirs • Alcohol-soluble ingredients are dissolved in alcohol. • Water-soluble ingredients are dissolved in water. • The aqueous solution is slowly added to the alcoholic solution with stirring. • The mixture is made up to the required volume with a suitable solvent or vehicle. • Filter the preparation. • Fill into a clean bottle and label it.
C) EMULSION • An emulsion is a biphasic liquid dosage form in which two immiscible liquids (such as oil and water) are mixed together with the help of an emulsifying agent. An emulsion has two phases: • Dispersed phase • Continuous phase ➢ Types of Emulsions • Oil in Water (O/W) Emulsion • Water in Oil (W/O) Emulsion • Multiple Emulsions
1. Oil in Water (O/W) Emulsion • An Oil in Water (O/W) emulsion is an emulsion in which oil is the dispersed phase and water is the continuous phase (dispersion medium). Example: Milk. 2. Water in Oil (W/O) Emulsion • A Water in Oil (W/O) emulsion is an emulsion in which water is the dispersed phase and oil is the continuous phase (dispersion medium). Example: Butter. 3. Multiple Emulsions • Multiple emulsions are emulsions in which one emulsion is dispersed within another emulsion. Types of Multiple Emulsions • Oil in Water in Oil (O/W/O) • Water in Oil in Water (W/O/W)
➢ Emulsifying Agents • Emulsifying agents are chemical substances that reduce the interfacial tension between two immiscible liquids (oil and water), allowing them to mix and form a stable emulsion. • Emulsifying agents are also called Emulsifiers. ✓ Properties of Emulsifying Agents • Chemically stable • Compatible with other ingredients of the emulsion • Non-toxic and safe • Capable of reducing the interfacial tension between oil and water to form a stable emulsion
➢ Preparation of Emulsions Emulsions are usually prepared by three methods: 1. Dry Gum Method 2. Wet Gum Method 3. Bottle Method 1. Dry Gum Method • The Oil : Water : Gum ratio is 4 : 2 : 1. • A mortar and pestle are used. • First, oil is mixed with gum and triturated (ground). • Then, a small amount of water is added and trituration is continued until a clicking sound is heard and a thick cream (primary emulsion) is formed. • Finally, the remaining water is added to prepare the final emulsion.
2. Wet Gum Method • The Oil : Water : Gum ratio is 4 : 2 : 1. • A mortar and pestle are used. • First, water is mixed with gum and triturated. • Then, the required amount of oil is added slowly while continuous trituration is carried out to form the primary emulsion. • Finally, the remaining water is added to prepare the final emulsion. 3. Bottle Method • The Oil : Water : Gum ratio is 2 : 2 : 1. • This method is mainly used for volatile and non-viscous oils. • First, oil is mixed with gum in a bottle and shaken thoroughly. • Then, the required amount of water is added and shaking is continued until a primary emulsion is formed. • Finally, the remaining water is added slowly to prepare the final emulsion.