Saturday , October 24 2020

Excipients for Tablets with examples

Excipients are an integral part of any pharmaceutical product necessary for manufacturing as well as performance. So, a formulator should have proper knowledge about excipients for tablets to make them properly. Drugs are rarely given as pure chemical substances only and are always administered as formulated dosage form with active pharmaceutical ingredients and inactive ingredients. These therapeutically inactive ingredients of pharmaceutical preparation are known as excipients.

Functional classifications of excipients for tablets and other pharmaceutical products are qualitative, broad, and descriptive. An excipient may be used in diverse ways or for diverse purposes in a pharmaceutical preparation and hence may require different material attributes to achieve the desired performance.

In most of the case, it is not necessary to use all of the excipients for tablets because some excipients serve two or more functions. For example, starch is a multi-functional excipient for tablets. It may serve as diluent, binder, and disintegrating agent. Besides, the function of some excipients not necessary in some formulation. For example, a sweetener is necessary for chewable tablets, sublingual tablets, dispersible tablets, but not for film-coated tablets.

Common Excipients for Tablets

  1. Diluents:  essential excipients for tablets to increase the weight or volume.
  2. Binders: vital excipients for tablets to facilitate the agglomeration of powder into granules.
  3. Disintegrants: essential excipients for tablets to assist dosage form’s breakup or disintegration into small units/fragments.
  4. Lubricants: vital excipients for tablets to reduce the frictional forces between particle-particle as well as particles and metal-contact surfaces.
  5. Glidant: to promote the flow properties of tablet granules or power materials.
  6. Coloring agent: to give a color or identification of the tablets as either pigment or coating materials.
  7. Flavoring agent: used only in some types of tablets such as chewable tablets or dispersible tablets or in coating suspension for bad smelled tablets such as Amlodipine + Olmesartan Medoxomil tablet.
  8. Sweetener or Sweetening agent: especially used in the chewable, dispersible, sublingual tablet.
  9. Surfactant: used for low solubility tablets to improve wetting and deaggregation of drug particles to get a rapid and improved dissolution.
  10. Release-Modifying Agents: especially used to control drug release in modified-release formulations (prolonged-release or controlled-release tablet).
  11. Coating materials:
  •   Film former which may be enteric or non-enteric
  •   Solvent
  •   Plasticizer
  •   Colorant
  •   Opaquant-Extender
  •   Miscellaneous coating solution components. READ: TABLET COATING DEFECTS AND REMEDIES

Firstly have a look at the definition of excipients, classification and ideal properties of excipients.

Definition of Excipient

An excipient is an inactive substance other than the active pharmaceutical ingredient(s) used in the formulation of pharmaceutical product to bring functionality to the formulation. The desire function of an excipient is to guarantee the required biopharmaceutical and physicochemical properties of the pharmaceutical product. Also, excipients for tablets are known as auxiliary substances.

According to British Pharmacopoeia (BP), “Excipient is any constituent of a medicinal product that is not an active substance. Adjuvants, stabilizers, antimicrobial preservatives, diluents, antioxidants are excipients” [1].

Classification of Excipients

Based on the pattern of uses and their manufacturing

1. Standard Excipients

It is either compendial or non-compendial inactive substances. For example, Lactose as a diluent and Magnesium Stearate as a lubricant etc. Here, compendial means the excipient is indexed in the pharmacopoeia.

2. Mixed Excipients

It is a simple physical mixture of two or more compendial or non-compendial excipients. Mixed excipients may be either liquid or solid. For example, Opadry, Opadry II, and Eudragit (Grades) etc.

3. Co-processed Excipients

It is a combination of two or more compendial or non-compendial excipients by various methods such as granulation, melt extrusion, spray drying, milling etc. For example, Cellactose® 80 (75% alpha-lactose monohydrate with 25% cellulose powder), StarLac® (85 % alpha-lactose monohydrate and 15 % maize starch (corn starch)) Ludipress, (combining of three excipients: lactose as carrier and filler, binding agent Kollidon® 30, and disintegrants Kollidon® CL).

Based on their origin [2]

  1. Animal sources: such as Lactose, Stearic acid, Gelatin, Beeswax, and Lanolin etc.
  2. Vegetable sources: such as Starch, Peppermint, Guar gum, and Acacia etc.
  3. Mineral sources: such as Calcium phosphate, Silica, Asbestos, Talc, Kaolin, and Paraffin, etc.
  4. Synthetic sources: such as Boric acid, Lactic acid, Saccharin, Polysorbates, Povidone, and Polyethylene glycols etc.

 According to the functionality

The excipients are several types such as Binders, Diluents/Fillers, Disintegrants, Lubricants, Glidant, Wetting agents, Solvents, Suspending agents, Emulsifiers, Antioxidant, Preservatives, Sweeteners, Stabilizing, Coating Agent, Surfactant, Coloring agent, and Flavoring agents.

Excipients for pharmaceutical preparations

Based on chemical nature excipients are classified as:

  1. Organics and their salts: for example, Mannitol as diluent.
  2. Inorganics excipients: such as calcium phosphate as filler, iron oxide as pigments.
  3. Polymeric excipients: that can be fully synthetic or naturally derived such as hypromellose.

Characteristics of ideal excipients for tablets

The ideal excipients must have the following characteristics:

  1. An excipient must be physiologically inert.
  2. Physically and chemically stable by themselves and in combination with drug(s) or other excipients in a formulation.
  3. Commercially available in an acceptable chemical and physical grade.
  4. Compatible with drug(s).
  5. Nontoxic and acceptable by FDA or regulatory agencies.
  6. It should have accepted organoleptic properties such as colorless or white to off-white color, odorless.
  7. Economical (acceptably low).
  8. Free from any impurities and microbial hazards.
  9. They may not be contraindicated among them.
  10. Do not hamper the bioavailability of drugs

Common Excipients for tablets Manufacturing

Diluents/ Fillers/ Bulking Agents

According to USP, Diluents are components that are incorporated into tablet or capsule dosage forms to increase dosage form volume or weight [3].

Diluents are filler designed to make up the required bulk of the tablet when the drug dosage itself is inadequate to produce this bulk [4].

Also, Diluents are known as Fillers or Bulking Agents. Other reasons to provide better tablet properties such as to provide improved cohesion, improve flow, allow direct compression manufacturing, and adjust tablet thickness or weight. The most important note is the only diluent is adjusted with the total quantity of active after potency calculation. Diluents are vital excipients for tablets with a small weight. 

List of Diluent for tablets and Capsules [3, 5]

  1. Microcrystalline Cellulose [trade name: Avicel 101, 102, 200; Celex, MCC Sanaq],
  2. Powdered Cellulose [5–40% for wet granulation and 10–30% for dry granulation]
  3. Anhydrous Lactose
  4. Lactose Monohydrate
  5.  Spray-Dried Lactose,
  6. Mannitol [preferable for chewable tablet]
  7. Starch
  8. Pregelatinized Starch
  9. Maize Starch
  10. Corn Starch
  11. Sorbitol
  12. Sucrose
  13. Compressible Sugar (20–60% for chewable tablets)
  14. Confectioner’s Sugar (10–50%)
  15. Sugar Spheres
  16. Dextrates
  17. Dextrin
  18. Dextrose
  19. Calcium Phosphate, Dibasic, Anhydrous
  20. Calcium Carbonate
  21. Maltose
  22. Maltodextrin
  23. Kaolin
  24. Calcium Phosphate, Dibasic, Dihydrate
  25. Tribasic Calcium Phosphate,
  26. Calcium Sulfate
  27. Cellaburate
  28. Calcium Lactate
  29. Cellulose Acetate
  30. Silicified Microcrystalline Cellulose,
  31. Cellulose Acetate
  32. Corn Syrup
  33. Pregelatinized Starch and Corn Starch
  34. Corn Syrup Solids
  35. Erythritol (30.0–90.0%)
  36. Ethylcellulose (1.0–3.0%)
  37. Ethyl Acrylate and Methyl Methacrylate Copolymer Dispersion
  38. Fructose
  39. Isomalt
  40. Alpha-Lactalbumin
  41. Lactitol
  42. Magnesium Carbonate (direct compression ≤45)
  43. Magnesium Oxide
  44. Methacrylic Acid and Ethyl Acrylate Copolymer
  45. Methacrylic Acid and Methyl Methacrylate Copolymer
  46. Polydextrose
  47. Sodium Chloride (Capsule diluent 10–80%)
  48. Simethicone
  49. Pregelatinized Modified Starch
  50. Starch, Pea
  51. Hydroxypropyl Pea Starch
  52. Starch, Pregelatinized Hydroxypropyl Pea
  53. Potato Starch
  54. Starch, Hydroxypropyl Potato
  55. Pregelatinized Hydroxypropyl Potato Starch,
  56. Starch, Tapioca
  57. Wheat Starch
  58. Starch Hydrolysate, Hydrogenated
  59. Pullulan
  60. Talc (Tablet and capsule diluent 5.0–30.0%)
  61. Amino Methacrylate Copolymer
  62. Trehalose
  63. Xylitol

Binders

According to USP, Tablet and capsule binders are substances that incorporated into formulations to facilitate the agglomeration of powder into granules during mixing with a granulating fluid such as water, hydroalcoholic mixtures, or other solvents [3].

Tablet binder or binding agent are the substances which are added either dry or in liquid form during wet granulation to form granules or to promote cohesive compacts for directly compressed tablets [4].

Binders are agents used to impart cohesive qualities to the powdered material are referred to as binders or granulators [6]. They impart cohesiveness to the tablet formulation that ensures the tablet remaining intact after compression, as well as improving the free-flowing qualities by the formulation of granules of desired hardness and size. Binders are vital excipients for tablets. READ: TABLET BINDER : TYPES AND EXAMPLES WITH CONCENTRATION.

List of Binder used in Pharmaceutical Preparations [3, 5]                          

  1. Polyvinylpyrrolidone  is also known as Povidone, [grade: Povidone K-15, K-30, K-60, K-90 (trade name: Kollidon®)]
  2. Copovidone (2.0 – 5.0 % in direct compression and 2.0 – 5.0% in wet granulation)
  3. Carbomer (0.75 – 3.0%)
  4. Corn Starch and Pregelatinized Starch (Commercially known as STARCH 1500)
  5. Pregelatinised starch (5-10%)
  6. Carboxymethylcellulose Sodium, Carmellose Sodium (1.0–6.0%)
  7. Hypromellose/ hydroxypropyl methylcellulose (HPMC), Methocel (2-5%)
  8. PEG (Polyethylene Glycol)
  9. Hydroxyethyl Cellulose
  10. Hydroxypropyl Cellulose (2.0 – 6.0%)
  11. Hydroxyethylmethyl Cellulose
  12. Calcium carboxymethylcellulose/ Calcium cellulose glycolate /Carmellosum calcium (5-15%)
  13. Guar Galactomannan/ Guar Gum (up to 10.0%)
  14. Ethylcellulose
  15. Chitosan Hydrochloride
  16. Dextrin
  17. Low-Substituted Hydroxypropyl Cellulose
  18. Hydroxypropyl Starch
  19. Ceratonia (0.15 – 0.75 %)
  20. Inulin
  21. Magnesium Aluminum Silicate (2.0 – 10.0%)
  22. Maltodextrin (2–40% for direct compression and 3–10% for wet granulation)
  23. Methylcellulose (1.0–5.0%)
  24. Dextrates
  25. Polyethylene Oxide (5.0 – 85.0%)
  26. Povidone (0.5 – 5.0%)
  27. Sodium Alginate (1.0 – 3.0%)
  28. Starch (3–20% w/w usually 5–10%)
  29. Liquid Glucose (5.0 – 10.0%)
  30. Sucrose (2–20% dry granulation and 50–67% wet granulation)
  31. Compressible sugar (5–20% as a dry binder in tablet formulations)
  32. Zein (30% for wet granulation)
  33. Gelatin (1–3% for wet mix)
  34. Polymethacrylates (10–35 % for dry mix and 15–35 % as a solution and 4.5–10.5% w/w solids)
  35. Sorbitol (2–10% for wet mix)
  36. Glucose (2–25% for wet mix)
  37. Sodium alginate (1–3% for wet mix)
  38. Zein
  39. Acacia (1.0 – 5.0%)

Disintegrants

A disintegrant is a substance or a mixture of substances added to a tablet to facilitate its breakup or disintegration into small units/fragments and allow a drug substance to fast dissolution.

According to USP, Disintegrants are functional components that are added to formulations to promote rapid disintegration into smaller units and to allow a drug substance to dissolve more rapidly [3].

When disintegrants come in contact with water or stomach or intestinal fluid, they absorbed liquid and start to swell, dissolve, or form gels. This causes the tablet structure to rupture and disintegrate, making increased surfaces for improved dissolution of the drug substance. Disintegrants are vital excipients for tablets.

Examples of common and most used disintegrants are L-HPC (Low-Substituted Hydroxypropyl Cellulose), Microcrystalline Cellulose, Starch Pregelatinized Modified etc.

Example of Super-disintegrant are Crospovidone (commercial name- Kollidon CL) [cross linked povidone], Croscarmellose Sodium (Trade name Ac-Di-Sol, Primellose) [cross-linked cellulose], Sodium Starch Glycolate (Commercial name Primogel, Explotab) [cross-linked starch] etc.

List of Disintegrants used in pharmaceutical preparations [03, 05]

  1. Crospovidone (commercial name- Kollidon CL) (2–5%)
  2. Croscarmellose Sodium (Commercial name Ac-Di-Sol, Primellose) (10–25% in capsules and 0.5–5.0% in tablets) Croscarmellose sodium at concentrations up to 5% w/w may be used as a tablet disintegrant. 2% w/w is used in direct compressed tablets and 3% w/w in wet-granulation processed tablets.)
  3. Low-Substituted Hydroxypropyl Cellulose
  4. Sodium Starch Glycolate (Commercial name Primogel, Explotab) (2-8%, Optimum concentration is about 4%, although 2% is sufficient in many cases).
  5. Chitosan Hydrochloride
  6. Corn Starch and Pregelatinized Starch
  7. Calcium Alginate & Calcium Sodium Alginate (<10%)
  8. Docusate Sodium (≈ 0.5%)
  9. Microcrystalline Cellulose (5–15%)
  10. Hydroxypropyl Starch
  11. Magnesium Aluminum Silicate (2-10%)
  12. Methylcellulose (2.0–10.0%)
  13. Sodium Alginate (2.5–10%)
  14. Starch (3–25% w/w)
  15. Pregelatinised Starch (5–10%)
  16. Calcium carboxymethylcellulose / calcium cellulose glycolate / carmellosum calcium (1–15%)
  17. Powdered Cellulose (5–20%)

Lubricants: vital excipients for tablets

Lubricant is a non-toxic, pharmacologically inactive substance added to the formulation to prevent adhesion of the tablet material to the surface of the dies and punches, reduce interparticle friction, facilitate the ejection of the tablets from the die cavity, and may improve the rate of flow of the tablet granulation [6].

According to USP, Lubricants are substances that typically are used to reduce the frictional forces between particles and between particles and metal-contact surfaces of manufacturing equipment such as tablet punches and dies used in the manufacture of solid dosage forms.  Before compaction, liquid lubricants may be absorbed into the tablet granule matrix. Lubricants are vital excipients for tablets. Magnesium stearate, Sodium Lauryl Sulphate, and calcium stearate are the most widely used lubricant.

List of lubricants used in pharmaceutical solid dosage form [3, 5]

  1. Magnesium stearate
  2. Magnesium silicate
  3. Calcium stearate
  4. Sodium Lauryl Sulphate
  5. Sodium Stearyl Fumarate
  6. Magnesium Lauryl Sulphate
  7. Stearic Acid
  8. Calcium Stearate
  9. Glyceryl Behenate
  10. Behenoyl Polyoxylglycerides
  11. Glyceryl Dibehenate
  12. Lauric Acid
  13. Glyceryl Monostearate
  14. Glyceryl Tristearate
  15. Myristic Acid
  16. Palmitic Acid
  17. Poloxamer
  18. Polyethylene Glycol
  19. Polyethylene Glycol 3350
  20. Polysorbate 20
  21. Polyoxyl 10 Oleyl Ether
  22. Polyoxyl 15 Hydroxystearate
  23. Polysorbate 40
  24. Polyoxyl 20 Cetostearyl Ether
  25. Polyoxyl 40 Stearate
  26. Polysorbate 60
  27. Polysorbate 80
  28. Potassium Benzoate
  29. Sodium Benzoate
  30. Sorbitan Monolaurate
  31. Sorbitan Monooleate
  32. Sodium Stearate
  33. Sorbitan Monopalmitate
  34. Sorbitan Monostearate
  35. Zinc Stearate
  36. Sorbitan Sesquioleate
  37. Sorbitan Trioleate
  38. Talc

Glidant / Anticaking Agent

Glidant is a non-toxic, pharmacologically inactive substance used to promote the flow properties of tablet granulation or powder materials by decreasing interparticle friction and cohesion. These always are added in the dry state during the lubrication step before compression. Compression vs Compaction

According to USP, Glidants and anticaking agents are used to promote powder flow and to reduce the caking or clumping that can occur when powders are stored in bulk. Besides, glidants and anticaking agents reduce the incidence of bridging during the emptying of powder hoppers and powder processing.

Colloidal silicon dioxide (Aerosil 200/Cab-o-sil) is the most commonly used glidant and generally is used in low concentrations of 1% or less. Talc (asbestos-free) also is used as a glidant. Glidants are vital excipients for tablets. READ: DIFFERENCE BETWEEN LUBRICANT AND GLIDANT

List of glidant used in pharmaceutical solid dosage form [3, 5]

  1. Colloidal Silicon Dioxide (trade name: Aerosil 200/ Cab-o-sil)
  2. Talc
  3. Tribasic Calcium Phosphate
  4. Calcium Silicate
  5. Cellulose, Powdered
  6. Magnesium Oxide
  7. Sodium Stearate
  8. Magnesium Silicate
  9. Silica, Dental-Type
  10. Magnesium Trisilicate
  11.  Hydrophobic Colloidal Silica

Coloring Agents / Colorant

Coloring agents are inactive substance(s) added into dosage forms to produce a distinctive appearance that may serve to differentiate a product from others that have a similar physical appearance or in some instances, to protect photolabile components of the dosage form. Also, Coloring agents are called colorant.

Coloring agents are categorized into:

  1. Dyes: Water-soluble coloring substances,
  2. Lakes: Insoluble forms of a dye that result from its irreversible adsorption onto a hydrous metal oxide,
  3. Inorganic pigments: Substances such as titanium dioxide or iron oxides, and
  4. Natural colorants: Colored compounds not considered dyes, such as riboflavin.

List of coloring agents used in a pharmaceutical solid dosage form such as tablets [3]

  1. Caramel
  2. Ferric Oxide
  3. Titanium Dioxide
  4. Ferrosoferric Oxide
  5. Aluminum Oxide
  6. FD & C Red #40 /Allura Red AC
  7. Amaranth
  8. FD & C Blue #1 /Brilliant Blue FCF
  9. Canthaxanthin
  10. Carmine
  11. Carmoisine (Azorubine)
  12. Curcumin (Tumeric)
  13. FD & C Red #3 /Erythrosine
  14. Fast Green FCF
  15. Green S (Lissamine Green)
  16. D & C Red #30 /Helendon Pink
  17. FD & C Blue #2 /Indigo Carmine
  18. Iron Oxide Black
  19. Iron Oxide Red
  20. D & C Red #7 / Lithol Rubin BK
  21. Patent Blue V
  22. D & C Red #28 / Phloxine B
  23. Iron Oxide Yellow
  24. D & C Red #27 / Phloxine O
  25. Ponceau 4R (Cochineal Red A)
  26. Quinoline Yellow WS
  27. D & C Yellow #10
  28. Riboflavin (Lactoflavin)
  29. FD & C Yellow #5 /Tartrazine
  30. FD & C Yellow #6 / Sunset Yellow FCF

Flavoring agent and Fragrance

According to USP, a flavor is a single chemical entity or a blend of chemicals of synthetic or natural origin that can produce a taste or aroma (i.e. fragrance) response when orally consumed or smelled [3]. Flavoring agents are consumed orally and appreciated by both smell and taste while fragrances are only for external use and appreciated only by smell. Generally, flavors are vital excipients for chewable tablets, oral disintegrating tablets, dispersible tablets, oral solutions, and oral suspensions to mask the unpleasant smell as well as taste and to make the product more palatable, thus increasing patient compliance.

List of Flavoring agent used in pharmaceutical solid dosage form [3, 5]

  1. Vanillin
  2. Peppermint flavor powder
  3. Berry flavor powder
  4. Strawberry flavor powder
  5. Orange flavor powder
  6. Lemon flavor powder
  7. Orange essence
  8. Ethyl Maltol (It has a flavor and odor 4–6 times as intense as maltol)
  9. Eucalyptus Oil
  10. Isobutyl Alcohol
  11. Sodium Succinate
  12. Adipic Acid
  13. Almond Oil
  14. Anethole
  15. Benzaldehyde
  16. Denatonium Benzoate
  17. Ethyl Acetate
  18. Ethyl Vanillin
  19. Ethylcellulose
  20. Fructose
  21. Fumaric Acid
  22. l-Glutamic Acid, Hydrochloride
  23. Lactitol
  24. Leucine
  25. Malic Acid
  26. Maltol
  27. Menthol / Racementhol (Tablets 0.2–0.4%)
  28. Methionine
  29. Methyl Salicylate
  30. Monosodium Glutamate
  31. Peppermint Oil
  32. Strawberry flavor, liquid
  33. Peppermint Spirit
  34. Racemethionine
  35. Rose Oil
  36. Rose Water, Stronger
  37. Sodium Acetate
  38. Sodium Lactate Solution
  39. Tartaric Acid
  40. Thymol
  41. Fumaric Acid
  42. Inulin
  43. Isomalt
  44. Neohesperidin Dihydrochalcone

Sweetener or Sweetening agent

Sweeteners are substances used to mask the unpleasant taste and sweeten oral dosage forms and also to mask unpleasant flavors. It binds to receptors on the tongue that are responsible for the sensation of sweetness. Sucrose is the standard for sweetness. Sweeteners are vital excipients for chewable tablets, lozenges, oral disintegrating tablets, dispersible tablets, oral solutions, emulsion, and oral suspensions.

List of sweetening agent used in tablet and other pharmaceutical products [3, 5]

  1. Sucralose
  2. Saccharin Sodium
  3. Neotame
  4. Sucrose
  5. Acesulfame Potassium
  6. Aspartame
  7. Aspartame Acesulfame
  8. Corn Syrup
  9. Corn Syrup Solids
  10. Dextrates
  11. Dextrose
  12. Dextrose Excipient
  13. Erythritol
  14. Fructose
  15. Galactose
  16. Glucose,
  17. Glycerin
  18. Inulin
  19. Invert Sugar
  20. Isomalt
  21. Lactitol
  22. Maltitol
  23. Maltose
  24. Mannitol
  25. Saccharin
  26. Saccharin Calcium
  27. Sorbitol
  28. Starch Hydrolysate, Hydrogenated
  29. Sugar, Compressible
  30. Sugar, Confectioner’s
  31. Tagatose
  32. Trehalose
  33. Xylitol

Surfactant

Surfactants are compound with well-defined polar and non-polar regions that allow them to aggregate in solution to form micelles and non-polar drugs can partition into these micelles and be solubilized [6]. They may decrease the surface tension (or interfacial tension) between a liquid and a solid or between a gas and a liquid or two liquids.

For example, Sodium lauryl sulphate used as a surfactant to dissolve aspirins. Polysorbate 80 in tablet formulations containing starch, had elicited faster drug dissolution rates despite the prolonged disintegration.

Surfactant used in the solid formulation [4, 5]

  1. Behenoyl Polyoxylglycerides
  2. Polysorbate 20
  3. Polysorbate 40
  4. Docusate Sodium
  5. Polysorbate 60
  6. Polysorbate 80
  7. Benzalkonium Chloride
  8. Caprylocaproyl Polyoxylglycerides
  9. Cetylpyridinium Chloride
  10. Lauroyl Polyoxylglycerides
  11. Linoleoyl Polyoxylglycerides
  12. Octoxynol 9
  13. Oleoyl Polyoxylglycerides
  14. Poloxamer
  15. Polyoxyl 10 Oleyl Ether
  16. Polyoxyl 15 Hydroxystearate
  17. Nonoxynol 9
  18. Polyoxyl 20 Cetostearyl Ether
  19. Polyoxyl 40 Stearate
  20. Pullulan
  21. Polyoxyl Lauryl Ether
  22. Polyoxyl Stearyl Ether
  23. Sodium Lauryl Sulfate
  24. Sorbitan Monolaurate
  25. Sorbitan Monooleate
  26. Polyoxyl Stearate
  27. Sorbitan Monopalmitate
  28. Sorbitan Monostearate
  29. Stearoyl Polyoxylglycerides
  30. Sorbitan Sesquioleate
  31. Sorbitan Trioleate
  32. Tyloxapol

Release-Modifying Agents

Release-modifying agents are substances used as an excipient to control drug release in a modified-release dosage form such as in prolonged-release or controlled-release tablets. They are vital excipients for modified-release tablets.

List of Release-Modifying Agents used in tablets [3, 5]

  1. Carbomer Copolymer
  2. Shellac
  3. Carbomer Homopolymer
  4. Hypromellose
  5. Carbomer Interpolymer
  6. Carboxymethylcellulose Sodium
  7. Carrageenan
  8. Cellaburate
  9. Ethylcellulose
  10. Glyceryl Monooleate
  11. Starch, Pregelatinized Modified
  12. Glyceryl Monostearate
  13. Guar Gum
  14. Hydroxypropyl Betadex
  15. Hydroxypropyl Cellulose
  16. Polyethylene Oxide
  17. Polyvinyl Acetate Dispersion
  18. Sodium Alginate
  19. Starch, Pregelatinized
  20. Xanthan Gum
  21. Alginic Acid

Coating materials

The substance used to coat tablets or particles. Any film-coating formulation consist mostly of a polymer, colorant, plasticizer, and solvent (or vehicle). Coating materials are vital excipients for tablets but not for all tablets. A proper coating formulation consists by the following materials:

  • Film formers, which may be enteric or non-enteric
  • Solvents
  • Plasticizers
  • Colourants
  • Opaquant-Extenders
  • Miscellaneous coating solution components

So, you are now well-informed about excipients for tablets. Only proper knowledge regarding API and excipients for tablets help to make proper tablets.

References 

1. British Pharmacopoeia Commission. British Pharmacopoeia 2016. [BP online]. London: TSO; 2020.
2. Giorgio Pifferi, Patrizia Restani. The safety of pharmaceutical excipients” Farmaco. 2003; 58 (8)541-550.
3. The United States Pharmacopeia. The National Formulary. Rockville, Md.: United States Pharmacopeial Convention, Inc.; 1979.
4. Lachman, Lieberman, H.A. and Kanig, J.L., The Theory and Practice of Industrial Pharmacy, Lea and Febiger, New York, 15th edition; 2013.
5. Rowe, R. C., Sheskey, P. J., Owen, S. C., & American Pharmacists Association. Handbook of pharmaceutical excipients. London: Pharmaceutical Press; 2006.
6. Remington, Joseph P, and Paul Beringer. Remington: The Science and Practice of Pharmacy. 21st edition. Philadelphia: Lippincott Williams & Wilkins; 2005.

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