A softgel is an oral dosage form for medicine similar to capsules. They consist of a gelatin based shell surrounding a liquid fill. Softgel shells are a combination of gelatin, water, opacifier and a plasticiser such as glycerin and/or sorbitol(s).
Softgels are produced in a process known as encapsulation using the Rotary Die Encapsulation process invented by Robert Pauli Scherer. The encapsulation process has been described as a form/fill/seal process. Two flat ribbons of shell material are manufactured on the machine and brought together on a twin set of rotating dies. The dies contain recesses in the desired size and shape, which cut out the ribbons into a two dimensional shape, and form a seal around the outside. At the same time a pump delivers a precise dose of fill material through a nozzle incorporated into a filling wedge whose tip sits between the two ribbons in between two die pockets at the point of cut out. The wedge is heated to facilitate the sealing process. The wedge injection causes the two flat ribbons to expand into the die pockets, giving rise to the three dimensional finished product. After encapsulation, the softgels are dried for two days to two weeks depending on the product.
In recent years, manufacturers have been able to replace gelatin in the shell with other polymers based on, for example, starch and carrageenan.
Catalent Pharma Solutions is the current owner of the RPScherer technology .
Saturday, February 19, 2011
Pills
A pill is a small, round, solid pharmacological oral dosage form that was in use before the advent of tablets and capsules. Pills were made by mixing the active ingredients with an excipient such as glucose syrup in a mortar and pestle to form a paste, then rolling the mass into a long cylindrical shape (called a "pipe"), and dividing it into equal portions, which were then rolled into balls, and often coated with sugar to make them more palatable.
In colloquial usage, tablets, capsules, and caplets are still often referred to as "pills" collectively.
In colloquial usage, tablets, capsules, and caplets are still often referred to as "pills" collectively.
Thursday, February 17, 2011
Tablet
A tablet is a pharmaceutical dosage form.
It comprises a mixture of active substances and excipients, usually in powder form, pressed or compacted from a powder into a solid dose.
Excipients:
Excipients are the ingredients in dosage forms which are not medically active. The excipients can include diluents, binders or granulating agents, glidants (flow aids) and lubricants to ensure efficient tabletting; disintegrants to promote tablet break-up in the digestive tract; sweeteners or flavours to enhance taste; and pigments to make the tablets visually attractive.
A polymer coating is often applied to make the tablet smoother and easier to swallow, to control the release rate of the active ingredient, to make it more resistant to the environment (extending its shelf life), or to enhance the tablet's appearance.
Most popular form of tablet in use today:
The compressed tablet is the most popular dosage form in use today. About two-thirds of all prescriptions are dispensed as solid dosage forms, and half of these are compressed tablets. A tablet can be formulated to deliver an accurate dosage to a specific site; it is usually taken orally, but can be administered sublingually, buccally, rectally or intravaginally. The tablet is just one of the many forms that an oral drug can take such as syrups, elixirs, suspensions, and emulsions. Medicinal tablets were originally made in the shape of a disk of whatever color their components determined, but are now made in many shapes and colors to help distinguish different medicines. Tablets are often stamped with symbols, letters, and numbers, which enable them to be identified. Sizes of tablets to be swallowed range from a few millimeters to about a centimeter. Some tablets are in the shape of capsules, and are called "caplets". Medicinal tablets and capsules are often called pills. This is technically incorrect, since tablets are made by compression, whereas pills are ancient solid dose forms prepared by rolling a soft mass into a round shape. Other products are manufactured in the form of tablets which are designed to dissolve or disintegrate; e.g. cleaning and deodorizing products.
Tabletting formulations:
In the tablet-pressing process, it is important that all ingredients be fairly dry, powdered or granular, somewhat uniform in particle size, and freely flowing. Mixed particle sized powders can segregate during manufacturing operations due to different densities, which can result in tablets with poor drug or active pharmaceutical ingredient (API) content uniformity but granulation should prevent this. Content uniformity ensures that the same API dose is delivered with each tablet.
Some APIs may be tableted as pure substances, but this is rarely the case; most formulations include excipients. Normally, an pharmacologically inactive ingredient (excipient) termed a binder is added to help hold the tablet together and give it strength. A wide variety of binders may be used, some common ones including lactose, dibasic calcium phosphate, sucrose, corn (maize) starch, microcrystalline cellulose, povidone polyvinylpyrrolidone and modified cellulose (for example hydroxypropyl methylcellulose and hydroxyethylcellulose).
Often, an ingredient is also needed to act as a disintegrant to aid tablet dispersion once swallowed, releasing the API for absorption. Some binders, such as starch and cellulose, are also excellent disintegrants.
Small amounts of lubricants are usually added, as well. The most common of these is magnesium stearate and calcium stearate ; however, other commonly used tablet lubricants include stearic acid (stearin), hydrogenated oil, and sodium stearyl fumarate. These help the tablets, once pressed, to be more easily ejected from the die and for fine finishing of tablets.
Advantages and Disadvantages:
Tablets are simple and convenient to use. They provide an accurately measured dosage of the active ingredient in a convenient portable package, and can be designed to protect unstable medications or disguise unpalatable ingredients. Colored coatings, embossed markings and printing can be used to aid tablet recognition. Manufacturing processes and techniques can provide tablets special properties, for example, sustained release or fast dissolving formulations.
Some drugs may be unsuitable for administration by the oral route. For example, protein drugs such as insulin may be denatured by stomach acids. Such drugs cannot be made into tablets. Some drugs may be deactivated by the liver when they are carried there from the gastrointestinal tract by the hepatic portal vein (the "first pass effect"), making them unsuitable for oral use. Drugs which can be taken sublingually are absorbed through the oral mucosae, so that they bypass the liver and are less susceptible to the first pass effect. The oral bioavailability of some drugs may be low due to poor absorption from the gastrointestinal tract. Such drugs may need to be given in very high doses or by injection. For drugs that need to have rapid onset, or that have severe side effects, the oral route may not be suitable. For example salbutamol, used to treat problems in the pulmonary system, can have effects on the heart and circulation if taken orally; these effects are greatly reduced by inhaling smaller doses direct to the required site of action.
Tablet Properties:
Tablets can be made in virtually any shape, although requirements of patients and tableting machines mean that most are round, oval or capsule shaped. More unusual shapes have been manufactured but patients find these harder to swallow, and they are more vulnerable to chipping or manufacturing problems.
Tablet diameter and shape are determined by the machine tooling used to produce them - a die plus an upper and a lower punch are required. This is called a station of tooling. The thickness is determined by the amount of tablet material and the position of the punches in relation to each other during compression. Once this is done, we can measure the corresponding pressure applied during compression. The shorter the distance between the punches, thickness, the greater the pressure applied during compression, and sometimes the harder the tablet. Tablets need to be hard enough that they don't break up in the bottle, yet friable enough that they disintegrate in the gastric tract.
Tablets need to be strong enough to resist the stresses of packaging, shipping and handling by the pharmacist and patient. The mechanical strength of tablets is assessed using a combination of (i) simple failure and erosion tests, and (ii) more sophisticated engineering tests. The simpler tests are often used for quality control purposes, whereas the more complex tests are used during the design of the formulation and manufacturing process in the research and development phase. Standards for tablet properties are published in the various international pharmacopeias (USP/NF, EP, JP, etc.). The hardness of tablets is the principle measure of mechanical strength. Hardness is tested using a hardness tester. The units for hardness have evolved since the 1930s.
Lubricants prevent ingredients from clumping together and from sticking to the tablet punches or capsule filling machine. Lubricants also ensure that tablet formation and ejection can occur with low friction between the solid and die wall.
Common minerals like talc or silica, and fats, e.g. vegetable stearin, magnesium stearate or stearic acid are the most frequently used lubricants in tablets or hard gelatin capsules.
Manufacturing:
Manufacturing of the Tablet Blend:
In the tablet pressing process, the main guideline is to ensure that the appropriate amount of active ingredient is in each tablet. Hence, all the ingredients should be well-mixed. If a sufficiently homogenous mix of the components cannot be obtained with simple blending processes, the ingredients must be granulated prior to compression to assure an even distribution of the active compound in the final tablet. Two basic techniques are used to granulate powders for compression into a tablet: wet granulation and dry granulation. Powders that can be mixed well do not require granulation and can be compressed into tablets through direct compression.
Wet granulation:
Wet granulation is a process of using a liquid binder to lightly agglomerate the powder mixture. The amount of liquid has to be properly controlled, as over-wetting will cause the granules to be too hard and under-wetting will cause them to be too soft and friable. Aqueous solutions have the advantage of being safer to deal with than solvent-based systems but may not be suitable for drugs which are degraded by hydrolysis.
Dry granulation:
Dry granulation processes create granules by light compaction of the powder blend under low pressures. The compacts so-formed are broken up gently to produce granules (agglomerates). This process is often used when the product to be granulated is sensitive to moisture and heat. Dry granulation can be conducted on a tablet press using slugging tooling or on a roll press called a roller compactor. Dry granulation equipment offers a wide range of pressures to attain proper densification and granule formation. Dry granulation is simpler than wet granulation, therefore the cost is reduced. However, dry granulation often produces a higher percentage of fine granules, which can compromise the quality or create yield problems for the tablet. Dry granulation requires drugs or excipients with cohesive properties, and a 'dry binder' may need to be added to the formulation to facilitate the formation of granules.
Granule Lubrication:
After granulation, a final lubrication step is used to ensure that the tableting blend does not stick to the equipment during the tableting process. This usually involves low shear blending of the granules with a powdered lubricant, such as magnesium stearate or stearic acid.
Tablet formulations are designed and tested using a laboratory machine called a Tablet Compaction Simulator or Powder Compaction Simulator. This is a computer controlled device that can measure the punch positions, punch pressures, friction forces, die wall pressures, and sometimes the tablet internal temperature during the compaction event. Numerous experiments with small quantities of different mixtures can be performed to optimise a formulation. Mathematically corrected punch motions can be programmed to simulate any type and model of production tablet press. Initial quantities of active pharmaceutical ingredients are very expensive to produce, and using a Compaction Simulator reduces the amount of powder required for product development.
Tablet Presses:
Tablet presses, also called tableting machines, range from small, inexpensive bench-top models that make one tablet at a time (single-station presses), with only around a half-ton pressure, to large, computerized, industrial models (multi-station rotary presses) that can make hundreds of thousands to millions of tablets an hour with much greater pressure. The tablet press is an essential piece of machinery for any pharmaceutical and nutraceutical manufacturer. Common manufacturers of tablet presses include Fette, Korsch, Kikusui, Manesty, IMA and Courtoy. Tablet presses must allow the operator to adjust the position of the lower and upper punches accurately, so that the tablet weight, thickness and density can each be controlled. This is achieved using a series of cams, rollers, and/or tracks that act on the tablet tooling (punches). Mechanical systems are also incorporated for die filling, and for ejecting and removing the tablets from the press after compression. Pharmaceutical tablet presses are required to be easy to clean and quick to reconfigure with different tooling, because they are usually used to manufacture many different products.
Tablet Coating:
Many tablets today are coated after being pressed. Although sugar-coating was popular in the past, the process has many drawbacks. Modern tablet coatings are polymer and polysaccharide based, with plasticizers and pigments included. Tablet coatings must be stable and strong enough to survive the handling of the tablet, must not make tablets stick together during the coating process, and must follow the fine contours of embossed characters or logos on tablets. Coatings are necessary for tablets that have an unpleasant taste, and a smoother finish makes large tablets easier to swallow. Tablet coatings are also useful to extend the shelf-life of components that are sensitive to moisture or oxidation. Opaque materials like titanium dioxide can protect light-sensitive actives from photodegradation. Special coatings (for example with pearlescent effects) can enhance brand recognition.
If the active ingredient of a tablet is sensitive to acid, or is irritant to the stomach lining, an enteric coating can be used, which is resistant to stomach acid, and dissolves in the less acidic area of the intestines. Enteric coatings are also used for medicines that can be negatively affected by taking a long time to reach the small intestine, where they are absorbed. Coatings are often chosen to control the rate of dissolution of the drug in the gastrointestinal tract. Some drugs will be absorbed better at different points in the digestive system. If the highest percentage of absorption of a drug takes place in the stomach, a coating that dissolves quickly and easily in acid will be selected. If the rate of absorption is best in the large intestine or colon, then a coating that is acid resistant and dissolves slowly would be used to ensure it reached that point before dispersing. The area of the gastrointestinal tract with the best absorption for any particular drug is usually determined by clinical trials.
Pill Splitters:
It is sometimes necessary to split tablets into halves or quarters. Tablets are easier to break accurately if scored, but there are devices called pill-splitters which cut unscored and scored tablets. Tablets with special coatings (for example enteric coatings or controlled-release coatings) should not be broken before use, as this will expose the tablet core to the digestive juices, short-circuiting the intended delayed-release effect.
It comprises a mixture of active substances and excipients, usually in powder form, pressed or compacted from a powder into a solid dose.
Excipients:
Excipients are the ingredients in dosage forms which are not medically active. The excipients can include diluents, binders or granulating agents, glidants (flow aids) and lubricants to ensure efficient tabletting; disintegrants to promote tablet break-up in the digestive tract; sweeteners or flavours to enhance taste; and pigments to make the tablets visually attractive.
A polymer coating is often applied to make the tablet smoother and easier to swallow, to control the release rate of the active ingredient, to make it more resistant to the environment (extending its shelf life), or to enhance the tablet's appearance.
Most popular form of tablet in use today:
The compressed tablet is the most popular dosage form in use today. About two-thirds of all prescriptions are dispensed as solid dosage forms, and half of these are compressed tablets. A tablet can be formulated to deliver an accurate dosage to a specific site; it is usually taken orally, but can be administered sublingually, buccally, rectally or intravaginally. The tablet is just one of the many forms that an oral drug can take such as syrups, elixirs, suspensions, and emulsions. Medicinal tablets were originally made in the shape of a disk of whatever color their components determined, but are now made in many shapes and colors to help distinguish different medicines. Tablets are often stamped with symbols, letters, and numbers, which enable them to be identified. Sizes of tablets to be swallowed range from a few millimeters to about a centimeter. Some tablets are in the shape of capsules, and are called "caplets". Medicinal tablets and capsules are often called pills. This is technically incorrect, since tablets are made by compression, whereas pills are ancient solid dose forms prepared by rolling a soft mass into a round shape. Other products are manufactured in the form of tablets which are designed to dissolve or disintegrate; e.g. cleaning and deodorizing products.
Tabletting formulations:
In the tablet-pressing process, it is important that all ingredients be fairly dry, powdered or granular, somewhat uniform in particle size, and freely flowing. Mixed particle sized powders can segregate during manufacturing operations due to different densities, which can result in tablets with poor drug or active pharmaceutical ingredient (API) content uniformity but granulation should prevent this. Content uniformity ensures that the same API dose is delivered with each tablet.
Some APIs may be tableted as pure substances, but this is rarely the case; most formulations include excipients. Normally, an pharmacologically inactive ingredient (excipient) termed a binder is added to help hold the tablet together and give it strength. A wide variety of binders may be used, some common ones including lactose, dibasic calcium phosphate, sucrose, corn (maize) starch, microcrystalline cellulose, povidone polyvinylpyrrolidone and modified cellulose (for example hydroxypropyl methylcellulose and hydroxyethylcellulose).
Often, an ingredient is also needed to act as a disintegrant to aid tablet dispersion once swallowed, releasing the API for absorption. Some binders, such as starch and cellulose, are also excellent disintegrants.
Small amounts of lubricants are usually added, as well. The most common of these is magnesium stearate and calcium stearate ; however, other commonly used tablet lubricants include stearic acid (stearin), hydrogenated oil, and sodium stearyl fumarate. These help the tablets, once pressed, to be more easily ejected from the die and for fine finishing of tablets.
Advantages and Disadvantages:
Tablets are simple and convenient to use. They provide an accurately measured dosage of the active ingredient in a convenient portable package, and can be designed to protect unstable medications or disguise unpalatable ingredients. Colored coatings, embossed markings and printing can be used to aid tablet recognition. Manufacturing processes and techniques can provide tablets special properties, for example, sustained release or fast dissolving formulations.
Some drugs may be unsuitable for administration by the oral route. For example, protein drugs such as insulin may be denatured by stomach acids. Such drugs cannot be made into tablets. Some drugs may be deactivated by the liver when they are carried there from the gastrointestinal tract by the hepatic portal vein (the "first pass effect"), making them unsuitable for oral use. Drugs which can be taken sublingually are absorbed through the oral mucosae, so that they bypass the liver and are less susceptible to the first pass effect. The oral bioavailability of some drugs may be low due to poor absorption from the gastrointestinal tract. Such drugs may need to be given in very high doses or by injection. For drugs that need to have rapid onset, or that have severe side effects, the oral route may not be suitable. For example salbutamol, used to treat problems in the pulmonary system, can have effects on the heart and circulation if taken orally; these effects are greatly reduced by inhaling smaller doses direct to the required site of action.
Tablet Properties:
Tablets can be made in virtually any shape, although requirements of patients and tableting machines mean that most are round, oval or capsule shaped. More unusual shapes have been manufactured but patients find these harder to swallow, and they are more vulnerable to chipping or manufacturing problems.
Tablet diameter and shape are determined by the machine tooling used to produce them - a die plus an upper and a lower punch are required. This is called a station of tooling. The thickness is determined by the amount of tablet material and the position of the punches in relation to each other during compression. Once this is done, we can measure the corresponding pressure applied during compression. The shorter the distance between the punches, thickness, the greater the pressure applied during compression, and sometimes the harder the tablet. Tablets need to be hard enough that they don't break up in the bottle, yet friable enough that they disintegrate in the gastric tract.
Tablets need to be strong enough to resist the stresses of packaging, shipping and handling by the pharmacist and patient. The mechanical strength of tablets is assessed using a combination of (i) simple failure and erosion tests, and (ii) more sophisticated engineering tests. The simpler tests are often used for quality control purposes, whereas the more complex tests are used during the design of the formulation and manufacturing process in the research and development phase. Standards for tablet properties are published in the various international pharmacopeias (USP/NF, EP, JP, etc.). The hardness of tablets is the principle measure of mechanical strength. Hardness is tested using a hardness tester. The units for hardness have evolved since the 1930s.
Lubricants prevent ingredients from clumping together and from sticking to the tablet punches or capsule filling machine. Lubricants also ensure that tablet formation and ejection can occur with low friction between the solid and die wall.
Common minerals like talc or silica, and fats, e.g. vegetable stearin, magnesium stearate or stearic acid are the most frequently used lubricants in tablets or hard gelatin capsules.
Manufacturing:
Manufacturing of the Tablet Blend:
In the tablet pressing process, the main guideline is to ensure that the appropriate amount of active ingredient is in each tablet. Hence, all the ingredients should be well-mixed. If a sufficiently homogenous mix of the components cannot be obtained with simple blending processes, the ingredients must be granulated prior to compression to assure an even distribution of the active compound in the final tablet. Two basic techniques are used to granulate powders for compression into a tablet: wet granulation and dry granulation. Powders that can be mixed well do not require granulation and can be compressed into tablets through direct compression.
Wet granulation:
Wet granulation is a process of using a liquid binder to lightly agglomerate the powder mixture. The amount of liquid has to be properly controlled, as over-wetting will cause the granules to be too hard and under-wetting will cause them to be too soft and friable. Aqueous solutions have the advantage of being safer to deal with than solvent-based systems but may not be suitable for drugs which are degraded by hydrolysis.
- Procedure
- Step 1: The active ingredient and excipients are weighed and mixed.
- Step 2: The wet granulate is prepared by adding the liquid binder–adhesive to the powder blend and mixing thoroughly. Examples of binders/adhesives include aqueous preparations of cornstarch, natural gums such as acacia, cellulose derivatives such as methyl cellulose, gelatin, and povidone.
- Step 3: Screening the damp mass through a mesh to form pellets or granules.
- Step 4: Drying the granulation. A conventional tray-dryer or fluid-bed dryer are most commonly used.
- Step 5: After the granules are dried, they are passed through a screen of smaller size than the one used for the wet mass to create granules of uniform size.
Dry granulation:
Dry granulation processes create granules by light compaction of the powder blend under low pressures. The compacts so-formed are broken up gently to produce granules (agglomerates). This process is often used when the product to be granulated is sensitive to moisture and heat. Dry granulation can be conducted on a tablet press using slugging tooling or on a roll press called a roller compactor. Dry granulation equipment offers a wide range of pressures to attain proper densification and granule formation. Dry granulation is simpler than wet granulation, therefore the cost is reduced. However, dry granulation often produces a higher percentage of fine granules, which can compromise the quality or create yield problems for the tablet. Dry granulation requires drugs or excipients with cohesive properties, and a 'dry binder' may need to be added to the formulation to facilitate the formation of granules.
Granule Lubrication:
After granulation, a final lubrication step is used to ensure that the tableting blend does not stick to the equipment during the tableting process. This usually involves low shear blending of the granules with a powdered lubricant, such as magnesium stearate or stearic acid.
Manufacture of the tablets
Whatever process is used to make the tableting blend, the process of making a tablet by powder compaction is very similar. First, the powder is filled into the die from above. The mass of powder is determined by the position of the lower punch in the die, the cross-sectional area of the die, and the powder density. At this stage, adjustments to the tablet weight are normally made by repositioning the lower punch. After die filling, the upper punch is lowered into the die and the powder is uniaxially compressed to a porosity of between 5 and 20%. The compression can take place in one or two stages (main compression, and, sometimes, pre-compression or tamping) and for commercial production occurs very fast (500–50 msec per tablet). Finally, the upper punch is pulled up and out of the die (decompression), and the tablet is ejected from the die by lifting the lower punch until its upper surface is flush with the top face of the die. This process is simply repeated many times to manufacture multiple tablets.
Common problems encountered during tablet manufacturing operations include:- poor (low) weight uniformity, usually caused by uneven powder flow into the die
- poor (low) content uniformity, caused by uneven distribution of the API in the tableting blend
- sticking of the powder blend to the tablet tooling, due to inadequate lubrication, worn or dirty tooling, and sub-optimal material properties
- capping, lamination or chipping. Such mechanical failure is due to improper formulation design or faulty equipment operation.
Tablet formulations are designed and tested using a laboratory machine called a Tablet Compaction Simulator or Powder Compaction Simulator. This is a computer controlled device that can measure the punch positions, punch pressures, friction forces, die wall pressures, and sometimes the tablet internal temperature during the compaction event. Numerous experiments with small quantities of different mixtures can be performed to optimise a formulation. Mathematically corrected punch motions can be programmed to simulate any type and model of production tablet press. Initial quantities of active pharmaceutical ingredients are very expensive to produce, and using a Compaction Simulator reduces the amount of powder required for product development.
Tablet Presses:
Tablet presses, also called tableting machines, range from small, inexpensive bench-top models that make one tablet at a time (single-station presses), with only around a half-ton pressure, to large, computerized, industrial models (multi-station rotary presses) that can make hundreds of thousands to millions of tablets an hour with much greater pressure. The tablet press is an essential piece of machinery for any pharmaceutical and nutraceutical manufacturer. Common manufacturers of tablet presses include Fette, Korsch, Kikusui, Manesty, IMA and Courtoy. Tablet presses must allow the operator to adjust the position of the lower and upper punches accurately, so that the tablet weight, thickness and density can each be controlled. This is achieved using a series of cams, rollers, and/or tracks that act on the tablet tooling (punches). Mechanical systems are also incorporated for die filling, and for ejecting and removing the tablets from the press after compression. Pharmaceutical tablet presses are required to be easy to clean and quick to reconfigure with different tooling, because they are usually used to manufacture many different products.
Tablet Coating:
Many tablets today are coated after being pressed. Although sugar-coating was popular in the past, the process has many drawbacks. Modern tablet coatings are polymer and polysaccharide based, with plasticizers and pigments included. Tablet coatings must be stable and strong enough to survive the handling of the tablet, must not make tablets stick together during the coating process, and must follow the fine contours of embossed characters or logos on tablets. Coatings are necessary for tablets that have an unpleasant taste, and a smoother finish makes large tablets easier to swallow. Tablet coatings are also useful to extend the shelf-life of components that are sensitive to moisture or oxidation. Opaque materials like titanium dioxide can protect light-sensitive actives from photodegradation. Special coatings (for example with pearlescent effects) can enhance brand recognition.
If the active ingredient of a tablet is sensitive to acid, or is irritant to the stomach lining, an enteric coating can be used, which is resistant to stomach acid, and dissolves in the less acidic area of the intestines. Enteric coatings are also used for medicines that can be negatively affected by taking a long time to reach the small intestine, where they are absorbed. Coatings are often chosen to control the rate of dissolution of the drug in the gastrointestinal tract. Some drugs will be absorbed better at different points in the digestive system. If the highest percentage of absorption of a drug takes place in the stomach, a coating that dissolves quickly and easily in acid will be selected. If the rate of absorption is best in the large intestine or colon, then a coating that is acid resistant and dissolves slowly would be used to ensure it reached that point before dispersing. The area of the gastrointestinal tract with the best absorption for any particular drug is usually determined by clinical trials.
Pill Splitters:
It is sometimes necessary to split tablets into halves or quarters. Tablets are easier to break accurately if scored, but there are devices called pill-splitters which cut unscored and scored tablets. Tablets with special coatings (for example enteric coatings or controlled-release coatings) should not be broken before use, as this will expose the tablet core to the digestive juices, short-circuiting the intended delayed-release effect.
Tuesday, February 8, 2011
The Simplex Method
It is a mathematical optimization method, which is used in many operations including pharmaceutical operations and processes.Simplex algorithm is adopted for simplex method.
Simplex method was developed by George Dantzig in 1947. He was an American mathematician.
The name of the algorithm is derived from the concept of a simplex. "Simplex" represents a geometric figure. Simplex is represented by the minimum number of dimensions of the space such as a line is represented by the two dimensional space and triangle is represented by the two dimensional space (i.e. corners - 1 = dimensions). From these illustrations it can be clear that for two independent variables or factors the shape of the simplex will be triangle. Simplices are not actually used in the method, but one interpretation of it is that it operates on simplicial cones and these become simplices with an additional constraint.
Simplex method works on linear programs in standard form.
Effectiveness:
Simplex is one of the most effective methods of optimization.
Simplex method was developed by George Dantzig in 1947. He was an American mathematician.
The name of the algorithm is derived from the concept of a simplex. "Simplex" represents a geometric figure. Simplex is represented by the minimum number of dimensions of the space such as a line is represented by the two dimensional space and triangle is represented by the two dimensional space (i.e. corners - 1 = dimensions). From these illustrations it can be clear that for two independent variables or factors the shape of the simplex will be triangle. Simplices are not actually used in the method, but one interpretation of it is that it operates on simplicial cones and these become simplices with an additional constraint.
Simplex method works on linear programs in standard form.
Effectiveness:
Simplex is one of the most effective methods of optimization.
Thursday, January 20, 2011
Evolutionary operations in Optimization
Evolutionary operations is also referred to "EVOP" and is well suited for the production side of the industry.
In this prcoess, constant repetition and careful planning of the production process such as formulation is used to move towards better processes.
In this prcoess, constant repetition and careful planning of the production process such as formulation is used to move towards better processes.
Monday, January 10, 2011
Pharmaceutical Incompatibility
Introduction:Incompatibility refers to the inability of something or some process to co-exist with another process or thing.
So, Pharmaceutical incompatibility refers to the inability of a pharmaceutical substance to exist in combination with another pharmaceutical entity.
Types of Incompatibility:
There are three types of incompatibility:
1. Therapeutical incompatibility
2. Chemical incompatibility
3. Pharmaceutical or physical incompability
1. Therapeutical incompatibility:
This incompabitlity is resulted due to the combination of drugs having antagonistic or opposing properties.
2. Chemical incompatibility:
This type of incompatibility is resulted due to the formation of undesirable new product when two or more drugs are combined.
Examples of Chemical incompatibility:
1. Precipitation
2. Colour change
3. Effervescences
4. Decomposition
Types of Chemical Incompatibility:
Chemical incompatibility can be intentional i.e. a prescriber knowingly gives incompatible drugs, or unintentional i.e. prescriber does not know that the drugs are incompatible.
There are two types of chemical incompatibility:
1. Tolerated
In this type of incompatibility, chemical reaction can be reduced by mixing the solution in dilute forms or by changing the order of mixing.
2. Adjusted
In this type of incompatibility, change in the formulation is needed with a compound of equal therapeutic value e.g. in the mixture of caffeine citrate and sodium salicylate, caffeine citrate is replaced with caffeine.
3. Pharmaceutical or physical Incompatibility:
This type of incompatibility results by the slow or immediate formation of decomposed solutions or precipitates, when the drugs are combined in a pharmacy setup or laboratoy.
Examples of Pharmaceutical or physical incompatibility:
1. Insolubility
2. Liquefaction
When the substances with low melting points such as camphor, menthol and thymol are mixed together, a liquid mixture i.e. eutectic mixture is formed and this process is known as liquefaction.
3. Precipitation
Precipitation can result when the solvent in which the solute is insoluble is added to the solution. Resins are normally not soluble in water. So, the tinctures of resins may form precipitate on addition to water.
4. Immiscibility
Correction of pharmaceutical or physical incompatibiliy:
This can be corrected by using one or more of the following methods:
1. Addition of suspending agents or thickening agents:
In the following prescription tragacanth (mucilage or compound powder) is used as a suspending agent.
Phenacetin 3g
Caffeine 1g
Orange Syrup 12ml
Water upto 90ml
As Phenacetin is an indiffusible substance.
On the other hand, tinctures of resins are made soluble in water by the addition of some thickening agents or with vigorous stirring and shaking.
2. Emulsification:
Water and oil are immiscible in each other and they can be made miscible by the addition of Emulsions. This is known as Emulsification.
3. Changing the mixing or order of prescription
4. Changing the form of ingredients i.e. from liquid to solid form or from hydrous form to anhydrous form:
This is often helpful in increasing the solubility of a substance e.g.a solution of ephedrine sulfate, an alkaloidal salt, and liquid paraffin is not possible as alkaloidal salt of ephedrine sulfate is not soluble in liquid paraffin but anhydrous form of ephedrine is soluble in it. So we use anhydrous form.
Examples of Incompatibility:
1. Acids are incompatible with alkaline salts, carbonates and oxides. They causes the precipitation of albumin. So, acids are prescribed alone.
2. Bases and alkaline carbonates must not be prescribed alongwith other drugs in solution. They may precipitate metallic and alkaloidal salts.
Bibliography:
A text-book of materia medica and pharmacy for medical students
**REPRINT** Introduction to materia medica and pharmacology, including the elements of medical pharmacy, prescription writing, medical Latin, toxicology, and methods of local treatment
Survey of active pharmaceutical ingredients-excipient incompatibility: Nature and mechanism
Incompatibilities in prescriptions: For students in pharmacy and medicine and practicing pharmacists and physicians
Prescription writing: Including weights and measures, preparation of solutions, doses, administration and incompatibilities
Davis's Drug Guide for Nurses
Friday, June 4, 2010
Paste, Poultice, Plaster and Suppository
Q: What do you mean by paste?
Ans: These are preparations having finely dispersed solids in the preparation.
Q: What do you mean by poultice?
Ans: These are slightly wet substances for application on the injury. These are composed of hydrophilic substances or basis having the ability of retention of heat containing solid or liquid active substances.
Q: What do you mean by medicated plaster?
Ans: These are preparations having one or more active substances. These are made in such a way that they remain in close contact with the skin at body temperature, so that the active substances can be absorbed slowly and easily through the skin or protect the skin from external environment.
Q: What do you mean by suppository?
Ans: It represents the small solid which is dissolvable at body temperature. It is usually in the form of cone or cylinder. It is usually inserted into the rectum, vagina (suppositories for vaginal insertion are called as pessaries) or urethra, nostrils or ears (Suppositories for insertion into urethra, ears or nostrils are called as bougies).
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Books reading:
The Immortal Life of Henrietta Lacks
New Atkins for a New You: The Ultimate Diet for Shedding Weight and Feeling Great.
The Other Brain: From Dementia to Schizophrenia, How New Discoveries about the Brain Are Revolutionizing Medicine and Science
Brain Rules: 12 Principles for Surviving and Thriving at Work, Home, and School
Ans: These are preparations having finely dispersed solids in the preparation.
Q: What do you mean by poultice?
Ans: These are slightly wet substances for application on the injury. These are composed of hydrophilic substances or basis having the ability of retention of heat containing solid or liquid active substances.
Q: What do you mean by medicated plaster?
Ans: These are preparations having one or more active substances. These are made in such a way that they remain in close contact with the skin at body temperature, so that the active substances can be absorbed slowly and easily through the skin or protect the skin from external environment.
Q: What do you mean by suppository?
Ans: It represents the small solid which is dissolvable at body temperature. It is usually in the form of cone or cylinder. It is usually inserted into the rectum, vagina (suppositories for vaginal insertion are called as pessaries) or urethra, nostrils or ears (Suppositories for insertion into urethra, ears or nostrils are called as bougies).
------------------------
Books reading:
The Immortal Life of Henrietta Lacks
New Atkins for a New You: The Ultimate Diet for Shedding Weight and Feeling Great.
The Other Brain: From Dementia to Schizophrenia, How New Discoveries about the Brain Are Revolutionizing Medicine and Science
Brain Rules: 12 Principles for Surviving and Thriving at Work, Home, and School
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