Topical
Encyclopedia
In medicine
, a topical medication
is applied to body surfaces
such as the skin
or mucous membrane
s such as the vagina
, anus
, throat
, eye
s and ear
s.
Many topical medications are epicutaneous, meaning that they are applied directly to the skin. Topical medications may also be inhalational, such as asthma medications, or applied to the surface of tissues other than the skin, such as eye drops
applied to the conjunctiva
, or ear drop
s placed in the ear, or medications applied to the surface of a tooth
. As a route of administration
, topical medications are contrasted with enteral (in the digestive tract) and parenteral administration (injected into the circulatory system).
A topical effect, in the pharmacodynamic sense, may refer to a local, rather than systemic, target for a medication. However, many topically administered drugs have systemic effects.
Some hydrophobic
chemicals, such as steroid hormone
s, can be absorbed
into the body after being applied to the skin in the form of a cream
, gel
or lotion
. Transdermal patch
es have become a popular means of administering some drugs for birth control
, hormone replacement therapy
, and prevention of motion sickness
. One example of an antibiotic
that may be applied topically is chloramphenicol
.
The word topical is derived from the Ancient Greek topos (plural: topoi), meaning "place" or "location".
s will be classified one or two strengths higher when moving from cream to ointment. As a rule of thumb, an ointment base is more occlusive and will drive the medication into the skin more rapidly than a solution or cream base.
The manufacturer of each topical products has total control over the content of the base of a medication. Although containing the same active ingredients, one manufacturer's cream might be more acidic than the next, which could cause skin irritation or change its absorption rate. For example, a vaginal formulation of miconazole
antifungal cream might irritate the skin less than an athlete foot formulation of miconazole cream. These variations can, on occasion, result in different clinical outcomes, even though the active ingredient is the same. No comparative potency labeling exists to ensure equal efficacy between generic and brand name topical steroids (percentage of oil vs water dramatically affect the potency of topical steroid). Studies have confirmed that the potency of some topical steroid products may differ according to manufacturer or brand. An example of this is the case of brand name Valisone cream and Kenalog cream in clinical studies have demonstrated significantly better vasoconstrictions than some forms of this drug produced by generic drug manufacturers. However, in a simple base like an ointment, much less variation between manufacturers is common.
In dermatology
, the base of a topical medication is often as important as the medication itself. It is extremely important to receive a medication in the correct base, before applying to the skin. A pharmacist should not substitute an ointment for a cream, or vice-versa, as the potency of the medication can change. Some physicians use a thick ointment to replace the waterproof barrier of the inflamed skin in the treatment of eczema, and a cream might not accomplish the same clinical intention.
Topical solutions are of low viscosity and often use water or alcohol in the base. The solution can cause drying of the skin if alcohol is used in the base. These are usually a powder dissolved in water, alcohol, and sometimes oil. Alcohol in topical steroids can frequently cause drying if it is used as a base ingredient. There is significant variability between generic brands and name brands. There is a risk of irritation, depending on the preservative(s) and fragrances used in the base. Some examples of topical solutions are given below:
1:Aluminium Acetate topical' solution: This is a colorless, with a faint acetous odour and sweetish taste. It is applied topically as an astringent after dilution with 10-40 parts of water. This is used in many types of dermatologic lotions, creams, and pastes. Commercial premeasured and packed tablets and powders are available for this preparation.
2- Povidone Iodine Topical solution: This is a chemical complex of iodine with polyvinylpyrrolidone, the agent being a polymer having an average molecular weight of 40,000. The povidone iodine contains 10% Available iodine, slowly released when applied to skin. This preparation is employed topically as a surgical scrub and non irritating antiseptic solution, with its effectiveness being directly attributed to the presence and release of iodine from the complex. Commercial Product: BETADINE SOLUTION
s are similar to solutions but are thicker and tend to be more emollient in nature than solution. They are usually an oil mixed with water, and more often than not have less alcohol than solutions. Lotions can be drying if they contain a high amount of alcohol. There is a significant variability in the ingredients of base of generic lotions when compared to brand name lotions.
"Shake well before use".
is an emulsion of oil and water in approximately equal proportions. It penetrates the stratum corneum
outer layer of skin well. Cream is thicker than lotion, and maintains its shape when removed from its container. It tends to be moderate in moisturizing tendency. For topical steroid products, oil-in-water emulsions are common. Creams have a significant risk of causing immunological sensitization due to preservative
s. It has a high rate of acceptance by patients. There is a great variation in ingredients, composition, pH, and tolerance among generic brands.
Ointments are used topically on a variety of body surfaces. These include the skin
and the mucous membrane
s of the eye
(an eye ointment), vagina
, anus
, and nose
. An ointment may or may not be medicated.
Ointments are usually very moisturizing, and good for dry skin. They have a low risk of sensitization due to having few ingredients beyond the base oil or fat, and low irritation risk. There is typically little variability between brands of generics and namebrand drugs. They are often disliked by patients due to greasiness.
The vehicle of an ointment is known as the ointment base. The choice of a base depends upon the clinical indication for the ointment. The different types of ointment bases are:
The medicaments are dispersed in the base, and later they get divided after the drug penetration into the living cells of skin.
Ointments are formulated using hydrophobic, hydrophilic, or water-emulsifying bases to provide preparations that are immiscible, miscible, or emulsifiable with skin secretions. They can also be derived from hydrocarbon (fatty), absorption, water-removable, or water-soluble bases.
Evaluation of ointments
Properties which affect choice of an ointment base are:
Methods of preparation of ointments
Trituration: In this finely subdivided insoluble medicaments are evenly distributed by grinding with a small amount of the base followed by dilution with gradually increasing amounts of the base.
Fusion: In this method the ingredients are melted together in descending order of their melting points and stirred to ensure homogeneity.
s are thicker than a solution. Often a semisolid emulsion in an alcohol base. Some will melt at body temperature. Tends to be cellulose cut with alcohol or acetone. Tends to be drying. Tends to have greatly variable ingredients between generic brands and trade names. Significant risk of inducing hypersensitivity due to fragrances and preservatives. Useful for the scalp and body folds. Avoid fissures and erosions due to drying and stinging effect of alcohol base. High rate of acceptance due to its cosmetic elegance.
es can be a very precise time released method of delivering a drug. Cutting a patch in half might affect the dose delivered. The release of the active component from a transdermal delivery system (patch) may be controlled by diffusion through the adhesive which covers the whole patch, by diffusion through a membrane which may only have adhesive on the patch rim or drug release may be controlled by release from a polymer matrix. Cutting a patch might cause rapid dehydration of the base of the medicine and affect the rate of diffusion.
is either the pure drug by itself (talcum powder), or is made of the drug mixed in a carrier such as corn starch or corn cob powder (Zeosorb AF - miconazole powder). Can be used as an inhaled topical (cocaine powder used in nasal surgery).
by tape. This greatly increase the potency and absorption of the topical steroid and is used to treat inflammatory skin diseases.
s and smelling salt.
combines three agents - oil, water, and powder. It is an ointment in which a powder is suspended.
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
, a topical medication
Medication
A pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...
is applied to body surfaces
Body surface area
In physiology and medicine, the body surface area is the measured or calculated surface of a human body. For many clinical purposes BSA is a better indicator of metabolic mass than body weight because it is less affected by abnormal adipose mass...
such as the skin
Human skin
The human skin is the outer covering of the body. In humans, it is the largest organ of the integumentary system. The skin has multiple layers of ectodermal tissue and guards the underlying muscles, bones, ligaments and internal organs. Human skin is similar to that of most other mammals,...
or mucous membrane
Mucous membrane
The mucous membranes are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion. They line cavities that are exposed to the external environment and internal organs...
s such as the vagina
Vagina
The vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...
, anus
Anus
The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...
, throat
Pharynx
The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...
, eye
Human eye
The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
s and ear
Ear
The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of the auditory system....
s.
Many topical medications are epicutaneous, meaning that they are applied directly to the skin. Topical medications may also be inhalational, such as asthma medications, or applied to the surface of tissues other than the skin, such as eye drops
Eye Drops
Eye Drops was a television program on TechTV that showcased short computer animation movies and clips made using off the shelf 3D animation software. The show claimed to showcase all different types of animation, but only a very small number of shorts featured non-CG animation...
applied to the conjunctiva
Conjunctiva
The conjunctiva covers the sclera and lines the inside of the eyelids. It is composed of rare stratified columnar epithelium.-Function:...
, or ear drop
Ear drop
Ear drops are a form of medicine used to treat or prevent ear infections, especially infections of the outer ear and ear canal .Bacterial infections are sometimes treated with antibiotics...
s placed in the ear, or medications applied to the surface of a tooth
Tooth
Teeth are small, calcified, whitish structures found in the jaws of many vertebrates that are used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are embedded in the Mandible bone or the Maxillary bone and are...
. As a route of administration
Route of administration
A route of administration in pharmacology and toxicology is the path by which a drug, fluid, poison, or other substance is taken into the body.-Classification:Routes of administration are usually classified by application location...
, topical medications are contrasted with enteral (in the digestive tract) and parenteral administration (injected into the circulatory system).
A topical effect, in the pharmacodynamic sense, may refer to a local, rather than systemic, target for a medication. However, many topically administered drugs have systemic effects.
Some hydrophobic
Hydrophobe
In chemistry, hydrophobicity is the physical property of a molecule that is repelled from a mass of water....
chemicals, such as steroid hormone
Steroid hormone
A steroid hormone is a steroid that acts as a hormone. Steroid hormones can be grouped into five groups by the receptors to which they bind: glucocorticoids, mineralocorticoids, androgens, estrogens, and progestogens...
s, can be absorbed
Absorption (skin)
Skin absorption is a route by which substances can enter the body through the skin. Along with inhalation, ingestion and injection, dermal absorption is a route of exposure for toxic substances and route of administration for medication...
into the body after being applied to the skin in the form of a cream
Cream (pharmaceutical)
A cream is a topical preparation usually for application to the skin. Creams for application to mucus membranes such as those of the rectum or vagina are also used. Creams may be considered pharmaceutical products as even cosmetic creams are based on techniques developed by pharmacy and...
, gel
Gel
A gel is a solid, jelly-like material that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state...
or lotion
Lotion
A lotion is a low- to medium-viscosity, topical preparation intended for application to unbroken skin. By contrast, creams and gels have higher viscosity.Lotions are usually applied to external skin with bare hands, a clean cloth, cotton wool or gauze...
. Transdermal patch
Transdermal patch
A transdermal patch is a medicated adhesive patch that is placed on the skin to deliver a specific dose of medication through the skin and into the bloodstream. Often, this promotes healing to an injured area of the body. An advantage of a transdermal drug delivery route over other types of...
es have become a popular means of administering some drugs for birth control
Birth control
Birth control is an umbrella term for several techniques and methods used to prevent fertilization or to interrupt pregnancy at various stages. Birth control techniques and methods include contraception , contragestion and abortion...
, hormone replacement therapy
Hormone therapy
Hormone therapy, or hormonal therapy is the use of hormones in medical treatment. Treatment with hormone antagonists may also referred to as hormonal therapy...
, and prevention of motion sickness
Motion sickness
Motion sickness or kinetosis, also known as travel sickness, is a condition in which a disagreement exists between visually perceived movement and the vestibular system's sense of movement...
. One example of an antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
that may be applied topically is chloramphenicol
Chloramphenicol
Chloramphenicol is a bacteriostatic antimicrobial that became available in 1949. It is considered a prototypical broad-spectrum antibiotic, alongside the tetracyclines, and as it is both cheap and easy to manufacture it is frequently found as a drug of choice in the third world.Chloramphenicol is...
.
The word topical is derived from the Ancient Greek topos (plural: topoi), meaning "place" or "location".
Choice of base formulation
A medication's potency often is changed with its base. For example, some topical steroidTopical steroid
Topical steroids are the topical forms of corticosteroids. Topical steroids are the most commonly prescribed topical medications for the treatment of rash, eczema, and dermatitis. Topical steroids have anti-inflammatory properties, and are classified based on their vasoconstriction abilities. There...
s will be classified one or two strengths higher when moving from cream to ointment. As a rule of thumb, an ointment base is more occlusive and will drive the medication into the skin more rapidly than a solution or cream base.
The manufacturer of each topical products has total control over the content of the base of a medication. Although containing the same active ingredients, one manufacturer's cream might be more acidic than the next, which could cause skin irritation or change its absorption rate. For example, a vaginal formulation of miconazole
Miconazole
Miconazole is an imidazole antifungal agent, developed by Janssen Pharmaceutica, commonly applied topically to the skin or to mucus membranes to cure fungal infections. It works by inhibiting the synthesis of ergosterol, a critical component of fungal cell membranes...
antifungal cream might irritate the skin less than an athlete foot formulation of miconazole cream. These variations can, on occasion, result in different clinical outcomes, even though the active ingredient is the same. No comparative potency labeling exists to ensure equal efficacy between generic and brand name topical steroids (percentage of oil vs water dramatically affect the potency of topical steroid). Studies have confirmed that the potency of some topical steroid products may differ according to manufacturer or brand. An example of this is the case of brand name Valisone cream and Kenalog cream in clinical studies have demonstrated significantly better vasoconstrictions than some forms of this drug produced by generic drug manufacturers. However, in a simple base like an ointment, much less variation between manufacturers is common.
In dermatology
Dermatology
Dermatology is the branch of medicine dealing with the skin and its diseases, a unique specialty with both medical and surgical aspects. A dermatologist takes care of diseases, in the widest sense, and some cosmetic problems of the skin, scalp, hair, and nails....
, the base of a topical medication is often as important as the medication itself. It is extremely important to receive a medication in the correct base, before applying to the skin. A pharmacist should not substitute an ointment for a cream, or vice-versa, as the potency of the medication can change. Some physicians use a thick ointment to replace the waterproof barrier of the inflamed skin in the treatment of eczema, and a cream might not accomplish the same clinical intention.
Classes of topical medications
There are many general classes, with no clear dividing line between similar formulations. As a result, what the manufacturer's marketing department chooses to list on the label of a topical medication might be completely different from what the form would normally be called. For example, Eucerin "cream" is more appropriately described as an ointment than as a cream.Topical solutions are of low viscosity and often use water or alcohol in the base. The solution can cause drying of the skin if alcohol is used in the base. These are usually a powder dissolved in water, alcohol, and sometimes oil. Alcohol in topical steroids can frequently cause drying if it is used as a base ingredient. There is significant variability between generic brands and name brands. There is a risk of irritation, depending on the preservative(s) and fragrances used in the base. Some examples of topical solutions are given below:
1:Aluminium Acetate topical' solution: This is a colorless, with a faint acetous odour and sweetish taste. It is applied topically as an astringent after dilution with 10-40 parts of water. This is used in many types of dermatologic lotions, creams, and pastes. Commercial premeasured and packed tablets and powders are available for this preparation.
2- Povidone Iodine Topical solution: This is a chemical complex of iodine with polyvinylpyrrolidone, the agent being a polymer having an average molecular weight of 40,000. The povidone iodine contains 10% Available iodine, slowly released when applied to skin. This preparation is employed topically as a surgical scrub and non irritating antiseptic solution, with its effectiveness being directly attributed to the presence and release of iodine from the complex. Commercial Product: BETADINE SOLUTION
Lotion
LotionLotion
A lotion is a low- to medium-viscosity, topical preparation intended for application to unbroken skin. By contrast, creams and gels have higher viscosity.Lotions are usually applied to external skin with bare hands, a clean cloth, cotton wool or gauze...
s are similar to solutions but are thicker and tend to be more emollient in nature than solution. They are usually an oil mixed with water, and more often than not have less alcohol than solutions. Lotions can be drying if they contain a high amount of alcohol. There is a significant variability in the ingredients of base of generic lotions when compared to brand name lotions.
Shake lotion
A mixture that separates into two or three parts with time. Frequently an oil mixed with a water-based solution. Needs to be shaken into suspension before use."Shake well before use".
Cream
A creamCream (pharmaceutical)
A cream is a topical preparation usually for application to the skin. Creams for application to mucus membranes such as those of the rectum or vagina are also used. Creams may be considered pharmaceutical products as even cosmetic creams are based on techniques developed by pharmacy and...
is an emulsion of oil and water in approximately equal proportions. It penetrates the stratum corneum
Stratum corneum
The stratum corneum is the outermost layer of the epidermis, consisting of dead cells that lack nuclei and organelles. The purpose of the stratum corneum is to form a barrier to protect underlying tissue from infection, dehydration, chemicals and mechanical stress...
outer layer of skin well. Cream is thicker than lotion, and maintains its shape when removed from its container. It tends to be moderate in moisturizing tendency. For topical steroid products, oil-in-water emulsions are common. Creams have a significant risk of causing immunological sensitization due to preservative
Preservative
A preservative is a naturally occurring or synthetically produced substance that is added to products such as foods, pharmaceuticals, paints, biological samples, wood, etc. to prevent decomposition by microbial growth or by undesirable chemical changes....
s. It has a high rate of acceptance by patients. There is a great variation in ingredients, composition, pH, and tolerance among generic brands.
Ointment
An ointment is a homogeneous, viscous, semi-solid preparation, most commonly a greasy, thick oil (oil 80% - water 20%) with a high viscosity, that is intended for external application to the skin or mucous membranes. They are used as emollients or for the application of active ingredients to the skin for protective, therapeutic, or prophylactic purposes and where a degree of occlusion is desired.Ointments are used topically on a variety of body surfaces. These include the skin
Human skin
The human skin is the outer covering of the body. In humans, it is the largest organ of the integumentary system. The skin has multiple layers of ectodermal tissue and guards the underlying muscles, bones, ligaments and internal organs. Human skin is similar to that of most other mammals,...
and the mucous membrane
Mucous membrane
The mucous membranes are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion. They line cavities that are exposed to the external environment and internal organs...
s of the eye
Human eye
The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
(an eye ointment), vagina
Vagina
The vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...
, anus
Anus
The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...
, and nose
Human nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...
. An ointment may or may not be medicated.
Ointments are usually very moisturizing, and good for dry skin. They have a low risk of sensitization due to having few ingredients beyond the base oil or fat, and low irritation risk. There is typically little variability between brands of generics and namebrand drugs. They are often disliked by patients due to greasiness.
The vehicle of an ointment is known as the ointment base. The choice of a base depends upon the clinical indication for the ointment. The different types of ointment bases are:
- Hydrocarbon bases, e.g. hard paraffin, soft paraffinPetroleum jellyPetroleum jelly, petrolatum, white petrolatum or soft paraffin, CAS number 8009-03-8, is a semi-solid mixture of hydrocarbons , originally promoted as a topical ointment for its healing properties...
, microcrystalline waxMicrocrystalline waxMicrocrystalline waxes are a type of wax produced by de-oiling petrolatum, as part of the petroleum refining process. In contrast to the more familiar paraffin wax which contains mostly unbranched alkanes, microcrystalline wax contains a higher percentage of isoparaffinic hydrocarbons and...
and ceresine - Absorption bases, e.g. wool fat, beeswaxBeeswaxBeeswax is a natural wax produced in the bee hive of honey bees of the genus Apis. It is mainly esters of fatty acids and various long chain alcohols...
- Water soluble bases, e.g. macrogolMacrogolMacrogol is the International Nonproprietary Name for polyethylene glycol. Macrogols have been used as laxatives, i.e. to treat constipation....
s 200, 300, 400 - Emulsifying bases, e.g. emulsifying waxEmulsifying waxEmulsifying wax is a cosmetic emulsifying ingredient. The ingredient name is often followed by the initials NF, indicating that it conforms to the specifications of the National Formulary....
, cetrimide - Vegetable oils, e.g. olive oilOlive oilOlive oil is an oil obtained from the olive , a traditional tree crop of the Mediterranean Basin. It is commonly used in cooking, cosmetics, pharmaceuticals, and soaps and as a fuel for traditional oil lamps...
, coconut oilCoconut oilCoconut oil is an edible oil extracted from the kernel or meat of matured coconuts harvested from the coconut palm . Throughout the tropical world, it has provided the primary source of fat in the diets of millions of people for generations. It has various applications in food, medicine, and industry...
, sesame oilSesame oilSesame oil is an edible vegetable oil derived from sesame seeds. Besides being used as a cooking oil in South India, it is often used as a flavor enhancer in Chinese, Japanese, Korean, and to a lesser extent Southeast Asian cuisine.The oil from the nutrient rich seed is popular in alternative...
, almond oil and peanut oilPeanut oilPeanut oil is an organic material oil derived from peanuts, noted to have the aroma and taste of its parent legume....
.
The medicaments are dispersed in the base, and later they get divided after the drug penetration into the living cells of skin.
Ointments are formulated using hydrophobic, hydrophilic, or water-emulsifying bases to provide preparations that are immiscible, miscible, or emulsifiable with skin secretions. They can also be derived from hydrocarbon (fatty), absorption, water-removable, or water-soluble bases.
Evaluation of ointments
- Drug content
- Release of medicament from base
- Medicament penetration
- Consistency of the preparation
- Absorption of medicament into blood stream
- Irritant effect
Properties which affect choice of an ointment base are:
- Stability
- Penetrability
- Solvent property
- Irritant effects
- Ease of application and removal
Methods of preparation of ointments
Trituration: In this finely subdivided insoluble medicaments are evenly distributed by grinding with a small amount of the base followed by dilution with gradually increasing amounts of the base.
Fusion: In this method the ingredients are melted together in descending order of their melting points and stirred to ensure homogeneity.
Gel
GelGel
A gel is a solid, jelly-like material that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state...
s are thicker than a solution. Often a semisolid emulsion in an alcohol base. Some will melt at body temperature. Tends to be cellulose cut with alcohol or acetone. Tends to be drying. Tends to have greatly variable ingredients between generic brands and trade names. Significant risk of inducing hypersensitivity due to fragrances and preservatives. Useful for the scalp and body folds. Avoid fissures and erosions due to drying and stinging effect of alcohol base. High rate of acceptance due to its cosmetic elegance.
Transdermal patch
Transdermal patchTransdermal patch
A transdermal patch is a medicated adhesive patch that is placed on the skin to deliver a specific dose of medication through the skin and into the bloodstream. Often, this promotes healing to an injured area of the body. An advantage of a transdermal drug delivery route over other types of...
es can be a very precise time released method of delivering a drug. Cutting a patch in half might affect the dose delivered. The release of the active component from a transdermal delivery system (patch) may be controlled by diffusion through the adhesive which covers the whole patch, by diffusion through a membrane which may only have adhesive on the patch rim or drug release may be controlled by release from a polymer matrix. Cutting a patch might cause rapid dehydration of the base of the medicine and affect the rate of diffusion.
Powder
PowderPowder (substance)
A powder is a dry,thick bulk solid composed of a large number of very fine particles that may flow freely when shaken or tilted. Powders are a special sub-class of granular materials, although the terms powder and granular are sometimes used to distinguish separate classes of material...
is either the pure drug by itself (talcum powder), or is made of the drug mixed in a carrier such as corn starch or corn cob powder (Zeosorb AF - miconazole powder). Can be used as an inhaled topical (cocaine powder used in nasal surgery).
Solid
Medication placed in a solid form. Such as deodorant, antiperspirants, astringents, and hemostatic agents. Some solids melts when they reach body temperature (e.g. rectal suppositories).Sponge
Certain contraceptive methods relies on the sponge as a carrier of a liquid medicine. Lemon juice embedded in a sponge has been used as a primitive contraception in some cultures.Tape
Cordran tape is an example of a topical steroid applied under occlusionOcclusive dressing
An occlusive dressing is an air- and water-tight trauma dressing used in first aid. These dressings are generally made with a waxy coating so as to provide a total seal, and as a result do not have the absorbent properties of gauze pads...
by tape. This greatly increase the potency and absorption of the topical steroid and is used to treat inflammatory skin diseases.
Vapor
Some medications are applied as an ointment or gel, and reach the mucous membrane via vaporization. Examples are nasal topical decongestantTopical decongestant
Topical decongestants are decongestants applied directly to the nasal cavity. By applying them directly to the site of action, topical decongestants relieve nasal congestion while reducing the side effects associated with systemically-acting decongestants, such as high blood pressure...
s and smelling salt.
Paste
PastePaste (rheology)
In physics, a paste is a substance that behaves as a solid until a sufficiently large load or stress is applied, at which point it flows like a fluid. In rheological terms, a paste is an example of a Bingham plastic fluid....
combines three agents - oil, water, and powder. It is an ointment in which a powder is suspended.
See also
- LinimentLinimentLiniment , from the Latin linere, to anoint, is a medicated topical preparation for application to the skin. Preparations of this type are also called balm...
- UnguentUnguentAn unguent is a soothing preparation spread on wounds, burns, rashes, abrasions or other topical injuries . It is similar to an ointment, though typically an unguent is less viscous and more oily....
- Topical solution
- Finger tip unitFinger tip unitIn medicine, a finger tip unit is defined as the amount of ointment, cream or other semi-solid dosage form expressed from a tube with a 5mm diameter nozzle, applied from the distal skin-crease to the tip of the index finger of an adult. One FTU is enough to treat an area of skin twice the size...
- List of topical drugs
- LidocaineLidocaineLidocaine , Xylocaine, or lignocaine is a common local anesthetic and antiarrhythmic drug. Lidocaine is used topically to relieve itching, burning and pain from skin inflammations, injected as a dental anesthetic or as a local anesthetic for minor surgery.- History :Lidocaine, the first amino...
- Topical anestheticTopical anestheticA topical anesthetic is a local anesthetic that is used to numb the surface of a body part. They can be used to numb any area of the skin as well as the front of the eyeball, the inside of the nose, ear or throat, the anus and the genital area. Topical anesthetics are available in creams,...
- Topical antibiotic
- Topical antifungal drugs
- Topical bacitracin
- Topical chemotherapy
- Topical corticosteroids
- Topical cream formulation
- Topical decongestantTopical decongestantTopical decongestants are decongestants applied directly to the nasal cavity. By applying them directly to the site of action, topical decongestants relieve nasal congestion while reducing the side effects associated with systemically-acting decongestants, such as high blood pressure...
- Topical drug delivery system
- Topical florides
- Topical gel formulation
- Topical glucocorticoids
- Topical hydrocortisone
- Topical prednisolone
- Topical steroidTopical steroidTopical steroids are the topical forms of corticosteroids. Topical steroids are the most commonly prescribed topical medications for the treatment of rash, eczema, and dermatitis. Topical steroids have anti-inflammatory properties, and are classified based on their vasoconstriction abilities. There...