Pharmaceutical Dosage Forms PDF

Pharmaceutical Dosage Form Pharmaceutics: Pharmaceutics is the discipline of pharmacy that deals with the process of turning a new chemical entity or old drugs into a medication to be used safely and effectively by patients. It is also called the science of dosage form...

Pharmaceutical Dosage Form Pharmaceutics: Pharmaceutics is the discipline of pharmacy that deals with the process of turning a new chemical entity or old drugs into a medication to be used safely and effectively by patients. It is also called the science of dosage form design. Drug: A drug is any substance (other than food that provides nutritional support) that, when inhaled, injected, smoked, consumed, absorbed via a patch on the skin, or dissolved under the tongue causes a physiological change in the body. In Pharmacology Drug is a chemical substance used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well-being. Dosage forms are pharmaceutical drug products in the form in which drug molecules are delivered to sites of action within the body, with a specific mixture of active ingredients and inactive components. Need of Excipients: 1. To give particular shape to the formulation. 2. To increase stability 3. To increase palatability and give more elegance to the preparation. Ned of Dosage form: 1. To protect the drug substance from oxidation, hydrolysis and reduction. Eg: Coated Tablet. 2. To protect the drug from the destructive effect of gastric juice of the stomach after oral administration. Eg: Enteric Coated Tablet. 3. To provide a safe and convenient delivery of accurate dosage. 4. To mask the bitter taste and bad odour of a drug. 5. To provide optimum drug action through various routes of administration. Eg: Ophthalmic, Transdermal, Parenteral, Nasal, 6. To provide delayed release of the drug. Eg: Sustained or controlled release dosage form Type of Dosage form: SOLID DOSAGE FORM LIQUID DOSAGE FORM SEMI-SOLID DOSAGE FORM SOLID DOSAGE FORM: 1. UNIT DOSAGE FORM: TABLETS Lozenges Chewable Tablets Modified Release Tablets Effervescent Tablets etc CAPSULE Hard gelatin Capsule Soft Gelatin Capsule 2. BULK INTERNAL Fine Powder Granules and Effervescent Granules EXTERNAL Dentifrices (Tooth Powder) Ear Powder Liquid Dosage from 1. Biphasic Liquid in Liquid Emulsions Solid in liquid Suspensions 2. Monophasic Internal Syrups Elixures Linctus Drops External Liniments Lotions Gargles Throat Paints Mouth Washes Sprays Eye Lotions Eye Drops Nasal Drops Parenteral 3. Semisolid Dosage from Internal External  Ointments Creams Pastes Jellies SOLID DOSAGE FORM: Solid dosage forms are available mostly in unit dosage forms, ie dosage form which are taken by numbers such as tablets, capsules, pills etc. Some solids are packed and supplied in bulk. The bulk forms meant for internal use are supplied either as granules or fine powders. The bulk powder meant for external use are dusting powders, tooth powders etc. POWDERS: Powders are the solid dosage form of medicament, which are meant for internal or external use. They are available in crystalline and amorphous form. In crystalline powders the constituent atoms and molecules are packed in a regularly ordered, repeating three-dimensional pattern. Amorphous powders are non-crystalline materials which possess no long-range order. Any material ranging in particle size from 0.1 to 10000 µ may be described as powder. However powders used in pharmacy generally have a size between 0.1 to 10 µ. The powders are generally used in the following forms: 1. Bulk powder for internal use, Eg: Fine powders or granules 2. Bulk powder for external use, Eg: snuffs, dusting powders and tooth powders. 3. Simple and compound powders for internal use. 4. Powders in the form of compressed tablets and tablet triturates. 5. Powders enclosed in cachets and capsules. 6. Insufflations: Micronized powders meant for being blown in the nasal tract, ears, tooth sokets, vagina etc. 7. Parenteral powders: Powders for dissolution into vehicles before injection. DUSTING POWDER: Dusting powders are meant for application to the intact or broken skin. They are meant for external applications. Desired Property: 1. Ease of flow 2. Spreadability 3. The powder should adhere to the skin and possess good covering. 4. The dusting powder should protect the skin from drying and irritation. 5. Dusting powder should not have any irritant effect. Types: Dusting powders are of two types 1. MEDICAL 2. SURGICAL Medical dusting powders are used mainly for superficial skin conditions whereas surgical dusting powders are used in body cavities and also on major wounds as a result of burns. Surgical dusting powders must be sterile (free from bacteria or other living microorganisms) before their use. Formulation: It is generally prepared by mixing two or more ingredients one of which must be either starch, kaolin or talc. Talc and kaolin are most commonly used because these are chemically inert. Use: Dusting powders are mainly used for antiseptic (preventing the growth of disease-causing microorganisms.), astringent (a mild protein precipitant suitable for topical application to shrink tissues), adsorbent (Substance that binds to the drug surface), antiperspirant (a substance that is applied to the skin, especially under the arms, to prevent or reduce perspiration.) and antipruritic (used to relieve itching.)Action. INSUFFLATIONS: Insufflations are meant for powders being blown in various body cavities, like nose, throat, ears etc. They are generally applied with the help of insufflators. It sprays the powder into a stream of finely divided particles all over the site of application. Desired Quality 1. It should be finely divided powder. 2. They should be absolutely free from irritation and sensitizing quality. Disadvantages: 1. It is difficult to obtain a measured quantity of the drug as a uniform dose 2. Particles adhere to each other and to the wall of the insufflators due to the electrostatic force. Use: Used for local effects, as in the treatment of ear, nose and throat infections with antibiotics (a medicine such as penicillin or its derivatives that inhibits the growth of or destroys microorganisms.).  INSUFFLATORS SNUFFS: These are finely divided solid dosage forms of medicament which are inhaled into nostrils for its antiseptic, bronchodilator and decongestion action. DENTIFRICES: Dentifrices or tooth powders are hygienic products of everyday use. They may also be medicated in order to exercise some definite action on individual person. These are applied with the help of tooth brush for cleaning the surface of the teeth. Formulation: They contain abrasive agents such as calcium sulphate, magnesium carbonate, sodium carbonate and sodium chloride. It may also contain some detergent and suitable flavor. Detergent action is given by incorporating surfactants. Flavour and taste qualities are very significant in the formulation of dentifrices. GRANULES: The primary powder particles are made to adhere to form larger, multiparticle entities called granules and the process is known as granulation. The bitter, nauseous and unpleasant powders cannot be given in tablet form or in a capsule because a large number of them are required to be taken as a single dose. They also cannot be given as liquid form because of stability problem. Such medicaments are given in the form of granules. The drug is mixed with sugar, flavouring agent and a granulating agent to prepare a coherent mass, which is passed through a sieve to convert it into granules and then dried. These dried granules are supplied in single dose sachets which are dissolved in water before taking. Eg: Granules of antibiotics, such as erythromycin, and penicillin salts. EFFERVESCENT GRANULES: The effervescent granules are the specially prepared solid dosage form of medicaments, meant for internal use. They contain a medicament mixed with citric acid, tartaric acid and sodium bicarbonate. Sometimes saccharin or sucrose may be added as a sweetening agent. Before administration, the desired quantity is dissolved in water, the acid and bicarbonate reacts together and produce effervescence. The carbonated water produced from the release of carbondioxide serves to mask the bitter taste of drugs. Moreover carbon dioxide stimulates the flow of gastric juice and helps in the absorption of medicaments. 3NaHCO3 + C6H8O7.H2O = C6H5Na3O7 + 3CO2 + 3H2O Sodium Bicarbonate + Citric Acid = Sodium Citrate TABLETS: Tablets are solid unit dosage form which are prepared by molding or by compression. Compressed tablets offer a number of advantages to the patients as well as the physician and the pharmacists and that is why their popularity continues to increase. For the patient a tablet or a capsule is the most convenient form to use, because it neither involves measurement of dose and easy to carry. Tablets are also easy to be administered and dispensed. It is also a stable dosage form and maintain accuracy of dosage. CAPSULES: Capsules are solid unit dosage from in which one or medicaments and inert substances are enclosed within a small shell, generally prepared from a suitable form of gelatin. Depending on their formulation, the gelatin capsule shell may be hard or soft. PILLS: Pills are small rounded solid dosage forms containing medicament and are intended to be administered orally. Pills are spherical in shape and sometimes coated with varnish, silver leaf, and gold leaf to improve the finish, mask the unpleasant tastes and increase stability. In olden days pills were preferred because of their spherical shape which can be easily swallowed. But now a days it is not used because of the following reasons: 1. Disintegration time of the pills is uncertain. 2. It is difficult to prepare pills of a uniform size. 3. It is difficult to prepare pills of uniform weight.  LIQUID DOSAGE FORM: The liquid dosage forms, whether for internal, parenteral or external use may be either monophasic or biphasic products. Monophasic products are represented by true or colloidal solutions and solubilised preparations. They are appeared to be similar in physical appearance and consists of only one phase. They may have water as the solvent or may be occasionally based on some other liquids. The biphasic products are exemplified by emulsions or suspensions and consists of two phases. In emulsions generally both the phases are liquids, while in suspensions the continuous phase is liquid and the dispersed phase is finely divided solids. Liquid preparations are easy to swallow and thus more useful for pediatrics and geriatrics. On the other hand drug in soluble state is chemically less stable than its insoluble state. Monophasic dosage forms are available as: 1. Liquid for internal use, Eg: Syrups, Elixirs, Linctus, drops and draughts. 2. Liquids for external use, which are of two types: A. Liquid to be applied to the skin, eg: liniments and lotions. B. Liquids for body cavities. Eg: Gargles, throat paints, mouth washes, eye drops, eye lotions, ear drops, nasal drops, spray and inhalations. Liquid for internal use: The largest proportion of the liquid formulations are liquid for internal use. Drug should have sufficient solubility in commonly used solvent, like water. Syrups: Syrups are sweet and viscous aqueous preparations. Simple syrup is a saturated solution of sucrose in purified water. The concentration of sucrose used is 66.7 % w/w (as per Indian Pharmacopoeia, IP). They are either flavoring syrups (syrups containing aromatic or flavored substances) and medicated syrups (Syrup containing medicinal substances). Syrups are used for formulating antibiotics, antitussives, antihistaminic, sedatives, vitamins etc. Most syrups are aqueous solutions of sucrose or dextrose. Artificial syrups are also in the market, where artificial sweetening agents (Eg: saccharine and sodium cyclamate) are used. The artificial syrups are having two points in their favour 1. They are free from carbohydrates and suitable for diabetics. 2. They have lesser stability problems as compared to sugar based syrups. Syrups are commonly used for the following reasons: 1. They are palatable 2. Syrups have high osmotic pressure which prevents growth of bacteria, fungi and prevent decomposition of many vegetable substances. Due to this syrups have the self-preservative activity. 3. Syrups retards oxidation because it is partly hydrolysed into reducing sugars, such as lavulose and dextrose. Elixirs: Elixirs are clear sweetened and flavoured hydroalcoholic solutions for oral use. Non medicated elixiers such as aromatic elixir are mainly used as flavoured vehicle. Medicated elixiers have their own therapeutic value. Alcohol content in elixiers varies from 3 to 40%. Due to high alcohol content, elixirs are not the choice of dosage forms for pediatrics. The main ingredients of elixirs are ethyl alcohol, water, glycerin, propylene glycol, flavouring agent, colouring agent and some preservative. The medicated elixirs usually contain a potent drug such as, antibiotics, antihistamines or sedatives. Eg: Piperazine Citrate Elixirs I.P (Piperazine Citrate) Linctuses: Linctuses are viscous liquid and oral preparations that are generally prescribed for the relief of cough. Mostly it contains ingredient with sedative action and some contains expectorants. Simple syrup is generally used as a vehicle for most of the linctuses. This give soothing to the sore mucous membrane of the throat. To obtain and prolong local action, linctuses should be taken undiluted and sipped and swallowed slowly. Eg: Codeine Linctus B.P.C (API: Codeine Phosphate) Drops: These are small dose liquids administered without dilution with the help of dropper. The oil soluble vitamins, such as vitamin A and D concentrates in fish liver oil are presented as drops for administration. Since these preparations contain potent medicaments, the dose must be measured accurately. Droppers is either graduated in fractions of a milliliters or pre calibrated. Liquid Formulations for External Use: Monophasic liquids for external use may be categorised into following classes a. Liquids for application to the intact skin, such as liniments, lotions etc b. Liquids for the use in one or the other body cavities such as gargles, throat paints, eye drops, eye lotions, ear drops, ear douches, nasal drops, enemas etc.  c. Liquids meant to be inhaled into or sprayed in nasal or respiratory tracts. Liniments: The liniments are liquid or semi-liquid preparations meant for application to the skin. The liniments are usually applied to the skin with friction and rubbing of the skin. They are solutions or emulsions in an aqueous or oily vehicles. They are used as counter irritant, rubefacient and soothing. Alcohols are also used in the preparation of liniments. Alcohol in the liniments helps in the penetration of medicaments into the skin and also increases its counter irritant and rubefacient action. In oily liniments arachis oil is used commonly, which spread more easily on the skin. A liniment should not be applied to the broken skin because it may causes excessive irritation. Eg: Liniment of Camphor. Lotions: Lotions are suspensions, emulsions, combination of emulsion-suspension or aqueous or non- aqueous solutions designed to be applied to the unbroken skin without friction. They are used for their epidermic effect, such as local cooling, soothing, protective, drying or moisturizing properties depending upon the ingredients used. They are directly applied to the skin with the help of some adsorbent material, such as, cotton wool. Eg: Calamine Lotion I.P Collodions: Collodions are liquid preparations for external use. It contains pyroxylin (nitrocellulose) in a mixture of ethyl ether and alcohol. They are applied to the skin by means of a soft brush or suitable applicator. After application ether and alcohol get evaporated and leaves a film of pyroxylin on the surface of the skin. As the preparation contains the volatile substances collodions are highly inflammable. Gargles: Gargles are clear aqueous solutions used in the posterior region of mouth by agitating the solution with exhaled air to produce local effect in throat and these are not to be swallowed in large amount. They are usually available in concentrated form with direction for dilution with warm water before use. They are brought into intimate contact with the mucous membrane of the throat and are allowed to remain in contact with it for a few seconds before they are thrown out of the mouth. They are used to relieve soreness in mild throat infection. Phenol or thymol is generally present in small concentration for its antibacterial activity. Potassium chlorate is also included in gargles for its weak astringent effect to tone up a relaxed throat. It also stimulates secretion of saliva which relieves dryness, eg: Phenol gargles, Potassium chloride and phenol gargles. Mouth Washes: These are aqueous solutions with a pleasant taste and odour used to make clean and deodorise the buccal cavity.  Generally they contain antibacterial agents, alcohol, glycerin, sweetening agents, flavouring agents and colouring agents. Eg: Sodium Chloride Mouth Wash, Compound B.P.C. Throat Paints: Throat paints are viscous preparations of medicaments for local action in the pharynx. Glycerin is commonly used as a base because, being viscous, it adheres to mucous membrane for a long period and it possesses sweet taste. They are applied to the throat with a brush. Throat paints are used in treatment of inflammations of various areas of the mouth and throat. Douches: Douches are aqueous solutions intended to clean, deodorise, soothe or medicate body cavities. Eye douches, often termed as eyewashes, are used to remove foreign particles and discharges from the eyes. Douches are generally dispensed in the form of a powder or tablet with a specific directions for dissolving it in a specific quantity of warm water. Vaginal douches must be sterile. They are used for: a. Cleansing agents: Isotonic sodium chloride solution b. Antiseptics. Eg: Mercuric chloride (0.001%) c. Astringent, Eg: Alum (1%) Enemas: Enemas are aqueous or oily solutions, suspension or emulsions of medicaments intended for rectal administration, to cause bowel evacuation, to bring about local or systemic therapeutic action etc. Enemas meant for cleaning purpose are used to evacuate faeces in constipation or before an operation. They act by any one of the following methods: a. By stimulating peristalsis. b. By lubricating impacted faeces. Ear Drops: Ear drops are solutions, suspensions or emulsions of drugs in water, glycerin or propylene glycol intended for instillation into the ear. These are used for removal of excessive cerumen, to treat infection, inflammation or pain and for cleaning and drying of ear. Eye Drops: These are sterile solutions or suspensions of drugs that are instilled into the eye with a dropper. The eye drops are usually made in aqueous vehicle. It should be sterile, isotonic with lachrymal secretions and free from foreign particles to avoid irritation to the eye. A suitable preservative like phenyl mercuric nitrate (0.002%), Benzalkonium chloride (0.01%) may be used to prevent bacterial or fungal growth.  Eye drops usually contain substances having antiseptic, anti-inflammatory, anesthetic and miotic properties. Nasal Drops: These are aqueous solutions of drops that are instilled into the nose with a dropper. Nasal drops should be isotonic with 0.9% sodium chloride having neutral pH and viscosity similar to nasal secretions by using0.5% methyl cellulose. Biphasic Liquid Dosage form: Liquids which consist of two phases are known biphasic liquids. Eg: Emulsions and suspensions. Emulsions: Emulsions are thermodynamically unstable heterogeneous biphasic system consisting of two immiscible liquids, one of which is dispersed as minute globules into the others. This type of formulations are stabilized by using emulsifying agent. Internal phase droplets are generally ranged in diameter of 0.1 µm to 100 µm. Emulsions are mostly classified as oil in water (o/w) emulsions and water in oil (w/o) emulsions. Emulsions are used for 1. Oral administration, Eg: Liquid Paraffin Emulsion IP 2. Intravenous administration, Eg: Emulsion of vitamin A,D and K and 3. For external use, Eg: Emulsions for topical administration. Suspensions: Suspensions are heterogeneous biphasic, thermodynamically unstable liquid dosage form of medicaments in which insoluble solid particles (as internal, discontinuous or dispersed phase) is uniformly distributed in liquid phase (External, continuous or dispersion phase). In suspensions finely divided particles ranging from 0.5 to 5 microns are dispersed in a liquid vehicle. Suspensions are used for oral, parenteral and external applications. Suspensions which are meant for external applications should have small particle size to avoid gritty feeling to the skin and to cover a larger area of the skin. Smaller particles also helps in the penetration of drug through the skin. Semisolids: Semisolid dosage forms are dermatological products of semisolid consistency and applied to skin for therapeutic or protective action or cosmetic function. Semisolid dosage forms usually are intended for localized drug delivery. In the past few years, however, these forms also have been explored for the systemic delivery of various drugs. Semisolids constitute a significant proportion of pharmaceutical dosage forms. They can be applied topically to the skin, cornea, rectal tissue, nasal mucosa, vagina, buccal tissue, urethral membrane, and external ear lining. Eg: Ointments, creams, jellies and pastes etc. Advantages of semi-solid dosage form: It is used externally The probability of side effects can be reduced First, pass gut and hepatic metabolism is avoided. Local action and Site-specific action of the drug on the affected area. Convenient for unconscious patients or patients to have difficulty in oral administration. Suitable dosage form for bitter drugs. More stable than a liquid dosage form. Disadvantages of semi-solid dosage form: The accuracy can’t be measured, for the semisolid dosage form. May cause staining. They are bulky to handle. Application with a finger may cause contamination. Physico-chemical is less stable than a solid dosage form. May cause irritation or allergy to some patients Ideal properties of semisolid dosage forms: Smooth texture Elegant in appearance Non-dehydrating Non-gritty Non-greasy and non-staining Non-hygroscopic Ingredients needed for semisolid dosage form: Bases Preservative Humectants Antioxidants Emulsifier Gelling agent Permeation enhancer Buffers Bases used in semisolid dosage form: It is one of the most important ingredients used in the formulation of the semisolid dosage form. Ointment bases do not merely act as the carriers of the medicaments, but they also control the extent of absorption of medicaments incorporated in them. Ideal characterization of bases used in semisolid dosage form: They should be: Inert, non-irritating, and non-sensitizing. Compatible with skin pH and the drug. Good solvent and/or emulsifying agent.  Emollient, protective, non-greasy and easily removable. Release medicament readily at the site of application. Pharmaceutically elegant and possess good stability Classification of Bases: According to USP ointment bases are classified into four general groups: Hydrocarbon bases (oleaginous bases) (Petrolatum, Paraffin, Lanolin, etc.) Absorption bases (cold cream, anhydrous lanolin, etc.) Water-removable bases ( oil in water) Water-soluble bases (polyethylene glycol) Antioxidants used in semisolid dosage form: Oxygen has the capability to become a part of potentially damaging molecules called “free radicals.” Free radicals can attack the healthy cells of the body. It can break their structure and that’s why the function is also affected. Example: Butylated hydroxyanisole, Butylated hydroxytoluene Ingredients that increase permeation: Skin can act as a barrier. There are various penetration enhancers that can help the drug to penetrate through the skin. Oleic acid The emulsifier used in semisolid dosage form: Emulsifiers are used to improve the stability of an emulsion by increasing its kinetic stability. It reduces surface tension and prevents coalescence. It helps to increase the viscosity at low concentration. Emulsifying agents used in semisolid dosage form: Sodium lauryl sulfate: Oil/Water emulsion – Sodium stearate and calcium stearate. Glyceryl monostearate: This is a weak Water/Oil emulsifying agent and it is used as a stabilizer and emollient in the Oil/Water emulsion. Humectant used in semisolid dosage form: The humectant is a hygroscopic substance used to increase the solubility of the active ingredient to increase skin penetration. It’s also used to improve the hydration of the skin. Buffers used in semisolid dosage form: Buffers are added for various purposes. Such as Compatibility with skin. Drug solubility. Drug stability. Influence the ionization of drugs. Preservatives used in semisolid dosage form: Preservatives are used to inhibit the growth of contamination of microorganisms. Example: Para-hydroxybenzoate (parabens), phenols, benzoic acid, sorbic acid, etc. Automatic Ointment/Cream Manufacturing Plant Pastes: Pastes are basically ointments containing high percentage of insoluble solids (usually 20-50 % or higher). They are semisolid preparations intended for external application. Pastes are generally very thick and stiff. They have good adhesion on skin and they form thick coat. They are used mainly as antiseptic, protective or soothing dressing. Ointments: Ointments are semisolid preparations with or without medicaments intended for application to the skin. Medicaments used in the formulation is dissolved, suspended or emulsified in an ointment base. The ointments are mainly used as protective or emollient for the skin. Ointments may be used as- 1. Antibiotic ointments. Drug used: Neomycin. 2. Antifungal ointment. Drug used: Benzoic acid, salicylic acid, nystatin. 3. Anti-inflammatory ointment. Drug used: hydrocortisone, etc ENVIRONMENT Temperature: 20-300 C, Humidity: 30-60 %, DOCUMENTS: 1. Standard Operating Procedure (SOP) 2. Batch Manufacturing Record (BMR) 3. Batch Packaging Record (BPR) 4. In House specification Process Flow Chart for ointment: Gels and Jellies: Gels and jellies are transparent to opaque semisolid preparations meant for external application to the skin or mucous membrane. Considered to be more rigid than jellies. Jellies contain more fluid and less cross-linking agent. They are non-greasy and prepared from Natural gums, eg: Tragacanth, Pectin, Sodium Alginate etc. Synthetic derivatives of natural substances, eg: Methyl cellulose, Sodium carboxymethyl cellulose. Poultices: Poultices are viscous pasty preparations applied hot to the skin to reduce inflammation and to act as counter irritant. Heavy kaolin is commonly included in the formulation because it act as a carrier of heat. It is an outdated preparation. Creams: These are viscous semisolid emulsions which are meant for external use. They usually contain a water soluble base due to which they can be easily removed from the skin.  They are of softer consistency and have light weight in comparison to true ointments when applied to the skin. Cream leave no visible evidence of their presence on the skin. They are of mostly two types a. Aqueous cream, Eg: Cetrimide Cream B.P b. Oily cream, Eg: Proflavine cream BPC Cream preparation Process Flow Chart Cream: Suppository: Suppository is another way to deliver drugs. It’s a small, round or cone shaped object that put in body orifice, often into bottom. Once its inside, its melt and dissolves and releases the medicine and exert local or systemic effects. Type of suppository There are three type of suppository Rectal Suppository – into the rectum. Vaginal Suppository – into the vagina. Urethral Suppository – into male urethra. ADVANTAGES OF SUPPOSITORIES Over Oral Drug Administration: Avoid first pass metabolism Introduce drugs into the body Does not cause nausea and vomiting due to gastric irritation in case of oral therapy Used before surgery since oral therapy is restricted Beneficial for patients suffering from severe vomiting Can be administered to unconscious patients Can be used as targeted drug delivery system Localized action with reduced systemic distribution Get to site of action with lower dose reducing systemic toxicity Highly beneficial in haemorrhoids or vaginal infections Prolonged drug action achieved Over parenteral drug administration: Self-medication No systemic side effects No pain or site of action related issues Over Vaginal Tablets: Suppositories dissolves faster Total bioavailability achieved No residue remains like tablet No need of applicator Non staining Non itching DISADVANTAGES OF SUPPOSITORIES: Mucosal irritation Patient compliance Erratic and undesired absorption Placement too high into rectum may lead to first pass metabolism Installation may trigger defecation reaction GI state affects absorption, Diarrhoea & disease states affect absorption