DRUG DOSAGE FORMS 1 Dosage forms 2 Definition

DRUG DOSAGE FORMS 1

Dosage forms: 2 Definition: Dosage forms are the means by which drug molecules are delivered to sites of action within the body. The need for dosage forms: 1 - Accurate dose. 2 - Protection e. g. coated tablets, sealed ampules. 3 - Protection from gastric juice. 4 - Masking taste and odour. 5 - Use of desired vehicle for insoluble drugs.

Medicine API (Active Pharmaceutical Ingredients) 3 Excipients

EXCIPIENTS: AN EXCIPIENT IS A PHARMACOLOGICALLY INACTIVE SUBSTANCE FORMULATED ALONGSIDE THE ACTIVE PHARMACEUTICAL INGREDIENT OF A MEDICATION . Purposes served by excipients: 4 • Provide bulk to the formulation. • Facilitate drug absorption or solubility • Aid in handling of “API” during manufacturing. • Provide stability and prevent from denaturation.

A list of Pharmaceutical Excipients used in pharmaceutical preparations usually: : l. Fillers. l. Binders. l. Disintegrants. l. Coatings. l. Sorbents. l. Anti adherent. l. Lubricants. l. Glidants. l. Preservatives. 5 l. Antioxidants. l. Flavoring Agents. l. Sweeting Agents. l. Coloring Agents. l. Solvent & Co-solvent. l. Buffering Agents. l. Chelating Agents. l l l Viscosity imparting Agents. Surface Active Agents. Humectants.

FILLERS: FILLERS TYPICALLY ALSO FILL OUT THE SIZE OF A TABLET OR CAPSULE, MAKING IT PRACTICAL AND CONVENIENT FOR THE CONSUMER TO USE. Typical features of fillers: A good filler should typically be inert, compatible with the other components of the formulation, relatively cheap, compactible, and preferably tasteless or pleasant tasting. Examples: Plant cellulose and dibasic calcium phosphate are used 6 popularly as fillers. A range of vegetable fats and oils can be used in soft gelatin capsules. Other examples of fillers include: lactose, sucrose, glucose, mannitol, sorbitol, calcium carbonate, and magnesium stearate.

BINDERS: BINDERS HOLD THE INGREDIENTS IN A TABLET TOGETHER. . Typical features of binders: A binder should be compatible with other products of formulation and add sufficient cohesion to the powders. Classification and examples: Binders are classified according to their application, • • 7 Solution binders are dissolved in a solvent (for example water or alcohol can be used in wet granulation processes). Examples include gelatin, cellulose derivatives, starch, sucrose and polyethylene glycol. Dry binders are added to the powder. Examples include cellulose, methyl cellulose, and polyethylene glycol.

DISINTIGRANTS: DISINTIGRANTS ARE SUBSTANCES OR MIXTURE OF SUBSTANCES ADDED TO THE DRUG FORMULATIONS, WHICH FACILITATE DISPERSION OR BREAKUP OF TABLETS AND CONTENTS OF CAPSULES INTO SMALLER PARTICLES FOR QUICK DISSOLUTION WHEN IT COMES IN CONTACT WITH WATER IN THE GIT . Ideal properties of disintigrants: Good hydration capacity , poor solubility , poor gel formation capacity. Examples: carboxymethyl cellulose, sodium starch glycolate. 8

COATING AGENT: COATING IS A PROCESS BY WHICH AN ESSENTIALLY DRY, OUTER LAYER OF COATING MATERIAL IS APPLIED TO THE SURFACE OF A DOSAGE FORM AND AGENTS WHICH ARE USED IN THIS COATING PROCESS IS CALLED COATING AGENTS. Types: Three types of coating agents are used pharmaceutically, Film coating. Sugar coating. Compression coating. Function of coating agents: Protection, masking, elegance, ease of swallowing, etc. . Examples: HPMC, HPC etc. . 9

SORBENTS: SORBENTS ARE MATERIALS THAT SOAK UP OIL FROM THE WATER. Types and examples of sorbents: • • Natural sorbents- sawdust, feathers, and anything else natural that contains carbon. Synthetic sorbents- polyethylene and nylon etc. . Functions of sorbents: Sorbent are used for tablet/capsule moisture-proofing by limited fluid sorbing (taking up of a liquid or a gas either by adsorption or by adsorption) in a dry state. 10

ANTIADHERENTS: ANTIADHERENTS OR ANTI-STICKING AGENTS PREVENT ADHESION OF THE TABLET SURFACE TO THE DIE WALLS AND THE PUNCHES AND AS A CONSEQUENCE COUNTER THE PICKING OR STICKING OF TABLET . Examples: Water insoluble lubricants such as magnesium stearate can be used as antiadherents , as can talc and starch. Lubricants: 11 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. Types: • Hydrophilic- Generally poor lubricants, no glidant or anti-adherent properties, and Hydrophobic that has have both anti- adherent and glidant properties. Examples: Polyethylene glycol, Magnesium stearate, Stearic acid and it’s derivatives.

Roles of lubricants: 1. True Lubricant Role: • To decrease friction at the interface between a tablet’s surface and the die wall during ejection and reduce wear on punches & dies. 2. Anti-adherent Role: • Prevent sticking to punch faces or in the case of encapsulation, lubricants • Prevent sticking to machine dosators, tamping pins, etc. 3. Glidant Role: • Enhance product flow by reducing interparticulate friction 12

GLIDANTS: A SUBSTANCE (AS COLLOIDAL SILICA) THAT ENHANCES THE FLOW OF A GRANULAR MIXTURE BY REDUCING INTER-PARTICLE FRICTION AND THAT IS USED IN THE PHARMACEUTICAL PRODUCTION OF TABLETS AND CAPSULE . Functions of glidants: Glidants are used to promote powder flow by reducing interparticle friction and cohesion. These are used in combination with lubricants as they have no ability to reduce die wall friction. Examples: Fumed silica, talc, and magnesium carbonate. 13

PRESERVATIVES: PRESERVATIVES ARE SUBSTANCES THAT COMMONLY ADDED TO VARIOUS FOODS AND PHARMACEUTICAL PRODUCTS IN ORDER TO PROLONG THEIR SHELF LIFE. Ideal properties of preservatives: In concept, the preservative system protects the product against microbial proliferation but does not compromise product performance. In practice, this means that it must: • • 14 Exert a wide spectrum of antimicrobial activity at low inclusion levels. Maintain activity throughout product manufacture, shelf life and usage. Not compromise the quality or performance of product, pack or delivery system. Not adversely affect patient safety or tolerance of the product. Examples: Methyl & Ethyl parabens, Propyl paraben, Benzoic acid and its salts, Sorbic acid and its salts.

ANTIOXIDANT: AN ANTIOXIDANT IS A MOLECULE THAT INHIBITS THE OXIDATION OF OTHER MOLECULES. OXIDATION IS A CHEMICAL REACTION THAT TRANSFERS ELECTRONS OR HYDROGEN FROM A SUBSTANCE TO AN OXIDIZING AGENT . 15 Ideal Properties of Antioxidants: • Effective at a low, nontoxic concentration • Stable and effective under normal conditions of use, over a wide p. H and temperature range • Soluble at the required concentration • Compatible with a wide variety of drugs and pharmaceutical excipients • Free from objectionable odor, objectionable taste • Colorless in both the original and oxidized form • Nontoxic both internally and externally at the required concentration • Reasonable cost • Unreactive (does not adsorb, penetrate, or interact) with containers or closures Examples: BHT( Butylated Hydroxy Toluene), BHA( Butylated Hydroxy Anisol), Sodium sulfite, Ascorbic acid etc. .

SWEETENING AGENTS: SWEETENING AGENTS ARE EMPLOYED IN LIQUID FORMULATIONS DESIGNED FOR ORAL ADMINISTRATION SPECIFICALLY TO INCREASE THE PALATABILITY OF THERAPEUTIC AGENT. Example: Sucrouse, Saccarine, Aspertame, Sorbitol etc. Uses of sweetening agent: The main sweetening agents employed in oral preparations are sucrose, liquid glucose, glycerol, sorbitol, saccharin sodium and aspartame. Aspartame is an artificial sweetening agent. The use of artificial sweetening agents in formulations is increasing. The use of sugars in oral formulations for children and patients with diabetes mellitus is to be avoided. 16

FLAVORING AGENTS: FLAVOURING AGENTS ARE ADDED TO INCREASE PATIENT ACCEPTANCE. THE FOUR BASIC TASTE SENSATIONS ARE SALTY, SWEET, BITTER AND SOUR. IT HAS BEEN PROPOSED THAT CERTAIN FLAVOURS SHOULD BE USED TO MASK THESE SPECIFIC TASTE SENSATIONS. Example: Clove oil, citric and syrup, glycerin, rose oil, orange oil, menthol etc. . Coloring agents: Coloring agents are pharmaceutical ingredients that impart the preferred color to the formulation. There are two types of coloring agents 1. Natural and 2. synthetic Example: 17 1. White: Titanium dioxide 2. Blue : Brilliant blue , Indigo carmine 3. Red : Amaranth Carmine 4. Yellow: saffron 5. Green 6. Brown: caramel

SOLVENT A SOLVENT IS A SUBSTANCE THAT CAN DISSOLVE A SOLUTE (A CHEMICALLY DIFFERENT LIQUID , SOLID OR GAS) RESULTING IN SOLUTION. A SOLVENT IS USUALLY A LIQUID BUT IT CAN ALSO BE SOLID OR A GAS. A SOLVENT NEVER CHANGES ITS STATE FORMING A SOLUTION. 18 Solvent classification • Polar • Non polar Example and uses of solvent • The first choice for a solvent is water in which a drug is freely soluble. • Water –miscible solvent such as Chlordiazepoxide hydrochloride can be used to improve solubility and stability. • Oils are used as emulsion, intramuscular injections and liquid fill oral preparation. • Aqueous methanol is widely used in HPLC and is the standard solvent in sample extraction. • Other acceptable non-aqueous solvents are glycerol , propylene glycol, ethanol and are used generally for a lipophilic drug.

CO-SOLVENT CO-SOLVENTS ARE DEFINED AS WATER-MISCIBLE ORGANIC SOLVENTS THAT ARE USED IN LIQUID DRUG FORMULATIONS TO INCREASE THE SOLUBILITY OF POORLY WATER SOLUBLE SUBSTANCES OR TO ENHANCE THE CHEMICAL STABILITY OF A DRUG. Properties of co-solvent • Co-solvent increases the solubility of a drug. • An ideal co-solvent should possess values of dielectric constant between 25 and 80. • The most widely used system that will cover this range is a water/ethanol blend. • It should not cause toxicity or irritancy when administrated for oral or parental use • Other co-solvents are sorbitol, glycerol, propylene glycol and syrup. . 19

CHELATING AGENTS ARE MOLECULES THAT ARE CAPABLE OF FORMING COMPLEXES WITH THE DRUG INVOLVING MORE THAN ONE BOND IT’S A COMPLEX COMPOUND CONTAINS ONE OR MORE RING IN ITS STRUCTURE. Example and uses of chelating agent • EDTA: ethylene diamine tetraacetate is used for the estimation of metals ions. • EDTAH 4: ethylene diamin tetraacetic acid is used for softening water. • Calcium Disodium Edetate: it is used in the treatment of heavy metal poisoning mostly caused by lead. • Disodium Edetate: it is used in hypercalcemic states. It is also useful ion the treatment of cardiac arrhythmias. 20

BUFFERING AGENT THESE ARE MATERIALS WHICH, WHEN DISSOLVED IN SOLVENT WILL ENABLE THE SOLUTION TO RESIST ANY CHANGE IN PH SHOULD AN ACID OR AN ALKALI BE ADDED. THE CHOICE OF SUITABLE BUFFER DEPENDS ON THE PH AND BUFFERING CAPACITY REQUIRED. Features of buffering agent It should have a low toxicity, it should be buffered at the range of 7. 4 as the p. H of the body is 7. 4, it should be non-irritant. 21 Examples of buffering agent Most of the buffering system are based on carbonate, citrates, gluconates , lactates, phosphates, or tartrates etc.

VISCOSITY IMPARTING AGENTS THESE AGENTS ARE USED WHEN IT IS DESIRABLE TO INCREASE OR DECREASE THE VISCOSITY OF A LIQUID EITHER TO SERVE AS ADJACENT FOR PALATABILITY OR TO IMPROVE POUR Viscosity imparting agents are of two types: ABILITY. THEY ARE ALSO CALLED THICKENING AGENTS. a) Viscosity modifier-Viscosity modifiers decrease the viscosity of a liquid to improve pour ability and make it more palatable. b) Viscosity enhancer- Viscosity enhancers increase the viscosity of a liquid to improve pour ability and make it more palatable. Most commonly used viscosity imparting agents are : Hydroxyethylcellulose Hydroxypropylmethylcellulose Methylcellulose Polyvinyl alcohol Polyvinylpyrrolidone 22

HUMECTANT ATTRACTS AND RETAINS THE MOISTURE IN THE NEARBY AIR VIA ABSORPTION, DRAWING THE WATER VAPOR INTO AND/OR BENEATH THE ORGANISM/OBJECT'S SURFACE . Humectants absorb water vapors from atmosphere till a certain degree of dilution is attained. Aqueous solutions of humectants can reduce the rate of loss of moisture. 23 Ideal properties of humectants : • It must absorb moisture from atmosphere and retain the same under the normal conditions of atmospheric humidity. • It should be colorless or not of too intense color. • It should have good odor and taste. • It should be nontoxic and nonirritant. • It should be noncorrosive to packaging materials • It should not solidify under normal conditions. • It should not be too costly. .

Classification of humectants with examples : There are three types of humectants such as inorganic humectants, metal organic humectants and organic humectants. Inorganic humectants: These are limited used in cosmetics. Calcium chloride is an example. It has compatibility problems and corrosive in nature. Hence it is not frequently used in cosmetics. Metal organic humectants: These are limited used in cosmetics because of compatibility problems, corrosive nature and pronounced taste. The example of this class is sodium lactate. Organic humectants: These are widely used in cosmetics. They include polyhydric alcohols, their esters and ethers. The most commonly used organic humectants are glycerol, ethylene glycol, polyethylene glycol (PEG), diethylene glycol, tri ethylene glycol, propylene glycol, dipropylene glycol, glycerin, sorbitol, mannitol, glucose. 24

SURFACTANTS ARE COMPOUNDS THAT LOWER THE SURFACE TENSION (OR INTERFACIAL TENSION) BETWEEN TWO LIQUIDS OR BETWEEN A LIQUID AND A SOLID AND INCREASE THE SOLUBILITY. THEY ARE ALSO KNOWN AS SURFACE ACTIVE AGENTS . Properties of surfactants : A surfactant must fulfill two structural requirements: a) b) A surfactant must contain a lipophilic region. A surfactant must contain a hydrophilic region. In a surfactant both hydrophilic and lipophilic region must be balanced because then both the regions will be concentrated at an interface and therefore surface tension will be lowered. Types of surfactants : There are of four types of surfactants based on the charge of the hydrophilic region : 25 1. Anionic surfactant ( here the hydrophilic region is negatively charged i. e. an anion) Sodium lauryl sulphate - It is used as an excipient on some dissolvable aspirins and other fiber therapy caplets.

2. Cationic surfactant (here hydrophilic region is positively charged i. e. a cation) Cetyl trimethyl ammonium bromide ( cetrimide ) - is an effective antiseptic agent against bacteria and fungi. 3. Non-ionic surfactants : Tween 80 ( polyoxyethylene sorbitol monooleate)- Polysorbate 80 is an excipient that is used to stabilize aqueous formulations of medications for parenteral administration Span ( sorbitan ester of lauric acid ) 4. Amphoteric surfactant : Lecithin- it acts as a wetting, stabilizing agent and a choline enrichment carrier, helps in emulsifications and encapsulation, and is a good dispersing agent. N-dodecyl alanine. 26

Types of dosage forms: They are classified according to: 27 Route of administration I) Oral II) Topical III) Rectal IV) Parenteral V) Vaginal VI) Inhaled VII) Ophthalmic VIII) Otic Physical form I) Solid II) Semisolid III) liquid IV) Gaseous

I) Oral dosage forms: 1 -Tablet: A tablet is a hard, compressed medication in round, oval or square shape. The excipients include: -Binders, glidants (flow aids) and lubricants to ensure efficient tabletting. -Disintegrants to ensure that the tablet breaks up in the digestive tract. -Sweeteners or flavours to mask the taste of bad-tasting active ingredients. -Pigments to make uncoated tablets visually attractive. 28 .

1 -Tablet (Cont. ) A coating may be applied to: 1 - hide the taste of the tablet's components. 2 - make the tablet smoother and easier to swallow. 3 - make it more resistant to the environment. 4 - extending its shelf life. 29

2 -Buccal and sublingual tablet: - Sublingual and buccal medications are administered by placing them in the mouth, either under the tongue (sublingual) or between the gum and the cheek (buccal). - The medications dissolve rapidly and are absorbed through the mucous membranes of the mouth, where they enter into the bloodstream. - Avoid the acid and enzymatic environment of the stomach and the drug metabolizing enzymes of the liver. - Examples of drugs administered by this route: e. g. vasodilators, steroidal hormones. 30

3 -Effervescent tablet: Effervescent tablets are uncoated tablets that generally contain acid substances (citric and tartaric acids) and carbonates or bicarbonates and which react rapidly in the presence of water by releasing carbon dioxide. -They are intended to be dissolved or dispersed in water before use providing: A- Very rapid tablet dispersion and dissolution. B- pleasant tasting carbonated drink. 31

4 - Chewable tablet: - 32 They are tablets that chewed prior to swallowing. They are designed for administration to children e. g. vitamin products.

Hard gelatin capsule Soft gelatin capsule Spansules 5 - Capsule: A capsule is a medication in a gelatin container. - Advantage: mask the unpleasant taste of its contents. - The two main types of capsules are: 1 - hard-shelled capsules, which are normally used for dry, powdered ingredients, 33 2 - soft-shelled capsules, primarily used for oils and for active ingredients that are dissolved or suspended in oil.

6 - Lozenge: -It is a solid preparation consisting of sugar and gum, the latter giving strength and cohesiveness to the lozenge and facilitating slow release of the medicament. - It is used to medicate the mouth and throat for the slow administration of indigestion or cough remedies. 34

7 - Pastilles: They are solid medicated preparations designed to dissolve slowly in the mouth. They are softer than lozenges and their bases are either glycerol and gelatin, or acacia and sugar. 35

8 - Dental Cones: - A tablet form intended to be placed in the empty socket following a tooth extraction, for preventing the local multiplication of pathogenic bacteria associated with tooth extractions. - The cones may contain an antibiotic or antiseptic. 36

9 -Pills: - - 37 Pills are oral dosage forms which consist of spherical masses prepared from one or more medicaments incorporated with inert excipients. Pills are now rarely used.

10 - Granules: - They are consisting of solid, dry aggregates of powder particles often supplied in single-dose sachets. - Some granules are placed on the tongue and swallowed with water, others are intended to be dissolved in water before taking. - Effervescent granules evolve carbon dioxide when added to water. 38

11 - Powder (Oral): There are two kinds of powder intended for internal use. 1 -Bulk Powders are multidose preparations consisting of solid, loose, dry particles of varying degrees of fineness. They contain one or more active ingredients, with or without excipients and, if necessary, coloring matter and flavoring substances. - usually contain non-potent medicaments such as antacids since the patient measures a dose by volume using a 5 ml medicine spoon. The powder is then usually dispersed in water or, in the case of effervescent powders, dissolved before taking. 39 2 -Divided Powders are single-dose presentations of powder ( for example, a small sachet) that are intended to be issued to the patient as such, to be taken in or with water.

12 - Powders for mixtures: - The mixed powders may be stored in dry form and mixture prepared by the pharmacist when required for dispensing , by suspending the powders in the appropriate vehicle. 40

13 -Liquid preparations: a- Oral solution: Oral solutions are clear Liquid preparations for oral use containing one or more active ingredients dissolved in a suitable vehicle. b- Oral emulsion: Oral emulsions are stabilized oil-in-water dispersions, either or both phases of which may contain dissolved solids. c-Oral suspension: - Oral suspensions are Liquid preparations for oral use containing one or more active ingredients suspended in a suitable vehicle. - Oral suspensions may show a sediment which is readily dispersed on shaking to give a uniform suspension which remains sufficiently stable to enable the correct dose to be delivered. 41

13 -Liquid preparations (Cont. ): d- Syrup: - It is a concentrated aqueous solution of a sugar, usually sucrose. - Flavored syrups are a convenient form of masking disagreeable tastes. e- Elixir: -It is pleasantly flavored clear liquid oral preparation of potent or nauseous drugs. - The vehicle may contain a high proportion of ethanol or sucrose together with antimicrobial preservatives which confers the stability of the preparation. 42

13 -Liquid preparations (Cont. ): f- Linctuses: - Linctuses are viscous, liquid oral preparations that are usually prescribed for the relief of cough. - They usually contain a high proportion of syrup and glycerol which have a demulcent effect on the membranes of the throat. - The dose volume is small (5 ml) and, to prolong the demulcent action, they should be taken undiluted. g- Oral drops: Oral drops are Liquid preparations for oral use that are intended to be administered in small volumes with the aid of a suitable measuring device. They may be solutions, suspensions or emulsions. 43

13 -Liquid preparations: h- Gargles: - They are aqueous solutions used in the prevention or treatment of throat infections. - Usually they are prepared in a concentrated solution with directions for the patient to dilute with warm water before use. i- Mouthwashes: These are similar to gargles but are used for oral hygiene and to treat infections of the mouth. 44

II) TOPICAL DOSAGE FORMS (SEMISOLID) PHYSICAL PROPERTIES: a)Smooth texture b) Elegant in appearance c) Non dehydrating d) Non greasy e) Non hygroscopic f) Non irritating g) Do not alter membrane / skin functioning 45

1 - Ointments: - Ointments are semi-solid, greasy preparations for application to the skin, rectum or nasal mucosa. - The base is usually anhydrous and immiscible with skin secretions. - Ointments may be used as emollients or to apply suspended or dissolved medicaments to the skin. 46

Topical dosage forms (Cont. ): 2 - Creams: - Creams are semi-solid emulsions, that is mixtures of oil and water. They are divided into two types: A- oil-in-water (O/W) creams: which are composed of small droplets of oil dispersed in a continuous aqueous phase. Oil-in-water creams are more comfortable and cosmetically acceptable as they are less greasy and more easily washed off using water. B- water-in-oil (W/O) creams: which are composed of small droplets of water dispersed in a continuous oily phase. Water-in-oil creams are more difficult to handle but many drugs which are incorporated into creams are hydrophobic and will be released more readily from a water-in-oil cream than an oil-in-water cream. Water-in-oil creams are also more moisturising as they provide an oily barrier which reduces water loss from the stratum corneum, the 47 outermost layer of the skin.

Topical dosage forms (Cont. ): 3 - Gels (Jellies): -Gels are semisolid system in which a liquid phase is constrained within a 3 -D polymeric matrix (consisting of natural or synthetic gum) having a high degree of physical or chemical cross-linking. -They are used for medication, lubrication and some miscellaneous applications like carrier for spermicidal agents to be used intra vaginally. 4 - Poultice: It is soft, viscous, pasty preparation for external use. They are applied to skin while they are hot. Poultice must retain heat for a considerable time because they are intended to supply warmth to inflamed parts of body. E. g. Kaolin poultice (B. P. C. ) 48

Topical dosage forms (Cont. ): 5 - Pastes : 49 - Pastes are basically ointments into which a high percentage of insoluble solid has been added - Pastes are less penetrating and less macerating and less heating than ointment. - Pastes make particularly good protective barrier when placed on the skin. - Like ointments, paste forms an unbroken relatively water – impermeable film unlike ointments the film is opaque. - Pastes are less greasy because of the absorption of the fluid hydrocarbon fraction to the particulates.

Topical dosage forms (Cont. ): There are two types of paste: a) Fatty pastes (e. g: leaser's paste). b) Non greasy pastes (e g: - bassorin paste). 6 - Dusting powders: - 50 These are free flowing very fine powders for external use. Not for use on open wounds unless the powders are sterilized.

Topical dosage forms (Cont. ): 7 - Transdermal patch: -A transdermal patch or skin 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. -An advantage of a transdermal drug delivery route over other types such as oral, topical, etc is that it provides a controlled release of the medicament into the patient. - The first commercially available patch was scopolamine for motion sickness. 51

Topical dosage forms (Cont. ): 8 -Plasters: - Plasters are solid or semisolid masses adhere to the skin when spread upon cotton felt line or muslin as a backing material and they are mainly used to, A- Afford protection and mechanical support. B- Furnish an occlusive and macerating action. C- Bring medication into close contact with the surface of the skin. 52

Topical dosage forms (Cont. ): 9 - Liniments: - Liniments are fluid, semi-fluid or, occasionally, semisolid preparations intended for application to the skin. - They may be alcoholic or oily solutions or emulsions. - Most are massaged into the skin (e. g. counterirritant). - Liniments should not be applied to broken skin. 53

Topical dosage forms (Cont. ): 10 -Lotions: - These are fluid preparations (aqueous) for external application without friction. - They are either dabbed on the skin or applied on a suitable dressing and covered with a waterproof dressing to reduce evaporation. 54

Topical dosage forms (Cont. ): 11 - Collodion: Collodion is a solution of nitrocellulose in ether or acetone, sometimes with the addition of alcohols. -Its generic name is pyroxylin solution. -It is highly flammable. - As the solvent evaporates, it dries to a celluloid-like film. 55 - Compound Wart Remover consists of acetic acid and salicylic acid in an acetone collodion base used in Treatment of warts by keratolysis.

Topical dosage forms (Cont. ): 12 - Paints: - Paints are liquids for application to the skin or mucous membranes. - 56 Skin paints contain volatile solvent that evaporates quickly to leave a dry resinous film of medicament. - Throat paints are more viscous due to a high content of glycerol, designed to prolong contact of the medicament with the affected site.

Topical dosage forms (Cont. ): 13 - Pressurized dispensers (aerosol sprays): - Several different types of pharmaceutical product may be packaged in pressurized dispensers, known as aerosols. - 57 May be used as surface disinfectants, wound or burn dressing, relieve irritation of bites. Spray-on dusting powders are also available from pressurized containers.

III) Rectal dosage forms: 1 - Suppository: It is a small solid medicated mass, usually cone-shaped , that is inserted either into the rectum (rectal suppository), vagina (vaginal suppository or pessaries) where it melts at body temperature. 58

Rectal dosage forms: 2 - Enema: An enema is the procedure of introducing liquids into the rectum and colon via the anus. Types of enema: 1 - Evacuant enema: used as a bowel stimulant to treat constipation. E. g. soft soap enema & Mgso 4 enema - The volume of evacuant enemas may reach up to 2 liters. 59

Rectal dosage forms (Cont. ): 2 - Retention enema: - Their volume does not exceed 100 ml. - No warming needed. - May exert: A- Local effect: e. g. a barium enema is used as a contrast substance in the radiological imaging of the bowel. B- Systemic effect: e. g. the administration of substances into the bloodstream. This may be done in situations where it is impossible to deliver a medication by mouth, such as antiemetics. e. g. nutrient enema which contains carbohydrates, vitamins & minerals. 60

Vaginal dosage forms: 1 - Pessary: Pessaries are solid medicated preparations designed for insertion into the vagina where they melt or dissolve. - There are three types: A- Moulded pessaries: they are cone shaped and prepared in a similar way to moulded suppositories. B- Compressed pessaries: made in a variety of shapes and are prepared by compression in a similar manner to oral tablets. C- Vaginal capsules: are similar to soft gelatin oral Capsules differing only in size and shape. -

Vaginal dosage forms: 2 - Vaginal ring: Vaginal rings are 'doughnut-shaped' polymeric drug delivery devices designed to provide controlled release of drugs to the vagina over extended periods of time. Several vaginal ring products are currently available, including: 62 Femring : a low-dose estradiol-acetate releasing ring, manufactured from silicone elastomer, for the relief of hot flashes and vaginal atrophy associated with menopause. Nuva. Ring: a low-dose contraceptive vaginal ring, releasing progesterone and estrogen.

Vaginal dosage forms (Cont. ): 4 - Intrauterine device: -It is a birth control device placed in the uterus, also known as an IUD or a coil. -It remains in place the entire time pregnancy is not desired. Depending on the type, a single IUD is approved for 5 to 10 years use. 63 -There are two broad categories of intrauterine contraceptive devices: A- inert and copper-based devices. B- hormonally-based devices that work by releasing a progesterone.

V) Parenteral dosage forms: An injection is an infusion method of putting liquid into the body, usually with a hollow needle and a syringe which is pierced through the skin to a sufficient depth for the material to be forced into the body. There are several methods of injection, including: 1 -An intravenous injection: It is a liquid administered directly into the bloodstream via a vein. It is advantageous when a rapid onset of action is needed. 64

Parenteral dosage forms : 2 - Intramuscular injection: -It is the injection of a substance directly into a muscle. - Many vaccines are administered intramuscularly. -Depending on the chemical properties of the drug, the medication may either be absorbed fairly quickly or more gradually. 65

Parenteral dosage forms: 3 - Subcutaneous injection: Subcutaneous injections are given by injecting a fluid into the sub cutis, the layer of skin directly below the dermis and epidermis. Subcutaneous injections are highly effective in administering vaccines and such medications as insulin. 66

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VI) Inhaled dosage forms: 1 - Inhaler : 68 - Inhalers are solutions, suspensions or emulsion of drugs in a mixture of inert propellants held under pressure in an aerosol dispenser. - It is commonly used to treat asthma and other respiratory problems.

Inhaled dosage forms (Cont. ): 2 - Nebulizer or (atomizer): 69 A nebulizer is a device used to administer medication to people in forms of a liquid mist to the airways. - It is commonly used in treating asthma, and other respiratory diseases. - It pumps air or oxygen through a liquid medicine to turn it into a vapor, which is then inhaled by the patient.

VII) Ophthalmic dosage forms: 1 - Eye drops: Eye drops are saline-containing drops used as a vehicle to administer medication in the eye. Depending on the condition being treated, they may contain steroids, antihistamines or topical anesthetics. Eye drops sometimes do not have medications in them and are only lubricating and tear-replacing solutions. 2 - Ophthalmic ointment & gel: These are sterile semi-solid Preparations intended for application To the conjunctiva or eyelid margin. 70

VIII) Otic dosage forms: 1 - Ear drops: - Ear drops are solutions, suspensions or emulsions of drugs that are instilled into the ear with a dropper. - It is used to treat or prevent ear infections, especially infections of the outer ear and ear canal. 71

IX) Nasal dosage forms: 1 - Nasal Drops and Sprays: Drugs in solution may be instilled into the nose from a dropper or from a plastic squeeze bottle. The drug may have a local effect, e. g. antihistamine, decongestant. Alternatively the drug may be absorbed through the nasal mucosa to exert a systemic effect. 72 The use of oily nasal drops should be avoided because of possible damage to the cilia of the nasal mucosa.

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