dosage forms and route of drug administration

Dosage form of Drugs &

Route of drug administration

By Abubakar salisu fago.

Drug substance are seldom administer alone; rather they are given as part of formulation in combination with one or more non-medicinal agents that serve varied and specialized Pharmaceutical functions. Selective uses of non medicinal agent referred to as pharmaceutical ingredients or excipients, produces dosage form of various types.

Pharmaceutical ingredients solubilized, suspend, thicken, dilute, emulsify, stabilized, preserve, color, flavor and fashioned medicinal agent into efficacious and appealing dosage forms.

Dosage form is mixture of medicinal substance and excipients together so that they designed in definite form , size , shape, color and in appearances. Dosage form is the way of identifying the drug in its physical form. In determining dosage form, FDA examines such factors as

(1) physical appearance of the drug product, (2) physical form of the drug product prior to dispensing to the patient, (3) the way the product is administered, (4) frequency of dosing, and (5) how pharmacists and other health professionals might recognize and handle the product."

Each type of dosage form is unique in physical and pharmaceutical characteristics.

Depending on the type of administration they come in several types

Solid

Semi solidLiquid

Solid dosage forms1. Powders2. Granules3. Tablets 4. Capsules5. Modified release dosage

forms (Tablet/Capsul)

6. Lozenges ( torches)

Semi-solid dosage forms1. Ointments2. Creams3. Liniments4. Suppository5. Gel/ jelly6. Paste7. Poultices8. Aerosols9. Transdermal Drug delivery

system

Liquid dosage formsNon–sterile1. Syrup2. Solution3. Tincture4. Suspension5. Emulsion6. Lotion7. Elixir8. Draughts9. Enemas10. Gargles

Sterile dosage forms1. Injectables2. Intravenous bolus dosage3. Drops ( Eye & Ear)

11. Linctus12. Lotions13. Mixture

Powders: oral unite dosage form that nowadays rarely prepared extemporaneouslyPowder may be prescribed in the form of 1. Bulk powders for (oral) internal use- eg. Gregory powder ( compound BPC)Heavy Mg carbonate- 325gLight Mg carbonate 325 gRhuberb in powde- 250gGinger in powder- 100g

2. Bulk powder for external use- dusting powder and insufflations

Dusting powder two types ( free flowing fine powder for external usesMedical- these are used for superficial skin condition and rarely require to be sterile. However they should be free from dangerous pathogens. Thet are not intended to use in open wounds.Eg. Light kaoline, talc, starch and zinc oxide

Surgical dusting powders;These are used in body cavity and major wounds. They often contain antibacterial agents.Eg. Chlorhexidine powdersHexachlorphen powdersNeomycin sulfate powders

Some times, oral solution and syrup or even I.V preparation dispense in the form of powder

Eg. Paracetamol dry syrupCephadoxile dry syrup( they require to add vehicle when use)

Neomycine sulfate, polymaxin

B and Dexomethasone

Granules:Solid dosage form oral preparation for large volume of medicaments where the active ingredients are compressed together with excipients to form suitable granules and passed through suitable sieve. Eg. Methyl cellulose granulesSodium Amino salicylate ( 6-12gm) for TB

Advantages of granules:a. Some time it is difficult to find satisfactory presentation of medicament with large dosages.b. Tablet and capsule may be impractical because of size and number of frequencyc. Liquid dosage forms are avoided due to instability in moisture.d. Administration of powder form is difficult due to unpleasant teste. Suitable amount of coloring, flavoring and sweetening agent can be included.

Tablets:Solid dosage form where powders are moulded into tablets. They are flat, circular dices usually contain a potent medicament mixed with sucrose, lactose, dextrose or any other suitable diluents along with sufficient binding, coloring and flavoring agents. They are intended for oral use, require prior dissolution upon contact with moisture of the stomach. Thus tables avoided ingredient those are not soluble in water.

Capsules:Solid dosage form intended for oral administration containing active ingredients along with suitable fillers. They are two types.1. Hard gelatin capsules:They consist a cylindrical body and cap, both with hemispherical ends, and are made from gelatin and water with added preservatives. Although they are quite hard, they soften and dissolve after swelling with water

2. Soft gelatin capsules: are for solid, liquids and semisolid liquids. They may be spherical , ovoid or cylindrical. In addition to the ingredients of hard capsules, they contain glycerol which provide the flexibility.

Modified Release dosage forms (Tablet/Capsule)In contrast to conventional ( Immediately release) forms, modified –release products provide either delayed release or extended release of drugs. Most delayed release products are enteric coated tablets or capsules designed to pass through the stomach unaltered, later to release their medication within the intestinal tract.

Delayed release product are used either to protect the substance from destruction by gastric fluids or to prevent stomach distress.

Extended release Products are designed to release their medication in a controlled manner, at predominant rate, duration and location to achieve and maintain optimum therapeutic blood levels of drugs.

Lozenges: (torches)These are solid preparation consisting mainly sugar and gum. Gum uses for increasing the hardness of preparation thus ensure slow release of medicaments. They are use to medicate the mouth and throat and for slow administration of indigestion and cough remedies.

Semisolid Dosage formsOintments: are semi-solid greasy preparation for application to the skin or mucosa. The base is usually anhydrous and containing medicaments in solution or suspension. They are generally used for theira. emollient effects b. protection effect of lesionsc. topical application of medications

eg. Acne- Sulphur or resorcinol ointmentAntibiotic- bacitracine, chlortetracyclineAnti-inflammatory- BetamethasoneAnti-septic- Zinc oxideDandruffs- Salicylic acidCounter irritant- Capcisin

Creams:These are semisolid emulsion for external use. There are two kinds, aqueous and oily cream, in which the emulsion are Oil in Water (O/W) or Water in Oil (W/O). The oil in water type are relatively non-greasy. Cream are of two type cold cream and

vanishing creams. Vanishing cream is an oil in water type of emulsion whereas cold cream is of water in oil type of emulsion. They also differ in their pH. vanishing cream is of neutral to slightly acidic pH but cold cream is of neutral pH. Vanishing creams are easily washable but cold creams can not be removed from the skin easily.

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