Practical Pharmacology

Lab.2

3rd-year class
Practical Pharmacology
2010-2011

Dosage Forms

Dr. Mohammed Qasim
&
Dr. Huda Ibrahim

I.Oral

1.Tablets:-
the most common preparation for oral use . Is made by compressing the drugs & inert binders as starch or lactose into hard mass which disintegrate in water . A tablet before being absorbed should disintegrate into granules& then dissolute into primary drug particles


The active substance in an oral solid dosage form such as tablet represents only a small proportion of the total weight
.
These include:-
diluents(Lactose, Calcium, Sulphate), binding agents(bentonile), lubricants(talc), disintegrating agents (starch , mixture of sodium bicarbonate & tartaric acid), coating formulation . material (sugar), special
Different manufacturing procedures may result in the production of different physical forms of the active drug(e.g. compression force & tablet hardness).

Coated tablets:-

a common type is a sugar coated tablet. The coat is an additional physical barrier for disintegration.

1-Coatings are used to mask the unpleasant tastes & odors.

2-To protect the tablet ingredients from decomposition in drug storage.
3-To improve the appearance of the tablet








Enteric-coated tablet:- a special film coat designed to resist gastric fluid & disrupt or dissolve in the intestine
1-They are used to protect a drug from degradation in the stomach.
2-To minimize gastric irritation caused by some drugs

Sustained-release tablets(SR)

this is designed to release their contents over extended period of time.


Advantages:
to eliminate the need for multiple dosage regimens , particularly for these drugs requiring reasonably constant blood level over a long period of time , or drugs which need to be given in high doses , but too rapid release is likely to cause undesirable side effect
(e.g. potassium chloride tablets)

2.Capsules:-

a drug formulation encapsulated in a hard gelatin shell .Drug particles in the capsule are not subjected to high compression that tend to compact the powder & to reduce the effective surface area. However, drug bioavailability from capsule isn't always better than a tablet.

Advantages:

• 1.Protection from light.
• 2. Mask the taste or odour of their components.
• 3. Attractive appearance.
• 4. Ease to identify.
• 5. Controlled release.

Spansule:

capsule containing drug granules with special pharmaceutical formulation to be disintegrated and dissolved in different times for prolonged action (theophyllin)

3.Granules:-

all irregular particles of drug, sugar & inert adjuvant stirred in water before taking

4.Effervescents tablet or granules:-

the basis of the effervescence is a mixture of citric acid & tartaric acid with sodium bicarbonate . When dissolve in water , the acid & bicarbonate react together to produce carbonic acid . The carbonated water partly disguises the unpleasant taste of drug & has refreshing properties.

5.Syrup:-

is a concentrated aqueous solution of sugar , useful vehicle for water soluble drugs act both as a solvent & flavoring agent .
Advantages:
1. Immediately available for absorption. 2. Useful for children or in swallow difficulties (elderly).

6.Elixir:-

is a sweetened hydro alcoholic solution that contains approximately 25%. It is a suitable vehicle for drugs soluble in either water or dilute alcohol.








7.Linctuses:-
are viscous liquid oral preparations that are usefully prescribed for the relief of cough

II.Topical:-

1.Aerosols:-
they are suspensions of fine solid or liquid particles in a gas . They are used to the respiratory tract or skin . The sprays used to treat respiratory diseases are atomized in devices known as nebulizers

2.Gargles:-

they are aqueous solutions used to treat or prevent throat infections, usually dispensed in concentrated form to be diluted in warm water before use

3.Drops:-

could be to the eye, ear, nasal or oral drops. Nasal drops are usually aqueous because oily drops inhibit movement of cilia in the nasal mucosa & if used for a long time , they may reach the lungs & cause lipoidal pneumonia

4.Ointments:-

are semisolid, greasy preparations for application to the skin , rectum . The base is usually anhydrous & contains the medicament in solution or suspension.
5.Cream:-
they are semisolid solution for external use. They are 2 kinds:-1. aqueous cream 2. oily cream.
In which the emulsions are oil in water or water in oil respectively

Ointment

Cream
1-greasy
1-relatively not greasy
2-semisolid anhydrous
2-semisoilid emulsion(oil + water)
3-less skin penetration
3-more skin penetration
4-used for dry, chronic skin lesion
4-used for wet lesions of skin
5-applid to skin & rectum
Applied to skin only

6.Lotions:-

aqueous preparations for external application without friction . They are rubbed on skin or applied on the suitable dressing

7.Suppositories:-

are conical or ovoid solid preparations for insertion into the rectum, where they exert local or less often systemic effect. Their base is fat, wax or glycerol gelatin

8.Pessaries:-

solid medicated preparations for introduction into vagina where they melt or dissolve & exert a local action

III.Injections:-

drugs given by injections act more rapidly & reliably, thus more useful for emergency situations . They require some technical skills, aseptic technique & suitable equipments

a. Injection:

highly purified & sterile dosage form either in ampoules or vials (for multidose)
.
b. Intravenous Admixture:
(i.v. fluid) large volume injection intended to be administered by i.v. infusion , for fluid replacement ; electrolytes balance restoration; supplementary nutrition; & as vehicle for other drug substance (G/W, Albumin, Dopamine).

There are 2 types of injections preparation:-

1-Ampoule:- which contains sterile drug solution & used once when opened.

2-Vial:- which is designed to contain one or multiple doses & having a rubber cover to avoid contamination.

IV.Some pharmaceutical preparations:-

1.Extract:- are concentrated preparations containing active principles of vegetable or animal drugs. The drugs are extracted with suitable solvents & the product is concentrated to a liquid, soft or dry extract.
2.Tinctures:- are alcoholic or hydro alcoholic solution of the active principles of drugs. They are medicated or non-medicated. The latter is used as flavoring agent.
3.Waters:- aromatic waters are saturated aqueous solutions of volatile oils, used as vehicle for water-soluble substances

Enema: a clyster or injection; a liquid injected or to be injected into the rectum (e.g. hydrocortisone enema), & barium enema (barium meal).
Powder:e.g. antacid.
Prefilled syringe: e.g.enoxaparn.
Pen: e.g. mixtard insulin

Transdermal delivery system (TDS):