Pharmaceutical dosageforms

Pharmaceutical dosageforms

o Pharmaceutical dosage forms are drug delivery systems: they are means of getting drugs into the body in a safe, effective and reproducible manner

o Drug substance are seldom administered alone, but rather as part of a formulation in combination with one or more non-medical agents (pharmaceutical ingredients) to give a practical dosage form : in other words the drugs must be formulated.

oIn addition to facilitate administration of     the drug, the dosage forms are needed for;           1-The protection of a drug substance from destructive influence of atmospheric oxygen or humidity (e.g.coated tablets and sealed ampoules)                                                                                                       
2-Protection of the drug from gastric acid after oral administration (e.g. enteric coated tablets).                                                                                                                                                                       
3-To mask the bitter, salty, or offensive taste or odor (capsules, flavoured syrup, coated tablets).                  

 4-To provide different  routes of drug administratione.g., oral, rectal, vaginal, topical, parenteral         lungs,  nasal, eye and ear.
  5-To provide time-controlled drug action (e.g., various controlled release tablet, capsule and    suspension).                                                                                                                                     

Before a drug substance can besuccessfully formulated into a dosage form manyfactors must be considered

1.Biopharmaceutical considerations, including factors affecting the absorption of the drug from different administration routes.
2.Drug factors, such as the physical and chemical properties of the drug.
3.Therapeutic factors including consideration of the disease to be treated and patient factors.

PHARMACEUTICA SOLUTION

Are liquid dosage forms that prepared by dissolving the active ingredients in an aqueous  or non-aqueous solvents.

Solution for different routes of administration:

1.Orally (syrups, elixirs, drops)
2.In mouth and throat (mouth washes, gargles, throat sprays)
3.In body orifices (enemas, ear drops)
4.In body surfaces (collodions, lotions, paints).

Advantages of solutions:

1. Young children and some adults have difficulty  in swallowing tablets and capsules.

2-They are more quickly effective than tablets  and capsules (solution > suspension > capsules  >tablets >coated tablets)

3-They give uniform dose than suspension due  to no need for shaking.

4-They dilute the irritant action of some drugs like I, KBr.        

•Disadvantages of solutions:

1. They are bulky to carry around

2. Difficult to mask bad taste or odor.

3. Need accurate spoon to measure the dose.

4. Less stable than solid dosage forms (precipitation, chemical and microbiological gasformation, color changes are major signs of solution instability).