1. Preformulation Studies
These studies are designed to identify those physical and chemical properties of a candidate drug molecule which may affect the development of a safe, stable and efficient dosage forms with good bioavailability.
2. Biopharmaceutical Considerations
The human body is considered here focusing on the absorption and elimination of the drug. For the adsorption, the route of administration is considered. The drug substance must be in a solution form before it can be absorbed into the membrane. Drug administered through buccal, respiratory, rectal, intramuscular or subcutaneous routes passes directly into the absorbing tissues unlike those of oral route that have to undergo first pass metabolism before absorption.
3. Route of Adminstration:
The route of administration is considered before choosing dosage form. The route of administration is determined by the available dosage form. The routes of administrations include: oral, rectal, parenteral, topical, and respiratory. When it comes to oral route, the taste is considered, the dissolution of the drug is considered. Rectal route is mainly used for local effect or when the drug cannot be taken through the oral route. Parenteral route involves use of injection. It includes intramuscular (im), intravenous (IV), subcutaneous (sb). The parenteral route is preferred when rapid absorption and action is essential. Topical route dosage form is meant to be applied on the skin for a local action. Respiratory route is used when drug is inhaled into the airways. The lungs provide an excellent surface for absorption.
4. Drug Factors in Dosage Forms Design
- Particle size and surface area
- Solubility
- Dissolution
- Partition coefficient PKA
- Crystal properties polymorphism
- Stability
- Organoleptic properties
- Other drug properties.
5. Therapeutic Considerations in Dosage Forms Design
The nature of the clinical indication, disease or illness against which the drug is intended is an important factor when selecting the range of dosage form to be prepared.