Factors Influencing Drug Absorption: Pharmaceutical Parameters

Compression force and granulation methods significantly impact dissolution rates during tablet manufacturing. High compression forces increase tablet density but reduce wettability, slowing dissolution. However, these forces may also cause drug particle deformation, increasing effective surface area and potentially enhancing dissolution. Different granulation methods yield tablets with varying dissolution rates, making these manufacturing parameters critical for controlling drug bioavailability.

Excipients are inactive ingredients that ensure drug stability, functionality, and optimal bioavailability. Common excipients include vehicles, diluents, disintegrants, surfactants, binders, and lubricants. Water-miscible vehicles rapidly mix with body fluids, enabling fast drug absorption. Disintegrants break tablets apart, while surfactants promote wettability and aid dissolution. However, binders and lubricants can slow dissolution by reducing interparticle friction and tablet breakdown.

Diluents elevate the dissolution rate of hydrophobic drugs by enhancing their interaction with aqueous body fluids. Hydrophilic diluents are particularly effective because their water-loving properties facilitate rapid mixing and dissolution of poorly soluble drug compounds. This strategic selection of diluent type is essential for optimizing bioavailability of drugs with low water solubility.

Surfactants lower surface tension between ingredients, making them more miscible and promoting wettability of the drug particles. This enhanced wettability accelerates dissolution. Disintegrants break the tablet matrix into smaller fragments, increasing the effective surface area available for dissolution. Together, these excipients work to overcome barriers to drug dissolution and enhance absorption.

Hydrophilic excipients are water-loving and enhance dissolution of poorly soluble drugs, while hydrophobic excipients are water-repelling and may hinder dissolution. Hydrophilic diluents facilitate rapid drug absorption by promoting mixing with body fluids. Conversely, hydrophobic binders and lubricants can slow dissolution by reducing tablet wettability and interparticle interactions. Selecting the appropriate excipient type is crucial for optimizing drug bioavailability.

Binders hold powder particles together to form cohesive granules and tablets, ensuring structural integrity during manufacturing and handling. Lubricants reduce interparticle friction, preventing ingredients from sticking together and facilitating tablet ejection from molds. However, both binders and lubricants can negatively impact dissolution rates by creating barriers to water penetration and drug release.

Wettability determines how readily water penetrates and interacts with tablet particles, directly influencing dissolution speed. High compression forces reduce wettability, slowing dissolution, while surfactants and hydrophilic excipients enhance wettability. Optimal wettability ensures rapid contact between drug particles and body fluids, facilitating dissolution and enabling effective mechanisms of drug absorption paracellular transcellular and vesicular transport.