Dosage form design and development

Drugs must be properly formulated for administration to patients, regardless of age. Pediatric patients provide some additional challenges to the formulator in terms of compliance and therapeutic efficacy. Due to the lack of sufficient drug products for the pediatric population, the pharmaceutical industry and compounding pharmacies must develop and provide appropriate medications designed for children.

The purpose of this article was to review the physical, chemical, and biological characteristics of drug substances and pharmaceutical ingredients to be used in preparing a drug product. In addition, stability, appearance, palatability, flavoring, sweetening, coloring, preservation, packaging, and storage are discussed.

Information for the current article was gathered from a literature review; from presentations at professional and technical meetings; and from lectures, books, and publications of the author, as well as from his professional experience. Professional society meetings and standards-setting bodies were also used as a resource.

The proper design and formulation of a dosage form requires consideration of the physical, chemical, and biological characteristics of all of the drug substances and pharmaceutical ingredients (excipients) to be used in fabricating the product. The drug and pharmaceutical materials utilized must be compatible and produce a drug product that is stable, efficacious, palatable, easy to administer, and well tolerated. Preformulation factors include physical properties such as particle size, crystalline structure, melting point, solubility, partition coefficient, dissolution, membrane permeability, dissociation constants, and drug stability.

Successful development of a formulation includes multiple considerations involving the drug, excipients, compliance, storage, packaging, and stability, as well as patient considerations of taste, appearance, and palatability.