Final answer:
Creams, patches, drops, and suppositories provide targeted drug delivery with reduced systemic effects, the potential for controlled and sustained release, and can bypass first-pass metabolism, increasing bioavailability and reducing GI side effects. Challenges include compatibility of compounds, formulation convenience, and potential DDIs.
Step-by-step explanation:
Formulations such as creams, patches, drops, or suppositories offer various advantages over traditional oral medications. Creams are semisolid emulsions and can be either oil-in-water or water-in-oil, with the former being less greasy and more cosmetically acceptable and the latter providing more moisture due to the oil barrier. They allow for targeted application, which is beneficial for treating local conditions with reduced systemic effects. Patches allow for the controlled release of medication over an extended period. Drops can be used for localized treatment in areas such as the eyes and ears. Suppositories bypass the gastrointestinal system, which is advantageous for patients with nausea or vomiting and for drugs with poor oral bioavailability.
These routes of administration can avoid first-pass metabolism by the liver, thus potentially increasing the bioavailability of the medication. They are particularly useful in targeting transporters, achieving sustained release, and overcoming drug resistance. Moreover, they present fewer gastrointestinal side effects as compared to oral medications. For example, moisturizing cream containing hydrocortisone can be highly effective against skin inflammation because it applies corticosteroids directly to the affected area, reducing histamine levels and providing temporary relief from itching and rashes.
However, these formulations also come with disadvantages such as the need for compounds to be compatible within the same dosing solution, potential difficulties in creating convenient dosage forms, and in certain cases, increased risk of drug-drug interactions (DDIs).