Iontophoresis: an alternative drug-delivery system

The selection of a drug's delivery route depends upon its physicochemical properties, including lipid or water solubility and ionization, as well as the therapeutic requirement, such as immediate or sustained effect. These routes can be divided into three primary categories: enteral, parenteral, and topical.
Enteral delivery involves administering drugs directly through swallowing, sublingual placement, or buccal application. Orally administered drugs predominantly navigate the gastrointestinal...

Drug delivery methods like oral inhalation, nasal sprays, transdermal patches, eye drops, intravitreal injection,  and rectal administration provide localized effects with reduced toxicity.
Oral inhalation and nasal sprays swiftly transfer drugs across the respiratory epithelium's mucosal layer. Inhaled glucocorticoids and bronchodilators directly target lung conditions such as asthma, while fluticasone nasal spray mitigates allergic rhinitis.
Transdermal patches transport drugs through the...

Continuous-release drug delivery systems offer a strategic approach to maintaining therapeutic drug levels over extended periods following oral administration. By modulating the release rate of active pharmaceutical ingredients, these systems minimize fluctuations in plasma concentrations, which enhances clinical efficacy and reduces the need for frequent dosing. Such characteristics make them particularly advantageous in managing chronic diseases where patient adherence and stable drug...

Parenteral drug delivery systems play a crucial role in modern therapeutics by enabling the direct administration of drugs into the systemic circulation, bypassing the gastrointestinal tract. These systems are particularly valuable for poorly absorbed oral medications that are unstable in the digestive environment or require rapid onset or sustained therapeutic levels. Delivery is achieved through intravenous, intramuscular, or subcutaneous routes, each selected based on the drug's properties...

Transdermal drug delivery systems (TDDS) enable the controlled release of drugs across the skin into systemic circulation. They are particularly advantageous for drugs with short half-lives or narrow therapeutic indices, as they maintain consistent plasma concentrations and reduce the risk of subtherapeutic or toxic levels.TDDS are categorized into monolithic, reservoir, and mixed systems. Monolithic systems embed the drug in a polymer matrix, where diffusion governs release. Reservoir systems...

Ophthalmic drug delivery faces major limitations due to poor absorption across the corneal membrane. This process is primarily driven by diffusion and is influenced by two main factors: the physicochemical properties of the drug and tear drainage. Most ophthalmic drugs, such as pilocarpine, epinephrine, atropine, and local anesthetics, are weak bases. They are typically formulated at an acidic pH to enhance chemical stability. However, this leads to high ionization, reducing their ability to...