What are drug delivery systems?
Drug delivery systems (DDS) consist of various technologies that deliver or carry drugs within the body to affected regions. Methods of delivery may include oral pills or tablets made of specific materials that dissolve at different rates in the body, locally applied topical creams or ointments, or injections of medications or vaccines that can be administered intravenously, intramuscularly, or subcutaneously.
Using the right DDS allows quick, accurate targeting of the medication to affected sites in the body with minimal degradation as it travels through the body. By the time the medication reaches the target site in the body, it can still provide the greatest effect on symptoms with minimal side effects to healthy tissues and organs.
Improving DDS technologies can advance the field of medicine by facilitating more precise delivery of medications in a convenient, easy, and patient-friendly way. Simultaneously, the right DDS can cut down on drug-related, negative side effects.
What are immediate and delayed releases in drug delivery?
Immediate-release DDS requires the rapid disintegration or dissolution and absorption of the drug into the body for quick onset of action for symptom relief. Oral administration of solid formulations, such as tablets, is one of the more popular routes of administration for immediate-release DDS due to higher patient compliance, ease of ingestion, versatility, lower cost, and higher efficiency for manufacturing. For classification as an immediate-release DDS, orally ingested, solid formulations must dissolve or disintegrate within the stomach within a very short time.
Other immediate-release drug formulations can also be administered orally through liquid capsules or by injections into the muscles, veins, or peritoneum, and various types of inhalers and nebulizers directly into the lungs. Other fast-acting medications used during seizures—called rescue medications)—may be administered under the tongue (sublingually) or between the cheek and gum (buccally), through the rectum, or the nose (intranasal sprays).
In contrast, delayed release DDS prevents immediate dissolution or disintegration of the drug, promoting a much later release of the active pharmaceutical ingredient. In oral medications, delayed drug release is often achieved using enteric coating on capsules, tablets, and other ingested dosage forms to prevent the breakdown of the underlying drug during its transit through the gastrointestinal tract as well as prevent the drug from irritating the gastric mucosa. Delayed release DDS avoids the effects of first-pass metabolism, allowing the drug to be absorbed through the gut and reach its target destination in the body in higher concentrations.
Rivaroxaban (Xarelto®) is classified as an anticoagulant drug, which is indicated to treat blood clots in the deep veins and lungs as well as preventively to reduce the risk of stroke and systemic embolisms in individuals with known blood clots or those at higher risk for developing clots, as observed in those with atrial fibrillation or following major surgical procedures.
Rivaroxaban works by selectively inhibiting factor Xa, which is involved in blood clotting, as well as prothrombinase activity, which promotes blood clotting via the production of thrombin. By reducing the production of thrombin, rivaroxaban indirectly inhibits platelet aggregation.
Rivaroxaban is administered orally, either as a tablet or a suspension (liquid). The tablet is formulated as an immediate-release DDS. Research showed that when taken with food or in a fed state, rivaroxaban exhibited delayed absorption with a lag time of 1.5 hours and a median delay in onset of 1.25 hours. To improve the bioavailability of rivaroxaban and reduce the food effect, researchers have explored sustained-release formulations of rivaroxaban within poly(lactic-co-glycolic acid) (PLGA) nanoparticles.
The active pharmaceutical ingredient in rivaroxaban must begin working right away (hence its immediate-release formulation) to prevent the growth of existing clots or the development of new ones that may break away from the blood vessel wall and lead to stroke, pulmonary embolisms, or other complications.
Technological innovations promoting immediate and delayed release in DDS
Three-dimensional (3D) printing technologies are well-equipped to explore different combinations of choices by manipulating the following aspects:
additive manufacturing processes
geometric shapes for oral dosage forms
polymers and other materials used to create the oral tablet
Some polymers rapidly dissolve to immediately release the drug, while others dissolve slowly for delayed release of the drug farther down the intestinal tract where it can then be absorbed systemically into the bloodstream.
3D printing offers the pharmaceutical industry the potential to manufacture complex drug delivery systems that are personalized to the patient’s needs with the ultimate goal of low-cost, on-demand production.
Laxxon Medical is dedicated to engineering patented 3D pharmaceutical solutions that optimize products and benefit patients. Our goal is to establish SPID®-Technology as a manufacturing process with the individual and the pharmaceutical partner in mind.
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