Drug Delivery Systems: An Overview
For centuries, drugs have been used to treat ailments, improve health and extend the lives of both humans and animals. The substances used as drugs have evolved greatly from the mixtures of medicinal plants and other ingredients found in ancient times. As the science of drugs and medicine developed into the heavily researched and tested chemical compounds that pharmaceutical companies produce today, the ways in which these drugs can be delivered to patients has evolved as well.
The idea of how patients would receive these medications, however, was not a widely discussed topic until the past few decades. Advancements in drug delivery have vastly changed the landscape of the effectiveness of medications, and even greater changes are anticipated for the near future. Read ahead to learn more about how drug delivery systems have become more innovative and complex along with the advancements in medicine.
What is Drug Delivery?
Drug delivery is the process of administering medication or other pharmaceutical compounds to achieve a therapeutic effect. Drug delivery has become an important topic in the pharmaceutical industry over the last several decades because it has been discovered that a drug’s efficacy can be impacted by the way in which it is delivered. Therefore, by finding the delivery system that is best suited for a specific medication, it’s possible to optimize the drug within the body.
What is a Drug Delivery System?
A drug delivery system is defined as a formulation or device which presents a drug to the body for administration and absorption. The goal of using drug delivery systems is to provide a therapeutic amount of medication while improving safety and efficacy by controlling the location, rate, and time of release of a particular drug in the body.
Drug delivery systems have greatly evolved over the last six decades. In the last 12 years specifically, there have been huge advancements in drug delivery technology. For instance, advanced medication delivery systems, such as transdermal patches, are able to deliver a drug more selectively to a specific site, which frequently leads to easier, more accurate, and less dosing overall. Drug delivery devices such as these can also lead to a drug absorption that is more consistent with the site and mechanism of action. There are other drug delivery systems used in both medical and home care settings that were developed because of various patient needs, and researchers continue to develop new methods.
What Are Drug Delivery Devices?
Drug delivery devices are the physical agents that are included in the drug delivery system. There are a multitude of devices that people interact with every day which fall under this category. In modern pharmaceuticals, novel drug delivery devices and combination products are being designed for a number of reasons, including giving patients the ability to self-administer some medications at home, which can help them adhere to recommended regimens. With modern technology and medicine, the combination product market is evolving. Any combination device, especially drug device combination devices, must follow strict guidelines. Thanks to advancements in engineering, an increasing number of drug delivery devices are being developed as electromechanical devices linked to apps in order to provide patients with more supervision when administering medications at home. Some of these medical apps may receive feedback from the device to track how much drug is being administered and how often, provide patients with dosing reminders and connect clinicians with this information so they can monitor patient compliance. The drug delivery devices that so many patients depend on must adhere to regulatory standards. There are strict guidelines for all methods of drug delivery, such as needle-based, aerosol, and needle-free injectors.
Examples of Drug Delivery Devices and Systems
These types of devices are very commonly used both inside and outside of clinical settings. A few examples include:
- Prefilled syringes
- Infusion pumps
- Metered dose inhalers (MDIs)
- Nasal sprays
- Intrauterine devices (IUDs)
- Transdermal patches
How Does Drug Delivery Work?
Drug delivery transfers a drug or medication to the body for absorption. But, not all of the delivery methods are created equal. Biomedical engineers have significantly contributed to our understanding of the physiological barriers that can make drug delivery inefficient, especially in the area of how drugs move through cells and tissue. These engineers and scientists have also contributed a tremendous amount of knowledge in regards to how drug delivery works.
The drug delivery devices and systems of today are being designed to do more than simply get a drug into the body. For example, some systems are designed to administer drugs locally rather than systemically. Common localized delivery methods include giving a lidocaine injection before a dental procedure or applying a topical ointment to a rash on the skin. Localized medication delivery can be received in other ways, but some drugs can only be given systemically. Today, drug delivery methods have advanced to meet the different needs of individuals.
What Are the Types of Drug Delivery Routes?
The way drugs are introduced into the body, or the route of drug delivery differs based on patient needs and the purpose of the drug. There are several different routes by which a drug can be delivered to the body. The oral route of drug delivery is the most common. Many drugs can be administered orally as capsules, tablets, or liquids, and the oral route is usually safe, convenient, and inexpensive. Other common delivery routes include:
- Injection: Injected into a vein (intravenously,) into a muscle (intramuscularly,) into the spinal canal (intrathecally,) or under the skin (subcutaneously)
- Inhalation: Breathed into the lungs through the mouth (inhaled) or mouth and nose (nebulized)
- Nasal: Sprayed into the nostril(s) and absorbed through the nasal membranes
- Topical: Applied to the skin for a local effect
- Transdermal: Delivered through the skin via a patch for a systemic effect
- Rectal: Inserted into the rectum to be absorbed into the bloodstream
- Sublingual: Placed underneath the tongue for rapid absorption into the bloodstream
Each route of drug delivery has its advantages and disadvantages. It is important that every treatment be delivered using the most appropriate and effective route, which is part of the reason why ongoing advancements in drug delivery are so vital.
What Are the Four Drug Delivery Methods?
Another important factor in medication delivery is the amount of time it takes for a drug to be released into the body. Drug delivery can be modified and controlled by different properties, so there are several methods of drug transfer that can occur.
- Immediate Release: The dosage form that is designed to give a rapid and complete release of the drug.
- Non-Immediate Release: The dosage form encompassing drugs that do not fully release upon administration.
- Site-Specific Release: The dosage form that offers targeted delivery of a drug directly to the location where it is administered.
- Sustained Release: The dosage form that releases a drug continuously at a slow or controlled rate over a prolonged period of time.
These and other delivery methods could enhance the performance of specific drugs by increasing the effectiveness, safety, and patient compliance that surrounds the drug, which can ultimately lead to better patient outcomes.
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