Sustained-release preparations refer to preparations that achieve better therapeutic effects by delaying the release rate of the drug from the dosage form and reducing the absorption rate of the drug into the body. However, the release rate of the drug from the preparation The rate is affected by factors such as external environment such as pH.
Controlled-release preparation is a dosage form that releases drugs externally at a timed, quantitative and uniform speed through a controlled-release coating film, so that the blood concentration of the drug is constant without "peaks and valleys", thereby better exerting the curative effect. .
What are the advantages of sustained-release and controlled-release preparations?
(1) Reduce the frequency of administration. Ordinary preparations generally need to be administered multiple times a day, so they often cause missed doses, and some patients even Dosing regimens may also be changed without authorization, thereby failing to achieve the intended therapeutic purpose. The drug loading capacity of sustained-release preparations is higher than that of a single dose of traditional dosage forms of drugs, and they can maintain effective blood drug concentrations for a longer period of time. Therefore, in order to facilitate medication use and improve patient compliance, once-daily administration is developed. Slow-release or controlled-release varieties are an important trend in the future. Especially suitable for patients with chronic diseases who take long-term medication, such as cardiovascular disease, angina pectoris, hypertension, asthma, etc., diltiazem, theophylline, nifedipine, felodipine, ketoprofen, pseudoephedrine, isosorbide dinitrate, chlorpheniramine , naproxen, tramadol, diclofenac sodium and other products or patents that are administered once a day.
(2) Convenient administration and improved patient compliance. Sustained and controlled-release preparations have features that ordinary preparations cannot provide that can improve patient compliance, such as reducing the frequency of medication. As the frequency of administration of sustained-release preparations decreases, patients rarely miss medication, and it also makes it easier for patients to take medications during the day and night.
(3) Complete absorption and improved drug efficacy. When the blood concentration of ordinary drug preparations is in the "trough", it is likely to be lower than the therapeutic concentration and cannot exert its therapeutic effect. Sustained-release preparations avoid the "peak and valley phenomenon" to a certain extent, and compared with ordinary preparations, drug sustained-release preparations stay at the absorption site for a longer time and are absorbed more completely, so they have higher bioavailability, thus to increase drug efficacy.
(4) Reduce blood drug concentration fluctuations. Ordinary preparations are prone to large peak and valley fluctuations due to multiple daily dosing methods, while sustained-release and controlled-release preparations can control the drug concentration by The release rate greatly reduces the fluctuation of blood drug concentration, allowing the human body to obtain a stable and effective therapeutic blood drug concentration, ensuring the therapeutic effect of the drug, and optimizing the efficacy-dose. ?
(5) Reduce toxic and side effects. When the blood concentration of ordinary preparations is at the "peak", it may be higher than the "minimum poisoning concentration" of the drug, so it is easy to produce adverse reactions or even poisoning. Sustained-release preparations overcome this problem, reduce the toxic and side effects of drugs, and improve the safety of medication. In addition, some sustained-release preparations have local localization effects, which can not only improve the local therapeutic effect, but also reduce the toxic and side effects caused by systemic absorption.
(6) Reduce the irritation of the drug to the gastrointestinal tract. Ordinary preparations rapidly disintegrate and dissolve in the gastrointestinal tract after oral administration, causing greater irritation to the gastrointestinal tract. If they are made into sustained-release preparations, this can be reduced. Irritation to the gastrointestinal tract caused by rapid drug dissolution. For example, ordinary aspirin tablets have an irritating effect on the gastrointestinal mucosa after being hydrolyzed into salicylic acid in the body. However, after being made into sustained-release tablets, the drug is slowly released, which can alleviate the irritation of the gastrointestinal mucosa to a large extent. sex.
(7) Reduction in the cost of the entire treatment. Although the initial cost of applying sustained-release preparations is higher than that of ordinary preparations, in terms of the cost of the entire treatment, sustained-release preparations have certain advantages. This is mainly due to their There are many reasons such as the improvement of curative effect, the reduction of side effects and the shortening of the nursing time of attendants.
(8) Suitable for sustained-release oral liquids in children and elderly patients with dysphagia. The controlled-release drug delivery system is suitable for making large-dose drugs into liquid preparations, and can be divided into doses according to individual needs. , which has a large distribution area in the gastrointestinal tract and is quickly absorbed. The drug delivery system is administered in the form of multi-unit granules, and the in vivo behavior is rarely affected by gastric emptying rate.
Sustained-release preparation (SRP): refers to a preparation that delays the release rate of the drug from the dosage form and reduces the absorption rate of the drug into the body, thereby achieving a better therapeutic effect, but the drug is The release rate in the preparation is affected by factors such as external environment such as pH. "Chinese Pharmacopoeia" stipulates that sustained-release preparations refer to the slow non-constant release of oral drugs in a specified release medium as required. Compared with other corresponding ordinary preparations, the number of doses per 24 hours should be reduced from 3 to 4 times to 1 to 1 2 preparations.