Sustained and controlled release drug delivery systems has always been one of the key points of domestic drug research and development. It uses sustained and controlled release preparation technology to delay and control the release rate of drugs, so as to improve the curative effect, reduce adverse reactions, prolong the dosing interval and improve the medication compliance of patients.

The sustained-release tablets in this study control the release rate of drugs through skeleton materials, so as to achieve the effect of 24-hour long-term sustained-release. In order to obtain more discriminative dissolution test data, the in vitro release of this product will be studied by flow-through cell method.

Dissolution Apparatus: Raytor RT7 Flow-Through Cell Dissolution System

Flow-Through Cell: 22.6mm inner diameter pharmacopoeia standard flow-through cell

Filtration System: Raytor patent flow-through cell online filtration device

A 5mm diameter ruby ball is placed at the bottom of the flow-through cell and filled with 1mm diameter glass beads.

The tablets were placed on a tablet holder for a flow-through cell with an inner diameter of 22.6mm.

The experimental samples include: reference and self-developed sample. The dissolution test was started according to the proposed research method, the sample solution was collected at each sampling time point, and the API concentration was detected by HPLC.

Release phenomenon of sustained release tablets on sample support

Through the test results, the Average Release Concentration - Time Curve and Dissolution Rate - Time Curve were drawn. The relative standard deviation (RSD) of the final dissolution rate of the reference is 1.38%, and that of the self-developed sample is 2.79%. The repeatability of this test method is good.

Average Release Concentration - Time Curve

Dissolution Rate - Time Curve

Results and Discussion

From the experimental results, we can find that the dissolution rate of the reference has been higher than that of the self-developed sample throughout the dissolution experiment. With the continuous release of the drug, the difference in the cumulative dissolution rate between the reference and the self-developed sample gradually increased.

Through the concentration-time curves of the reference and the self-developed sample, we can better analyze this phenomenon: the release concentration of the reference is continuously higher than that of the self-developed sample in the prophase and metaphase of the dissolution experiment, and the concentration change of the self-developed sample is more gentle.

Their different release behaviors may lead to differences in their bioavailability.