Method and device for the simulation of gastric pH histories for dissolution and release tests of pharmaceutical formulations in vitro
To improve conventional drug release and dissolution tests, the present invention introduces a method and device capable of faithfully simulating the pH variations occurring over time in the gastric environment, represented by a buffer solution used to test oral pharmaceutical dosage forms.
The proposed method utilizes two simple solutions (acidic and basic), compliant with pharmacopeia regulations, and a stand-alone device capable of feedback control of the solution’s pH. Specifically, the dissolution medium in the proposed method consists of common saline solutions recommended by various pharmacopeias, such as PBS (Phosphate Buffer Saline).
By dosing two solutions, one acidic and one basic, and using feedback control based on the pH value measured by a probe, it is possible to simulate in vitro pH profiles similar to those observed in vivo, including both decreasing and increasing pH trends. This allows for the generation of drug release data that more closely resemble real-world conditions.
The device draws from two separate reservoirs, via pumps such as peristaltic pumps, either a basic or an acidic solution, which serve to adjust the pH according to a reference value (set point) that varies over time. Non-limiting examples of such solutions include distilled water and sodium hydroxide, or distilled water and hydrochloric acid. In addition to verifying and controlling the pH of the aforementioned solution in feedback mode, the proposed device enables precise real-time monitoring of the volumes involved, thanks to an innovative system for determining the flow rate of the dosing pumps (e.g., peristaltic pumps). This eliminates the need for flow meters to be added to the device.
Given the current limitations of in vitro testing, this invention enhances the reliability of such tests by ensuring the simulation of pH profiles comparable to those occurring in vivo.
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