Method and device for the simulation of gastric pH histories for dissolution and release tests of pharmaceutical formulations in vitro
In order to improve conventional drug release and dissolution tests, according to the present invention, a method and a device capable of simulating, reproducing them faithfully, the pH variations that occur over time in the gastric environment have been developed. represented by a buffer solution, used to test pharmaceutical dosage units for oral use.
The proposed method makes use of the use of two simple solutions (acid and base), compatible with the rules of the pharmacopoeia, and the use of a stand-alone device capable of controlling the pH of the solution in feedback. Specifically, in the proposed method the dissolution medium is represented by the common saline solutions suggested by the various pharmacopoeias, such as PBS – Phospate Buffer Saline.
Thanks to the dosage of two solutions, one acidic and one basic, and by means of a feedback control based on the pH value measured by a probe, it is possible to simulate in vitro pH histories similar to those recorded in vivo, both with decreasing pH and increasing, thus being able to obtain release data of active ingredients more similar to the real ones. The device takes a basic or acid solution from two different tanks, for example peristaltic, to correct the pH following a reference value (set point) that varies over time. Non-limiting examples of such solutions can be distilled water and sodium hydroxide, and distilled water and hydrochloric acid.
The proposed device, in addition to the verification and feedback control of the pH of the aforementioned solution, allows accurate monitoring, instant by instant, of the volumes involved, thanks to an innovative system for determining the flow rate of the dosing pumps (for example peristaltic) which allows you to avoid adding flow meters to the device.
In light of the current limitations of in vitro tests, the present invention therefore confers greater veracity to said tests, guaranteeing the simulation of pH histories comparable to those that are carried out in vivo.
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