Abstract
In vitro release testing (IVRT) is used to check the release characteristics of any semi-solid topical drug formulations. A various diffusion system such as Franz diffusion cell, vertical diffusion cell system, horizontal diffusion cell system, static diffusion cell, side by side diffusion cell, immersion cell, flow through diffusion cell, are being used as a manual release system, but suffer from numerous manual errors. Therefore, valid and standard diffusion system is desirable for determination of release characteristics of topical formulations. To overcome these errors, recently, the manual system has been replaced by automated in-line diffusion cell system. This automated IVRT offers many advantages over manual system that include continuous flow of receptor solution, automated sampling, required less time, also safeguarding the hazards of the environment by limiting physical contacts, thereby overcome all the problems which are associated in manual diffusion system. An automated IVRT diffusion system is an advanced technique that is being used for development and evaluation of topical formulations. In this review, we are demonstrating the advanced IVRT diffusion system along with its various validation parameters and factors associated with sample analysis. Furthermore, the potential advantages and future prospective of it are also discussed.

Key words: Diffusion, In Vitro Release Testing (IVRT), In-Line Cell (ILC), Validation and application.