Jean-Michel Cardot

In vitro–in vivo correlation (IVIVC) is a biopharmaceutical tool recommended to be used in development of formulation. When validated, it can speed up development of formulation, be used to fix dissolution limits and also as surrogate of in vivo study. However, as do all tools, it presents limitations and traps. The aim of the present paper is to investigate five common traps which could limit either the setting or use of IVIVC (1) using mean or individual values; (2) correction of absolute bioavailability; (3) correction of lag time and time scaling; (4) flip-flop model; and (5) predictability corrections.

Nowadays the adjustment of medication for each patient is at the center of health strategy. Children can be considered as specific targets with their own specificities. In the oral route field some examples of drugs especially adapted to children can be found. Design is introduced in drug formulation to offer a better choice of products and now, children can be considered as partners in their own treatment. Enhanced comprehension of children's requirements can also lead to creation of drugs that improve compliance.

A novel abuse deterrent, prolonged release tablet formulation of Hydrocodone for once-daily dosing has been developed, based on the novel proprietary Egalet® ADPREM technology. The tablet is an injection molded polymer system consisting of an erodible matrix in which the Active Pharmaceutical Ingredient (API), such as Hydrocodone, is dispersed. The matrix is partly covered with a water-impermeable, non-erodible shell which leaves both ends of the cylindrical tablet exposed to erosion by the gastrointestinal (GI) fluid. In vivo–in vitro correlation (IVIVC) was initiated and validated with three formulations. A good internal predictability was observed for the three formulations. How the changing conditions in the GI tract influenced in vivo performance of an erosion based product was discussed. The validated IVIVC could be used to optimize the tablet formulation and to obtain a desired profile. In addition, this technique could help to establish the dissolution limits in which a certainty of bioequivalence is calculated. Based on this validated level A IVIVC, dissolution can be used as surrogate of bioequivalence for development, but also scale up post approval changes.

Standard compendia dissolution apparatus are the first choice for development of new dissolution methods. Nevertheless, limitations coming from the amount of material available, analytical sensitivity, lack of discrimination or biorelevance may warrant the use of non compendial methods. In this regard, the use of small volume dissolution methods offers strong advantages. The present study aims primarily to evaluate the dissolution performance of various drug products having different release mechanisms, using commercially available small volume USP2 dissolution equipment. The present series of tests indicate that the small volume dissolution is a useful tool for the characterization of immediate release drug product. Depending on the release mechanism, different speed factors are proposed to mimic common one liter vessel performance. In addition, by increasing the discriminating power of the dissolution method, it potentially improves know how about formulations and on typical events which are evaluated during pharmaceutical development such as ageing or scale–up. In this regard, small volume dissolution is a method of choice in case of screening for critical quality attributes of rapidly dissolving tablets, where it is often difficult to detect differences using standard working conditions.