Experimental Design in the Preparation of Modified HEMA-Based Superporous Hydrogels in an Aqueous Medium

Abstract

Due to a relatively large number of excipients and their concentrations, which can be used effectively in the preparation of superporous hydrogels, an experimental design based on the Taguchi matrix has proven to be a very valuable tool in screening and narrowing down the final formulation. In this study, the effect of starting materials, their concentrations as well as the starting reaction temperature, were examined in the preparation of superporous hydrogels based on hydroxyethyl methacrylate. A large number of possible formulations and conditions might lead to the production of a reasonable hydrogel network, but some formulations produce stronger or faster swelling superporous hydrogels than others. The final properties of the superporous hydrogels depend upon the events that occur during formation of the gel, including the presence of atmospheric oxygen, which is responsible for the inhibition period seen at the start of the reaction, and also including the change in temperature at which the reaction starts. These events can be largely affected by the choice of ingredients used in the reaction. For this study, eight variables were chosen, and their effects were examined using a Taguchi matrix. The parameters examined were the maximum temperature during the reaction, the time corresponding to the maximum temperature, and the reaction yield which is represented by the weight of the dry final SPH.

Keywords:

• experimental design
• gelation
• inhibition period
• poly (2-hydroxyethyl methacrylate)
• superporous hydrogels
• synthesis

Notes

All volumes are based on the use of 800 µL HEMA and 100 µL of 10 wt% aqueous F127 solution. The temperature column displays the temperature of the water in the water bath that was used to give heat to the reaction. The T_max column shows the maximum temperature that was recorded in the reaction mixture. The t_max column gives the time that was required by each reaction to reach its maximum temperature due to exotherm. *No gel was formed.

No gelation was observed for the reactions 1, 10, 13, and 17.