Multidisciplinary approach for the investigation of content-container interactions PhD thesis of Benedetta Briasco This thesis is presented as compendium of publications or works in phase of submission. 1 SUMMARY 1. GENERAL INTRODUCTION ..................................................................................... 7 1.1 What is “packaging”? .............................................................................................. 7 1.2 Plastics ..................................................................................................................... 8 1.2.1 Generality on polymers .................................................................................... 9 1.2.2 Polymers processing ....................................................................................... 10 1.2.3 Plastic Processing ........................................................................................... 11 1.2.4 Plastic additives .............................................................................................. 14 1.2.5 Plastic materials .............................................................................................. 17 1.3 Regulation of packaging industry .......................................................................... 26 1.4 Interactions between content and container ........................................................... 29 1.5 Semisolid formulations: emulsions ....................................................................... 31 1.5.1 Types of emulsion: Oil in Water (O/W) ......................................................... 32 1.5.2 Types of emulsion: Water in Oil (W/O) ......................................................... 32 1.5.3 Types of emulsion: Multiple emulsions (W/O/W or O/W/O) ........................ 32 1.5.4 Types of emulsion: Water in silicon (W/S) .................................................... 33 1.5.5 Stability of emulsions ..................................................................................... 34 1.6 Ingredients with critical issues .............................................................................. 35 1.6.1 Sunscreens ...................................................................................................... 36 1.6.2 Preservatives ................................................................................................... 40 1.6.3 Essential oils ................................................................................................... 43 REFERENCES ............................................................................................................ 47 2. OBJECTIVES .............................................................................................................. 60 3. RATIONAL OF PROJECT ......................................................................................... 61 Chapter I. ......................................................................................................................... 66 PROTOCOL AND SPECIMEN SET UP FOR MECHANICAL EVALUATION OF COSMETIC PACKAGING ................................................................................................... 66 ABSTRACT ................................................................................................................ 67 INTRODUCTION ....................................................................................................... 68 MATERIALS AND METHODS ................................................................................ 71 Set up of sample for mechanical analysis ................................................................ 71 Measurement of mechanical properties ................................................................... 72 Container test protocol ............................................................................................. 74 RESULTS AND DISCUSSION .................................................................................. 75 Sample set up ........................................................................................................... 75 Mechanical analysis ................................................................................................. 77 CONCLUSION ........................................................................................................... 81 REFERENCES ............................................................................................................ 82 Chapter II. ........................................................................................................................ 84 2 PACKING EVALUATION APPROACH TO IMPROVE COSMETIC PRODUCT SAFETY................................................................................................................................. 84 ABSTRACT ................................................................................................................ 85 INTRODUCTION ....................................................................................................... 86 MATERIALS .............................................................................................................. 89 EXPERIMENTAL ...................................................................................................... 89 Provision of Data ..................................................................................................... 89 Experimental Design ............................................................................................... 90 Degradation Testing Procedures .............................................................................. 91 Mechanical Test ....................................................................................................... 91 Extractables’ Analysis ............................................................................................. 92 RESULTS AND DISCUSSION .................................................................................. 93 CONCLUSIONS ....................................................................................................... 100 REFERENCES .......................................................................................................... 101 Chapter III. .................................................................................................................... 105 PROPOSAL OF ALKALINE SIMULANTS FOR COSMETIC-PACKAGING COMPATIBILITY ............................................................................................................... 105 ABSTRACT .............................................................................................................. 106 INTRODUCTION ..................................................................................................... 107 MATERIAL AND METHODS ................................................................................. 109 Preparation of simulants ........................................................................................ 110 Degradation testing procedures ............................................................................. 110 Mechanical test ...................................................................................................... 111 RESULTS AND DISCUSSION ................................................................................ 112 Choice of alkaline simulants .................................................................................. 112 Simulant F1: mechanical properties ...................................................................... 112 Simulant F2: mechanical properties ...................................................................... 114 CONCLUSION ......................................................................................................... 115 REFERENCES .......................................................................................................... 115 Chapter IV. .................................................................................................................... 118 MECHANICAL ANALYSIS AND EXTRACTABLE TESTING OF LDPE PACKAGING FOR SEMISOLID FORMULATION ......................................................... 118 ABSTRACT .............................................................................................................. 119 INTRODUCTION ..................................................................................................... 120 MATERIALS ............................................................................................................ 122 Packaging .............................................................................................................. 122 Formulation ........................................................................................................... 123 METHODS ................................................................................................................ 123 Preparation of formulation ..................................................................................... 123 Degradation testing procedures ............................................................................. 124 3 Mechanical test ...................................................................................................... 125 Statistical analysis.................................................................................................. 126 Extractables testing ................................................................................................ 126 Formulations’