Before and Preparatory to

Before adverb - So as to precede something in order of time.

Preparatory to and before are semantically related in prior to topic. In some cases you can use "Preparatory to" instead the word "Before" as a preposition or an adverb.

Before and preparatory to are semantically related in in preparation for topic. You can use "Before" instead an adverb phrase "Preparatory to".