The issue is the bot blocking that they have employed.

• The first clue is the "<!-" which is HTML code.
• I have then printed out the output of the morphine_mol variable, and it indeed indicates that the issue is due to some kind of blocking they have.

See this text:

    <h2 data-translate="blocked_resolve_headline">What can I do to resolve this?</h2>
        <p data-translate="blocked_resolve_detail">You can email the site owner to let them know you were blocked. Please include what you were doing when this page came up and the Cloudflare Ray ID found at the bottom of this page.</p>

This isn't my field of expertise, but for other tasks similar to this, I have used the API instead.

This seems to be their API information: https://docs.drugbank.com/v1/

API signup looks like it should be here. https://dev.drugbank.com/clients/sign_in

Alternatively, if you don't need access in that way - you could save down the file to local, and load it from there.