The reference to entity must end with the ';' delimiter

// For Blogger post if u got above error please try below code
// this will post html content in a publish post
$DB_ARTICLE[article_title]="Any Title";
$DB_ARTICLE[article_text] = <h1>Your content</h1>"
$entry = "<entry xmlns='http://www.w3.org/2005/Atom'>
<title type='text'>".$DB_ARTICLE[article_title]."</title>
<content type='text/html'>".htmlentities($DB_ARTICLE[article_text])."</content>
</entry>";