A 63-year-old man with chronic obstructive pulmonary disease and benign prostatic hyperplasia comes to the emergency department for sudden onset of severe right eye pain, headache, and nausea that began 1 hour after he used a newly prescribed inhaled medication for shortness of breath. He reports seeing “halos” around lights. Vital signs are normal. Eye examination shows a red right eye with a steamy-appearing cornea, a mid-dilated poorly reactive pupil, and markedly elevated intraocular pressure. Which of the following properties of the medication most directly precipitated this patient’s condition?