Title: Diphenoxylate
CAS Registry Number: 915-30-0
CAS Name: 1-(3-Cyano-3,3-diphenylpropyl)-4-phenyl-4-piperidinecarboxylic acid ethyl ester
Additional Names: 1-(3-cyano-3,3-diphenylpropyl)-4-phenylisonipecotic acid ethyl ester; ethyl 1-(3-cyano-3,3-diphenylpropyl)-4-phenylisonipecotate; ethyl 1-(3-cyano-3,3-diphenylpropyl)-4-phenyl-4-piperidinecarboxylate; 2,2-diphenyl-4-(4-carbethoxy-4-phenylpiperidino)butyronitrile
Manufacturers' Codes: R-1132
Molecular Formula: C30H32N2O2
Molecular Weight: 452.59
Percent Composition: C 79.61%, H 7.13%, N 6.19%, O 7.07%
Literature References: Prepn: Janssen, US 2898340 (1959). Pharmacokinetics and metabolism: Karim et al., J. Pharmacol. Exp. Ther. 177, 546 (1971); Clin. Pharmacol. Ther. 13, 407 (1972). See also Difenoxin, the active metabolite of diphenoxylate. Comprehensive description: D. D. Hung, Anal. Profiles Drug Subs. 7, 149-169 (1978).
Derivative Type: Hydrochloride
CAS Registry Number: 3810-80-8
Molecular Formula: C30H32N2O2.HCl
Molecular Weight: 489.05
Percent Composition: C 73.68%, H 6.80%, N 5.73%, O 6.54%, Cl 7.25%
Properties: Crystals, mp 220.5-222°. uv max (methanol): 252, 258, 264 nm. Soly in mg/ml at 25°: acetic acid 500; DMF 500; chloroform 360; methanol >50; ethanol 3; water 0.8; hexane 0.5.
Melting point: mp 220.5-222°
Absorption maximum: uv max (methanol): 252, 258, 264 nm
Derivative Type: Mixture of hydrochloride with atropine sulfate
Trademarks: Lomotil (Searle); Diarsed (Sanofi Winthrop); Reasec (Janssen)
NOTE: This is a controlled substance (opiate): 21 CFR, 1308.12.
Therap-Cat: Antiperistaltic; antidiarrheal.
Keywords: Antidiarrheal.
Diphenyl Sulfone Diphenylacetamide Diphenylacetic Acid Diphenylamine Diphenylcarbazone

Systematic (IUPAC) name
ethyl 1-(3-cyano-3,3-diphenylpropyl)-4-phenylpiperidine-4-carboxylate
Clinical data
AHFS/Drugs.com monograph
Legal status Controlled (S8) (AU) Class A (UK) Schedule II (US)
Routes Oral
Pharmacokinetic data
Protein binding 74-95%
Half-life 12–14 hours
CAS number 915-30-0 YesY
ATC code A07DA01
PubChem CID 13505
DrugBank DB01081
ChemSpider 12919 YesY
UNII 73312P173G YesY
KEGG D07861 YesY
Chemical data
Formula C30H32N2O2 
Mol. mass 452.587 g/mol
 N (what is this?)  (verify)

Diphenoxylate (R-1132) is an opioid agonist used for the treatment of diarrhea that acts by slowing intestinal contractions and peristalsis allowing the body to consolidate intestinal contents and prolong transit time, thus allowing the intestines to draw moisture out of them at a normal or higher rate and therefore stop the formation of loose and liquid stools. It is the main active ingredient in the anti-peristaltic medication Lomotil, which also contains atropine as noted below.

Diphenoxylate is the prototype of a small subfamily of opioids including difenoxin (diphenoxylic acid) (an active metabolite of diphenoxylate produced in the human body) and loperamide (which unlike the other two work exclusively in the intestines because it only crosses the blood–brain barrier in very small amounts). It was discovered at Janssen Pharmaceutica in 1956. It is a congener to the narcotic pethidine of which the common brand names are Dolantin and Demerol amongst others. Other somewhat more distant relatives include alphaprodine (Nisentil) and piritramide (Dipidolor).