title: Physicochemical and Microbiological Stability of the Extemporaneous Sildenafil Citrate Oral Suspension.
abstract: Sildenafil is a potent and selective phosphodiesterase-5 inhibitor that is effectively used in the treatment of pulmonary arterial hypertension. In several countries, hospital pharmacists prepare the drug in an extemporaneous liquid preparation as there are no liquid formulations available for pediatric and adult uses. The purpose of this study was to evaluate the stability of an extemporaneous sildenafil citrate oral suspension for 90 days, according to the ASEAN guideline on stability studies of drug products. The results showed that the preparation was a white suspension with a sweet taste. It was a viscous and weakly acidic mixture with pseudoplastic behavior. The drug content was in the range between 99.23% and 102.23%, and the microbial examination met the general requirements throughout the study period. Therefore, the extemporaneously compounded sildenafil suspensions were physically, chemically, and microbiologically stable for at least 90 days when stored at 30° and 40°C. Furthermore, the in-use stability study showed that the preparations had acceptable attributes at least 14 days after the first-time use. This might provide an alternative option when the commercial suspension is unavailable.
authors.affiliation: School of Pharmacy, Walailak University, Thasala, Nakhon Si Thammarat 80161, Thailand; Drug and Cosmetic Research and Development Unit, Walailak University, Thasala, Nakhon Si Thammarat 80161, Thailand.
authors.forename: Attawadee
authors.initials: A
authors.lastname: Sae Yoon
authors.affiliation: School of Pharmacy, Walailak University, Thasala, Nakhon Si Thammarat 80161, Thailand; Drug and Cosmetic Research and Development Unit, Walailak University, Thasala, Nakhon Si Thammarat 80161, Thailand.
authors.forename: Somchai
authors.initials: S
authors.lastname: Sawatdee
authors.affiliation: School of Pharmacy, Walailak University, Thasala, Nakhon Si Thammarat 80161, Thailand.
authors.forename: Chuthamas
authors.initials: C
authors.lastname: Woradechakul
authors.affiliation: School of Pharmacy, Walailak University, Thasala, Nakhon Si Thammarat 80161, Thailand.
authors.forename: Kridsada
authors.initials: K
authors.lastname: Sae Chee
authors.affiliation: School of Pharmacy, Walailak University, Thasala, Nakhon Si Thammarat 80161, Thailand; Drug and Cosmetic Research and Development Unit, Walailak University, Thasala, Nakhon Si Thammarat 80161, Thailand.
authors.forename: Apichart
authors.initials: A
authors.lastname: Atipairin
keywords: ASEAN guideline; Extemporaneous preparation; Sildenafil; Stability study; Suspension
references.citation: J Med Chem. 2005 May 19;48(10):3449-62
references.pmid: 15887951
references.citation: Sci Pharm. 2015 Jul 07;83(4):659-70
references.pmid: 26839846
references.citation: Nat Rev Cardiol. 2011 Jul 19;8(9):526-38
references.pmid: 21769113
references.citation: Am J Health Syst Pharm. 2006 Feb 1;63(3):254-7
references.pmid: 16434784
references.citation: Circulation. 2014 May 13;129(19):1914-23
references.pmid: 24637559
references.citation: Clin Ther. 2008 Nov;30(11):2112-9
references.pmid: 19108799
references.citation: Int J Pharm. 2008 Mar 20;352(1-2):217-24
references.pmid: 18068319
references.citation: N Engl J Med. 2005 Nov 17;353(20):2148-57
references.pmid: 16291984
references.citation: Pediatr Cardiol. 2013 Feb;34(2):213-9
references.pmid: 23250648
references.citation: Chest. 2011 Nov;140(5):1274-1283
references.pmid: 21546436
references.citation: Expert Rev Cardiovasc Ther. 2014 Oct;12(10):1157-84
references.pmid: 25223406
references.citation: Int J Pharm. 2014 Jan 2;460(1-2):234-9
references.pmid: 24231050
references.citation: J Pharm Biomed Anal. 2006 Jun 7;41(3):857-65
references.pmid: 16527440
references.citation: Nat Rev Drug Discov. 2006 Aug;5(8):689-702
references.pmid: 16883306
references.citation: Pediatr Cardiol. 2009 Oct;30(7):871-82
references.pmid: 19705181