Journal of Advanced Pharmaceutical Technology & Research

ORIGINAL ARTICLE
Year
: 2021  |  Volume : 12  |  Issue : 4  |  Page : 408--419

Preparation and physicochemical characterization of sildenafil cocrystals


Somchai Sawatdee1, Apichart Atipairin1, Supitchaya Rakkummerd3, Onsinee Suriyaphol3, David J Harding2, Poowadon Muenraya1, Phimphaka Harding2 
1 Drug and Cosmetics Excellence Center, Walailak University; School of Pharmacy, Walailak University, Thasala, Nakhon Si Thammarat, Thailand
2 Functional Materials and Nanotechnology Center of Excellence, Walailak University, Thasala, Nakhon Si Thammarat, Thailand

Correspondence Address:
Dr. Phimphaka Harding
Functional Materials and Nanotechnology Center of Excellence, Walailak University, Thasala, Nakhon Si Thammarat, 80160
Thailand
Mr. Poowadon Muenraya
Pharm.D, Drug and Cosmetics Excellence Center, Walailak University, Thasala, Nakhon Si Thammarat, 80160, Thailand; School of Pharmacy, Walailak University, Thasala, Nakhon Si Thammarat, 80160
Thailand

Sildenafil is a specific inhibitor of the phosphodiesterase type 5 (PDE-5) enzyme that protects cyclic guanosine monophosphate from breakdown by PDE-5. It is a biopharmaceutical categorization system Class II medication with low bioavailability because it is almost insoluble in water. The objectives of this study were to prepare sildenafil cocrystals with co-former molecules including aspirin (acetylsalicylic acid [ASA]), fumaric acid (FMA), and benzoic acid (BZA) to improve the water solubility of sildenafil. The cocrystals were prepared by antisolvent addition (AA) and slow solvent evaporation (SE) methods. The stoichiometric ratios of sildenafil and co-former molecules were varied. The obtained crystals were characterized by stereomicroscope, Fourier transformed infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), and powder X-ray diffraction (PXRD). The water solubility of sildenafil cocrystals was compared with sildenafil base. In the AA method, the crystals only form in sildenafil-ASA reaction. These crystals were not cocrystals between sildenafil and ASA because they were formed to new substances that were confirmed by single-crystal X-ray diffraction. In the SE method, the cocrystals were successfully prepared in the reaction of sildenafil with ASA, FMA, and BZA which use acetone or ethyl acetate as a solvent. The obtained crystals are irregular shapes and their FT-IR, NMR, and PXRD results exhibited the characteristics of sildenafil and its co-former. The stoichiometric ratios of sildenafil and co-formers after cocrystallization were different from an initial of crystallization. The sildenafil cocrystals with ASA, FMA, and BZA by SE method had higher water solubility than sildenafil base. The sildenafil-FMA cocrystals had the highest water solubility and increased up to five times when compared with sildenafil base.


How to cite this article:
Sawatdee S, Atipairin A, Rakkummerd S, Suriyaphol O, Harding DJ, Muenraya P, Harding P. Preparation and physicochemical characterization of sildenafil cocrystals.J Adv Pharm Technol Res 2021;12:408-419


How to cite this URL:
Sawatdee S, Atipairin A, Rakkummerd S, Suriyaphol O, Harding DJ, Muenraya P, Harding P. Preparation and physicochemical characterization of sildenafil cocrystals. J Adv Pharm Technol Res [serial online] 2021 [cited 2022 Jan 24 ];12:408-419
Available from: https://www.japtr.org/article.asp?issn=2231-4040;year=2021;volume=12;issue=4;spage=408;epage=419;aulast=Sawatdee;type=0