Compatibility Studies of Sildenafil with Different Excipients by Using TGA, DSC, XRD and FTIR

Abstract

Study of drug-excipient interactions is a crucial step in preformulation stage of drug development to achieve consistent chemical, physical, bioavailability, manufacturability and stability of the dosage form.In pre-formulation studies, it is important to use thermoanalytical and spectroscopic methods. These are important systems for achieving a suitable formulation. Sildenafil is a well-tolerated and highly effective treatment for erectile dysfunction. Erectile dysfunction was revolutionized with the development of a selective inhibitor of cyclic guanosine monophosphate-specific phosphodiesterase type 5. Thermogravimetric analysis, Differential Scanning Calorimetry, Fourier Transform Infrared Spectroscopy, and X-ray Powder Diffraction systems were used in the investigation and to determine the possible interactions between sildenafil and some excipients like butylated hydroxyanisole, cellulose, sodium carboxymethyl cellulose, ascorbic acid, and citric acid. Binary mixtures of drug:excipient=1:1 (mass/mass) have been analyzed. According to the results, there is incompatibility with butylated hydroxyanisole, ascorbic acid, and citric acid.

Identification of Sildenafil Compound in Selected Drugs Using X-ray Study and Thermal Analysis

“…According to the literature data, the DSC curve for Viagra ® shows that the first endothermic peak appears at a temperature of 189 °C [ 20 , 21 ]. It is worth highlighting that, based on much of the literature data, the melting point of pure sildenafil citrate is in the range 182–196 °C [ 22 , 23 ]. Whereas, in Ref.…”

“…The second endothermic peak observed on the DSC curves of examined drugs is a combination of two peaks: the first part indicates the melting point of sildenafil citrate ( m p 184–196 °C [ 22 , 23 ]) at temperatures of 188 °C and 183 °C for Sildena ® and Ernafil ® , respectively. The second part of the peak indicates the melting point of lactose monohydrate ( m p 202–215 °C [ 32 , 33 ]) at temperatures of 202 °C and 199 °C for Sildena ® and Ernafil ® , respectively.…”

Incorporation of Inclusion Complexes in the Dissolvable Microneedle Ocular Patch System for the Efficiency of Fluconazole in the Therapy of Fungal Keratitis

“…31 To create semitransparent pellets that allow light to pass through the detector, the sample and 100 mg of potassium bromide (KBr) were combined using a mortar and pounded for 5 min at 10 tons per square centimeter. 32 2.5.2. Differential Scanning Calorimetry.…”

Ispitivanje fizikalno-kemijske kompatibilnosti lijekova primjenom analitičkih tehnika: pregled istraživanja razvoja fiksne kombinacije 5-aminosalicilata i folne kiseline

“…36 Upravo se na tom principu temelji ispitivanje kompatibilnosti sastavnica lijeka tom tehnikom, odnosno prate se promjene u strukturi spojeva kad su prisutni u istoj smjesi. 37,67,[70][71][72] Primjenom rendgenske difrakcije na prahu, moguće je pratiti promjene u kristalnoj strukturi lijekova jer bilo koja promjena polimorfnog oblika lijeka može utjecati na njegovu topljivost, što u konačnici i mijenja njegovu bioraspoloživot, a time i terapijski učinak. 44,63,64,73,74 U slučaju ispitivanja kompatibilnosti balsalazida i olsalazina s folnom kiselinom čiste sastavnice pokazale su intenzivne oštre pikove karakteristične za kristalne tvari (slika 6).…”