Fingerprinting of sildenafil citrate and tadalafil tablets in pharmaceutical formulations via X-ray fluorescence (XRF) spectrometry.
The production of counterfeited drugs is a criminal problem that carries serious risks to public health in the worldwide. In Brazil, Viagra and Cialis are the most counterfeit medicines, being used to inhibit the phosphodiesterase type 5 (PDE-5), treating thus, problems related to erectile dysfunction. X-ray fluorescence (XRF) is a suitable technique to control the quality of new pharmaceutical formulations and distinguish between authentic and counterfeit tablets. XRF has advantageous features like multielemental capability, good detectivity, high precision, short analysis times, and is nondestructive, which makes it suitable to be extended to a great variety of samples. In this work, the inorganic fingerprinting chemical of forty-one commercial samples (Viagra, Cialis, Lazar, Libiden, Maxfil, Plenovit, Potent 75, Rigix, V-50, Vimax and Pramil) and fifty-six counterfeit samples (Viagra and Cialis) were obtained from XRF data. XRF presented an excellent analytical methodology for semi-quantitative determination of active ingredient (in case of sildenafil citrate that presents S in its structure) and excipients such as calcium phosphate, titanium oxide and iron oxide (P, Ca, Ti and Fe). The matrix data were allied to chemometric methods (Principal Component Analysis and Hierarchical Cluster Analysis) to classify the tablets investigated between authentic and counterfeit, grouping the samples into of seven groups: A, B, C, D and E (counterfeit group) and F and G (authentic group).
Rio Grande do Sul Technical and Scientifical Division, Brazilian Federal Police, 90160-093 Porto Alegre, RS, Brazil.
Rafael S
RS
Ortiz
Kristiane C
KC
Mariotti
Nicolas V
NV
Schwab
Guilherme P
GP
Sabin
Werickson F C
WF
Rocha
Eustáquio V R
EV
de Castro
Renata P
RP
Limberger
Paulo
P
Mayorga
Maria Izabel M S
MI
Bueno
Wanderson
W
Romão
D001938:Brazil; D002243:Carbolines / Q000032:analysis* / Q000737:chemistry; D002626:Chemistry, Pharmaceutical / Q000379:methods; D058110:Counterfeit Drugs / Q000032:analysis* / Q000737:chemistry; D015999:Multivariate Analysis; D058986:Phosphodiesterase 5 Inhibitors / Q000032:analysis* / Q000737:chemistry; D010879:Piperazines / Q000032:analysis* / Q000737:chemistry; D025341:Principal Component Analysis; D011634:Public Health; D011687:Purines / Q000032:analysis / Q000737:chemistry; D000068677:Sildenafil Citrate; D013052:Spectrometry, X-Ray Emission / Q000379:methods; D013450:Sulfones / Q000032:analysis* / Q000737:chemistry; D013607:Tablets / Q000737:chemistry; D000068581:Tadalafil
D002243:Carbolines; D058110:Counterfeit Drugs; D058986:Phosphodiesterase 5 Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D013607:Tablets; D000068581:Tadalafil; D000068677:Sildenafil Citrate