Evaluation of the residual solvent content of counterfeit tablets and capsules.

A group of counterfeit samples of Viagra and Cialis were screened for their residual solvent content and compared to the content of the genuine products. It was observed that all counterfeit samples had higher residual solvent contents compared to the genuine products. A more diverse range of residual solvents was found as well as higher concentrations. In general these concentrations did not exceed the international imposed maximum limits. Only in a few samples the limits were exceeded. A Projection Pursuit analysis revealed clusters of samples with similar residual solvent content, possibly enabling some future perspectives in forensic research.

VICTORY project: a study of counterfeit PDE5 inhibitor (sildenafil) in Indonesia.

AIM: to quantify the extent of counterfeit sildenafil in Indonesia. METHODS: the study was conducted in 4 big areas: Jakarta, Bandung, East Java (Surabaya and Malang), and Medan. Sildenafil 100 mg tablets were purchased from pharmacies, drugstores, street peddlers, and 3 Indonesian websites. The outlets were chosen by random sampling in each stratum (type of outlet). Sildenafil tablets purchased were sent to Pfizer Quality Operations Division, Dalian, China, for authenticity evaluations (by infra red spectral analysis). All counterfeit tablets were then sent to Pfizer Counterfeit Medicines Laboratory, Sandwich, UK, a portion of which were analyzed quantitatively for sildenafil concentration per tablet (by HPLC). RESULTS: a total of 518 sildenafil 100 mg tablets were collected and sent to Dalian. Of these tablets, 284 tablets (55%) were genuine sildenafil and 234 tablets (45%) were counterfeit sildenafil. Counterfeit sildenafil were mostly found in street peddlers (100%), in drugstores (56%), and from internet (33%), but pharmacies also had (13%) counterfeit sildenafil. The sildenafil content of 106 counterfeit tablets analyzed varied from 24 to 157 mg per 100 mg tablet. No analysis was done to determine other active ingredient. CONCLUSION: 45% sildenafil 100 mg tablets in Indonesia were found counterfeit and widely distributed in street peddlers, drugstores, and pharmacies. This report is aimed to alert the potential consumers, health professionals and regulators of this problem.

Rapid and sensitive determination of udenafil in plasma by LC-MS/MS for intranasal pharmacokinetic study in rats.

A rapid and sensitive analytical method for udenafil in rat plasma was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). This chromatographic procedure was then applied to the in vivo pharmacokinetic studies in rats for determining the advantages of intranasal administration of the drug over oral administration. Using liquid-liquid extraction (LLE), udenafil and the internal standard (IS) sildenafil were extracted with dichloromethane from 100 µl of plasma samples. Chromatographic separation was performed using Pursuit XRS C18 column (50 mm × 2.1 mm, i.d., 3 µm, Varian Inc., CA, U.S.A.) with an isocratic mobile phase consisting of acetonitrile and 10 mM ammonium acetate (90 : 10, v/v) at a flow rate of 0.2 ml/min over a total run time of 2.5 min. Detection and quantification was performed by mass spectrometry using the multiple reaction-monitoring mode at m/z 517.4→283.1 for udenafil and m/z 475.3→100.0 for IS. Results showed that the developed method was sensitive and specific for udenafil. Linearity was obtained in the range of 0.5-1000 ng/ml. The coefficient of variation of both intra- and inter-day validation were below 11.6% and the intra- and inter-day accuracy ranged from 91.5 to 109.9%. Udenafil concentration was successfully measured from plasma after intranasal as well as after intravenous or oral administration at clinical dose (1.67 mg/kg) in rats. Moreover, the T(max) values obtained from pharmacokinetic studies suggested that administration of udenafil intranasally could be more effective than by the oral route.

[Counterfeit phosphodiesterase type 5 inhibitors--growing safety risks for public health]. / Sfalszowane inhibitory fosfodiesterazy typu 5--narastajace zagrozenie dla zdrowia publicznego.

Counterfeit drugs, medical devises and dietary supplements are inherently dangerous and a growing problem. In Europe the growth of the counterfeit medication market is attributable in part to registration of phosphodiesterase type 5 inhibitors (PDE-5) used for the erectile dysfunction. "Viagra, Levitra and Cialis belong to this group. It has been estimated that up to 2.5 million men in Europe are exposed to an illicit sildenafil, suggesting that there may be as many illegal as legal users of sildenafil. In Europe a strong trend is observed towards increasingly professional counterfeits and imitations of Viagra, Cialis and Levitra, with regard to the appearance of tablets, capsules and packaging. The professional presentation will deceive potential consumers into assuming these products are legal, efficacious and safe. Globally, increased obstacles for counterfeiters are necessary to combat pharmaceutical counterfeiting, including fines and penalties. The worldwide nature of the counterfeit problem requires proper coordination between countries to ensure an adequate enforcement. We described the usefulness of the time-of-flight mass spectrometry with the electrospray ionization (LC-ESI-MS-TOF) and the X-ray powder diffraction method (XRPD) for PDE-5 counterfeit screening from the Polish illegal market.

Safety and quality assessment of 175 illegal sexual enhancement products seized in red-light districts in Singapore.

BACKGROUND: In recent years, there has been increasing interest in the use of herbs and supplements as an alternative to drugs used for the treatment of erectile dysfunction, in order to enhance sexual performance. Over the years, adverse events associated with the consumption of natural health products for sexual enhancement and the treatment of erectile dysfunction have been reported. OBJECTIVE: The objective of this work was to assess the safety and quality of 175 sexual enhancement health products seized from makeshift stalls in red-light districts of Singapore. METHOD: Seven raids were conducted by the Health Sciences Authority, Singapore, in two red-light districts in February and March 2008. 175 sexual enhancement health products seized from makeshift stalls were extracted with methanol and screened for Western drug adulterants using high performance liquid chromatography and gas chromatography-mass spectrometry. The labels and claims of the products were also evaluated. RESULTS: Of the 175 products evaluated, 134 (77%) were found to be adulterated with Western drugs or their analogues. Most of these 134 samples (123 [92%]) were found to be adulterated with sildenafil. The extent of adulteration of these illegal health products with Western drugs, including synthetic phosphodiesterase type 5 enzyme (PDE-5) inhibitors, and the risks of consuming such illegal sexual enhancement products are discussed in this study. Because of the scope of the raids, sildenafil was the most common adulterant found. In addition, some products were found to contain high contents of sildenafil (>100 mg) and high contents of the antidiabetic drug, glibenclamide (glyburide). The resultant severe hypoglycaemia has led to ten fatalities. CONCLUSION: The presence of Western drug adulterants and their analogues in illegal sexual enhancement products seized from red-light districts in Singapore, and their often misleading labels and claims, put the health of consumers at risk. To safeguard public health, greater public awareness of the danger of consuming such illegal products and the lack of quality control of these illegal sexual enhancement health products is important.

Determination of analogs of sildenafil and vardenafil in foods by column liquid chromatography with a photodiode array detector, mass spectrometry, and nuclear magnetic resonance spectrometry.

Two analogs of sildenafil and vardenafil in food were detected by column liquid chromatography (LC) with a photodiode array detector. They were isolated by preparative LC; their structures were established by mass spectrometry and nuclear magnetic resonance spectrometry. One analog was found to be methisosildenafil (compound A), 5-(5-(3,5-dimethylpiperazin-1-ylsulfonyl)-2-ethoxy-phenyl)-1-methyl-3-propyl-1H-pyrazolo[4,3-d]-pyrimidin-7(6H)-one. It is a sildenafil analog with a dimethylpiperazine ring substituted for the methylpiperazine group. The second analog, hydroxyvardenafil (compound B) is reported for the first time in this study. Hydroxyvardenafil's International Union of Pure and Applied Chemistry name is 2-(2-ethoxy-5-(4-(2-hydroxyethyl)-piperazin-1-ylsulfonyl)phenyl)-5-methyl-7-propyl-imidazo[1,5-f][1,2,4]triazin-4(3H)-one. The novel vardenafil analog has a hydroxyl group added to the ethylpiperazine group.

Viagra's rise above women's health issues: an analysis of the social and political influences on drug approvals in the United States and Japan.

In the United States, Viagra was approved in less than 6 months of its application to the Food and Drug Administration, while the medical abortion pill was approved 4 years after its application, and 17 years after research was first permitted. Congruently, the Ministry of Health in Japan legalized Viagra in 6 months, while oral contraceptives were approved 35 years after the ministry received initial applications. The pharmaceutical review agencies in each country are founded on safety and efficacy standards, in which objective decisions arise from science and clinical investigations. Analyses of these recent drug approvals demonstrate that conclusions may not have been based simply on science and health concerns. Instead, agency actions and application of pharmaceutical law appear to have been influenced by social and political pressures surrounding the products under scrutiny. Pharmaceutical regulations were effectively ignored or manipulated in the United States during the review process for medical abortion, and were applied inconsistently in Japan--ultimately yielding results that happened to conform to contemporary sociopolitical beliefs. Such disregard of legislation holds serious ramifications for public health, national consumer trust and the pharmaceutical industry. It is imperative that external pressures remain outside the scope of drug approval processes.

Screening suspected counterfeit Viagra and imitations of Viagra with near-infrared spectroscopy.

We describe a near-infrared spectroscopy (NIRS) method for fast-screening Viagra tablets, counterfeit Viagra tablets, and imitations of Viagra. The method can (1) check the homogeneity of a batch; (2) distinguish counterfeits and imitations from authentic Viagra; (3) screen for the presence of sildenafil citrate, the pharmacologically active substance in Viagra, irrespectively of the excipients present; (4) and detect whether similar samples have been previously analysed. We applied the method to 103 samples with a diversity of appearance, chemical composition, and origin. Other analytical methods confirmed the positive screening results for sildenafil citrate and the presence of other pharmacological active substances. The NIRS screening indicated the absence of sildenafil citrate in the presence of another pharmacological substance for only 2 samples, where the reference methods showed the presence of sildenafil citrate in addition to that of clomifene citrate. Otherwise, the method gave no false positive or negative results. The NIRS screening method is very fast and reliable for detecting counterfeits and imitations, and it correctly predicts the presence or absence of sildenafil citrate in 98% of the samples.