Pharmacologically effective red yeast rice preparations marketed as dietary supplements illustrated by a case report.

This paper reports a typical statin-related adverse reaction from a red yeast rice (RYR) supplement and the analytical findings from the supplement. It also examines the regulatory framework governing botanical supplements in Europe. Two key events that shaped the current regulatory framework are reviewed. First, the Hecht-Pharma judgement by the European Court of Justice (ECJ) that inverted the precautionary principle in the Medicines Act to a reactionary principle. Following the Hecht-Pharma judgement, pharmacological active dietary supplements can be sold until sufficient signals of harm show that they are an unregistered medicine, placing a huge burden on regulatory authorities. Secondly, the European Food Safety Authority (EFSA) in 2011 approved the first health claim for pharmacologically active RYR dietary supplements. If the current regulatory status for pharmacologically active RYR dietary supplements does not permit adequate warning and active monitoring of adverse drug reactions, then the current regulatory framework may not be adequate to ensure consumer safety.Copyright © 2016 John Wiley & Sons, Ltd.

Dose-to-dose variations with single packages of counterfeit medicines and adulterated dietary supplements as a potential source of false negatives and inaccurate health risk assessments.

In this report, we show three examples of how the variability in dose units in single packages of counterfeit medicines and adulterated dietary supplements may contribute to a false negative screening result and inaccurate health risk assessments. We describe a counterfeit Viagra 100mg blister pack and a box of an instant coffee both containing dose units with and without an active pharmaceutical ingredient (API). We also describe a purportedly herbal slimming product with capsules that mutually differed in API and impurities. The adulterated dietary supplements contained sibutramine, benzyl-sibutramine, N-desmethyl-sibutramine (DMS), N,N-didesmethyl-sibutramine (DDMS) and several other related impurities. Counterfeit medicines and adulterated dietary supplements are a health risk because their quality is unreliable. Health risks are even greater when such unreliability extends to fundamental differences between dose units in one package. Because dose-to-dose variability for these products is unpredictable, the confidence interval of a sample size is unknown. Consequently, the analyses of a selection of dose units may not be representative for the package. In the worst case, counterfeit or unauthorised medicines are not recognised as such or a health risk is not identified. In order to reduce erroneous results particular care should be taken when analysing a composite of dose units, when finding no API in a dietary supplement and when finding conformity in a suspect counterfeit medicine.

Sildenafil and analogous phosphodiesterase type 5 (PDE-5) inhibitors in herbal food supplements sampled on the Dutch market.

Herbal food supplements, claiming to enhance sexual potency, may contain deliberately added active pharmacological ingredients (APIs) that can be used for the treatment of erectile dysfunction (ED). The aim of this study was to determine whether herbal food supplements on the Dutch market indeed contain APIs that inhibit phosphodiesterase type 5 (PDE-5) inhibitors, such as sildenafil and analogous PDE-5 inhibitors. Herbal food supplements intended to enhance sexual potency (n = 71), and two soft drinks, were sampled from 2003 up to and including 2012. In 23 herbal supplements, nine different PDE-5 inhibitors were identified; in a few cases (n = 3), more than one inhibitor was indentified. The presence of these APIs was however not stated on the label. The concentrations of PDE-5 inhibitors per dose unit were analysed. Furthermore, the potential pharmacologically active properties of the detected PDE-5 inhibitors were estimated by using data from the scientific and patent literature regarding (1) in vitro PDE-5 activity, (2) reported effective doses of registered drugs with PDE-5 inhibitor activity and (3) similarity to other structural analogues. It was concluded that 18 of the 23 herbal food supplements, when used as recommended, would have significant pharmacological effects due to added APIs. Adequate use of existing regulation and control measures seems necessary to protect consumers against the adverse effects of these products.

Towards a decade of detecting new analogues of sildenafil, tadalafil and vardenafil in food supplements: a history, analytical aspects and health risks.

The scale at which erectile dysfunction (ED) medicines are obtained outside of the official health system rivals and possibly exceeds legitimate sales. According to literature a high-risk segment of this market is occupied by adulterated food supplements. The principle adulterants identified were structural analogues of the registered ED drugs sildenafil, tadalafil, and vardenafil. Currently, at least 46 different analogues have been reported and still more are expected. The intellectual origin of analogues was found in patent literature which described the drug discovery process. Patent literature offers a flexible approach to synthesize hundreds of analogues. Most of the analogues currently known had long been disclosed in patent literature. Screening for (new) analogues is best carried out by using advanced LC-MS/MS techniques that focus on marker fragment ions. Analogues are experimental drugs in essence because most have no known efficacy or safety profile. Their use in seemingly harmless food supplements is expected to cause serious adverse effects. However, few reports have emerged in literature on actual harm. Considering the exposure to analogues and their adverse effects being unknown a gross underreporting of complaints is expected.

On the formation of bromhexine impurity E and its chromatographic behaviour.

An unknown bromhexine hydrochloride (BRH) degradation product in BRH oral solutions (finished products) was potentially related to the purity of this API. Several degradation experiments were conducted and its identity and formation were investigated using LC-DAD and LC-DAD-MS/MS. Using the LC method described in the Ph.Eur monograph BRH the degradation product was observed at RRTBRH 0.1 and the specified impurities A-D were ruled out as candidates. Impurity E was initially not considered as a candidate as EDQM reported an expected RRTBRH of 1.8. Still, the LC-DAD-MS/MS results were consistent with the M+ ion for impurity E and its expected fragment ions. Therefore, standard addition was carried out using the Ph. Eur. method which confirmed that the degradation product at RRT 0.1 was impurity E. Upon changing the column type to a column described in the knowledge database, impurity E eluted at an RRT of 1.5. Nevertheless, both columns met all of the criteria in the monograph. The formation of impurity E was even observed in BRH solutions without added reagents. As the conversion from BRH to impurity E requires a source of carbon, we suggest that one BRH molecule degrades through a radical mechanism to a reactive species which subsequently is quenched by another BRH molecule producing impurity E. We suggest the transparency list for BRH to be more explicit on the formation of impurity E, its RRT and the permissible LC columns.

The identification of rimonabant polymorphs, sibutramine and analogues of both in counterfeit Acomplia bought on the internet.

Acomplia was ordered over the internet resulting in the delivery of counterfeit Acomplia and imitation products. The tablets were analyzed for the presence of rimonabant. Using LC-DAD-MSn the presence of effective quantities of rimonabant was confirmed in samples A-D. Samples A and D also contained traces of the rimonabant analogue NIDA-41020. Furthermore, NIR spectroscopy on the tablets indicated the presence of an unapproved rimonabant polymorph in samples C and D which was confirmed by Raman spectroscopy and X-ray diffraction (XRD). In sample E a low dose of sibutramine was found as well traces of N-desmethylsibutramine and bis-N-desmethylsibutramine. Rimonabant was withdrawn from the market because of serious adverse events and lack of efficacy. The availability of poor quality products with rimonabant, impurities and unapproved polymorphs is worrying. Suspect weight-loss medicines should be screened for the presence of novel analogues.

Consistency of FMEA used in the validation of analytical procedures.

In order to explore the consistency of the outcome of a Failure Mode and Effects Analysis (FMEA) in the validation of analytical procedures, an FMEA was carried out by two different teams. The two teams applied two separate FMEAs to a High Performance Liquid Chromatography-Diode Array Detection-Mass Spectrometry (HPLC-DAD-MS) analytical procedure used in the quality control of medicines. Each team was free to define their own ranking scales for the probability of severity (S), occurrence (O), and detection (D) of failure modes. We calculated Risk Priority Numbers (RPNs) and we identified the failure modes above the 90th percentile of RPN values as failure modes needing urgent corrective action; failure modes falling between the 75th and 90th percentile of RPN values were identified as failure modes needing necessary corrective action, respectively. Team 1 and Team 2 identified five and six failure modes needing urgent corrective action respectively, with two being commonly identified. Of the failure modes needing necessary corrective actions, about a third were commonly identified by both teams. These results show inconsistency in the outcome of the FMEA. To improve consistency, we recommend that FMEA is always carried out under the supervision of an experienced FMEA-facilitator and that the FMEA team has at least two members with competence in the analytical method to be validated. However, the FMEAs of both teams contained valuable information that was not identified by the other team, indicating that this inconsistency is not always a drawback.

The identification of a nitrosated prodrug of the PDE-5 inhibitor aildenafil in a dietary supplement: a Viagra with a pop.

A new unapproved analogue of sildenafil was detected in capsules of a herbal dietary supplement promoted as a libido enhancing product. Using LC-DAD-MS, MS-MS, HRMS, IR and NMR the analogue was shown to be a derivative of the PDE-5 inhibitor aildenafil with a nitrosamine moiety. A hydrolysis experiment showed that the new analogue was a prodrug of aildenafil and was therefore named nitroso-prodenafil. A capsule contained 108 mg of nitroso-prodenafil which is equivalent to 84 mg of aildenafil and 5.1 mg of nitrogen monoxide (NO). Although it is unknown how much NO can be usefully generated there is 3-fold more NO present than in a 10 mg isorbide nitrate tablet. Both PDE-5 inhibitors and nitrosamines cause vasodilatation by increasing levels of NO. To their coincidental use is warned against because it may cause a fatal drop in blood pressure. In addition, nitrosamines are known carcinogens. This is the first time a PDE-5 inhibitor and a potential NO donor were identified in one molecule. The findings indicate the dangerous level of advancement in medicinal chemistry by producers of unapproved drugs.

The identification of (-)-trans-tadalafil, tadalafil, and sildenafil in counterfeit Cialis and the optical purity of tadalafil stereoisomers.

Four blisters with suspect Cialis (tadalafil) 20mg tablets were screened for authenticity using near infrared spectroscopy (NIRS) and for the presence of phosphodiesterase 5 (PDE-5) inhibitors using LC-DAD-MS. All samples were identified as counterfeit Cialis and contained sildenafil or a combination of tadalafil and sildenafil. Although the tablets contained efficacious amounts of PDE-5 inhibitors, neither the active ingredient nor the dosage corresponded to the description on the blister. This is the first reported case of a diastereomeric mixture of tadalafil and trans-tadalafil (3:1) being identified in a counterfeit medicine. The LC-DAD-CD revealed that both diastereomers had a high optical purity. The optical rotation of the diastereomeric mixture was measured indicating the presence of (-)-trans-tadalafil, which is the only other stereoisomer with some PDE-5 inhibitory activity. As no safety profiles are known for the stereoisomers of tadalafil, there is a potential health risk. In addition, the optical purity of tadalafil needs to be taken into account when calculating the dosage in illegal medicines.

Risk analysis by FMEA as an element of analytical validation.

We subjected a Near-Infrared (NIR) analytical procedure used for screening drugs on authenticity to a Failure Mode and Effects Analysis (FMEA), including technical risks as well as risks related to human failure. An FMEA team broke down the NIR analytical method into process steps and identified possible failure modes for each step. Each failure mode was ranked on estimated frequency of occurrence (O), probability that the failure would remain undetected later in the process (D) and severity (S), each on a scale of 1-10. Human errors turned out to be the most common cause of failure modes. Failure risks were calculated by Risk Priority Numbers (RPNs)=O x D x S. Failure modes with the highest RPN scores were subjected to corrective actions and the FMEA was repeated, showing reductions in RPN scores and resulting in improvement indices up to 5.0. We recommend risk analysis as an addition to the usual analytical validation, as the FMEA enabled us to detect previously unidentified risks.

Detection of Lipitor counterfeits: a comparison of NIR and Raman spectroscopy in combination with chemometrics.

Research has been carried on the feasibility of near infrared (NIR) and Raman spectroscopy as rapid screening methods to discriminate between genuine and counterfeits of the cholesterol-lowering medicine Lipitor. Classification, based on partial least squares discriminant analysis (PLS-DA) models, appears to be successful for both spectroscopic techniques, irrespective of whether atorvastatine or lovastatine has been used as the active pharmaceutical ingredient (API). The discriminative power of the NIR model, in particular, largely relies on the spectral differences of the tablet matrix. This is due to the relative large sample volume that is probed with NIR and the strong spectroscopic activity of the excipients. PLS-DA models based on NIR or Raman spectra can also be applied to distinguish between atorvastatine and lovastatine as the API used in the counterfeits tested in this study. A disadvantage of Raman microscopy for this type of analysis is that it is primarily a surface technique. As a consequence spectra of the coating and the tablet core might differ. Besides, spectra may change with the position of the laser in case the sample is inhomogeneous. However, the robustness of the PLS-DA models turned out to be sufficiently large to allow a reliable discrimination. Principal component analysis (PCA) of the spectra revealed that the conditions, at which tablets have been stored, affect the NIR data. This effect is attributed to the adsorption of water from the atmosphere after unpacking from the blister. It implies that storage conditions should be taken into account when the NIR technique is used for discriminating purposes. However, in this study both models based on NIR spectra and Raman data enabled reliable discrimination between genuine and counterfeited Lipitor tablets, regardless of their storage conditions.

Structure elucidation of a novel synthetic thiono analogue of sildenafil detected in an alleged herbal aphrodisiac.

A new analogue of sildenafil was detected in a herbal aphrodisiac. The structure of the compound was established using LC-MS, UV and IR spectroscopy, MS-MS, and NMR. The compound, named thio-homosildenafil is a synthetic N-ethylpiperazine analogue of sildenafil in which also the CO moiety has been converted into a CS group. This is the first time a sildenafil analogue modified at the chromophore was identified as an adulterant of a herbal aphrodisiac. Preliminary pharmacological analysis confirmed the erectogenic potency of thio-homosildenafil.

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.

Results of a market surveillance study in The Netherlands on break-mark tablets.

A representative market surveillance study on break-mark tablets for human use, having a marketing authorization (MA) in The Netherlands (NL), was carried out. The uniformity of mass of subdivided break-mark tablets into halves was assessed according to Ph.Eur.5.5, now current; and for comparison also according to Ph.Eur. 4.1 (no longer in force) and Pharmeuropa 16.2. The compliance was 24%, 14% and 45%, respectively. The compliance with a criterion for loss of mass by subdivision of break-mark tablets (< or = 1.0% of the total mass) was 86%. The compliance with a criterion for ease of subdivision of break-mark tablets (> or = 80% of a panel of elderly able to break, > or = 90% probability) was 34%. Of the 29 studied tablets, 5 complied with all criteria, amongst which were all three oblong tablets that were included in the study. The Summary of Product Characteristics (SmPC) of the tablets was independently evaluated by experts to assess whether their break-mark was needed for the posology. The experts came to a uniform conclusion for only 66% of the tablets. It is concluded that the proposed test procedures for ease of subdivision and loss of mass by subdivision are workable, that the proposed criteria are reasonable and that their inclusion in Ph.Eur. can be considered. From a pharmaceutical-technological point of view, the requirements of Ph.Eur. 5.5 Subdivision of tablets for uniformity of mass of subdivided tablets, and the proposed criteria for ease of subdivision and loss of mass, are all simultaneously attainable. It is also concluded that the majority of the break-mark tablets with a MA in NL do not meet the requirements of Ph.Eur.5.5 Subdivision of tablets, and that they do not fulfill the proposed criterion for ease of subdivision. This is expected to also be the case in other countries. It is proposed that the test Ph.Eur. 5.5 Subdivision of tablets should give instructions on how to handle tablets that cannot be broken, or that crumble upon subdivision. It is also proposed that the criteria Ph.Eur. 5.5 Subdivision of tablets should not be restricted to break-marks needed for the posology, as dosing instructions in SmPCs are open to different interpretations, and that this restriction should be deleted.

Disintegration of sublingual tablets: proposal for a validated test method and acceptance criterion.

In the Netherlands the market share of isosorbide dinitrate 5 mg sublingual tablets is dominated by 2 products (A and B). In the last few years complaints have been received from health care professionals on product B. During patient use the disintegration of the tablet was reported to be slow and/or incomplete, and ineffectiveness was experienced. In the European Pharmacopoeia (Ph. Eur.) no requirement is present for the disintegration time of sublingual tablets. The purpose of this study was to compare the in vitro disintegration time of products A and B, and to establish a suitable test method and acceptance criterion. A and B were tested with the Ph. Eur. method described in the monograph on disintegration of tablets and capsules as well as with 3 modified tests using the same Ph. Eur. apparatus, but without movement of the basket-rack assembly. In modified test 1 and modified test 2 water was used as medium (900 ml and 50 ml respectively), whereas in modified test 3 artificial saliva was used (50 ml). In addition, disintegration was tested in Nessler tubes with 0.5 and 2 ml of water. Finally, the Ph. Eur. method was also applied to other sublingual tablets with other drug substances on the Dutch market. With modified test 3 no disintegration could be achieved within 20 min. With the Ph. Eur. method and modified tests 1 and 2 product A and B differed significantly (p < 0. 001), with product B having longer disintegration times. These 3 methods were capable of discriminating between products and between batches. The time measured with the Ph. Eur. method was significantly lower compared to modified tests 1 and 2 (p < 0.001) and correlated well with the Nessler tube results. It is concluded that the in vivo complaints on product B could be related to the in vitro data. Furthermore, it is proposed that for immediate release of sublingual tablets the disintegration time should be tested. The Ph. Eur. method is considered suitable for this test. In view of the products currently on the market and taking into consideration requirements in the United States Pharmacopeia and Japanese Pharmacopoeia, an acceptance criterion of not more than 2 min is proposed.

Structure elucidation of sildenafil analogues in herbal products.

The structure of unknown compounds present in herbal products was elucidated using liquid chromatography-electrospray ionization-mass spectrometry, direct-infusion electrospray ionization-mass spectrometry, and nuclear magnetic resonance. Compounds 1-3 were identified as sildenafil analogues, 1 bearing an N-ethylpiperazine moiety instead of an N-methylpiperazine, and an acetyl group instead of the sulfonyl group, named acetildenafil, 2 bearing an N-ethylpiperazine moiety instead of an N-methylpiperazine (homosildenafil), and 3 bearing an N-hydroxylethylpiperazine moiety instead of an N-methylpiperazine, named hydroxyhomosildenafil. When analysing products marketed for penile erectile dysfunction or marketed as aphrodisiacs, attention should be given to the possible presence of these components.

Analysis of optically active compounds using conventional chromatography with a circular dichroism detector.

Analysis of optically active compounds in complex samples is often based on chiral chromatography or capillary electrophoresis in order to separate the enantiomers. This requires a chiral reagent, when using conventional chromatography, or an expensive chiral column, or a chiral selector, when using capillary electrophoresis. The type of column, reagent, or additive depends highly on the compound to be analysed. A simple and generally applicable method is using a conventional HPLC column coupled to a CD detector. Separation of enantiomers is not required, as they can be identified by a positive or negative peak. A racemate does not produce a peak; neither does an optically inactive compound. The application of HPLC-CD for the identification of pharmacologically active compounds, such as dexamphetamine, 5-hydroxytryptophan, (-)-huperzine A, and interferon, as standards, in registered drugs, in falsifications, and in food supplements is described.

An improved in vitro method for the evaluation of antacids with in vivo relevance.

An improved in vitro method for the evaluation of antacids for use with standard equipment is described. The method is a modification of an older method (RIGO method) and has in vivo relevance. The improved method uses USP dissolution test apparatus 2 with a stirring rate of 125 rpm in combination with a computerized automatic burette. The test solution is 250 ml 0.02 M HCl. A total of 20 min after addition of an antacid to the test solution titration starts at a constant speed of 2.0 ml/min 0.1 M HCl. The proposed acceptance criteria for a waiver for clinical studies are: pH after 4 min not less than 2.5 to ensure a rapid onset of effect, pH after 20 min not exceeding 7.0 to ensure that the pH in the stomach remains within physiological values, buffering capacity between pH 2.5 and 4.5 not less than 8 meq/dose and neutralizing capacity not less than 10 meq/dose to ensure sufficient efficacy within the physiological range. The improved method has been validated with respect to robustness to variations in sample preparation, repeatability and intermediate precision and has been cross-validated versus the RIGO method. The improved method has been found to be rather insensitive to variations in sample pretreatment and at least equivalent to the RIGO method.

Pharmaceutical analysis of the oral iron chelator deferiprone (DMHP,L1).

The oral iron chelator deferiprone (1,2-dimethyl-3-hydroxy-pyrid-4-one, DMHP, LT or CP20) can be a useful drug in patients with transfusional hemosiderosis. From 1987 about 1000 patients in 16 countries have taken this drug on the base of clinical trials or compassionate use. Since this compound is only available as a raw substance, it is important to ascertain its purity before bringing the drug into a pharmaceutical formulation. Because deferiprone is administered chronically and in high doses, intake of potential toxic impurities can be substantial. In this article a proposal for the quality control of deferiprone is presented in the form of a pharmaceutical monograph. This includes the analytical methods required for identification, purity checking and assay. Furthermore the way we synthesized the drug to get hold of it in a pure form is described. This synthesis is also used in manufacturing the drug commercially. The monograph can be used as a guideline for standardization of the quality of deferiprone to be used for further study and treatment.

Computer modelling of the binding of non-selective ligands to biological receptors.

The application of common linearization methods (log-probit analysis or Hill plot transformation) to the evaluation of receptor binding experiments leads to serious errors, if the ligands used possess insufficient receptor selectivity. The use of simultaneous non-linear curve-fitting procedures in this case is recommended and illustrated.