Clustering of Tadalafil API Samples According to their Manufacturer in the Context of API Falsification Detection.

This paper reports the results of the active pharmaceutical ingredient (API) fingerprint study, organised by the General European Official Medicines Control Laboratory Network (GEON), on tadalafil. A classical market surveillance study, evaluating compliance to the European Pharmacopoeia, was combined with a fingerprint study, the latter to obtain characteristic data for the different manufacturers, allowing the network laboratories to conduct authenticity tests for future samples, as well as to detect substandard and falsified samples. In total, 46 tadalafil API samples from 13 different manufacturers were collected. For all samples fingerprint data was collected through analysis of impurities and residual solvents, mass spectrometric screening, X-ray powder diffraction and proton nuclear magnetic resonance (1H-NMR). Chemometric analysis revealed that all manufacturers could be characterised based on the impurity, residual solvent and 1H-NMR data. Future suspicious samples in the network will therefore be analysed with these techniques in order to attribute the sample to one of the manufacturers. If the sample cannot be attributed, a more profound investigation will be necessary to reveal the origin of the sample. In cases where the suspect sample is claimed to be from one of the manufacturers included in this study, analysis can be limited to the test distinguishing that manufacturer.

European fingerprint study on omeprazole drug substances using a multi analytical approach and chemometrics as a tool for the discrimination of manufacturing sources.

Like drug products, Active Pharmaceutical Ingredients (APIs) are subject to substandard and falsification issues, which represent a threat to patient health. In order to monitor the quality of drug substances and prevent the use of non-compliant APIs, Official Medicine Control Laboratories work together in a European network developing coordinated strategies and programmes. The API working group proposed a market surveillance study on omeprazole and omeprazole magnesium with the objectives of controlling the pharmaceutical quality of samples, checking compliance with the monographs of the European Pharmacopoeia, and collecting analytical fingerprints that could be further used to differentiate manufacturing sources for future authenticity investigations. The study described in this article reports the analysis carried out by 7 European laboratories on 28 samples from 11 manufacturers with 5 analytical techniques (related substances with HPLC, residual solvents with GC-MS, near infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and X-ray powder diffractometry). The large amount of resulting analytical data were centralized and treated with two chemometric methods: Principal Component Analysis and Hierarchical Clustering Analysis. Data were analyzed separately and in combination (data fusion), allowing us to conclude that NMR and XRPD were suitable to differentiate samples originating from 9 out of 11 manufacturers. Analytical fingerprints associated with chemometrics were demonstrated to be a valuable methodology to discriminate manufacturers of omeprazole and omeprazole magnesium APIs and detect future substandard and falsified APIs.

GEONs API fingerprint project: Selection of analytical techniques for clustering of sildenafil citrate API samples.

Through its Active Pharmaceutical Ingredient Working Group (API-WG) the General European Official Medicines Control Laboratory (OMCL) Network (GEON), co-ordinated by the European Directorate for the Quality of Medicines & HealthCare (EDQM), regularly organises market surveillance studies for specific APIs for conformity to their monograph in the European Pharmacopoeia. During the past years some studies were combined with a fingerprint study of the APIs. The idea is to obtain a fingerprint for each manufacturer of the API under investigation, allowing the OMCL network to identify future samples as well as to detect substandard and falsified APIs. This paper reports the results of the latest fingerprint study, organised on sildenafil citrate API samples. Seventy-nine samples from 14 different manufacturers were collected throughout the Network. Fingerprint data was collected through Mid-Infrared spectroscopy, Raman spectroscopy, liquid chromatography for related substances, gas chromatography for residual solvents, X-ray diffraction and Nuclear Magnetic Resonance (NMR) spectroscopy. Chemometrics applied to the collected data showed that all manufacturers could be discriminated based on the data of only three of these tests, i.e. gas chromatography for residual solvents, X-ray diffraction and proton NMR. Suspicious API samples for sildenafil citrate will therefore be analysed in the future with the selected techniques in order to link the sample to a manufacturer or demonstrate the absence of such link. If the sample cannot be attributed to one of the manufacturers, further analysis and research on provenance and identity will be required. Of course, if the suspected sample claims to originate from one of the manufacturers included in the study, analysis can be limited to the test distinguishing this manufacturer.

[Evolution of the prevalence of HIV infection and risk behavior of drug injection among intravenous drug users infected or not infected by HIV in 3 Spanish cities. Working Group of Physicians of the World for the monitoring of HIV infection and risk behaviors in intravenous drug users]. / Evolución de la prevalencia de infección por VIH y de prácticas de riesgo de inyección entre inyectores de drogas infectados o no por el VIH de tres ciudades españolas. Grupo de Trabajo de Médicos del Mundo para la monitorización de la infección por VIH y las prácticas de riesgo en usuarios de drogas inyectables.

OBJECTIVE: To know the evolution of HIV prevalence and risk behavior practices of drug injection in three spanish cities on the basis of the serologic status of injecting drug users. METHODS: Cross-sectional surveys among users in syringe interchange programmes. RESULTS: HIV prevalence (self-reported) decreased in Madrid from 50% (1992) down to 41% (1996) (p = 0.01) and did not change in Seville and Valencia from 1994 to 1996. Among HIV-positive injecting drug users, a decrease was observed in the practice of giving and taking used syringes in the three cities, although this decrease reached a statistically significance (p = 0.006) only for giving in Valencia from 1994 to 1996 and was almost significant (p = 0.08) for taking in Madrid from 1993 to 1996. Among HIV-negative injecting drug users, no decreases were observed in the practice of giving and taking used syringes and even a significant increase in giving syringes in Seville was recorded (p = 0.01) from 1994 to 1996. CONCLUSIONS: HIV prevalence among injecting drug users is stabilized or decreasing in the three studied cities. The prevalence of injecting risk behavior evolves differently according to the serologic status.

Metabolism of primaquine by liver homogenate fractions. Evidence for monoamine oxidase and cytochrome P450 involvement in the oxidative deamination of primaquine to carboxyprimaquine.

The role of monoamine oxidase (MAO) and cytochrome P450 (P450) in the oxidative deamination of primaquine by rat liver fractions was studied. Rat liver fractions including liver homogenate, mitochondria, microsomes and 100,000 g supematant fractions were prepared from a pool of rat livers and characterised using benzylamine as a probe for MAO activity and N,N-dimethylbenzamide as a probe for P450 N-dealkylation activity. Incubation of all fractions with primaquine yielded carboxyprimaquine as the only metabolite detectable by HPLC. The mitochondrial fraction, which contained MAO activity but not P450 activity, presented the highest Vmax/K(M) value for the formation of carboxyprimaquine (8.5 x 10(-6) dm3mg(-1)h(-1). A substantially lower Vmax/K(M) value (1.3 x 10(-6) dm3mg(-1)h(-1)) was obtained in the microsomal fraction, which contained P450 but not MAO activity. The liver homogenate fraction presented a similar value (1.8 x 10(-6) dm3mg(-1)h(-1), though it contained both enzyme systems. Incubations of all the fractions that presented MAO activity, in presence of the MAO inhibitor pargiline, resulted in a marked inhibition of primaquine oxidation. P450 inhibitor SKF 525-A effectively inhibited primaquine metabolism in the microsomal fraction but inhibition in the liver homogenate was less effective. The results are consistent with an important role for MAO in primaquine biotransformation, though clearly metabolism by P450 has a contribution role.

Dipeptide derivatives of primaquine as transmission-blocking antimalarials: effect of aliphatic side-chain acylation on the gametocytocidal activity and on the formation of carboxyprimaquine in rat liver homogenates.

PURPOSE: Dipeptide derivatives of primaquine (PQ) with reduced oxidative deamination to the inactive metabolite carboxyprimaquine were synthesized and evaluated as a novel class of transmission-blocking antimalarials. METHODS; Antimalarial activity was studied using a model consisting of mefloquine-resistant Plasmodium berghei ANKA 25R/10, Balb C mice, and Anopheles stephensi mosquitoes. Metabolic studies were performed with rat liver homogenates, and the incubates were analyzed by HPLC. RESULTS: All dipeptide derivatives and glycyl-PQ completely inhibited the appearance of oocysts in the midguts of the mosquitoes at 15 mg/ kg, while N-acetylprimaquine was not active at this dose. However, none of the title compounds were able to block oocyst production at 3.75 mg/kg, in contrast with primaquine. Exception for sarc-gly-PQ, all remaining compounds prevented sporozoite formation in the salivary glands of mosquitoes at a dose of 3.75 mg/kg. Simultaneous hydrolysis to primaquine and gly-PQ ocurred with the following order of Vmax/Km: for primaquine formation. L-ala-gly-PQ > L-phe-gly-PQ > gly-gly-PQ; and for gly-PQ formation, L-phe-gly-PQ > L-ala-gly-PQ > gly-gly-PQ. In contrast, primaquine was not released from D-phe-gly-PQ, sarc-gly-PQ, and N-acetylprimaquine. Neither carboxyprimaquine nor 8-amino-6-methoxyquinoline were detected in any of the incubation mixtures. CONCLUSIONS: The title compounds prevent the development of the sporogonic cycle of Plasmodium berghei. Gametocytocidal activity is independent of the rate and pathway of primaquine formation. Acylation of the aliphatic side-chain effectively prevents the formation of carboxyprimaquine, but the presence of a terminal amino group appears to be essential for the gametocytocidal activity.

[Drug injection method risky for transmission of blood-borne diseases: are we careful enough?]. / Estamos estudiando adecuadamente las prácticas de inyección de drogas que implican riesgo de transmisión de enfermedades por vía parenteral?

In the last 20 years, research on the determinants of the HIV epidemic among drug users has focused mainly on studies of risk behaviour for drug injection. Studies involving human behaviour present special methodological problems. This paper presents a review of 1) the most important features that make this field different from the study of blood-borne diseases in other populations, and 2) the basic variables used in epidemiology to analyse injecting risk behaviour. Alternatives to improve research planning and results are proposed based on collaborating with other disciplines and improving the methodological resources of epidemiology.

[Risk behaviors for HIV transmission among the recent clients of a syringe-exchange program in Madrid, 1993]. / Conductas de riesgo para transmisión del VIH entre los usuarios recientes de un programa de intercambio de jeringas en Madrid, 1993.

OBJECTIVE: To determine the prevalence of the major risk behavior in HIV transmission (syringe sharing and failure to use condoms) and associated factors among drug injectors recruited for a syringe exchange program (PIJ) in the city of Madrid. METHODS: Cross-section study. All the information was obtained in 1993 through structured interviews with 441 users who had injected drugs during the previous month and had resorted to the PIJ five times, at most. The reference period for drug use and risk behaviour was the month prior to the interview. The statistical analysis included bivariate methods and logistical regression techniques. RESULTS: 29.2% shared syringes (18% passing and 21.7% taking used syringes) and of those that had sexual intercourse (49.4%), 42.5% always used a condom. 89.5% had an HIV antibody test and of those that knew the results, 48.6% were HIV-positive. Multivariate analysis showed that the association between certain behaviour patterns was significant; i.e., taking used syringes and: passing used syringes (odds ratio -OR- = 6.1; 95% confidence interval -CI- = 3.0-12.5), being HIV-positive (OR = 4.1; CI = 1.8-9.1), being unaware of HIV antibody test status (OR = 4.2; CI = 1.7-10.2) and having used intravenous drugs for 5-9 years (OR = 2.9; CI = 1.1-7.9); the association was significant between passing used syringes and: using a mixture of heroin and cocaine (OR = 2.7; CI = 1.1-6.4) and being unaware of HIV antibody test status (OR = 2.5; CI = 1.1-6.0). In the sample as a whole, the association between not using condoms ever and consuming cocaine (OR = 1.7; CI = 1.1-2.9) or crack (OR = 3.0; CI = 1.5-5.9) was significant; furthermore, among those that had sexual intercourse, the association was significant between not using condoms ever and: having been in jail (OR = 2.9; CI = 1.3-6.4), injecting drugs 2-4 times a day (OR = 2.4; CI = 1.0-5.8), having sexual intercourse with drug injectors (OR = 2.6; CI = 1.2-5.9) and having intercourse with two or more partners (OR = 0.4; CI = 0.2-0.9). CONCLUSIONS: The prevalence of HIV infection and risk behavior in the transmission of this virus remain high among drug injectors in Madrid. The habit of sharing syringes is still common, especially among HIV-positive drug injectors (a high percentage take used syringe) and among those who are unaware of their HIV antibody test status. The use of condoms is less frequent among those who have sexual intercourse with other drug injectors or with only one partner.

The epidemiology of cocaine use in Spain.

Trends and patterns of cocaine use in Spain are described with the aid of different information sources such as population surveys, the State Information System on Drug Abuse, and anthropological studies. In recent years the magnitude of cocaine supply indicators has increased greatly. High levels of last-month prevalence of cocaine use have been detected among the general population--consistently higher than those for heroin-- and cocaine consumption among heroin users has increased. Although the frequency of some health problems related to cocaine use--treatment admissions, hospital emergency admissions--has increased, it is still 30 times less than for heroin. Various hypotheses to explain these discrepancies are discussed.