This in vitro study evaluated the therapeutic equivalence of two multisource (generic) formulations of 100-mg phenytoin as immediate-release tablets available in the Peruvian pharmaceutical market, compared with the reference medicine, to establish interchangeability. The mean weight, hardness, and content of active substance were evaluated, prior to analyzing the dissolution profile. USP dissolution apparatus 2 (paddle) was used at 75 rpm with 900 mL of dissolution medium at 37 ± 0.5 °C at pH levels of 1.2, 4.5, and 6.8. The generic and reference formulations had similar weight or drug content, but hardness values were significantly different (p = 0.029). At pH 1.2, the generic products were considered therapeutically equivalent to the reference product based on similarity factor (f 2 ) and dissolution efficiency values; however, at pH 4.5 and 6.8, there were differences in dissolution performance based on f 2 values below the acceptable range.
Background A large number of studies have suggested a correlation between the status of telomeres and disease risk. High-throughput quantitative fluorescence in situ hybridization (HT Q-FISH) is a highly accurate telomere measurement technique that can be applied to the study of large cell populations. Here we describe the analytical performance testing and validation of Telomere Analysis Technology (TAT®), a laboratory-developed HT Q-FISH-based methodology that includes HT imaging and software workflows that provide a highly detailed view of telomere populations. Methods TAT was developed for the analysis of telomeres in peripheral blood mononuclear cells (PBMCs). TAT was compared with Terminal Restriction Fragment (TRF) length analysis, and tested for accuracy, precision, limits of detection (LOD) and specificity, reportable range and reference range. Results Using 6 different lymphocyte cell lines, we found a high correlation between TAT and TRF for telomere length (R2 ≥ 0.99). The standard variation (assay error) of TAT was 454 base pairs, and the limit of detection of 800 base pairs. A standard curve was constructed to cover human median reportable range values and defined its lower limit at 4700 bp and upper limits at 14,400 bp. Using TAT, up to 223 telomere associated variables (TAVs) can be obtained from a single sample. A pilot, population study, of telomere analysis using TAT revealed high accuracy and reliability of the methodology. Conclusions Analytical validation of TAT shows that is a robust and reliable technique for the characterization of a detailed telomere profile in large cell populations. The combination of high-throughput imaging and software workflows allows for the collection of a large number of telomere-associated variables from each sample, which can then be used in epidemiological and clinical studies.
This research evaluated the biopharmaceutical equivalence in vitro of three brands of glibenclamide 5-mg tablets (reference, brand name, and generic drugs) from Lima, Peru following the guidelines of the Biopharmaceutical Classification System (BCS). Glibenclamide is a BCS class 2 drug. Quality control parameters were evaluated including hardness, weight, friability, and drug content (hardness: 2.6-2.8 kg-f; weight [mean ± SD]: 103.3-109.8 mg ± 0.27-0.53; friability: 0.19-0.55%; content: 100.65-103.3%). To assess dissolution, apparatus 2 was used at 75 rpm, 900 mL of dissolution medium (37 ± 0.5 °C) at pH 6.8; simulated intestinal fluid without enzymes was used as the dissolution medium.
Carbamazepine is an antiepileptic iminostilbene that is dispensed from multiple sources in Peru without bioequivalence studies. The biopharmaceutical equivalence of two generic (A and B) and one commercial brand (C) of carbamazepine sodium as compared to the innovator drug was determined by an in vitro study of commercial 200-mg tablets, following the guidelines of the Biopharmaceutical Classification System. Hardness, weight, friability, and content were evaluated for compliance with official specifications. A United States Pharmacopeia (USP) dissolution apparatus 2 (paddle) was used at with 900 mL of medium (pH 1.2, 4.5, and 6.8) at 75 rpm and 37 ± 0.5 °C. Samples (5 mL) were withdrawn at 5, 10, 15, 30, 45, 60, and 90 minutes and analyzed in a UV spectrophotometer at 288 nm. The studied drugs did not release 85% of the active pharmaceutical ingredient within 30 minutes in any media. When compared to the innovator brand using the similarity factor (f2), product A was < 50 at all three pH levels; B was < 50 at pH 4.5, and C was < 50 at pH 1.2 and 4.5. For all products, dissolution efficiency was 56.1-84.3% and mean dissolution time was 18.0-47.5 min. Despite meeting the official specifications for quality control tests, the evaluated samples are not in vitro biopharmaceutical equivalents with the innovator brand based on the dissolution profiles (f2 < 50).
Introducción. El citocromo CYP2C9 metaboliza, aproximadamente, el 15 % de los fármacos prescritos. Su gen presenta alelos cuyas frecuencias difieren entre grupos étnicos y poblaciones. Los alelos CYP2C9*2 y CYP2C9*3 dan cuenta de una enzima con actividad disminuida cuya frecuencia no ha sido determinada en la población mestiza peruana.Objetivo. Caracterizar la frecuencia de las variantes *2 (rs1799853) y *3 (rs1057910) del gen CYP2C9 en muestras de población mestiza peruana provenientes de Lima, Tacna y Junín.Materiales y métodos. Se hizo un estudio descriptivo, observacional y prospectivo, con muestreo no probabilístico, por conveniencia e incidental. Se incluyeron 218 sujetos según los criterios de inclusión y exclusión; todos los participantes otorgaron su consentimiento informado. El ADN genómico se obtuvo mediante hisopado de mucosa oral, y la detección de los genotipos para los alelos CYP2C9*2 y CYP2C9*3 se hizo mediante reacción en cadena de la polimerasa (PCR) en tiempo real, utilizando sondas TaqMan™.Resultados. Las variantes de CYP2C9*2 y CYP2C9*3 están presentes en la población mestiza peruana con frecuencias de 0,046 y 0,062, respectivamente. El análisis de las frecuencias genotípicas observadas permitió predecir que la frecuencia de fenotipos metabolismo intermedio sería del 15,13 % (CYP2C9*1/*2: 5,96 %; CYP2C9*1/*3: 9,17 %), y la de fenotipos de metabolismo lento, del 3,22 % (CYP2C9*2/*2: 1,38 %; CYP2C9*3/*3: 1,38 %; CYP2C9*2/*3: 0,46 %).Conclusiones. Se lograron determinar las frecuencias genotípicas y alélicas para las variantes *2 y *3 del gen CYP2C9 en una muestra no probabilística de población mestiza peruana.
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