Marcela Hurtado - Academia.edu (original) (raw)

Papers by Marcela Hurtado

Research paper thumbnail of Estimation of in Vitro and in Vivo Performance of Metronidazole Oral Dosage Forms

International Journal of Applied Pharmaceutics

Objective: To estimate plasma concentrations-time profiles of metronidazole commercial tablets th... more Objective: To estimate plasma concentrations-time profiles of metronidazole commercial tablets through in vitro dissolution data using the Inverse Release Function approach and a convolution method. Methods: Dissolution profiles of metronidazole reference tablets (500 mg) were obtained using USP Apparatus 1 at 100 rpm, USP Apparatus 4 at 16 ml/min, and 0.1 N HCl, pH 4.5 acetate buffer and pH 6.8 phosphate buffer as dissolution media. Additionally, three generic drug products were tested using USP Apparatus 1 and pH 4.5 acetate buffer. Drug was quantified at 278 nm until 60 min. Dissolution parameters such as mean dissolution time, area under the cumulative dissolution curve, and dissolution efficiency were calculated. Metronidazole plasma levels were predicted considering the in vitro release data and published information. Percent of prediction error (PE) for Cmax and AUC0-inf at each condition was calculated. Results: When comparing dissolution profiles with common dissolution par...

Research paper thumbnail of Studies on the Selective S-oxidation of Albendazole, Fenbendazole, Triclabendazole, and Other Benzimidazole Sulfides

Revista de la Sociedad Química de Mexico, 2005

The selective S-oxidation of albendazole, fenbendazole, and other benzimidazole sulfides with sod... more The selective S-oxidation of albendazole, fenbendazole, and other benzimidazole sulfides with sodium periodate in acid medium, afforded the corresponding sulfoxides or sulfones. In contrast, triclabendazole and other 2-methylthiobenzimidazole derivatives could not be S-oxidized under the same smooth conditions with this reagent, but with MCPBA, a stronger oxidizing agent.

Research paper thumbnail of Estudio de liberación in vitro de ibuprofeno en grageas: influencia de la dosis y el aparato de disolución

Con el objetivo de evaluar el efecto de la dosis y el sistema de disolucion empleado en la libera... more Con el objetivo de evaluar el efecto de la dosis y el sistema de disolucion empleado en la liberacion de ibuprofeno, a partir de medicamentos solidos de liberacion inmediata, se obtuvieron los perfiles de disolucion del medicamento de referencia Motrin® (grageas de 400 y 600 mg) en los Aparatos 2 y 4 USP y a diferentes pHs. Con el Aparato 2 USP (50 rpm) a pH 6.8 unicamente el medicamento de 400 mg alcanzo el 85 % disuelto en 30 min. Se encontraron diferencias significativas en la eficiencia de disolucion, atribuibles a la dosis y al aparato empleado (p< 0.05). Los resultados sugieren la necesidad de reconsiderar los criterios de bioexencion para medicamentos que contienen ibuprofeno

Research paper thumbnail of HPLC Method with Solid-Phase Extraction for Determination of (R)- and (S)-Ketoprofen in Plasma without Caffeine Interference: Application to Pharmacokinetic Studies in Rats

Journal of Chromatographic Science, 2013

A fast and reproducible high-performance liquid chromatography method has been developed for the ... more A fast and reproducible high-performance liquid chromatography method has been developed for the determination of (R)-and (S)ketoprofen. Ketoprofen enantiomers were determined in plasma samples (50 mL), after solid-phase extraction, using diclofenac as internal standard. Analyses were performed on a (S, S)-Whelk-O 1 stainless steel column (5 mm, 250 3 4.6 mm) using hexaneethanol-acetic acid (93:7:0.5, v/v/v) as the mobile phase and detection at 254 nm. The method was selective for ketoprofen enantiomers in the presence of caffeine and endogenous plasma compounds. Standard curves were linear (R 2 > 0.999) over the concentration range of 0.25-12.50 and 0.25 mg/mL was taken as the limit of quantification. The intra-and interday precision (relative standard deviation) values were <15.0% and the accuracy (relative error) was within + + + + +12.0% at 1.0, 5.0 and 10.0 mg/mL. Enantiomer recoveries yielded 100.0 + + + + + 15%. No significant differences were determined in plasma samples stored at room temperature for 24.0 h, after two freeze-thaw cycles, and between 0 and 4 weeks at 2208 8 8 8 8C (P > 0.05). The validated method was successfully applied in determination of (S)-ketoprofen in Wistar rats after oral administration of 3.2 mg/kg of (S)-ketoprofen alone or 3.2 mg/kg of (S)ketoprofen 1 17.8 mg/kg of caffeine.

Research paper thumbnail of PHARMACEUTICAL EQUIVALENCE OF METRONIDAZOLE TABLETS USING THE FLOW-THROUGH CELL (USP APPARATUS 4) AND MEDIA OF PHYSIOLOGICAL pH RANGE

International Journal of Applied Pharmaceutics

Objective: The aim of this work was to evaluate the pharmaceutical equivalence of metronidazole t... more Objective: The aim of this work was to evaluate the pharmaceutical equivalence of metronidazole tablets through the study of hydrodynamics of the flow-through cell (USP Apparatus 4) on the dissolution performance of four commercial formulations (500 mg). The results were compared with those found using the USP basket apparatus. Methods: Experiments were performed with 0.1 N hydrochloric acid (pH 1.2), acetate buffer pH 4.5 and phosphate buffer pH 6.8. A USP Apparatus 4 was used with laminar flow at 16 ml/min and 22.6-mm cells. USP basket apparatus was used with 900 ml of each dissolution medium. The dissolution profiles were compared in terms of the mean dissolution time and dissolution efficiency. Results: Significant differences in MDT and DE values of generic formulations vs. reference with both USP apparatuses were found (*P<0.05) hence, dissolution profiles of metronidazole generic formulations cannot be considered similar to the dissolution profile of the reference. After u...

Research paper thumbnail of Comparison of Generic Furosemide Products by In Vitro Release Studies using USP Apparatus 2 and 4

Dissolution Technologies, 2021

Dissolution studies are essential for comparing the quality of generic drugs to their reference p... more Dissolution studies are essential for comparing the quality of generic drugs to their reference products. The objective of this work was to evaluate the in vitro release of furosemide in tablets under official dissolution conditions and using the flow-through cell method. To this end, two USP apparatus were used: apparatus 2 (paddle at 50 rpm) containing 900 mL of phosphate buffer solution pH 5.8, and apparatus 4 (flow-through cell at 16 mL/min) with the same medium. The dissolved drug was quantified by UV spectrophotometry at 274 nm for 60 min. Although the results at a single time point met the acceptance criterion of Q = 80% at 60 min, the dissolution profiles of generic drugs were not similar to the reference product. The similarity factor (f2 < 50), mean dissolution time, dissolution efficiency, t50%, t80%, and Td values corroborate the difference between the profiles (p < 0.05). In vitro release testing demonstrates that, for furosemide tablets available in Mexico, the g...

Research paper thumbnail of An exploratory study of enantioselective behavior of Sol-Gel encapsulated human serum albumin using frontal analysis

Pakistan journal of pharmaceutical sciences, 2019

Adsorption behavior of pure enantiomers and racemic mixtures of nonsteroidal anti-inflammatory dr... more Adsorption behavior of pure enantiomers and racemic mixtures of nonsteroidal anti-inflammatory drugs (ibuprofen and naproxen) on human serum albumin (HSA) was evaluated. The HSA was immobilized by Sol-Gel technique and this biomaterial was used in a chromatographic system where frontal analysis experiments were performed at pH 7.4 and temperatures of 25°C and 37°C. The association constants for enantiomers of the drugs were determined by linear adjustment for data corrected just for dead volume. In uncorrected data for non-specific retention, an inverse ratio between the number of sites and the value of the association constant was found. The participation of non-specific retention was estimated by non-linear regression and the values of association constants (Kass), which were determined considering this information, are comparable to some values reported by other methods at 37°C: 1.4 x105 and 5.7 x104 for Ibuprofen (IBU) R and S, respectively, and 2.3 x105 and 1.8x105 for naproxen...

Research paper thumbnail of In vitro release study of ibuprofen dragees: dose and dissolution apparatus influence

Research paper thumbnail of Comparative dissolution of indomethacin capsules using the USP Apparatus 1 and 4

Research paper thumbnail of Design of a DNA-Based Biomaterial by Sol-Gel Method: Application for the Recognition of Albendazole Sulfoxide

MRS Advances, 2019

We describe the use of immobilized deoxyribonucleic acid (DNA) in a silica matrix as a biorecogni... more We describe the use of immobilized deoxyribonucleic acid (DNA) in a silica matrix as a biorecognition agent for the detection of albendazole sulfoxide (ASU), the primary metabolite of albendazole and a suspected teratogenic and embryotoxic agent. The biomaterial (DNA-containing gel) was synthesized by physical entrapment of salmon sperm in an inorganic silicate matrix by the sol-gel method. Functionality of the DNA-containing gel was evaluated by comparative offline frontal chromatography followed by HPLC analysis of ASU and caffeine (CAF, control) using DNA-containing gel and DNA-free gel. The DNA-containing gel showed relatively high specific retention for ASU, while CAF showed no retention using frontal analysis. We anticipate that the DNA-containing gel can be implemented to identify the interactions of DNA with other active pharmaceutical ingredients (APIs) and their metabolites in a readily available, sensitive and selective frontal chromatography experiment.

Research paper thumbnail of Perfiles de disolución de supositorios de paracetamol en el aparato 4 USP

Revista Mexicana De Ciencias Farmaceuticas, 2002

Research paper thumbnail of Desarrollo de un método analítico por cromatografía de líquidos de alta resolución para la cuantificación de sulfóxido de albendazol en orina

Revista Mexicana …, 2010

Se desarrolló un método analítico por CLAR y detección UV para la cuantificación de sulfóxido de ... more Se desarrolló un método analítico por CLAR y detección UV para la cuantificación de sulfóxido de albendazol en orina. La extracción en fase sólida permitió concentrar la muestra y cuantificar el metabolito en las concentraciones esperadas en orina después de administrar una dosis de albendazol. El método fue selectivo, con un recobro absoluto > 80%; lineal (R 2 > 0.99), preciso (CV < 7%) y exacto (diferencia ≤ 15% del valor nominal) en el intervalo de concentraciones utilizadas (0.125 a 4 µg/mL). La aplicabilidad del método se demostró mediante la determinación del metabolito en dos voluntarios sanos a los que se les administró una dosis oral de 400 mg (tabletas) de albendazol. No se detectó sulfona de albendazol en el período de recolección de las muestras.

Research paper thumbnail of Effect of metamizol on morphine pharmacokinetics and pharmacodynamics after acute and subchronic administration in arthritic rats

European Journal of Pharmacology, 2010

The aim of the present study was to investigate whether metamizol alters the pharmacokinetics of ... more The aim of the present study was to investigate whether metamizol alters the pharmacokinetics of morphine and to determine the relationship between morphine plasma levels and antinociceptive effect produced after co-administration of drugs under acute and subchronic treatments using the pain-induced functional impairment model in rat (PIFIR model). Administration of morphine+metamizol under acute treatment produced a significantly higher antinociceptive effect than that obtained with morphine alone (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). This effect remained unaltered after subchronic treatments for 6 and 12 days. In addition, after the simultaneous administration of the drugs in a single dose, a pharmacokinetic interaction was found, which significantly…

Research paper thumbnail of Antinociceptive Activity of Metamizol Metabolites in a Rat Model of Arthritic Pain

Drug Development Research, 2013

Preclinical Research The aim of the present study was to evaluate the antinociceptive activity of... more Preclinical Research The aim of the present study was to evaluate the antinociceptive activity of the main metamizol (MET) metabolites, 4‐methylaminoantipyrine (MAA), 4‐aminoantipyrine (AA), 4‐formylaminoantipyrine (FAA), and 4‐acetylaminoantipyrine (AAA) using the “pain‐induced functional impairment in rat” model (PIFIR model). The antinociceptive efficacies of MAA and AA were 288.3% h and 281.1% h, respectively, close to the efficacy of MET (333.80% h). The effective dose to attain 50% of the maximum response (ED50) values for MET, MAA and AA were 126.1, 124.9, and 110.7 mg/kg, respectively. FAA and AAA were essentially inactive in this experimental model. Part of the antinociceptive effect showed by MET in this study might be attributed to the effect of the metabolites MAA and AA on cyclooxygenases COX‐1 and COX‐2 activity.

Research paper thumbnail of Comparison of Dissolution Profiles for Albendazole Tablets Using USP Apparatus 2 and 4

Drug Development and Industrial Pharmacy, 2003

The in vitro dissolution of albendazole from three different commercially available products (200... more The in vitro dissolution of albendazole from three different commercially available products (200 mg tablets) was studied using U.S. Pharmacopeia (USP) Apparatus 2 and USP Apparatus 4 in order to compare the release performance of the drug in two essentially different dissolution systems. For both cases, 0.1 N HCl was used as dissolution medium. Only the reference product and one of the generic products studied met the 80% USP 24 specification for albendazole dissolved at 30 min, using USP Apparatus 2. Although the reference product reached 80% of albendazole dissolved at 30 min when Apparatus 4 was used, the generic products&amp;amp;amp;amp;amp;amp;#39; dissolution performance was markedly reduced in this system. Though dissolution rate was slower using Apparatus 4, the total quantity of albendazole dissolved from the reference product, represented by area under the dissolution profile, was practically the same regardless of the system used. Dissolution kinetics of albendazole was adequately described by Weibull&amp;amp;amp;amp;amp;amp;#39;s function for all the products. The dissolution time (t(d)) derived from data fitting to this function showed significant differences among the products studied. Data analysis based on analysis of variance (ANOVA) showed nonequivalence among the dissolution profiles of generic products compared with the reference product either with the dissolution vessel system or the flow-through cell, as well as nonequivalence among the dissolution profiles using both apparatuses with the same product. Though differences in the dissolution profiles for generic products against the reference product in both systems were found, USP Apparatus 4 showed higher discriminative capacity in differentiating the release characteristics of the products tested.

Research paper thumbnail of In Vitro Equivalence Study of Different Doses of Carbamazepine Reference Tablets Using Usp Apparatuses 2 and 4

International Journal of Applied Pharmaceutics, 2019

Objective: To perform an in vitro equivalence study of two doses of carbamazepine reference table... more Objective: To perform an in vitro equivalence study of two doses of carbamazepine reference tablets sold in the local market under hydrodynamic conditions of USP Apparatus 4, a dissolution apparatus that better simulates the human gastrointestinal tract. Results were compared with dissolution official conditions using USP Apparatus 2. Methods: Dissolution profiles of both formulations were carried out with an automated USP Apparatus 2 at 75 rpm and 900 ml of dissolution medium. USP Apparatus 4 with laminar flow at 16 ml/min and 22.6 mm cells were used. 1% lauryl sulfate aqueous solution at 37.0±0.5 °C was used as dissolution medium. Spectrophotometric determination of drug at 285 nm was carried out during 60 min. Dissolution profiles were compared with model-independent and-dependent approaches. Results: When comparing dissolution profiles of low vs. high dose similar profiles were found (f2>50) in each dissolution apparatus, however, when the same dose was compared, USP 2 vs. US...

Research paper thumbnail of Dissolution Behavior of Carbamazepine Suspensions Using the Usp Dissolution Apparatus 2 and the Flow-Through Cell Method with Simulated Gi Fluids

International Journal of Pharmacy and Pharmaceutical Sciences

Objective: To characterize the dissolution behaviour of carbamazepine generic suspensions using t... more Objective: To characterize the dissolution behaviour of carbamazepine generic suspensions using the USP Dissolution Apparatus 2 and the flow-through cell method with simulated gastrointestinal fluids as dissolution media.Methods: Tegretol® suspension and two generic formulations were tested. Dissolution studies were performed using the USP Apparatus 2 (75 rpm and 900 ml of dissolution medium) and the flow-through cell method (laminar flow at 16 ml/min). Simulated gastric fluid (SGF) (with and without pepsin) and simulated intestinal fluid (SIF) (without pancreatin) at 37.0±0.5 °C, was used as dissolution media. The quantity of dissolved carbamazepine was determined at 5 min intervals until reaching 60 min, at 285 nm. Percentage dissolved at 60 min, mean dissolution time, dissolution efficiency values (model-independent parameters), as well as t50% and t63.2% were calculated (model-dependent parameters). Values for all parameters were compared between the reference and generic formul...

Research paper thumbnail of Simultaneous Determination of Ketoprofen and Acetaminophen in Fixed-Dose Combination Formulations by First-Order Derivative Spectroscopy: Application to Dissolution Studies

Objective: To develop and validate a new and easy zero-crossing derivative method for the simulta... more Objective: To develop and validate a new and easy zero-crossing derivative method for the simultaneous determination of ketoprofen and acetaminophen in fixed-dose combination formulations and to demonstrate its application in dissolution studies. Methods: Measurement was achieved using the first derivative signals at 243.2 nm for ketoprofen and at 260.5 nm for acetaminophen. The method was validated according to ICH guidelines. The proposed method was applied for the simultaneous quantification of both drugs in samples taken during the study of dissolution profiles (USP Apparatus 2, 75 rpm and 900 ml of 0.1 M phosphate buffer pH 7.4) of Bifebral® reference product (100/300 mg ketoprofen and acetaminophen, respectively). Samples were also analyzed by a previously validated HPLC-PDA method. Dissolution profiles were compared by similarity factor f2. Additionally values of: t50%, t85% Results: The first derivative spectrophotometric method was linear in the range of 25–200 μg/ml for ke...

Research paper thumbnail of Logic of Selecting Suitable Dissolution Parameters in New Drug Formulations Based on A BCS Approach

Iranian Journal of Pharmaceutical Research : IJPR, 2020

Since the biopharmaceutical quality of generic drug formulations depends on the quality of the re... more Since the biopharmaceutical quality of generic drug formulations depends on the quality of the reference products and also information about the in-vitro release performance of drugs under different conditions is scarce in the literature, a dissolution study of four reference tablets was performed. Each drug was representative of one Class of the Biopharmaceutical Classification System. The in-vitro release performance of propranolol-HCl, carbamazepine, ranitidine-HCl, and metronidazole was evaluated using a USP basket and paddle apparatus at different agitation rates (50, 75, and 100 rpm) with two doses of each drug. In all experiments, pharmacopeial dissolution media was used and the samples were taken with automatic equipment at specific times up to 60 min, except for propranolol-HCl, for which the samples were taken up to 30 min. The dissolution profiles were compared by model-independent, model-dependent, and ANOVA-based comparisons. The three methods of data comparison showed ...

Research paper thumbnail of In Vitro Release Performance of Metformin Hydrochloride Formulations Using the Flow-Through Cell Method

International Journal of Applied Pharmaceutics, 2020

Objective: The objective of this work was to evaluate the in vitro release performance of metform... more Objective: The objective of this work was to evaluate the in vitro release performance of metformin hydrochloride formulations (500-mg tablets) using the hydrodynamic environment of the flow-through cell method. Results were compared with those generated by the official dissolution test (USP basket apparatus). Methods: The reference drug product and three generic formulations were tested with phosphate buffer pH 6.8 as dissolution medium. Dissolution profiles were carried out with an automated flow-through cell apparatus using laminar flow at 16 ml/min. Drug was quantified at 233 nm during 45 min. Dissolution profiles were compared with the calculation of f2 similarity factor, mean dissolution time, dissolution efficiency, t50% and t63.2%. Dissolution data were adjusted to several mathematical models such as Makoid-Banakar, Peppas-Sahlin, Weibull and Logistic. Results: With the flow-through cell method and at 45 min less than 60% of metformin hydrochloride dissolved was found, while...

Research paper thumbnail of Estimation of in Vitro and in Vivo Performance of Metronidazole Oral Dosage Forms

International Journal of Applied Pharmaceutics

Objective: To estimate plasma concentrations-time profiles of metronidazole commercial tablets th... more Objective: To estimate plasma concentrations-time profiles of metronidazole commercial tablets through in vitro dissolution data using the Inverse Release Function approach and a convolution method. Methods: Dissolution profiles of metronidazole reference tablets (500 mg) were obtained using USP Apparatus 1 at 100 rpm, USP Apparatus 4 at 16 ml/min, and 0.1 N HCl, pH 4.5 acetate buffer and pH 6.8 phosphate buffer as dissolution media. Additionally, three generic drug products were tested using USP Apparatus 1 and pH 4.5 acetate buffer. Drug was quantified at 278 nm until 60 min. Dissolution parameters such as mean dissolution time, area under the cumulative dissolution curve, and dissolution efficiency were calculated. Metronidazole plasma levels were predicted considering the in vitro release data and published information. Percent of prediction error (PE) for Cmax and AUC0-inf at each condition was calculated. Results: When comparing dissolution profiles with common dissolution par...

Research paper thumbnail of Studies on the Selective S-oxidation of Albendazole, Fenbendazole, Triclabendazole, and Other Benzimidazole Sulfides

Revista de la Sociedad Química de Mexico, 2005

The selective S-oxidation of albendazole, fenbendazole, and other benzimidazole sulfides with sod... more The selective S-oxidation of albendazole, fenbendazole, and other benzimidazole sulfides with sodium periodate in acid medium, afforded the corresponding sulfoxides or sulfones. In contrast, triclabendazole and other 2-methylthiobenzimidazole derivatives could not be S-oxidized under the same smooth conditions with this reagent, but with MCPBA, a stronger oxidizing agent.

Research paper thumbnail of Estudio de liberación in vitro de ibuprofeno en grageas: influencia de la dosis y el aparato de disolución

Con el objetivo de evaluar el efecto de la dosis y el sistema de disolucion empleado en la libera... more Con el objetivo de evaluar el efecto de la dosis y el sistema de disolucion empleado en la liberacion de ibuprofeno, a partir de medicamentos solidos de liberacion inmediata, se obtuvieron los perfiles de disolucion del medicamento de referencia Motrin® (grageas de 400 y 600 mg) en los Aparatos 2 y 4 USP y a diferentes pHs. Con el Aparato 2 USP (50 rpm) a pH 6.8 unicamente el medicamento de 400 mg alcanzo el 85 % disuelto en 30 min. Se encontraron diferencias significativas en la eficiencia de disolucion, atribuibles a la dosis y al aparato empleado (p< 0.05). Los resultados sugieren la necesidad de reconsiderar los criterios de bioexencion para medicamentos que contienen ibuprofeno

Research paper thumbnail of HPLC Method with Solid-Phase Extraction for Determination of (R)- and (S)-Ketoprofen in Plasma without Caffeine Interference: Application to Pharmacokinetic Studies in Rats

Journal of Chromatographic Science, 2013

A fast and reproducible high-performance liquid chromatography method has been developed for the ... more A fast and reproducible high-performance liquid chromatography method has been developed for the determination of (R)-and (S)ketoprofen. Ketoprofen enantiomers were determined in plasma samples (50 mL), after solid-phase extraction, using diclofenac as internal standard. Analyses were performed on a (S, S)-Whelk-O 1 stainless steel column (5 mm, 250 3 4.6 mm) using hexaneethanol-acetic acid (93:7:0.5, v/v/v) as the mobile phase and detection at 254 nm. The method was selective for ketoprofen enantiomers in the presence of caffeine and endogenous plasma compounds. Standard curves were linear (R 2 > 0.999) over the concentration range of 0.25-12.50 and 0.25 mg/mL was taken as the limit of quantification. The intra-and interday precision (relative standard deviation) values were <15.0% and the accuracy (relative error) was within + + + + +12.0% at 1.0, 5.0 and 10.0 mg/mL. Enantiomer recoveries yielded 100.0 + + + + + 15%. No significant differences were determined in plasma samples stored at room temperature for 24.0 h, after two freeze-thaw cycles, and between 0 and 4 weeks at 2208 8 8 8 8C (P > 0.05). The validated method was successfully applied in determination of (S)-ketoprofen in Wistar rats after oral administration of 3.2 mg/kg of (S)-ketoprofen alone or 3.2 mg/kg of (S)ketoprofen 1 17.8 mg/kg of caffeine.

Research paper thumbnail of PHARMACEUTICAL EQUIVALENCE OF METRONIDAZOLE TABLETS USING THE FLOW-THROUGH CELL (USP APPARATUS 4) AND MEDIA OF PHYSIOLOGICAL pH RANGE

International Journal of Applied Pharmaceutics

Objective: The aim of this work was to evaluate the pharmaceutical equivalence of metronidazole t... more Objective: The aim of this work was to evaluate the pharmaceutical equivalence of metronidazole tablets through the study of hydrodynamics of the flow-through cell (USP Apparatus 4) on the dissolution performance of four commercial formulations (500 mg). The results were compared with those found using the USP basket apparatus. Methods: Experiments were performed with 0.1 N hydrochloric acid (pH 1.2), acetate buffer pH 4.5 and phosphate buffer pH 6.8. A USP Apparatus 4 was used with laminar flow at 16 ml/min and 22.6-mm cells. USP basket apparatus was used with 900 ml of each dissolution medium. The dissolution profiles were compared in terms of the mean dissolution time and dissolution efficiency. Results: Significant differences in MDT and DE values of generic formulations vs. reference with both USP apparatuses were found (*P<0.05) hence, dissolution profiles of metronidazole generic formulations cannot be considered similar to the dissolution profile of the reference. After u...

Research paper thumbnail of Comparison of Generic Furosemide Products by In Vitro Release Studies using USP Apparatus 2 and 4

Dissolution Technologies, 2021

Dissolution studies are essential for comparing the quality of generic drugs to their reference p... more Dissolution studies are essential for comparing the quality of generic drugs to their reference products. The objective of this work was to evaluate the in vitro release of furosemide in tablets under official dissolution conditions and using the flow-through cell method. To this end, two USP apparatus were used: apparatus 2 (paddle at 50 rpm) containing 900 mL of phosphate buffer solution pH 5.8, and apparatus 4 (flow-through cell at 16 mL/min) with the same medium. The dissolved drug was quantified by UV spectrophotometry at 274 nm for 60 min. Although the results at a single time point met the acceptance criterion of Q = 80% at 60 min, the dissolution profiles of generic drugs were not similar to the reference product. The similarity factor (f2 < 50), mean dissolution time, dissolution efficiency, t50%, t80%, and Td values corroborate the difference between the profiles (p < 0.05). In vitro release testing demonstrates that, for furosemide tablets available in Mexico, the g...

Research paper thumbnail of An exploratory study of enantioselective behavior of Sol-Gel encapsulated human serum albumin using frontal analysis

Pakistan journal of pharmaceutical sciences, 2019

Adsorption behavior of pure enantiomers and racemic mixtures of nonsteroidal anti-inflammatory dr... more Adsorption behavior of pure enantiomers and racemic mixtures of nonsteroidal anti-inflammatory drugs (ibuprofen and naproxen) on human serum albumin (HSA) was evaluated. The HSA was immobilized by Sol-Gel technique and this biomaterial was used in a chromatographic system where frontal analysis experiments were performed at pH 7.4 and temperatures of 25°C and 37°C. The association constants for enantiomers of the drugs were determined by linear adjustment for data corrected just for dead volume. In uncorrected data for non-specific retention, an inverse ratio between the number of sites and the value of the association constant was found. The participation of non-specific retention was estimated by non-linear regression and the values of association constants (Kass), which were determined considering this information, are comparable to some values reported by other methods at 37°C: 1.4 x105 and 5.7 x104 for Ibuprofen (IBU) R and S, respectively, and 2.3 x105 and 1.8x105 for naproxen...

Research paper thumbnail of In vitro release study of ibuprofen dragees: dose and dissolution apparatus influence

Research paper thumbnail of Comparative dissolution of indomethacin capsules using the USP Apparatus 1 and 4

Research paper thumbnail of Design of a DNA-Based Biomaterial by Sol-Gel Method: Application for the Recognition of Albendazole Sulfoxide

MRS Advances, 2019

We describe the use of immobilized deoxyribonucleic acid (DNA) in a silica matrix as a biorecogni... more We describe the use of immobilized deoxyribonucleic acid (DNA) in a silica matrix as a biorecognition agent for the detection of albendazole sulfoxide (ASU), the primary metabolite of albendazole and a suspected teratogenic and embryotoxic agent. The biomaterial (DNA-containing gel) was synthesized by physical entrapment of salmon sperm in an inorganic silicate matrix by the sol-gel method. Functionality of the DNA-containing gel was evaluated by comparative offline frontal chromatography followed by HPLC analysis of ASU and caffeine (CAF, control) using DNA-containing gel and DNA-free gel. The DNA-containing gel showed relatively high specific retention for ASU, while CAF showed no retention using frontal analysis. We anticipate that the DNA-containing gel can be implemented to identify the interactions of DNA with other active pharmaceutical ingredients (APIs) and their metabolites in a readily available, sensitive and selective frontal chromatography experiment.

Research paper thumbnail of Perfiles de disolución de supositorios de paracetamol en el aparato 4 USP

Revista Mexicana De Ciencias Farmaceuticas, 2002

Research paper thumbnail of Desarrollo de un método analítico por cromatografía de líquidos de alta resolución para la cuantificación de sulfóxido de albendazol en orina

Revista Mexicana …, 2010

Se desarrolló un método analítico por CLAR y detección UV para la cuantificación de sulfóxido de ... more Se desarrolló un método analítico por CLAR y detección UV para la cuantificación de sulfóxido de albendazol en orina. La extracción en fase sólida permitió concentrar la muestra y cuantificar el metabolito en las concentraciones esperadas en orina después de administrar una dosis de albendazol. El método fue selectivo, con un recobro absoluto > 80%; lineal (R 2 > 0.99), preciso (CV < 7%) y exacto (diferencia ≤ 15% del valor nominal) en el intervalo de concentraciones utilizadas (0.125 a 4 µg/mL). La aplicabilidad del método se demostró mediante la determinación del metabolito en dos voluntarios sanos a los que se les administró una dosis oral de 400 mg (tabletas) de albendazol. No se detectó sulfona de albendazol en el período de recolección de las muestras.

Research paper thumbnail of Effect of metamizol on morphine pharmacokinetics and pharmacodynamics after acute and subchronic administration in arthritic rats

European Journal of Pharmacology, 2010

The aim of the present study was to investigate whether metamizol alters the pharmacokinetics of ... more The aim of the present study was to investigate whether metamizol alters the pharmacokinetics of morphine and to determine the relationship between morphine plasma levels and antinociceptive effect produced after co-administration of drugs under acute and subchronic treatments using the pain-induced functional impairment model in rat (PIFIR model). Administration of morphine+metamizol under acute treatment produced a significantly higher antinociceptive effect than that obtained with morphine alone (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). This effect remained unaltered after subchronic treatments for 6 and 12 days. In addition, after the simultaneous administration of the drugs in a single dose, a pharmacokinetic interaction was found, which significantly…

Research paper thumbnail of Antinociceptive Activity of Metamizol Metabolites in a Rat Model of Arthritic Pain

Drug Development Research, 2013

Preclinical Research The aim of the present study was to evaluate the antinociceptive activity of... more Preclinical Research The aim of the present study was to evaluate the antinociceptive activity of the main metamizol (MET) metabolites, 4‐methylaminoantipyrine (MAA), 4‐aminoantipyrine (AA), 4‐formylaminoantipyrine (FAA), and 4‐acetylaminoantipyrine (AAA) using the “pain‐induced functional impairment in rat” model (PIFIR model). The antinociceptive efficacies of MAA and AA were 288.3% h and 281.1% h, respectively, close to the efficacy of MET (333.80% h). The effective dose to attain 50% of the maximum response (ED50) values for MET, MAA and AA were 126.1, 124.9, and 110.7 mg/kg, respectively. FAA and AAA were essentially inactive in this experimental model. Part of the antinociceptive effect showed by MET in this study might be attributed to the effect of the metabolites MAA and AA on cyclooxygenases COX‐1 and COX‐2 activity.

Research paper thumbnail of Comparison of Dissolution Profiles for Albendazole Tablets Using USP Apparatus 2 and 4

Drug Development and Industrial Pharmacy, 2003

The in vitro dissolution of albendazole from three different commercially available products (200... more The in vitro dissolution of albendazole from three different commercially available products (200 mg tablets) was studied using U.S. Pharmacopeia (USP) Apparatus 2 and USP Apparatus 4 in order to compare the release performance of the drug in two essentially different dissolution systems. For both cases, 0.1 N HCl was used as dissolution medium. Only the reference product and one of the generic products studied met the 80% USP 24 specification for albendazole dissolved at 30 min, using USP Apparatus 2. Although the reference product reached 80% of albendazole dissolved at 30 min when Apparatus 4 was used, the generic products&amp;amp;amp;amp;amp;amp;#39; dissolution performance was markedly reduced in this system. Though dissolution rate was slower using Apparatus 4, the total quantity of albendazole dissolved from the reference product, represented by area under the dissolution profile, was practically the same regardless of the system used. Dissolution kinetics of albendazole was adequately described by Weibull&amp;amp;amp;amp;amp;amp;#39;s function for all the products. The dissolution time (t(d)) derived from data fitting to this function showed significant differences among the products studied. Data analysis based on analysis of variance (ANOVA) showed nonequivalence among the dissolution profiles of generic products compared with the reference product either with the dissolution vessel system or the flow-through cell, as well as nonequivalence among the dissolution profiles using both apparatuses with the same product. Though differences in the dissolution profiles for generic products against the reference product in both systems were found, USP Apparatus 4 showed higher discriminative capacity in differentiating the release characteristics of the products tested.

Research paper thumbnail of In Vitro Equivalence Study of Different Doses of Carbamazepine Reference Tablets Using Usp Apparatuses 2 and 4

International Journal of Applied Pharmaceutics, 2019

Objective: To perform an in vitro equivalence study of two doses of carbamazepine reference table... more Objective: To perform an in vitro equivalence study of two doses of carbamazepine reference tablets sold in the local market under hydrodynamic conditions of USP Apparatus 4, a dissolution apparatus that better simulates the human gastrointestinal tract. Results were compared with dissolution official conditions using USP Apparatus 2. Methods: Dissolution profiles of both formulations were carried out with an automated USP Apparatus 2 at 75 rpm and 900 ml of dissolution medium. USP Apparatus 4 with laminar flow at 16 ml/min and 22.6 mm cells were used. 1% lauryl sulfate aqueous solution at 37.0±0.5 °C was used as dissolution medium. Spectrophotometric determination of drug at 285 nm was carried out during 60 min. Dissolution profiles were compared with model-independent and-dependent approaches. Results: When comparing dissolution profiles of low vs. high dose similar profiles were found (f2>50) in each dissolution apparatus, however, when the same dose was compared, USP 2 vs. US...

Research paper thumbnail of Dissolution Behavior of Carbamazepine Suspensions Using the Usp Dissolution Apparatus 2 and the Flow-Through Cell Method with Simulated Gi Fluids

International Journal of Pharmacy and Pharmaceutical Sciences

Objective: To characterize the dissolution behaviour of carbamazepine generic suspensions using t... more Objective: To characterize the dissolution behaviour of carbamazepine generic suspensions using the USP Dissolution Apparatus 2 and the flow-through cell method with simulated gastrointestinal fluids as dissolution media.Methods: Tegretol® suspension and two generic formulations were tested. Dissolution studies were performed using the USP Apparatus 2 (75 rpm and 900 ml of dissolution medium) and the flow-through cell method (laminar flow at 16 ml/min). Simulated gastric fluid (SGF) (with and without pepsin) and simulated intestinal fluid (SIF) (without pancreatin) at 37.0±0.5 °C, was used as dissolution media. The quantity of dissolved carbamazepine was determined at 5 min intervals until reaching 60 min, at 285 nm. Percentage dissolved at 60 min, mean dissolution time, dissolution efficiency values (model-independent parameters), as well as t50% and t63.2% were calculated (model-dependent parameters). Values for all parameters were compared between the reference and generic formul...

Research paper thumbnail of Simultaneous Determination of Ketoprofen and Acetaminophen in Fixed-Dose Combination Formulations by First-Order Derivative Spectroscopy: Application to Dissolution Studies

Objective: To develop and validate a new and easy zero-crossing derivative method for the simulta... more Objective: To develop and validate a new and easy zero-crossing derivative method for the simultaneous determination of ketoprofen and acetaminophen in fixed-dose combination formulations and to demonstrate its application in dissolution studies. Methods: Measurement was achieved using the first derivative signals at 243.2 nm for ketoprofen and at 260.5 nm for acetaminophen. The method was validated according to ICH guidelines. The proposed method was applied for the simultaneous quantification of both drugs in samples taken during the study of dissolution profiles (USP Apparatus 2, 75 rpm and 900 ml of 0.1 M phosphate buffer pH 7.4) of Bifebral® reference product (100/300 mg ketoprofen and acetaminophen, respectively). Samples were also analyzed by a previously validated HPLC-PDA method. Dissolution profiles were compared by similarity factor f2. Additionally values of: t50%, t85% Results: The first derivative spectrophotometric method was linear in the range of 25–200 μg/ml for ke...

Research paper thumbnail of Logic of Selecting Suitable Dissolution Parameters in New Drug Formulations Based on A BCS Approach

Iranian Journal of Pharmaceutical Research : IJPR, 2020

Since the biopharmaceutical quality of generic drug formulations depends on the quality of the re... more Since the biopharmaceutical quality of generic drug formulations depends on the quality of the reference products and also information about the in-vitro release performance of drugs under different conditions is scarce in the literature, a dissolution study of four reference tablets was performed. Each drug was representative of one Class of the Biopharmaceutical Classification System. The in-vitro release performance of propranolol-HCl, carbamazepine, ranitidine-HCl, and metronidazole was evaluated using a USP basket and paddle apparatus at different agitation rates (50, 75, and 100 rpm) with two doses of each drug. In all experiments, pharmacopeial dissolution media was used and the samples were taken with automatic equipment at specific times up to 60 min, except for propranolol-HCl, for which the samples were taken up to 30 min. The dissolution profiles were compared by model-independent, model-dependent, and ANOVA-based comparisons. The three methods of data comparison showed ...

Research paper thumbnail of In Vitro Release Performance of Metformin Hydrochloride Formulations Using the Flow-Through Cell Method

International Journal of Applied Pharmaceutics, 2020

Objective: The objective of this work was to evaluate the in vitro release performance of metform... more Objective: The objective of this work was to evaluate the in vitro release performance of metformin hydrochloride formulations (500-mg tablets) using the hydrodynamic environment of the flow-through cell method. Results were compared with those generated by the official dissolution test (USP basket apparatus). Methods: The reference drug product and three generic formulations were tested with phosphate buffer pH 6.8 as dissolution medium. Dissolution profiles were carried out with an automated flow-through cell apparatus using laminar flow at 16 ml/min. Drug was quantified at 233 nm during 45 min. Dissolution profiles were compared with the calculation of f2 similarity factor, mean dissolution time, dissolution efficiency, t50% and t63.2%. Dissolution data were adjusted to several mathematical models such as Makoid-Banakar, Peppas-Sahlin, Weibull and Logistic. Results: With the flow-through cell method and at 45 min less than 60% of metformin hydrochloride dissolved was found, while...