In vitro evaluation of cutaneous penetration of acyclovir from semisolid commercial formulations and relation with its effective antiviral concentration

The evaluation of drug permeation/penetration of semisolid formulations into animal skin can be useful to supplement the pharmaceutical equivalence. This paper describes the in vitro assessment of acyclovir (ACV) into porcine skin from commercial formulations with etermination of drug concentration in different layers of cutaneous tissue to correlate with effective antiviral concentration in order to improve the equivalence decision. Studies were conducted using Franz cells and porcine skin. Selected pharmaceutical creams containing ACV had identical (reference and generic) and different (similar) excipients. A software program was employed for the simulation of antiviral effectiveness in the skin. Regarding ACV skin penetration, the first batch of the generic product showed a significant difference from reference and similar products, while in the second batch all products demonstrated equivalent drug penetration in the skin. Simulation studies suggest that formulations analysed exhibit a pharmacological effect even when in contact with Herpes simplex strains of high IC50 (inhibitory concentration required to reduce viral replication by 50%). According to results, it can be assumed that the in vitro cutaneous permeation/penetration study does not supply sensitivity information regarding small alterations of ACV semisolid formulations due to the variability inherent to the method, although it can be relevant to pharmaceutical equivalence studies in the development of semisolid products

LC-UV method to assay raloxifene hydrochloride in rat plasma and its application to a pharmacokinetic study

A specific, precise, and accurate LC-UV method was developed and validated to assay raloxifene hydrochloride in rat plasma. Raloxifene was analyzed after liquid-liquid extraction and quantified by reversed phase liquid chromatography (C18 column) using acetonitrile and ammonium acetate buffer 0.05 M (pH 4.0) as mobile phase at a flow rate of 1 mL.min-1 and UV detection at 287 nm. Retention times of raloxifene and internal standard (dexamethasone) were approximately 11 min and 14 min, respectively. Linearity was checked for a concentration range between 25 ng.mL-1 and 1000 ng.mL-1. Intra- and inter-day precision had relative standard deviation lower than 10% and 15%, respectively. Recovery from plasma was higher than 90%. Accuracy values were 98.21%, 99.70%, and 102.70% for lower, medium, and upper limits of quantification, respectively. Limit of quantification was 25 ng.mL-1. Drug stability was analyzed at room temperature using plasma kept in a freezer at -80 °C for 45 days after processing for 6 h and three freeze-thaw cycles. The advantages of the method developed include stability under different conditions and low limit of quantification. Its applicability was confirmed by the analysis of raloxifene levels in plasma samples in a designed pharmacokinetic study in rats after intravenous administration (5 mg.kg-1)

Development of a dissolution method based on lipase for preclinical level A IVIVC of oral poly(ε-caprolactone) microspheres

Level A in vitro/in vivo correlation (IVIVC) of poly (ε-caprolactone) (PCL) microspheres for oral administration is challenging since in vitro PCL dissolution takes longer. The aims of this study were: 1) to develop three compositionally equivalent formulations of PCL microspheres with a different release rate of 6-methylcoumarin (6 MC), a drug candidate class IIc according to biopharmaceutical classification systems. 2) To develop a dissolution test for 6 MC-loaded PCL microspheres for oral administration. 3) To evaluate the influence of the PCL microspheres on the pharmacokinetic parameters of 6 MC and 4) to investigate a possible level A IVIVC of the 6 MC-loaded PCL microspheres. 6 MC-loaded PCL microspheres with different release rate were prepared and its physicochemical properties were evaluated as well as its release profiles. The pharmacokinetic parameters of the microspheres were investigated in Wistar rats. As results, it was possible to develop three compositionally equivalent 6 MC-loaded PCL microspheres with different release rate. Microspheres significantly affect pharmacokinetic parameters of 6 MC and a level A IVIVC was achieved for 6 MC-loaded PCL microspheres by using a dissolution method that includes lipase in the release medium. Developed dissolution method was able to predict the in vivo performance of 6 MC-loaded PCL microspheres in the investigated animal model.Fil: Cárdenas, Paola A.. Universidad Nacional de Colombia; ColombiaFil: Jimenez Kairuz, Alvaro Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Investigación y Desarrollo en Tecnología Farmacéutica. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Unidad de Investigación y Desarrollo en Tecnología Farmacéutica; ArgentinaFil: Verlindo de Araujo, Bibiana. Universidade Federal do Rio Grande do Sul; BrasilFil: Aragón, Diana Marcela. Universidad Nacional de Colombia; Colombi

In vitro evaluation of cutaneous penetration of acyclovir from semisolid commercial formulations and relation with its effective antiviral concentration

ABSTRACT The evaluation of drug permeation/penetration of semisolid formulations into animal skin can be useful to supplement the pharmaceutical equivalence. This paper describes the in vitro assessment of acyclovir (ACV) into porcine skin from commercial formulations with etermination of drug concentration in different layers of cutaneous tissue to correlate with effective antiviral concentration in order to improve the equivalence decision. Studies were conducted using Franz cells and porcine skin. Selected pharmaceutical creams containing ACV had identical (reference and generic) and different (similar) excipients. A software program was employed for the simulation of antiviral effectiveness in the skin. Regarding ACV skin penetration, the first batch of the generic product showed a significant difference from reference and similar products, while in the second batch all products demonstrated equivalent drug penetration in the skin. Simulation studies suggest that formulations analysed exhibit a pharmacological effect even when in contact with Herpes simplex strains of high IC50 (inhibitory concentration required to reduce viral replication by 50%). According to results, it can be assumed that the in vitro cutaneous permeation/penetration study does not supply sensitivity information regarding small alterations of ACV semisolid formulations due to the variability inherent to the method, although it can be relevant to pharmaceutical equivalence studies in the development of semisolid products

Development and Validation of a Sensitive UFLC–MS/MS Method for Quantification of Quercitrin in Plasma: Application to a Tissue Distribution Study

Quercitrin, a glycosylated form of the flavonoid quercetin, is one of the major constituents of Copaifera langsdorffii leaves and potentially contributes to the medicinal properties reported for this plant species, including the treatment and prevention of kidney stones. To better understand the pharmacokinetics of quercitrin, a simple, rapid, and sensitive ultra fast liquid chromatography−tandem mass spectrometry method was developed and validated for the quantification of quercitrin in rat plasma and applied to a tissue distribution study. Sample preparation involved simple liquid−liquid extraction by ethyl acetate with high efficiency, using afzelin as internal standard. The chromatographic separation was performed on a Phenomenex Synergi Polar-RP (100 × 3.0 mm2, 2.5 μm), with a gradient elution of acetonitrile and 0.5% formic acid in water. The mass spectrometry analysis was conducted in negative ionization mode with multiple reaction monitoring transitions at m/z 447 → 300 for quercitrin and m/z 431 → 281 for afzelin. The method showed linearity in the concentration range of 5−100 ng/mL (r2 > 0.9959) and the lower limit of quantification was 5 ng/mL. The intraday and interday precision (relative standard deviation) were less than 10.73%, whereas the accuracy ranged from 81.4 to 111.0%. The extraction recovery, stability, matrix effect, and integrity dilution involved in the method were also validated. In addition, tissue distribution was assessed after an intravenous administration of 1 mg/kg quercitrin. This is the first report quantifying quercitrin in kidneys, demonstrating that the free tissue/plasma ratio was 23.7