Formulation and Characterization of Ursodeoxycholic Acid Nanosuspension Based on Bottom-Up Technology and Box-Behnken Design Optimization.

BACKGROUND: Ursodeoxycholic acid (UDCA) is a therapeutic agent used for the treatment of cholestatic hepatobiliary diseases in pediatric patients. It is a bile acid that presents high lipophilicity, and it belongs to Class II of the Biopharmaceutical Classification System (BCS), which exhibits low water solubility and high intestinal permeability, which leads to poor oral absorption. The objective of this work was to design and optimize UDCA nanosuspensions by means of the precipitation-ultrasonication method to improve the solubility, dissolution, and oral bioavailability of UDCA. METHODS: A three-level, three-factor Box-Behnken design was used to optimize formulation variables and obtain uniform, small-particle-size UDCA nanosuspensions. The independent variables were: stabilizer percentage (X1), amplitude (X2), and sonication time (X3), and the dependent variable was the particle size (Y1). In the precipitation-ultrasonication method, UDCA was dissolved in acetone:PEG 400 (1:1 v/v) and quickly incorporated into the antisolvent (pre-cooled aqueous dispersion of HPMC E-15 0.3%), by means of intense sonication at 50 W for 5 min, controlling temperature through an ice water bath. The lyophilization efficacy was evaluated by means of a cryoprotective efficacy test, working with 10% maltose at -80 °C. The nanosuspensions were characterized by dynamic light scattering (DLS), X-ray diffraction, and scanning electron microscopy (SEM). The physicochemical stability was determined at 25 °C and 4 °C at 7, 14, 30, and 60 days, and the UDCA content was analyzed via HPLC-UV. An in vitro dissolution assay and an oral bioavailability study were performed in male Wistar rats. RESULTS: A significant impact was achieved in the optimized nanosuspension with 0.3% (stabilizer), 50 W (amplitude), and 5 min (sonication time), with a particle size of 352.4 nm, PDI of 0.11, and zeta potential of -4.30 mV. It presented adequate physicochemical stability throughout the study and the UDCA content was between 90% and 110%. In total, 86% of UDCA was dissolved in the in vitro dissolution test. The relative oral bioavailability was similar without significant statistical differences when comparing the lyophilized nanosuspension and the commercial tablet, the latter presenting a more erratic behavior. The pharmacokinetic parameters of the nanosuspension and the commercial tablet were Tmax (1.0 ± 0.9 h vs. 2.0 ± 0.8 h, respectively), Cmax (0.558 ± 0.118 vs. 0.366 ± 0.113 µM, respectively), ΔCmax (0.309 ± 0.099 vs. 0.232 ± 0.056, respectively), AUC (4.326 ± 0.471 vs. 2.188 ± 0.353 µg/mL.h, respectively, p < 0.02), and IAUC0-24h (2.261 ± 0.187 µg/mL.h vs. 1.924 ± 0.440 µg/mL.h, respectively). CONCLUSIONS: The developed nanosuspension presents an appropriate dosage and administration for pediatric patients. On the other hand, it exhibits an adequate absorption and UDCA oral bioavailability.

Pharmaceutical suspensions of ursodeoxycholic acid for pediatric patients: in vitro and in vivo studies.

Ursodeoxycholic acid (UDCA) is used in the oral therapy of hepatobiliary cholestatic diseases. Due to UDCA low aqueous solubility, two pediatric oral suspensions (25 mg/mL) were formulated with a few excipients, suspension A (SA) and suspension B (SB) with a vehicle, including two suspending agents. Physical, chemical and microbiological stability and a rheological study were performed at three different conditions (5 °C ± 3 °C, 25 °C ± 2 °C/60% RH ± 5% RH and 40 °C ± 2 °C/75% RH ± 5% RH) for 120 days. Moreover, dissolution study, content uniformity, related substances, and a study of relative oral bioavailability were also carried out. Both suspensions were physically, chemically and microbiologically stable throughout the study. SA and SB can be stored at 25 °C and 5 °C for at least 120 days whereas SA can be kept at 40 °C for at least 90 days and SB for 120 days. They both met USP specifications for dissolution, content uniformity, and related substances. SA and SB showed an improved relative oral bioavailability compared to the solid dosage form and they both displayed similar relative oral bioavailability with no significant differences between them. The developed suspensions proved to be safe and adequate and they are ideal for pediatric use for their acceptability, accurate dose administration and treatment adherence.

Formulation and Stability Study of Omeprazole Oral Liquid Suspension for Pediatric Patients.

Objectives: To develop and to study the physicochemical and microbiological stability of omeprazole liquid oral formulations used as therapeutic agent in many acid-related disorders, for pediatric use. Furthermore, to optimize and validate a stability-indicating high-performance liquid chromatography (HPLC) method for the analysis of omeprazole in the studied formulations. Method: Oral liquid suspensions of omeprazole were prepared at 2 mg/mL using crushed omeprazole pellets (formulation A) and pure omeprazole (formulation B) with a complete vehicle including humectant, suspending, sweetening, antioxidant, and flavoring agents. Samples were stored at 4°C and 25°C. Omeprazole content of each formulation was analyzed in triplicate using micro-HPLC at 0, 3, 7, 14, 30, 60, 90, 120, and 150 days. Other parameters were also determined, such as appearance, pH, resuspendibility, and viscosity. Microbiological studies were conducted according to the United Stated Pharmacopeia (USP) guidelines for non-sterile products. Results: Formulation A stayed physicochemical and microbiologically stable at refrigerated (4°C) conditions during at least 150 days and it only stayed stable during 14 days at 25°C. Formulation B was stayed physicochemical and microbiologically stable at refrigerated (4°C) conditions at least 90 days, but it is not recommended to store at 25°C for more than 1 day. Conclusions: Formulation A and formulation B can be stored for at least 150 and 90 days, respectively, at refrigerated conditions. Formulation A can be stored at room temperature for 14 days. Both formulations are perfectly suitable for pediatric patients who are usually notable to swallow solid oral formulations. The proposed analytical method was suitable for the study of stability of different formulations.

Development and validation of a capillary electrophoresis method applied to the analysis of l-citrulline in an oral formulation for pediatric use.

A simple and highly sensitive CE-UV method was applied in the determination of l-ctrulline, which was developed from an oral formulation for pediatric use. The novel method was based on the analysis of l-citrulline for direct ultraviolet detection at 198 nm. The BGE consisted of 10 mM sodium tetraborate and 50 mM SDS at pH 9, and the electrophoretic parameters were optimized. The method was validated in terms of specificity, linearity, LOD, LOQ, precision, accuracy, and robustness. The LOD and LOQ obtained were 1.36 and 4.54 µg/mL, respectively. In addition, the method offers higher sensitivity and specificity compared with the results obtained from HPLC method using UV-detectors, in which l-citrulline needs to be derivatizated. Furthermore, low cost and simplicity of the system allowed the rapid and simple quantitation of l-citrulline in the oral formulation for quality control and stability indicated method.