Development and validation of dissolution testings in acidic media for rabeprazole sodium delayed-release capsules.

Rabeprazole sodium (RAB) dissolved in acidic media is accompanied by its degradation in the course of dissolution testing. To develop and establish the accumulative release profiles of ACIPHEX(®) Sprinkle (RAB) delayed-release capsules (ACIPHEX(®) Sprinkle) in acidic media using USP apparatus 2 (paddle apparatus) as a dissolution tester, the issues of determination of accumulative release amount of RAB in these acidic media and interference of hydroxypropylmethyl cellulose phthalate were solved by adding appropriate hydrochloric acid (HCl) into dissolution samples coupled with centrifugation so as to remove the interference and form a solution of degradation products of RAB, which is of a considerably stable ultraviolet (UV) absorbance at the wavelength of 298 nm within 2.0 h. Therefore, the accumulative release amount of RAB in dissolution samples at each sample time points could be determined by UV-spectrophotometry, and the accumulative release profiles of ACIPHEX(®) Sprinkle in the media of pH 1.0, pH 6.0, and pH 6.8 could be established. The method was validated per as the ICH Q2 (R1) guidelines and demonstrated to be adequate for quality control of ACIPHEX(®) Sprinkle and the accumulative release profiles can be used as a tool to guide the formulation development and quality control of a generic drug for ACIPHEX(®) Sprinkle.

Formulation and evaluation of novel reverse microemulsions containing salmon calcitonin in hydrofluoroalkane propellants.

To develop reverse microemulsion as a potential strategy for pulmonary delivery of salmon calcitonin (sCT) in HFA134a propellant of pressurized metered dose inhalers (pMDIs), pluronic P85 (P85) was chosen as the most appropriate surfactant to form microemulsions containing sCT. Formulation parameters, including the surfactant and ethanol content, water content, and sCT loading, were optimized to obtain two desired pMDI formulations A and B with clear and transparent appearance, Tyndall effect, good physical stability and aerosolization properties. Aerosolization properties of the optimized pMDIs were assessed by next generation impactor (NGI) and twin-stage impactor (TSI), and the dose of sCT in each stage was assayed by HPLC. The fine particle fraction (FPF) of formulations A and B were both at the range of approximately 28.0-36.0%. Cytotoxicity studies indicated the cell viability determined by MTT assay only slightly dropped when the A549 cells were exposed to the pMDI formulations. Pharmacological study performed on the male Wistar rats showed the intratracheal administration of the microemulsion pMDIs containing sCT exhibited similar but prolonged hypocalcemic activity compared with the intravenous injection of sCT solution. Therefore, such reverse microemulsions are potential for pulmonary delivery of therapeutic peptides using HFA-pMDIs.

Development of amphotericin B-loaded cubosomes through the SolEmuls technology for enhancing the oral bioavailability.

The oral administration of amphotericin B (AmB) has the major drawback of poor bioavailability. The aim of this work was to evaluate the potential of AmB-loaded cubosomes as an oral formulation with improved bioavailability. This manuscript firstly developed AmB-loaded cubosomes by using the SolEmuls technology. The encapsulation efficiency, the in vitro release, and stability studies in simulated gastrointestinal fluid were used to evaluate AmB-loaded cubosomes. The acute nephrotoxicity, bioavailability, and tissue distribution study of AmB-loaded cubosomes were assayed upon oral administration to rats. SAXS and cryo-TEM exhibited AmB-loaded cubosomes as a bicontinuous cubic liquid crystalline phase with Pn3m geometry. The encapsulation efficiency and the results of in vitro release and stability studies in simulated gastrointestinal fluid further demonstrated that AmB was successfully encapsulated in cubosomes. AmB-loaded cubosomal formulation orally administrated in rats did not show nephrotoxicity and its relative bioavailability was approximately 285% as compared to Fungizone®. The AmB-loaded cubosomal formulation presented an effective potential approach for enhancing the oral bioavailability of AmB.

Stability and aerosolization of pressurized metered dose inhalers containing thymopentin nanoparticles produced using a bottom-up process.

The objective of this study was to investigate the stability and aerosolization of pressurized metered dose inhalers (pMDIs) containing thymopentin nanoparticles. Thymopentin nanoparticles, fabricated by a bottom-up process, were suspended in hydrofluoroalkane (HFA) 134a together with cineole and/or n-heptane to produce pMDI formulations. The stability study of the pMDIs obtained was carried out at ambient temperature for 6 months. The amount of thymopentin and the aerosolization properties of pMDIs were determined using high-performance liquid chromatography (HPLC) and a twin-stage impinger (TSI), respectively. Based on the results, thymopentin nanoparticles were readily suspended in HFA 134a with the aid of cineole and/or n-heptane to form physically stable pMDI formulations, and more than 98% of the labeled amount of thymopentin and over 50% of the fine particle fraction (FPF) of the pMDIs were achieved. During storage, it was found that for all pMDIs more than 97% of the labeled amount of thymopentin and FPF greater than 47% were achieved. Moreover, the size of thymopentin nanoparticles in propellant containing cineole and n-heptane showed little change. It is, therefore, concluded that the pMDIs comprising thymopentin nanoparticles developed in this study were stable and suitable for inhalation therapy for systemic action.

A novel bottom-up process to produce nanoparticles containing protein and peptide for suspension in hydrofluoroalkane propellants.

To overcome the disadvantages of microemulsion and nanoprecipitation methods to produce protein-containing nanoparticles, a novel bottom-up process was developed to produce nanoparticles containing the model protein lysozyme. The nanoparticles were generated by freeze-drying a solution of lysozyme, lecithin and lactose in tert-butyl alcohol (TBA)/water co-solvent system and washing off excess lecithin in lyophilizate by centrifugation. Formulation parameters such as lecithin concentration in organic phase, water content in TBA/water co-solvent, and lactose concentration in water were optimized so as to obtain desired nanoparticles with retention of the bioactivity of lysozyme. Based on the results, 24.0% (w/v) of lecithin, 37.5% (v/v) of water content, and 0.56% (w/v) of lactose concentration were selected to generate spherical nanoparticles with approximately 200 nm in mean size, 0.1 in polydispersity index (PI), and 99% retained bioactivity of lysozyme. These nanoparticles rinsed with ethanol containing dipalmitoylphosphatidylcholine (DPPC), Span 85 or oleic acid (3%, w/v) could readily be dispersed in HFA 134a to form a stable suspension with good redispersibility and 98% retained bioactivity of lysozyme. The study indicates there is a potential to produce pressed metered dose inhaler (pMDI) formulations containing therapeutic protein and peptide nanoparticles.