Predicting capsule fill weight from in-situ powder density measurements using terahertz reflection technology

The manufacturing of the majority of solid oral dosage forms is based on the densification of powder. A good understanding of the powder behavior is therefore essential to assure high quality drug products. This is particularly relevant for the capsule filling process, where the powder bulk density plays an important role in controlling the fill weight and weight variability of the final product. In this study we present a novel approach to quantitatively measure bulk density variations in a rotating container by means of terahertz reflection technology. The terahertz reflection probe was used to measure the powder density using an experimental setup that mimics a lab-scale capsule filling machine including a static sampling tool. Three different grades of α-lactose monohydrate excipients specially designed for inhalation application were systematically investigated at five compression stages. Relative densities predicted from terahertz reflection measurements were correlated to off-line weight measurements of the collected filled capsules. The predictions and the measured weights of the powder in the capsules were in excellent agreement, where the relative density measurements of Lactohale 200 showed the strongest correlation with the respective fill weight (R 2 =0.995). We also studied how the density uniformity of the powder bed was impacted by the dosing process and the subsequent filling of the holes (with excipient powder), which were introduced in the powder bed after the dosing step. Even though the holes seemed to be filled with new powder (by visual inspection), the relative density in these specific segments were found to clearly differ from the undisturbed powder bed state prior to dosing. The results demonstrate that it is feasible to analyze powder density variations in a rotating container by means of terahertz reflection measurements and to predict the fill weight of collected capsules

Entwicklung einer Methode zur quantitativen Erfassung von Proteinexpressionsveränderungen bei Adaption einesPilzes an extreme Umweltbedingungen

Abweichender Titel laut Übersetzung der Verfasserin/des VerfassersOriginally black fungi - also called dematiaceous fungi - were characterized as inhabitants of living and dead plant material. In the last 30 years they have been isolated from hypersaline waters, acidic environments, radioactive areas, as human pathogens or opportunists and as a dominant part of the epi- and endolithic microbial communities. Recent studies have shown that their stress resistance against solar radiation, radioactivity, desiccation and oligotrophic conditions even allows them to survive in space and under Martian conditions. Due to all these facts this organism is of great interest for many studies to acquire knowledge about their biological behavior in extreme environments. Findings of the regulation of cell products will help to understand the enormous stress tolerance. For this a method for relative protein quantitation can be helpful to get deeper insight into biological functions. To develop an appropriate method Bovine Serum Albumin (BSA) has been used to establish a quantitation method based on iTRAQ (isobaric Tags for Relative and Absolute Protein Quantitation) labeling. With molecular weight matched iTRAQ labels peptides in different samples were labeled and up to 4 samples were measured and relatively quantified in parallel by matrix-assisted laser desorption/ionization reflectron time-of-flight mass spectrometry (MALDI-RTOF-MS). Analytical parameters like reproducibility of peptide labeling, sample clean-up and relative quantities were gathered and the dynamic range for concentration differences for different samples was evaluated. To adapt the established method to black fungi samples of the strain Exophiala dermatitidis, different clean-up steps necessary to remove interfering substances have been tested. The implementation of a suitable method proved to be difficult because of the high amount of disturbing buffer substances necessary for efficient protein extraction of Exophiala dermatitidis samples as well as the thick melanized cell walls. Nevertheless, the established iTRAQ based quantitation method gave insights into biological up- and down regulation of some peptides of Exophiala dermatitidis samples. Although the developed method still requires improvement, it has high potential for the final analysis. To get deeper insights into biological functions of black fungi also protein identification of separated proteins is essential. Therefore protein identification after two dimensional (2D) gel electrophoresis was carried out. 25 spots of a 2D gel of an extract of microcolonial black fungi were cut out, trypsinized and measured by MALDI mass spectrometry. An online available gel of Saccharomyces cerevisiae was used as a reference gel to get a first idea of protein identity. Using this approach some proteins of the strain Exophiala dermatitidis could be identified with the demanded significance.13

Permeation of Therapeutic Drugs in Different Formulations across the Airway Epithelium In Vitro.

Pulmonary drug delivery is characterized by short onset times of the effects and an increased therapeutic ratio compared to oral drug delivery. This delivery route can be used for local as well as for systemic absorption applying drugs as single substance or as a fixed dose combination. Drugs can be delivered as nebulized aerosols or as dry powders. A screening system able to mimic delivery by the different devices might help to assess the drug effect in the different formulations and to identify potential interference between drugs in fixed dose combinations. The present study evaluates manual devices used in animal studies for their suitability for cellular studies.Calu-3 cells were cultured submersed and in air-liquid interface culture and characterized regarding mucus production and transepithelial electrical resistance. The influence of pore size and material of the transwell membranes and of the duration of air-liquid interface culture was assessed. Compounds were applied in solution and as aerosols generated by MicroSprayer IA-1C Aerosolizer or by DP-4 Dry Powder Insufflator using fluorescein and rhodamine 123 as model compounds. Budesonide and formoterol, singly and in combination, served as examples for drugs relevant in pulmonary delivery.Membrane material and duration of air-liquid interface culture had no marked effect on mucus production and tightness of the cell monolayer. Co-application of budesonide and formoterol, applied in solution or as aerosol, increased permeation of formoterol across cells in air-liquid interface culture. Problems with the DP-4 Dry Powder Insufflator included compound-specific delivery rates and influence on the tightness of the cell monolayer. These problems were not encountered with the MicroSprayer IA-1C Aerosolizer. The combination of Calu-3 cells and manual aerosol generation devices appears suitable to identify interactions of drugs in fixed drug combination products on permeation

Transport rate of budesonide when applied in solution on cells in submersed culture (SLE) and on cells at an air-liquid interface (ALE).

<p>Abbreviations: SLE mix, ALE mix: mixture containing 50 μM budesonide and 0.5 mM formoterol fumarate was applied (n = 3). The total amount of drug applied to the cells was set as 100% and the transport rate was normalized to a membrane area of 1 cm².</p

Differences in TEER values between start and end of the transport studies when fluorescein, rhodamine 123, budesonide and formoterol were applied as solution to cells grown in submersed culture (SLE) and at the air-liquid interface (ALE) or applied by MicroSprayer IA-1C Aerosolizer (AID_M) and by DP-4 Dry Powder Insufflator (AID_D) to cells grown at the air-liquid interface culture (n = 12).

<p>Significant decrease is marked by asterisk.</p

Transport of budesonide and formoterol fumarate as single substance and as combination product Symbicort in AID_D exposure.

<p>Abbreviations: Form mix: formoterol when applied as Symbicort powder; Bud mix: budesonide when applied as Symbicort (n = 3). The total amount of drug applied to the cells was set as 100% and the transport rate normalized to a membrane area of 1 cm². Asterisks indicate differences between application as single substance and as combination.</p

Transport of marker dyes across the Calu-3 monolayer (green, fluorescein; red, rhodamine 123) when applied as solution to cells grown in submersed culture (SLE) or applied with MicroSprayer IA-1C Aerosolizer (AID_M) and DP-4 Dry Powder Insufflator (AID_D) to cells cultured at the air-liquid interface (n = 6).

<p>The total amount of drug applied to the cells was set as 100% and the transport rate was normalized to a membrane area of 1 cm².</p

Limitations and advantages of the manual devices for permeability testing.

<p>Limitations and advantages of the manual devices for permeability testing.</p