The interprocess NIR sampling as an alternative approach to multivariate statistical process control for identifying sources of product-quality variability.

We are presenting a new approach of identifying sources of variability within a manufacturing process by NIR measurements of samples of intermediate material after each consecutive unit operation (interprocess NIR sampling technique). In addition, we summarize the development of a multivariate statistical process control (MSPC) model for the production of enteric-coated pellet product of the proton-pump inhibitor class. By developing provisional NIR calibration models, the identification of critical process points yields comparable results to the established MSPC modeling procedure. Both approaches are shown to lead to the same conclusion, identifying parameters of extrusion/spheronization and characteristics of lactose that have the greatest influence on the end-product's enteric coating performance. The proposed approach enables quicker and easier identification of variability sources during manufacturing process, especially in cases when historical process data is not straightforwardly available. In the presented case the changes of lactose characteristics are influencing the performance of the extrusion/spheronization process step. The pellet cores produced by using one (considered as less suitable) lactose source were on average larger and more fragile, leading to consequent breakage of the cores during subsequent fluid bed operations. These results were confirmed by additional experimental analyses illuminating the underlying mechanism of fracture of oblong pellets during the pellet coating process leading to compromised film coating.

Study of a low-dose capsule filling process by dynamic and static tests for advanced process understanding.

Precise filling of capsules with doses in the mg-range requires a good understanding of the filling process. Therefore, we investigated the various process steps of the filling process by dynamic and static mode tests. Dynamic tests refer to filling of capsules in a regular laboratory dosator filling machine. Static tests were conducted using a novel filling system developed by us. Three grades of lactose excipients were filled into size 3 capsules with different dosing chamber lengths, nozzle diameters and powder bed heights, and, in the dynamic mode, with two filling speeds (500, 3000 caps/h). The influence of the gap at the bottom of the powder container on the fill weight and variability was assessed. Different gaps resulted in a change in fill weight in all materials, although in different ways. In all cases, the fill weight of highly cohesive Lactohale 220 increased when decreasing the gap. Furthermore, experiments with the stand-alone static test tool indicated that this very challenging powder could successfully be filled without any pre-compression in the range of 5 mg-20 mg with acceptable RSDs. This finding is of great importance since for very fine lactose powders high compression ratios (dosing-chamber-length-to-powder-bed height compression ratios) may result in jamming of the piston. Moreover, it shows that the static mode setup is suitable for studying fill weight and variability. Since cohesive powders, such as Lactohale 220, are hard to fill, we investigated the impact of vibration on the process. Interestingly, we found no correlation between the reported fill weight changes in dynamic mode at 3000 cph and static mode using similar vibration. However, we could show that vibrations during sampling in the static mode dramatically reduced fill weight variability. Overall, our results indicate that by fine-tuning instrumental settings even very challenging powders can be filled with a low-dose dosator capsule filling machine. This study is a further step towards a scientific qualification of dosator nozzles for low-fill weight (1-45 mg) capsule filling.

Critical assessment of inverse gas chromatography as means of assessing surface free energy and acid-base interaction of pharmaceutical powders.

Inverse gas chromatography (IGC) has been employed as a research tool for decades. Despite this record of use and proven utility in a variety of applications, the technique is not routinely used in pharmaceutical research. In other fields the technique has flourished. IGC is experimentally relatively straightforward, but analysis requires that certain theoretical assumptions are satisfied. The assumptions made to acquire some of the recently reported data are somewhat modified compared to initial reports. Most publications in the pharmaceutical literature have made use of a simplified equation for the determination of acid/base surface properties resulting in parameter values that are inconsistent with prior methods. In comparing the surface properties of different batches of alpha-lactose monohydrate, new data has been generated and compared with literature to allow critical analysis of the theoretical assumptions and their importance to the interpretation of the data. The commonly used (simplified) approach was compared with the more rigorous approach originally outlined in the surface chemistry literature.

Endotoxin testing in inhalation grade lactose-a useful quality parameter?

Alpha-lactose monohydrate is the standard carrier used for dry powder inhalation drug products. The physico-chemical characteristics of this carrier material need to be monitored and specified carefully in order to guarantee functionality of the powder formulation. But also microbiological acceptance criteria need to be considered during development and routine testing. In this study, the endotoxin content of 19 batches of alpha-lactose monohydrate provided by two different manufacturers was determined with a semi-quantitative LAL assay. The endotoxin content was found to be less than 18 endotoxin units (EU)/g lactose in all cases and less than 3 EU/g in most cases. Assuming that the typical lactose has an endotoxin content of 10 EU/g and that a patient inhales six times daily 25 mg of lactose and that the total amount of lactose reaches the lung, this translates to an endotoxin exposure of 1.5 EU per day. On the other hand, the proposal for endotoxins in air limits the endotoxin concentration to 50 EU/m3 which corresponds to approximately 3333 EU inhaled endotoxins a day during normal breathing (breathing at rest conditions). The maximum endotoxin exposure by dry powder inhalations is thus two log steps lower than the recommended acceptable daily intake.

Factors affecting motion characteristics of frozen-thawed stallion spermatozoa.

Five experiments were conducted to evaluate damage incurred in each processing step for cryopreservation of stallion spermatozoa. In Experiment 1, semen was centrifuged for 9 centrifugation times and the percentage of spermatozoa recovered after each treatment was calculated and spermatozoal motion characteristics analysed. Recovery of spermatozoa was > or = 80% when spermatozoa were centrifuged for > or = 10 min. Experiment 2 evaluated spermatozoa cryopreserved at 5 different concentrations in each of 2 extenders (skim milk-egg yolk-glycerol, SM-EYG; and lactose-EDTA, LAC). In SM-EYG, TMOT and PMOT were higher at spermatozoal concentrations of 20, 200 and 400 x 10(6)/ml (51%/41%, 52%/44%, 50%/43%, respectively) than for samples frozen at > or = 800 x 10(6) spermatozoa/ml (41%/35%, 32%/27%; P < 0.05). Spermatozoa frozen in LAC at a concentration of 20 x 10(6)/ml resulted in the highest TMOT and PMOT (43% and 30%, respectively, P < 0.05). The effect of freezing rate on motion characteristics of spermatozoa was evaluated in Experiment 3. The VCL of spermatozoa frozen in SM-EYG was the only parameter affected by freezing rate (P < 0.05). Experiment 4 evaluated motion characteristics after cryopreservation of spermatozoa in different sized straws (0.5 or 2.5 ml) in each of 2 extenders (SM-EYG and LAC). In SM-EYG, PMOT (38%) and VCL (109 microns/s) were highest when spermatozoa were frozen in 0.5 ml straws (P < 0.05). In Experiment 5, spermatozoa thawed immediately after cryopreservation or thawed after storage in liquid nitrogen for 24-48 h were evaluated. There was no effect of length of storage in liquid nitrogen on spermatozoal motion characteristics (P < 0.05). Experiment 6 evaluated the effects of cooling time to 5 degrees C (0, 2.5 and 5 h) on motion characteristics of spermatozoa cryopreserved in 2 extenders (SM-EYG and LAC). TMOT and PMOT were effected by cooling time, and there was a cooling-time-by-extender interaction (P < 0.05). In SM-EYG, TMOT and PMOT were higher if spermatozoa were cooled to 5 degrees C prior to initiation of freezing than if freezing was initiated at 20 degrees C (P < 0.05). A suggested protocol for cryopreservation of stallion spermatozoa would include: 1) centrifugation at 400 g for 14 to 16 min; 2) extension at 23 degrees C with SM-EYG to 400 x 10(6) spermatozoa/ml; 3) cool to 5 degrees C for 2.5 h; 4) package in 0.5 ml straws at 5 degrees C; 5) freeze in liquid nitrogen vapour at -160 degrees C; and 6) thaw for 30 s in 37 degrees C water.

Effect of weaning diet on the ecology of adherent lactobacilli in the gastrointestinal tract of the pig.

Sixteen pigs were included in an investigation of the effects of weaning and weaning diet on the ecology of adherent Lactobacillus species in the gastrointestinal tract. At 28 d of age four pigs were killed and were designated as the preweaning control (PW). Four pigs remained on the sow (Sow), four pigs were fed a corn-soy-lactose (CSL) diet, and the remaining four pigs were fed a corn-soy (CS) diet. Pigs from the latter three treatments were killed at 38 d of age. Tissue samples were taken from the pars esophagus, ileum, and cecum and the adherent lactobacilli were enumerated using Rogosa SL agar. Bacterial colonies were randomly selected from Rogosa SL agar plates and speciated using cell type, morphology, and substrate fermentation tests. The species data were used to calculate the Shannon, Simpson, and evenness diversity indices. Shannon and Simpson diversity index values when averaged across tissues were lower (P < .05) for PW than for postweaning treatments (Sow, CSL, and CS) and lower (P < .05) when pigs receiving sow's milk (PW and Sow) were compared with pigs receiving the dry diets (CSL and CS). The diversity of adherent Lactobacillus is altered by the form of the diet fed to weanling pigs, and statistical ecological methods provide a powerful way of analyzing the ecology of the gastrointestinal tract.

Influence of raw material properties upon critical quality attributes of continuously produced granules and tablets.

Continuous manufacturing gains more and more interest within the pharmaceutical industry. The International Conference of Harmonisation (ICH) states in its Q8 'Pharmaceutical Development' guideline that the manufacturer of pharmaceuticals should have an enhanced knowledge of the product performance over a range of raw material attributes, manufacturing process options and process parameters. This fits further into the Process Analytical Technology (PAT) and Quality by Design (QbD) framework. The present study evaluates the effect of variation in critical raw material properties on the critical quality attributes of granules and tablets, produced by a continuous from-powder-to-tablet wet granulation line. The granulation process parameters were kept constant to examine the differences in the end product quality caused by the variability of the raw materials properties only. Theophylline-Lactose-PVP (30-67.5-2.5%) was used as model formulation. Seven different grades of theophylline were granulated. Afterward, the obtained granules were tableted. Both the characteristics of granules and tablets were determined. The results show that differences in raw material properties both affect their processability and several critical quality attributes of the resulting granules and tablets.

Mapping amorphous material on a partially crystalline surface: nanothermal analysis for simultaneous characterisation and imaging of lactose compacts.

The use of nanothermal analysis for mapping amorphous and crystalline lactose at a nanoscale is explored. Compressed tablets of amorphous and crystalline lactose (alone and mixed) were prepared and localised thermomechanical analysis (L-TMA) performed using micro- and nanothermal analysis in a addition to single point variable temperature pull-off force measurements. L-TMA was shown to be able to identify the different materials at a nanoscale via measurement of the thermal events associated with the amorphous and crystalline regions, while pull off force measurements showed that the adhesion of the amorphous material increased on approaching the T(g). Imaging was performed isothermally using topographic and pulsed force mode (PFM) measurements; both approaches were capable of discriminating two regions which L-TMA conformed to correspond to the two materials. In addition, force volume imaging (FVI) is suggested as a further approach to mapping the surfaces. We demonstrate that performing heated tip PFM measurements at a temperature close to the T(g) allows greater discrimination between the two regions. We therefore suggest that the nanothermal approach allows both characterisation and imaging of partially amorphous surfaces, and also demonstrate that heated tip imaging allows greater discrimination between crystalline and amorphous materials than is possible using ambient studies.

Granule characterization during fluid bed drying by development of a near infrared method to determine water content and median granule size.

PURPOSE: Water content and granule size are recognized as critical process and product quality parameters during drying. The purpose of this study was to enlighten the granule behavior during fluid bed drying by monitoring the major events i.e. changes in water content and granule size. METHODS: NIR spectra collected during drying and water content of sampled granules were correlated by principal component analysis (PCA) and partial least squares regression (PLSR). NIR spectra of dried granules were correlated to median granule size in a second PCA and PLSR. RESULTS: The NIR water model discriminates between various stages in fluid-bed drying. The water content can be continuously predicted with errors comparable to the reference method. The four PLS factors of the granule size model are related to primary particle size of lactose, median granule size exceeding primary particle size and amorphous content of granules. The small prediction errors enable size discrimination between fines and granules. CONCLUSION: For product quality reasons, discrimination between drying stages and end-point monitoring is highly important. Together with the possibilities to determine median granule size and to distinguish fines this approach provides a tool to design an optimal drying process.

Volume of pharmaceutical powders probed by frequency-domain photon migration measurements of multiply scattered light.

Using probability distribution analysis to describe the propagation of multiply scattered light between a point source and point detector located a known distance apart, mathematical expressions predicting the volume of sampled powder were determined for infinite and semi-infinite powder beds and then compared to experimental measurements of frequency-domain photon migration (FDPM). Our results show that the volume of powder sampled varies with optical properties and, when using FDPM techniques, with modulation frequency. For a typical measurement in lactose powder, the volume of powder sampled by multiply scattered light propagating between a 1000-microm-diameter point source and point detector pair separated by 8 mm is predicted to be 1.8 and 1.5 cm3 at modulated frequencies of 50 and 100 MHz, respectively. Experimental measurements in lactose powder confirm the predictions.

Additives to biological substances. V--The stability of lactose as a carrier for Biological Standards.

The stability of freeze-dried lactose has been studied, by accelerated degradation, after being ampouled under the conditions employed for the preparation of International Standards and Reference Preparations and also under less stringent conditions which might facilitate degradation. The possible formation of the reactive product, 5-hydroxymethyl-furfural, has been monitored over a period of 10 years at temperatures up to 56 degrees C. No evidence has been obtained to suggest that the formation of this compound would present a hazard to the stability of standards prepared by the procedures customarily employed.