Characterization of critical physical and mechanical properties of freeze-dried grape powder for development of a clinical patient delivery system.

Grapes are hypothesized to be a "food medicine." Freeze-dried grape powder (FDGP) is being used to test clinical activity for a variety of applications and a reproducible and reliable delivery system was required. The FDGP was characterized using traditional physico-chemical methods to generate the data needed to identify its primary liability, i.e. moisture sorption. Above a threshold level of moisture content (~25% w/w, at RT), the material becomes both difficult to handle and exhibits significant degradation of several potentially clinically important chemical components (catechin, epicatechin, resveratrol). A moisture sorption isotherm was then used to tie the threshold to the exposure relative humidity above which this occurs. Kinetic uptake studies were used to estimate the maximum safe exposure time at a given humidity (a square root time dependence of moisture uptake was observed). Armed with this knowledge, a FDGP compact coated with a compression coat [100% bees wax or combinations of carnauba wax (70%) with HPC (30%) or Avicel(®) PH 102 (30%) or lactose monohydrate (30%)] was developed that will insure the shelf life of the material without the need for special handling for approximately more than 3 months.

Data fusion of Fourier transform infrared spectra and powder X-ray diffraction patterns for pharmaceutical mixtures.

Fusing complex data from two disparate sources has been demonstrated to improve the accuracy in quantifying active ingredients in mixtures of pharmaceutical powders. A four-component simplex-centroid design was used to prepare blended powder mixtures of acetaminophen, caffeine, aspirin and ibuprofen. The blends were analyzed by Fourier transform infra-red spectroscopy (FTIR) and powder X-ray diffraction (PXRD). The FTIR and PXRD data were preprocessed and combined using two different data fusion methods: fusion of preprocessed data (FPD) and fusion of principal component scores (FPCS). A partial least square (PLS) model built on the FPD did not improve the root mean square error of prediction. However, a PLS model built on the FPCS yielded better accuracy prediction than PLS models built on individual FTIR and PXRD data sets. The improvement in prediction accuracy of the FPCS may be attributed to the removal of noise and data reduction associated with using PCA as a preprocessing tool. The present approach demonstrates the usefulness of data fusion for the information management of large data sets from disparate sources.

Difference in the lubrication efficiency of bovine and vegetable-derived magnesium stearate during tabletting.

The purpose of this work was to evaluate and compare the functionality of bovine fatty acids-derived (MgSt-B) and vegetable fatty acids-derived (MgSt-V) magnesium stearate powders when used for the lubrication of granules prepared by high-shear (HSG) and fluid bed (FBG) wet granulation methods. The work included evaluation of tablet compression and ejection forces during tabletting and dissolution testing of the compressed tablets. Granules prepared by both granulation methods required significantly lower ejection force (p < 0.01) when lubricated with the MgSt-V powder as compared to those lubricated with the MgSt-B powder. Granules prepared by the HSG method and lubricated with the MgSt-V powder also required significantly lower compression force (p < 0.01) to produce tablets of similar weight and hardness as compared to those lubricated with the MgSt-B powder. The dissolution profiles were not affected by these differences and were the same for tablets prepared by same granulation method and lubricated with either magnesium stearate powder. The results indicate significant differences (p < 0.01) between lubrication efficiency of the MgSt-B and the MgSt-V powders and emphasize the importance of functionality testing of the MgSt powders to understand the impact of these differences.

Participation of women in clinical trials for new drugs approved by the food and drug administration in 2000-2002.

OBJECTIVE: This study aimed to track the inclusion of women in clinical trials for new drugs approved by the Food and Drug Administration (FDA) between 2000 and 2002 and to evaluate the extent of analyses by sex. METHODS: Data were extracted from FDA reviewers' reports, summaries of clinical trials in New Drug Applications (NDAs), and product labeling and organized into a Microsoft Access database. The information collected includes subject enrollment by sex per clinical phase and sex differences in pharmacokinetics, safety, and efficacy as determined by either sponsors or reviewers. RESULTS: There were 67 New Molecular Entities (NMEs) approved by the FDA between 2000 and 2002. A total of 397,825 subjects were enrolled in 2,323 clinical trials. If 9 sex-specific NMEs are excluded, 297,697 subjects were enrolled in 1,974 clinical trials. Forty-seven percent of participants were male, 49% were female, and 4% of subjects were not specified. Of the 58 sex-nonspecific products in the study, 71% (41 of 58) of sex analyses were performed either by the sponsor or FDA reviewers. Twenty-five NMEs were found to have sex differences in pharmacokinetics, efficacy or adverse events. However, no recommendation was made to adjust dosage based on sex differences. CONCLUSIONS: The percentages of women and men participating in clinical trials varied by year, phase, and product type. However, the overall participation by women and men was comparable, suggesting an improvement in including more women in clinical trials when compared with the previous FDA study evaluating women's participation from 1995 through 1999. As with the previous study, however, a significant underrepresentation of women in early phase trials and in certain areas, such as cardiovascular products, was observed and continues to be an issue of concern. Lack of appropriate analyses by sex should also be noted as an issue of concern.

Measuring the distribution of density and tabletting force in pharmaceutical tablets by chemical imaging.

In pharmaceutical processing, the lubricant magnesium stearate (MgS) can affect compaction efficiency based on blend time and amount of MgS used. Insufficient lubrication produces intra-tablet variations in density. Consistent tablet density profiles and uniform compaction force, as managed by proper lubrication, are important for predictable performance. The current work demonstrates the utility of near-infrared (NIR) chemical imaging in measuring density variations within compacts, and relates these variations to tabletting forces as controlled by frictional properties and quantity of MgS. Lactose monohydrate was blended with 0%, 0.25%, or 1.0% MgS for 30s or 30 min. Compacts were prepared of each blend, with compaction forces monitored by load cells. Frictional properties were measured by automated shear cell. NIR chemical images were collected for each tablet, and the density at each image pixel was calculated. Density distribution within compacts was well perceived within the NIR images. Uniformity of intra-tablet density was strongly dependent upon friction between powder and die walls: tablets with no MgS or 0.25% MgS were less uniform than tablets with 1.0% MgS. In addition, absorbance variations along tablet edges, reflective of corresponding density variation, agreed with force transmission within the tablet and final tablet ejection force. Chemical imaging techniques can be used to non-destructively assess density profiles of tablets, and confirm prediction of friction alleviation and improvement in force distribution during tabletting. The density profiles were both qualitative, showing differences in density profiles between tablets of different blends, and quantitative, providing actual density and tabletting force information within a single tablet. This work demonstrates that near-infrared chemical imaging can be an effective tool in monitoring not only the physical quality of pharmaceutical tablets, but the corresponding die forces controlling tabletting and final ejection.

Functionality of magnesium stearate derived from bovine and vegetable sources: dry granulated tablets.

Magnesium stearate is a functional excipient used to ensure efficient ejection of tablets. This study compares the functionality of a vegetable and bovine grade of magnesium stearate. Tablets were prepared by direct compression and dry granulation of a model formulation. Physical and chemical tests were performed on bulk powders, granule intermediates, and finished tablets to provide a comprehensive comparison of the two grades of magnesium stearates. Raw material characterization of the two grades showed no difference in particle size, surface area, true density, and total moisture content. However, significant differences in fatty acid composition, surface tension, and zeta potential were detected. Tablet ejection force for the physical mixture formulations was variable, showing similar ejection force for the two grades of magnesium stearate at some concentrations and different ejection forces at other concentrations. The dry granulated formulation containing vegetable-based magnesium stearate showed a lower ejection force than the formulation containing bovine-based magnesium stearate. There was no difference between the dissolution profiles of the tablets containing the two grades of magnesium stearate prepared by both methods. The results indicated that magnesium stearate interchangeability with respect to lubricant efficiency depends upon the level in which it is used and the manufacturing method.

Drug product characterization by macropixel analysis of chemical images.

Traditional monitoring of pharmaceutical manufacturing combines physical sampling and analytical methodologies (e.g. HPLC). Process analytical technology (PAT) can be implemented to collect real-time measurements, although successful monitoring requires that sampling be representative. The maximum spot size for a spectroscopic tool (e.g. near-infrared; Raman) should be equivalent to a single dosage size. A smaller spot size may provide a PAT tool that is sensitive to monitoring process changes, but if too small, produces non-reproducible data. The current study uses chemical imaging to determine appropriate spot size. A chemical image is an array of pixels which maps the chemical composition of the sample. "Macropixel Analysis" is introduced as a measure of image heterogeneity based on clusters of pixels (macropixels) within near-infrared chemical images. Analyses were conducted using non-overlapping tiles of macropixels (Discrete-Level Tiling) and all possible macropixels of the image (Continuous-Level Moving Block). Both methods minimize the variance between macropixel intensities by varying the size of the macropixels. Spot size is then chosen as the minimum macropixel size for which the range of macropixel intensities falls within an acceptable criterion. Both imaging-based algorithms provide useful quantitative information about the heterogeneity of pharmaceutical products.

Monitoring of a pharmaceutical nanomilling process using grating light reflection spectroscopy.

An optical diagnostic method, grating light reflection spectroscopy (GLRS), has been demonstrated for the in situ monitoring of properties of heterogeneous matrices in industrial processes. The technique is based on measurements near the critical points of intensity and phase in waves reflected from a transmission diffraction grating in contact with a diagnostic sample. The features contained in the reflection spectrum near these thresholds allow for the simultaneous determination of the real and imaginary parts of the dielectric function of the sample. Using these data, the milling progress of highly concentrated fluid suspensions is observed as the material is milled from approximately 40 mm to 160 nm in diameter. A theoretical model that closely resembles experimentally determined spectra was constructed and applied in combination with principal components analysis (PCA) to demonstrate that GLRS can be used to closely monitor changes in the mean particle size of the nanomilled drug product.

A dynamic liquid-liquid interfacial pressure detector for the rapid analysis of surfactants in a flowing organic liquid.

Design and development of a dynamic interfacial pressure detector (DIPD) is reported. The DIPD measures the differential pressure as a function of time across the liquid-liquid interface of organic liquid drops (i.e., n-hexane) that repeatedly grow in water at the end of a capillary tip. Using a calibration technique based on the Young-Laplace equation, the differential pressure signal is converted, in real-time, to a relative interfacial pressure. This allows the DIPD to monitor the interfacial tension of surface active species at liquid-liquid interfaces in flow-based analytical techniques, such as flow injection analysis (FIA), sequential injection analysis (SIA) and high performance liquid chromatography (HPLC). The DIPD is similar in principle to the dynamic surface tension detector (DSTD), which monitors the surface tension at the air-liquid interface. In this report, the interfacial pressure at the hexane-water interface was monitored as analytes in the hexane phase diffused to and arranged at the hexane-water interface. The DIPD was combined with FIA to analytically measure the interfacial properties of cholesterol and Brij((R))30 at the hexane-water interface. Results show that both cholesterol and Brij((R))30 exhibit a dynamic interfacial pressure signal during hexane drop growth. A calibration curve demonstrates that the relative interfacial pressure of cholesterol in hexane increases as the cholesterol concentration increases from 100 to 10,000mugml(-1). An example of the utility of the DIPD as a selective detector for a chromatographic separation of interface-active species is also presented in the analysis of cholesterol in egg yolk by normal-phase HPLC-DIPD.