Simulated medication adherence: First and second-year pharmacy students' perceptions of adhering to a multi-drug medication regimen.

BACKGROUND AND PURPOSE: Through a realistic medication adherence activity, the objective was to improve students' ability to identify non-adherent patients, build empathy toward patients, and prepare them to provide patient-centered care. EDUCATIONAL ACTIVITY AND SETTING: First- and second-year student pharmacists completed a two-month activity, which required adherence to a pre-specified medication regimen. Prior to starting, a survey was administered to assess students' perceived difficulty and success of the medication adherence activity. Upon completion, students were asked their perceived success and difficulty with the activity, challenges to maintaining adherence, and lessons learned from the project. Changes in perceived difficulty and success were analyzed using Wilcoxon signed rank tests. Challenges and lessons learned were coded for similar themes and frequencies. FINDINGS: 298 student pharmacists completed the pre- and post-survey (response rate 99%). Students' perceived difficulty of adherence was higher on the post-survey (median on post = 7.0 (out of 10) versus median on pre = 6.0, p = 0.023). Students' perceived success was higher on the presurvey (median on pre = 8.0 versus median on post = 6.0, p < 0.001). The most frequent challenges were remembering to take the medications (n = 133) and medication regimen timing (n = 98). The most frequent lesson learned was that "adherence is a difficult concept" (n = 143). SUMMARY: Students participated in a "hands-on" medication adherence activity. Students found that medication adherence is more difficult than perceived. Future research should examine the long-term impact of students maintaining empathy toward patients and provision of medication adherence services.

Impact of comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry experimental design on data trilinearity and parallel factor analysis deconvolution.

Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOFMS) is a powerful instrument for the analysis of complex samples. Deconvolution of overlapped analytes using a suitable chemometric data analysis method such as Parallel Factor Analysis (PARAFAC) is often required. However, PARAFAC is designed to require a strict data trilinearity requirement. In this study we examine how strict this requirement is in the context of GC × GC experimental conditions, and demonstrate that under suitable conditions the data is sufficiently trilinear to achieve accurate deconvolution. The term trilinear deviation ratio (TDR) was previously introduced as a quantitative metric to predict the accuracy of PARAFAC deconvolution. Trilinear deviation ratio is defined as the run-to-run retention time shift, Δ2tR, for a given analyte on the second dimension (2D) separation, divided by the 2D analyte peak width-at-base, 2Wb. We demonstrate that experimental conditions impact the TDR range produced and PARAFAC performance. Column selection and modulation period, PM, are shown to significantly influence the TDR range. Two column sets were evaluated, giving rise to different k' ranges for the 2D separations. Each column set was used with an optimum PM as well as a longer PM to demonstrate the effect of PM selection on the TDR range and PARAFAC quantification. A PM of 6 s produced a Δ2tR range from -19.5 ms to -98 ms and TDRs from 0.157 to 0.439, translating into a PARAFAC bias from +1.6% to -13.5%. However, a PM of 1.5 s produced a Δ2tR range of -1.1 ms to -8.8 ms, and significantly lower TDRs from 0.013 to 0.057, translating into PARAFAC errors from +2.1% to -3.9%, with an average of -1.1% ± 1.4. These results validate the idea that a suitable GC × GC experimental design will provide accurate quantification with PARAFAC.

Examination of the two-dimensional mass channel cluster plot method for gas chromatography - mass spectrometry in the context of the statistical model of overlap.

Evaluation of a recently developed data reduction method for gas chromatography time-of-flight mass spectrometry (GC-TOFMS) is presented in the context of the statistical model of overlap (SMO) using simulated chromatographic data. The two-dimensional mass cluster plot method (2D m/z cluster plot method) significantly improves separation visualization by measuring the retention time, tR, and peak width-at-base, wb, of each analyte peak on a per mass channel, m/z, basis and plotting wb versus tR as a single point for each peak. Additional selectivity is provided by the peak width dimension, allowing for the differentiation of "pure" or selective m/z and shared or overlapped m/z. Analyte clusters in the 2D mass cluster plot are defined based on clustering of individual points, representing the selective m/z for those analytes, and encompassed by a box of user-specified size. The method is applied to simulated chromatographic data with a random, independent distribution of analyte peaks and constant peak wb. Two levels of chromatographic saturation factor, α, and two sets of analyte mass spectra with varying spectral similarity are studied to assess method performance. The percentage of analyte clusters found relative to the number of analytes simulated in the chromatogram increases as the box size (analogous to chromatographic resolution, Rs) is decreased, resulting in an Rs limit of 0.05 for the method. Additionally, the percentage of analyte clusters discovered also increases with lower α and greater dissimilarity between analyte mass spectra, demonstrating the immense benefit of improving the chromatographic separation and chemical selectivity in analyte discovery, identification, and quantification.

Synthesis of the seco-Limonoid BCD Ring System Identifies a Hsp90 Chaperon Machinery (p23) Inhibitor.

D-Ring-seco-limonoids (tetranortriterpenoids), such as gedunin and xylogranin B display anti-cancer activity, acting via inhibition of Hsp90 and/or associated chaperon machinery (e.g., p23). Despite this, these natural products have received relatively little attention, both in terms of an enabling synthetic approach (which would allow access to derivatives), and as a consequence their structure-activity relationship (SAR). Disclosed herein is a generally applicable synthetic route to the BCD ring system of the seco-D-ring double bond containing limonoids. Furthermore, cell based assays revealed the first skeletal fragment that exhibited inhibition of the p23 enzyme at a level which was equipotent to that of gedunin, despite being much less structurally complex.

Implications of phase ratio for maximizing peak capacity in comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry.

The relationship between the phase ratio, ß, of the primary (1D) and secondary (2D) separation dimensions of comprehensive two-dimensional (2D) gas chromatography (GC×GC) separations, and the implications of ß on realization of maximal 2D peak capacity, nc,2D, are examined. A GC×GC chromatographic system with time-of-flight mass spectrometry, TOFMS, was otherwise held constant for the separation of a multi-component test mixture spanning a range of chemical functionalities, while only the ß of the two analytical columns were changed, 1ß for 1D and 2ß for 2D. Six column sets were studied using common, commercially available ß values. The ß ratio, ßR=1ß/2ß, is defined as a quantitative metric to facilitate this study. It is demonstrated that ßR plays a key role in maximizing nc,2D. Overall, ßR substantially affected nc,2D by influencing retention factors on the 2D column, 2k, and thereby changing the modulation period, PM, necessary for proper 2D column separations. The necessary changes to PM modify the modulation ratio, MR, which affects the 1D column peak widths and 1nc due to the impact of undersampling. Through changes to 1ß, the range of 2k can be controlled, with subsequent effects to both 2nc and 1nc. These effects were opposite in direction, such that improvements to 2nc may result in declines in 1nc. It is observed that due to the pseudo-isothermal nature of the 2D separation, there are diminishing returns to extending the 2nc at the cost of 1nc. In this particular study, column set 3 (1D: 20m length, 250µm i.d., 0.25µm film; 2D: 2m, 180µm i.d., 0.2µm film; ßR=1.11) with a PM of 3s provided the highest theoretical nc,2D of ∼8200, though this was at a relatively low MR of ∼1.8. Column set 2 (1D: 20m length, 250µm i.d., 0.5µm film; 2D: 2m, 180µm i.d., 0.2µm film; ßR=0.56) with a PM of 1.5s provided a high theoretical nc,2D of ∼5800, at a much higher MR of ∼3.7. Though column set 2 had a lesser total peak capacity than column set 3, its higher MR suggests that by improving the 1D column efficiency (i.e., narrowing the 1D column peak widths) to improve 1nc, can result in an increased theoretical nc,2D.

7-Step total synthesis of (+)-EBC-329: Photoisomerisation reveals new seco-casbane family member.

The first seco-casbane, EBC-329, isolated from the Australian rainforest, was synthesised from (+)-2-carene in seven steps. This endeavour not only established the absolute stereochemical assignment as (8R,9S)-EBC-329, but also identified, via photoisomerisation, a new seco-casbane family member.

Determining the Probability of Achieving a Successful Quantitative Analysis for Gas Chromatography-Mass Spectrometry.

A new approach is presented to determine the probability of achieving a successful quantitative analysis for gas chromatography coupled with mass spectrometry (GC-MS). The proposed theory is based upon a probabilistic description of peak overlap in GC-MS separations to determine the probability of obtaining a successful quantitative analysis, which has its lower limit of chromatographic resolution Rs at some minimum chemometric resolution, Rs*; that is to say, successful quantitative analysis can be achieved when Rs ≥ Rs*. The value of Rs* must be experimentally determined and is dependent on the chemometric method to be applied. The approach presented makes use of the assumption that analyte peaks are independent and randomly distributed across the separation space or are at least locally random, namely, that each analyte represents an independent Bernoulli random variable, which is then used to predict the binomial probability of successful quantitative analysis. The theoretical framework is based on the chromatographic-saturation factor and chemometric-enhanced peak capacity. For a given separation, the probability of quantitative success can be improved via two pathways, a chromatographic-efficiency pathway that reduces the saturation of the sample and a chemometric pathway that reduces Rs* and improves the chemometric-enhanced peak capacity. This theory is demonstrated through a simulation-based study to approximate the resolution limit, Rs*, of multivariate curve resolution-alternating least-squares (MCR-ALS). For this study, Rs* was determined to be ∼0.3, and depending on the analytical expectations for the quantitative bias and the obtained mass-spectral match value, a lower value of Rs* ∼ 0.2 may be achievable.

Gaining Synthetic Appreciation for the Gedunin ABC Ring System.

Gedunin, first isolated in 1960, displays a remarkable range of biological activity, but has yet to receive dedicated synthetic attention from a ground up construction perspective. Presented herein is a successfully executed approach to the fully functionalized ABC ring system of this challengingly complex natural product.

Method to determine the true modulation ratio for comprehensive two-dimensional gas chromatography.

A new method is presented to determine the true modulation ratio, MR, from the measurable effective modulation ratio, MR*, in comprehensive two-dimensional gas chromatography, GC×GC, without the requirement for a detector at the end of the primary column. The method was developed through the investigation of modulator induced band broadening, as a function of 1Wb and the selected modulation period, PM, for simulated GC×GC data, by first defining primary column 1D peak(s) and simulating the modulation process. Gaussian curve fitting is used to model each modulated secondary column separation peaklet, 2D, in the unfolded GC×GC data to accurately determine the maxima of the peaklet distribution, followed by Gaussian curve fitting to the maxima to determine the effective 1D peak profile and width, 1Wb*. The relationship between 1Wb and 1Wb* is studied as a function of the effective modulation ratio, MR*, which is 1Wb* divided by PM, in order to determine the true modulation ratio, MR, which is 1Wb divided by PM. We explore how peak sampling phase (in-phase and out-of-phase) plays a role in the relationship between MR and MR*. Experimental validation of the simulated results is also provided, to span a range of commonly implemented conditions with typical 1Wb (2-4.5s) and PM (0.25-8s). Use of MR<2 significantly broadens the 1D peak (MR*≥1.2MR) corresponding to a loss in 1D peak capacity, 1nc≥20%. The new method relies upon mapping from MR* to MR, which is discussed in relation to peak capacity theories for GC×GC. It is found that optimizing 1nc in GC×GC requires that 1Wb is minimized and must be sampled with a sufficiently short PM (1-2s) to minimize modulator induced band broadening and a subsequent reduction in the effective 1D peak capacity.

Chemical characterization of the acid alteration of diesel fuel: Non-targeted analysis by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry with tile-based Fisher ratio and combinatorial threshold determination.

The illicit chemical alteration of petroleum fuels is of keen interest, particularly to regulatory agencies that set fuel specifications, or taxes/credits based on those specifications. One type of alteration is the reaction of diesel fuel with concentrated sulfuric acid. Such reactions are known to subtly alter the chemical composition of the fuel, particularly the aromatic species native to the fuel. Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS) is well suited for the analysis of diesel fuel, but may provide the analyst with an overwhelming amount of data, particularly in sample-class comparison experiments comprised of many samples. Tile-based Fisher-ratio (F-ratio) analysis reduces the abundance of data in a GC×GC-TOFMS experiment to only the peaks which significantly distinguish the unaltered and acid altered sample classes. Three samples of diesel fuel from differently branded filling stations were each altered to discover chemical features, i.e., analyte peaks, which were consistently changed by the acid reaction. Using different fuels prioritizes the discovery of features likely to be robust to the variation present between fuel samples and may consequently be useful in determining whether an unknown sample has been acid altered. The subsequent analysis confirmed that aromatic species are removed by the acid alteration, with the degree of removal consistent with predicted reactivity toward electrophilic aromatic sulfonation. Additionally, we observed that alkenes and alkynes were also removed from the fuel, and that sulfur dioxide or compounds that degrade to sulfur dioxide are generated by the acid alteration. In addition to applying the previously reported tile-based F-ratio method, this report also expands null distribution analysis to algorithmically determine an F-ratio threshold to confidently select only the features which are sufficiently class-distinguishing. When applied to the acid alteration of diesel fuel, the suggested per-hit F-ratio threshold was 12.4, which is predicted to maintain the false discovery rate (FDR) below 0.1%. Using this F-ratio threshold, 107 of the 3362 preliminary hits were deemed significantly changing due to the acid alteration, with the number of false positives estimated to be about 3. Validation of the F-ratio analysis was performed using an additional three fuels.

Trilinearity deviation ratio: a new metric for chemometric analysis of comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry data.

Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS) is a well-established instrumental platform for complex samples. However, chemometric data analysis is often required to fully extract useful information from the data. We demonstrate that retention time shifting from one modulation to the next, Δ(2)tR, is not sufficient alone to quantitatively describe the trilinearity of a single GC×GC-TOFMS run for the purpose of predicting the performance of the chemometric method parallel factor analysis (PARAFAC). We hypothesize that analyte peak width on second dimension separations, (2)Wb, also impacts trilinearity, along with Δ(2)tR. The term trilinearity deviation ratio, TDR, which is Δ(2)tR normalized by (2)Wb, is introduced as a quantitative metric to assess accuracy for PARAFAC of a GC×GC-TOFMS data cube. We explore how modulation ratio, MR, modulation period, PM, temperature programming rate, Tramp, sampling phase (in-phase and out-of-phase), and signal-to-noise ratio, S/N, all play a role in PARAFAC performance in the context of TDR. Use of a PM in the 1-2 s range provides an optimized peak capacity for the first dimension separation (500-600) for a 30 min run, with an adequate peak capacity for the second dimension separation (12-15), concurrent with an optimized two-dimensional peak capacity (6000-7500), combined with sufficiently low TDR values (0-0.05) to facilitate low quantitative errors with PARAFAC (0-0.5%). In contrast, use of a PM in the 5s or greater range provides a higher peak capacity on the second dimension (30-35), concurrent with a lower peak capacity on the first dimension (100-150) for a 30 min run, and a slightly reduced two-dimensional peak capacity (3000-4500), and furthermore, the data are not sufficiently trilinear for the more retained second dimension peaks in order to directly use PARAFAC with confidence.

Redox and Lewis acid relay catalysis: a titanocene/zinc catalytic platform in the development of multicomponent coupling reactions.

A titanocene-catalyzed multicomponent coupling is described herein. Using catalytic titanocene, phosphine, and zinc dust, zinc acetylides can be generated from the corresponding iodoalkynes to affect sequential nucleophilic additions to aromatic aldehydes. The intermediate propargylic alkoxides are trapped in situ with acetic anhydride, which are susceptible to a second nucleophilic displacement upon treatment with a variety of electron-rich species, including acetylides, allyl silanes, electron-rich aromatics, silyl enol ethers, and silyl ketene acetals. Additionally, employing cyclopropane carboxaldehydes led to ring-opened products resulting from iodine incorporation. Taken together, these results form the basis for a new mode of three-component coupling reactions, which allows for rapid access to value added products in a single synthetic operation.

Enhancing gas chromatography-time of flight mass spectrometry data analysis using two-dimensional mass channel cluster plots.

A novel data reduction and representation method for gas chromatography time-of-flight mass spectrometry (GC-TOFMS) is presented that significantly facilitates separation visualization and analyte peak deconvolution. The method utilizes the rapid mass spectral data collection rate (100 scans/s or greater) of current generation TOFMS detectors. Chromatographic peak maxima (serving as the retention time, tR) above a user specified signal threshold are located, and the chromatographic peak width, W, are determined on a per mass channel (m/z) basis for each analyte peak. The peak W (per m/z) is then plotted against its respective tR (with 10 ms precision) in a two-dimensional (2D) format, producing a cluster of points (i.e., one point per peak W versus tR in the 2D plot). Analysis of GC-TOFMS data by this method produces what is referred to as a two-dimensional mass channel cluster plot (2D m/z cluster plot). We observed that adjacent eluting (even coeluting) peaks in a temperature programmed separation can have their peak W vary as much as ∼10-15%. Hence, the peak W provides useful chemical selectivity when viewed in the 2D m/z cluster plot format. Pairs of overlapped analyte peaks with one-dimensional GC resolution as low as Rs ≈ 0.03 can be visually identified as fully resolved in a 2D m/z cluster plot and readily deconvoluted using chemometrics (i.e., demonstrated using classical least-squares analysis). Using the 2D m/z cluster plot method, the effective peak capacity of one-dimensional GC separations is magnified nearly 40-fold in one-dimensional GC, and potentially ∼100-fold in the context of comparing it to a two-dimensional separation. The method was studied using a 73 component test mixture separated on a 30 m × 250 µm i.d. RTX-5 column with a LECO Pegasus III TOFMS.

Aryl aldehydes as traceless dielectrophiles in bifunctional titanocene-catalyzed propargylic C-X activations.

The titanocene-catalyzed construction of all-carbon substituted tertiary centers directly from aromatic aldehydes is described. The starting aldehyde behaves as a traceless functionality in the formation of multiple carbon-carbon bonds through consecutive carbon-heteroatom bond activations. The sequential addition of a metal acetylide and a second carbon nucleophile to the dielectrophilic aldehyde enables the construction of symmetrical and unsymmetrical 1,4-diynes in good yields.

Antimicrobial and cytotoxic activities of synthetically derived tambjamines C and E - J, BE-18591, and a related alkaloid from the marine bacterium Pseudoalteromonas tunicata.

In the first comprehensive biological assessment of the tambjamine class of marine alkaloids, synthetically derived samples of compounds 1-9 have been subjected to evaluation as antimicrobial agents and screened for their cytotoxic effects on various human cancer cell lines. Most were strongly active against the fungus Malassezia furfur (>amphotericin B) and showed considerable, but non-selective, antiproliferative activity against both human cancer and normal cell lines. Tambjamines I and J (6 and 7, resp.) displayed significant apoptosis-inducing effects.

(+)-hexacyclinol.

A SAMPLE OF THE TITLE COMPOUND [SYSTEMATIC NAME: (1aS,2aS,3S,5aS,6aS,7R,7aS,7bS,8R,8aS,10R)-7-hydr-oxy-3-(1-meth-oxy-1-methyl-ethyl)-10-(2-methyl-1-propen-yl)-1a,5a,6a,7,7a,7b,8,8a-octa-hydro-2H-8,2a-(epoxy-methano)phenanthro[2,3-b:6,7-b']bis-oxirene-2,5(3H)-dione], C(23)H(28)O(7), was generated by enanti-oselective synthesis. There are three mol-ecules of the compound in the crystallographic asymmetric unit. Hydrogen bonding between alcohol H atoms and keto groups of adjacent mol-ecules appears to stabilize the structure. The compound is enanti-omerically pure but the absolute configuration could not be determined directly in this study. Accordingly, the illustrated configuration was assigned on the basis of the nature of the chiral nonracemic precursor used in the synthesis.

Chemoenzymatic access to versatile epoxyquinol synthons.

The enantiomerically pure and readily available metabolites 10-12 have been converted over four simple steps into the epoxyquinol derivatives 22-24, respectively. Compounds 23 and 24 or their immediate precursors have been exploited in efficient total syntheses of (-)-bromoxone (ent-1), (-)-epiepoformin (ent-2), (-)-harveynone (4), (+)-panepophenanthrin (6), and (+)-hexacyclinol (9).

Total syntheses of tambjamines C, E, F, G, H, I and J, BE-18591, and a related alkaloid from the marine bacterium Pseudoalteromonas tunicata.

The acetate salts of tambjamines C, E, and F (2-4, respectively), as well as those of the related alkaloids BE-18591 (5) and 6, have been prepared by treatment of bipyrrole aldehyde 16 with the relevant amine in the presence of acetic acid. The 5'-bromo-analogue, 30, of compound 16 has also been prepared and used to obtain the acetate salts of tambjamines G, H, I, and J (8-11 respectively).