The comparative analysis of gastrointestinal toxicity of azithromycin and 3'-decladinosyl azithromycin on zebrafish larvae.

The most commonly reported side effect of azithromycin is gastrointestinal (GI) disorders, and the main acid degradation product is 3'-Decladinosyl azithromycin (impurity J). We aimed to compare the GI toxicity of azithromycin and impurity J on zebrafish larvae and investigate the mechanism causing the differential GI toxicity. Results of our study showed that the GI toxicity induced by impurity J was higher than that of azithromycin in zebrafish larvae, and the effects of impurity J on transcription in the digestive system of zebrafish larvae were significantly stronger than those of azithromycin. Additionally, impurity J exerts stronger cytotoxic effects on GES-1 cells than azithromycin. Simultaneously, impurity J significantly increased ghsrb levels in the zebrafish intestinal tract and ghsr levels in human GES-1 cells compared to azithromycin, and ghsr overexpression significantly reduced cell viability, indicating that GI toxicity induced by azithromycin and impurity J may be correlated with ghsr overexpression induced by the two compounds. Meanwhile, molecular docking analysis showed that the highest -CDOCKER interaction energy scores with the zebrafish GHSRb or human GHSR protein might reflect the effect of azithromycin and impurity J on the expression of zebrafish ghsrb or human ghsr. Thus, our results suggest that impurity J has higher GI toxicity than azithromycin due to its greater ability to elevate ghsrb expression in zebrafish intestinal tract.

Research on the relationship between cephalosporin structure, solution clarity, and rubber closure compatibility using volatile components profile of butyl rubber closures.

OBJECTIVE: Establish an effective experimental strategy to determine the compatibility of rubber closures for drugs. SIGNIFICANCE: Various types of rubber closures with different compositions are available for drug packaging. Many additives of rubber closures can be released from rubber closures and may affect the quality of drugs and pose a risk to human health. In this study, we aimed to determine the relationship between cephalosporin structure, solution clarity, and rubber closure compatibility using volatile components profile of butyl rubber closures. METHODS: Two opposite polarity gas chromatography (GC) systems and GC-mass spectrometry (MS) were used to achieve rapid qualitative determination of the main volatile components in rubber closures. Simulated adsorption experiment was performed to investigate the adsorption of main volatile components in rubber closures by cephalosporins with different side chain structures, and to determine the effects of adsorption on solution clarity. RESULTS: A volatile components screening library of rubber closures was established and the structures of some volatile component were confirmed. The specific adsorption of the structure of cephalosporins on volatile components from rubber closures was studied. CONCLUSION: Based on the results of this study, rubber closures with good compatibility for cephalosporins with different side chain structures can be selected rapidly. This experimental strategy not only facilitates the screening of suitable rubber closures more effectively, but also enables the quick determination of volatile components adsorbed by drugs.

Rapid Analysis of the Quality of Amoxicillin and Clavulanate Potassium Tablets Using Diffuse Reflectance Near-Infrared Spectroscopy.

The cycle-closed dimer of amoxicillin influences its critical quality and is an important impurity in amoxicillin and clavulanate potassium tablets. The quality of the tablets could be rapidly evaluated using the impurity as an indicator. Here, we report a quantitative model to determine the cycle-closed dimer in samples from different manufacturers using diffuse reflectance near-infrared (NIR) spectroscopy by partial least squares regression for one y variable (PLS1) and hierarchical cluster analysis. Because the contents of the (active pharmaceutical ingredients) APIs (amoxicillin and clavulanate potassium) and water are also the important indexes of the tablet quality, three other quantitative models were used to confirm the API data and water content. All of the four models facilitate rapid and complete control of the tablet quality. In addition, quantitative models were validated in terms of specificity, linearity, accuracy, repeatability, and intermediate precision according to the International Conference on Harmonisation guidelines by evaluating the characteristics of the NIR spectra. These results confirmed that the models were satisfactory.

[Drug Discrimination Method Based on Near Infrared Reflectance Spectrum and Balance Cascading Sparse Representation Based Classification].

The combination of near infrared spectrum and pattern recognition methods has a wide application prospect in rapid and nondestructive supervision and management of drugs. The traditional identification methods regard the smallest error rate as the goal while the imbalance of classes is ignored. This makes the positive class is overwhelming covered by the negative class and reduces its effect for the classifier, so that the classification results tend to recognize the negative class correctly, which severely affects the identification accuracy. In this paper, we mainly studied the class imbalance problems of true or false drugs via infrared spectral data of its, and then propose a balance cascading and sparse representation based classification method (BC-SRC) by combining the Balance Cascading with SRC. We sampling majority samples from the majority class for several times, which has the same size as minority samples and the majority samples we sampled can contain all the majority class samples entirely (sampling times is ceiling the result of majority samples number divide minority samples number). We can get sets of results, and then obtain the final predict labels form those results. Experiments of three databases achieved on Matlab2012a shows that the method is effective. From the experimental results, it can be seen that the method is superior to the commonly used Partial Least Squares (PLS), Extreme Learning Machine (ELM) and BP. Particularly, for the imbalanced databases, when the imbalance factor is greater than 10, the proposed method has more stable performance with higher classification accuracy than the existing ones mentioned above.

[The control of the critical quality attributes of amoxicillin and clavulanate potassium tablet].

The critical attribute was analyzed in clavulanate potassium tablet of amoxicillin according to the principle QbD. By investigation of the drug impurity profile, the cycle-closed dimer and penicilloic acid of amoxicillin were considered to be the critical impurities, and the sources and the degradation pathways of these two impurities were discussed. The research confirmed that crystal form was the critical attribute of drug substance. The drying process in the tablet granulation was regarded as the critical process parameter. The tablet formulation was also another factor in the impurity generation. This study provides a new idea for the evaluation of drug quality.

[Study on the Selection of Parameters for Evaluating Drug NIR Universal Quantitative Models].

In order to find out the optimum combination of the evaluation parameters for the selection of the best drug near infrared (NIR) universal quantitative model during model optimization, 13 common evaluation parameters of NIR quantitative models were collected and arranged from commercial chemometrics software or References based on the requirements of validation of quantitative analytical procedures of ICH (International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use). Then all these parameters of 92 drug NIR universal quantitative models were calculated and analyzed. By studying the correlation of these parameters, the optimum combination of evaluation parameters for drug NIR universal quantitative models was determined. And the value range of these parameters in the optimum combination was also obtained. Root mean square error of cross-validation(RMSECV)/root mean square error of prediction (RMSEP), average relative deviation (ARD) and ratio of (standard error of) prediction (validation) to (standard) deviation (RPD) were used as the key parameters to evaluate the model accuracy. Most of RMSECV/RMSEP was within 3%, and the value of RMSECV was roughly equivalent to the average absolute deviation of the corresponding model. Most of RPD was more than 2. The value of ARD was related to the type of universal models (such as the drug preparation and packing) and the content range which the test sample belonged to. Determination coefficient (R2) was used as the key parameter to evaluate the model linearity and most of its values were from 80% to 100%. The ratio of RMSEP to RMSECV was selected as the key evaluation parameter of model robustness and its value was usually within 1.5. The standard deviation of repeated measurement data was chosen to evaluate model precision. And it was an important parameter for standardizing operation of NIR instruments and studying the feasibility of model transfer in different instruments. However, the parameter for NIR universal quantitative models received much less attention in previous studies and it was difficult to give a value range for this parameter at present. All the results can not only provide evidence for evaluation of drug NIR universal quantitative models for the model builders or users, but also supply basic data to establish and improve the parameter evaluation system of drug NIR universal quantitative models.

Cardiotoxicity evaluation of anthracyclines in zebrafish (Danio rerio).

Drug-induced cardiotoxicity is a leading factor for drug withdrawals, and limits drug efficacy and clinical use. Therefore, new alternative animal models and methods for drug safety evaluation have been given great attention. Anthracyclines (ANTs) are widely prescribed anticancer agents that have a cumulative dose relationship with cardiotoxicity. We performed experiments to study the toxicity of ANTs in early developing zebrafish embryos, especially their effects on the heart. LC50 values for daunorubicin, pirarubicin, doxorubicin (DOX), epirubicin and DOX-liposome at 72 h post-fertilization were 122.7 µM, 111.9 µM, 31.2 µM, 108.3 µM and 55.8 µM, respectively. At the same time, zebrafish embryos were exposed to ANTs in three exposure stages and induced incomplete looping of the heart tube, pericardia edema and bradycardia in a dose-dependent manner, eventually leading to death. DOX caused the greatest heart defects in the treatment stages and its liposome reduced the effects on the heart, while daunorubicin produced the least toxicity. Genes and proteins related to heart development were also identified to be sensitive to ANT exposure and downregulated by ANTs. It revealed ANTs could disturb the heart formation and development. ANTs induced cardiotoxicity in zebrafish has similar effects in mammalian models, indicating that zebrafish may have a potential value for assessment of drug-induced developmental cardiotoxicity.

[Determination of furbenicillin sodium and its related substances by HPLC].

Furbenicillin is a broad-spectrum semisynthetic penicillin with strong antibacterial activity against Gram-negative bacteria. Furbenicillin sodium is determined by volumetric method in current criteria. However, the criteria does not contain an assay of related substances of furbenicillin sodium. In this study, we established a method for detection and analysis of furbenicillin sodium and its related substances by HPLC. The analysis was performed with a C18 column under a gradient elution, the detection wavelength was 225 nm, and the column temperature was 35 degrees C. The reliability and accuracy of established method was validated in this study. Pure samples of furbenicillin sodium and its related substances were prepared. The structures, biological activities, and chromatographic retention behaviors of furbenicillin sodium and its related substances were identified using NMR, CLSI agar dilution method, and HPLC. All results in the current study provide ample evidence that this method is able to determine the reasonable limits in the quality-control protocol for furbenicillin sodium.

[Construction of the quantitative structure retention relationship of cefdinir related substances].

The molecular descriptors of impurities with known structure in cefdinir were calculated, selected and associated with the chromatographic retention behavior to establish a model. This quantitative structure retention relationships (QSRR) model for the related substances of cefdinir was established under specific chromatographic condition and verified by other impurities. 12 molecular descriptors were used to establish the QSRR model, F_AFRBWF, Blbn_J, SsCH3, SssCH2, SsNH2, SssNH, SssS, SHdCH2, EEM_AFc, EEM_AFpl, EEM_XFpl and Pi_MaxQ. The relativity between true values and predictions in QSRR of cefdinir is R2 = 0.9836 (n = 18), ΔRRT is no more than 0.154, as 10.17% in RRT. The results indicate that the QSRR model for the related substances of cefdinir can be used to evaluate the analysis methods for related substances and predict the chromatographic behavior of new impurities, which will provide a new way for the evaluation of the effectiveness for drug quality control.

[Development and application of reference materials containing mixed degradation products of amoxicillin and ampicillin].

Reference materials containing mixed degradation products of amoxicillin and ampicillin were developed after optimization of preparation processes. The target impurities were obtained by controlled stress testing, and each major component was identified with HPLC-MS and compared with single traceable reference standard each. The developed reference materials were applied to system suitability test for verifying HPLC system performed in accordance with set forth in China Pharmacopeia and identification of major impurities in samples based on retention and spectra information, which have advantages over the methods put forth in foreign pharmacopoeias. The development and application of the reference materials offer an effective way for rapid identification of impurities in chromatograms, and provide references for analyzing source of impurities and evaluation of drug quality.

[Dissolution testing combined with computer simulation technology to evaluate the bioequivalence of domestic amoxicillin capsule].

Re-evaluation of bioequivalence of generic drugs is one of the key research focus currently. As a means to ensure consistency of the therapeutic effectiveness of drug products, clinical bioequivalence has been widely accepted as a gold standard test. In vitro dissolution testing based on the theory of the BCS is the best alternative to in vivo bioequivalence study. In this article, the conventional dissolution method and flow-through cell method were used to investigate the dissolution profiles of domestic amoxicillin capsules in different dissolution media, and the absorption behavior of the drugs with different release rates (t85% = 15-180 min) in the gastrointestinal tract was predicted by Gastro Plus. The flow-through cell method was thought better to reflect the release characteristics in vivo, and amoxicillin capsules with regard to the release rates up to 45 min (t85% = 45 min) were having a satisfied bioequivalence with the oral solution according to the C(max) and AUC. Although two different dissolution profiles of domestic amoxicillin capsules were found by flow-through cell methods, prediction results revealed that domestic capsules were probably bioequivalent to each other.

[Subtype classification of ceftriaxone sodium and its influence on the quality of product].

Powder X-ray diffraction (PXRD) technology combined with cluster analysis method was used to classify 75 batches of crystalline ceftriaxone sodium into subtypes, the crystalline characteristics of each subtype were measured with scanning electron microscope (SEM). By comparing some parameters of these subtypes correlated to crystallization process of ceftriaxone sodium, such as salification rate, water content in different subtypes, as well as by studying different lattice stabilities, different compatibilities with rubber closures during accelerated stability tests, the key point to improve the quality of domestic ceftriaxone sodium was disclosed. The results of this paper indicated that the fine structure of the products could be controlled well by improving the salification and crystallization process. As a result, the subtype II of ceftriaxone sodium with high stability can be produced.

[Research progress in using near infrared for monitoring drug quality in domestic circulation].

Drugs are special goods that are directly related to public health, so their quality should be monitored in any link of their whole lifecycle. With nondestructive, rapid and environmentally friendly characteristics, near infrared technique is highly suitable for monitoring drug quality in the open market as well as the distribution channels. The present paper reviewed the current situation (analytical objects, methods and instruments) about the application of near infrared spectroscopy in monitoring the quality of the final drug products, Chinese crude drug or decoction pieces in domestic circulation since 1997, expounded the unsolved problems and future prospects.

[Update of near-infrared models for testing ceftazidime, water and arginine in ceftazidime for injection].

UNLABELLED: To find a more reasonable index to decide whether the universal quantitative NIR model needs to be updated and to develop a general method to update universal quantitative NIR models, the quantitative models for testing ceftazidime, water and arginine contents in ceftazidime for injection were taken as example. The study was performed by analyzing the similarity between new sample spectra and the training set spectra of the original models. At first, new samples of ceftazidime for injection were divided into five groups by cluster analysis. Then representative samples of each group were selected by sample selection strategy. Spectra of those samples were used to update the original quantitative models. The prediction deviation of the new ceftazidime powder injection samples by the models before and after updating was calculated. Decreasing the prediction deviation was regarded as the standard to decide if the updating was effective. At the same time, the correlation coefficient of new sample spectra and reference sample spectra was defined as the index to study the general method for model updating. (Reference sample refers to training set sample) Finally, the proposed method was validated by updating universal models for testing ceftazidime, water and arginine contents in ceftazidime powder injections. Results show that the correlation coefficient of new sample spectra and training set sample spectra of the original model was calculated within modeling wavelength range. It was proved that when correlation coefficient rT < 96.5%, the model needs to be updated. Accordingly, rT = 96.5% was set as the threshold. The quantitative models were updated by the method mentioned above. As a result, when testing ceftazidime for injection containing sodium carbonate using newly updated models, the average predicting deviation of ceftazidime contents decreased from 8.1% to 2.3%. And the average predicting deviation of water contents decreased from 2.2% to 0.3%. Meanwhile, with regard to samples containing arginine using the updated models, the average predicting deviation of ceftazidime contents decreased from 7.0% to 1.9%. The average predicting deviation of water contents decreased from 0.6% to 0.3%. And that of arginine contents de- creased from 2.3% to 0.4%. CONCLUSION: The newly updated models can be used for testing ceftazidime, water and arginine contens in ceftazidime for injection samples of domestic market. It is reasonable to set rT as the index to decide whether the model needs updating. Moreover, it is necessary to take PCA scores graph of new sample spectra and training set spectra of the original model into account. The proposed method for updating models can be used as a usual approach. And rT = 96.5% can be set as the threshold to determine whether the model needs to be updated.

[Impurity profiling of macrolide antibiotics by liquid chromatography-mass spectrometry].

Macrolide antibiotics are broad-spectrum, with activity against a range of Gram-positive, Gram-negative organisms and some anaerobes. The components of macrolide antibiotics are generally complicated. Therefore, it is very important to establish impurity profiles of these antibiotics to ensure their safety and process control. Compared with classical methods, the liquid chromatography-mass spectrometry method is particularly advantageous to characterize minor components at trace levels in terms of sensitivity, efficiency and selectivity, thus more and more widely used in establishments of impurity profiles. In this study, the general approaches to characterize minor components in complex pharmaceutical matrix, fragmentation pathways of 14- and 16-membered macrolide antibiotics and the establishment of the impurity profile of acetylspiramycin were given to provide valuable enlightenments to establish the impurity profiles of pharmaceutical products.

Influence of impurities on the specific optical rotation of cefozopran.

The impurities of cefozopran hydrochloride are analyzed using high-performance liquid chromatography (HPLC) with UV absorbance and optical rotation (OR) detection. The results show that the impurities can affect the specific optical rotation of the cefozopran product. Due to the different composition of impurities, the Chinese cefozopran hydrochloride product has a specific optical rotation different from the Japanese product. The relationship between impurity limits and specific optical rotation of cefozopran hydrochloride is revealed. The results provide a scientific rationale for setting the limit of specific optical rotation of cefozopran hydrochloride.

Simultaneous determination of purity and potency of the components of gentamycin using high-performance liquid chromatography.

The quality of some earlier developed antibiotics is usually ensured by the combination of HPLC purity and microbiological potency measurement in the pharmacopoeias of various countries because the relationship between their purity and potency is not clearly quantified. Due to potency is assessed using certain units of measurement, it can not be directly traced to the international system of units (SI unit). This has become a hotspot in the study of the quantitative relationship between purity and potency of antibiotics. It would be quite an achievement to simultaneously determine both purity and potency using HPLC methods during quality control. This study evaluated a multicomponent antibiotic product, gentamycin, as a test sample. First, pure samples of the C components of gentamycin: C1a, C2, C2a and C1 were prepared, separately. Second, quantitative relationship (theoretical potency) between the purity and potency of each C component of gentamycin were determined using 1H NMR, HPLC-ELSD and microbiological assay method. One milligram of gentamycin C1a, C2, C2a and C1 was equal to 1 286.98, 1 095.74, 1 079.52 and 739.61 gentamycin units, respectively. Finally, a method for the determination of gentamycin potency was established based on the proportion and content of C components of gentamycin. The unification of purity and potency for gentamycin was achieved using only HPLC-ELSD. It is also demonstrated that C components of gentamycin and micronomicin produce the same responses under ELSD, which means that it is not necessary to prepare separate reference standards for each C component of gentamycin and that quantitative testing can be performed accurately using only one micronomicin reference standard. This study simplified the previous method for the determination of the content of C components of gentamycin using HPLC-ELSD. The developed method is suitable for regular use as a part of quality control and can simplify the rigmarole quality control procedures provided in current pharmacopeias.

[Identification of impurity peaks in the HPLC chromatogram by LC-MS and two-dimensional chromatographic correlation spectroscopy].

A novel qualitative analytical method by using two-dimensional chromatographic correlation spectroscopy techniques for recognizing impurity peaks of HPLC methods of quality control and LC-MS chromatographic system was established. The structures of major degradation products of ceftizoxime and cefdinir were identified by LC-MS and MassWorks application; the standard chromatographic and spectral data of the degradation impurities were obtained by high-performance liquid chromatography with diode array detection. The impurity peaks of two-dimensional chromatography were matched by comparison of spectra and calculating correlation coefficients. Peaks in chromatography can be identified accurately and rapidly in different chromatographic systems such as column and mobile phase changed. The method provides a new way and thought to identify the peaks in quality control of impurities without reference impurity substances.

A Rapid Assessment Model for Liver Toxicity of Macrolides and an Integrative Evaluation for Azithromycin Impurities.

Impurities in pharmaceuticals of potentially hazardous materials may cause drug safety problems. Macrolide antibiotic preparations include active pharmaceutical ingredients (APIs) and different types of impurities with similar structures, and the amount of these impurities is usually very low and difficult to be separated for toxicity evaluation. Our previous study indicated that hepatotoxicity induced by macrolides was correlated with c-fos overexpression. Here, we report an assessment of macrolide-related liver toxicity by ADMET prediction, molecular docking, structure-toxicity relationship, and experimental verification via detection of the c-fos gene expression in liver cells. The results showed that a rapid assessment model for the prediction of hepatotoxicity of macrolide antibiotics could be established by calculation of the -CDOCKER interaction energy score with the FosB/JunD bZIP domain and then confirmed by the detection of the c-fos gene expression in L02 cells. Telithromycin, a positive compound of liver toxicity, was used to verify the correctness of the model through comparative analysis of liver toxicity in zebrafish and cytotoxicity in L02 cells exposed to telithromycin and azithromycin. The prediction interval (48.1∼53.1) for quantitative hepatotoxicity in the model was calculated from the docking scores of seven macrolide antibiotics commonly used in clinics. We performed the prediction interval to virtual screening of azithromycin impurities with high hepatotoxicity and then experimentally confirmed by liver toxicity in zebrafish and c-fos gene expression. Simultaneously, we found the hepatotoxicity of azithromycin impurities may be related to the charge of nitrogen (N) atoms on the side chain group at the C5 position via structure-toxicity relationship of azithromycin impurities with different structures. This study provides a theoretical basis for improvement of the quality of macrolide antibiotics.

A training set selection strategy for a universal near-infrared quantitative model.

The purpose of this article is to propose an empirical solution to the problem of how many clusters of complex samples should be selected to construct the training set for a universal near infrared quantitative model based on the Naes method. The sample spectra were hierarchically classified into clusters by Ward's algorithm and Euclidean distance. If the sample spectra were classified into two clusters, the 1/50 of the largest Heterogeneity value in the cluster with larger variation was set as the threshold to determine the total number of clusters. One sample was then randomly selected from each cluster to construct the training set, and the number of samples in training set equaled the number of clusters. In this study, 98 batches of rifampicin capsules with API contents ranging from 50.1% to 99.4% were studied with this strategy. The root mean square errors of cross validation and prediction were 2.54% and 2.31% for the model for rifampicin capsules, respectively. Then, we evaluated this model in terms of outlier diagnostics, accuracy, precision, and robustness. We also used the strategy of training set sample selection to revalidate the models for cefradine capsules, roxithromycin tablets, and erythromycin ethylsuccinate tablets, and the results were satisfactory. In conclusion, all results showed that this training set sample selection strategy assisted in the quick and accurate construction of quantitative models using near-infrared spectroscopy.