Establishment of a cocrystal characterization method for sacubitril valsartan sodium / 药学学报

Sacubitril valsartan sodium (LCZ696) is an ionic cocrystal drug. The purpose of this study was to explore the cocrystal features of LC696 by establishing a variety of characterization methods, and thus provide basic research data for effective quality control. The cocrystal characteristics of LCZ696 and its tablets were identified by applying analytical means including powder X-ray diffraction (PXRD), fourier transform infrared spectroscopy (FTIR), Raman spectra (RM), differential scanning calorimetry (DSC) and solid-state nuclear magnetic resonance spectroscopy (ssNMR). The crystalline water and hygroscopicity of LCZ696 were analyzed by thermogravimetric analysis (TGA), dynamic vapor sorption (DVS), hygroscopicity test and Karl Fischer reaction method. The results show that PXRD, FTIR, DSC and ssNMR can effectively distinguish the features of LCZ696 cocrystal, sacubitril monomer, valsartan monomer, and sacubitril-valsartan (1∶1) mixture. RM can be used as a supplementary approach. Combined with the analysis by TGA, DVS, hygroscopicity test and Karl Fischer reaction method results, LCZ696 contains 2.5 crystalline water molecules and is very hygroscopic; we recommend that LCZ696 be stored in an environment with a relative humidity below 60%. By characterizing the crystal features we can establish quality control measure and evaluate the stability of the drug tablets. This study provides data in support for the establishment of the LCZ696 quality standard.

Quantitative Detection for Polymorph of Levonorgestrel by Powder X-ray Diffraction / 医药导报

Objective According to the clinical medicinal crystal form———form γ of levonorgestrel, to establish the quantitative analysis method for levonorgestrel form γ by powder X-ray diffraction (PXRD) . Methods Firstly, single crystal X-ray diffractometry and powder X-ray diffractometry were used to confirm that the prepared levonorgestrel form γ was 100％ polymorphic purity, which provided a standard sample for quantitative analysis by single peak method; then, the standard samples of different quality levonorgestrel form γ for powder X-ray diffraction were weighed, the peak intensity values of characteristic diffraction peaks d = 6.4 , d = 6. 1  and d = 5. 6  of form γ as quantitative parameters selected, a linear relationship between the peak intensity value and the quality of form γ was established; finally, the content of levonorgestrel form γ was quantitatively analyzed. Results The peak intensity values of characteristic diffraction peaks d = 6.4 , d = 6.1  and d = 5.6  of levonorgestrel form γ and the quality showed a good linear relationship.In the range of form γ masses of 5 mg to 50 mg, the regression linear equations wereY = 459.59X+5 536.5, R2 = 0.993 0, Y = 430.03X+6 867.6, R2 = 0.990 5,Y = 615.95X+ 6 209.5, R2 = 0.990 8,respectively. Conclusion The method is simple, rapid, accurate and reliable, it can be used as quality control method for levonorgestrel polymorphs.

Crystal form Analysis of Felodipine and Its Preparations / 中国药学杂志

OBJECTIVE: To clarify the crystal forms of the active pharmaceutical ingredient and preparations of felodipine from different sources, and explore the relationship between quality and efficacy of felodipine and its crystal form. METHODS: Crystal form characterization of the active pharmaceutical ingredient from different sources was carried out by powder X-ray diffraction (PXRD), infrared spectroscopy (IR) and differential scanning calorimetry (DSC). The Origin software was used to analyze the crystal forms of felodipine in the sample preparations from different sources. Biological evaluation in vivo was conducted by using whole animals. RESULTS: There were some differences in the crystal state of the active pharmaceutical ingredient from different sources, but the main components were basically the same, all of which were type I. Biological studies showed significant differences in the main pharmacokinetic parameters of felodipine sustained release tablets from different sources. Among them, the ρmax, tmax, t1/2, and AUC0-t had maximal 1.8, 1.4, 8.2 and 1.5 times of differences. CONCLUSION: Although the main crystal forms of felodipine bulk drug from different origins are consistent, the crystal state significantly changes after the preparation process. This finding is of important scientific significance to guide the improvement of process and product quality.

Solubility and dissolution studies of tibolone polymorphs

ABSTRACT Different solid forms of an active pharmaceutical ingredient can have distinct chemical and physical characteristics. In this work, we studied the solubility and dissolution properties of the described tibolone polymorphic forms (I and II). Both forms were successively recrystallized and characterized by powder X-ray diffraction and attenuated total reflection infrared spectroscopy. Equilibrium solubility and dissolution profiles were performed for both forms. Solubility studies demonstrated that form II is statistically more soluble in water, 0.01 mol L-1 HCl and pH 4.5 acetate buffer. The solubility of forms I and II were explained in terms of crystal packing. Dissolution tests of tablets showed a lower release of polymorphic form II than form I from tablets. The results showed an impact of polymorphism on the quality of tibolone tablets and suggest that tibolone forms I and II can show distinct interactions with pharmaceutical excipients used in tablets. Therefore, only form I is acceptable for the preparation of tablet forms. Based on our results, we propose the quality control on tibolone raw materials using X-ray diffraction analysis and attenuated total reflection infrared spectroscopy.

Pharmacokinetics of two kinds of nimodipine crystal tablets in rhesus monkey / 药学学报

Nimodipine is a selective calcium channel antagonist of cerebral vessels smooth muscle and also has polymorphs. It hasn't been reported that different crystal forms influence the metabolism process in huge animals like rhesus monkeys in vivo. This article may provide reference in the control of the quality of nimodipine and quality consistency evaluation. The powder X-ray diffraction (PXRD) method was used to identify different crystal forms and the dissolution test in vitro was used to detect the dissolution. The LC-MS method of assay nimodipine in rhesus monkey plasm was established to determine pharmacokinetics characters of different tablets from different crystal forms in rhesus monkey in vivo. As a result, the tablets inherit difference crystal forms and the dissolution of reference tablets is 1.3% higher than crystal tablets. However, the maximal blood concentration (Cmax) of crystal tablet was 37.3% higher than reference tablet and AUC of crystal tablet was 29.8% higher than reference tablet. After administrated 2.5 mg·kg-1 orally, calculated pharmacokinetics characters were observed as following:Cmax was 381.4 ±327.3 and 178.0 ±214.8 μg·L-1; AUC0-t was 853.1 ±500.7 and 646.5 ±430.3 μg·L-1·h respectively. The serum concentration result of different nimodipine tablets in rhesus monkeys in vivo suggests that polymorphs has a significantly distinction, which points out that controlling the crystal forms of nimodipine is essential to ensure the therapeutic efficacy. It is essential to execute quality consistency evaluation.

Effects of β-Cyclodextrin from Different Sources on Inclusion Rate of Menthol / 中国药师

Objective: To compare the inclusion rate of menthol with β-cyclodextrin (β-CD) from different sources.Methods: β-Cyclodextrin-menthol inclusion complexes were prepared by a grinding method.The inclusion compound was verified by thin layer chromatography (TLC), powder X-ray diffraction (PXRD) and gas chromatography (GC).The optimized conditions of PXRD were as follows: the graphite monochromator was Cu Kα, the voltage was 40 kV, the current was 40 mA, the 2θ scanning range was from 3° to 35°, the scanning step was 0.02° and the scanning rate was 5°·min-1.The optimized conditions of GC were as follows: an Agilent DB-wax capillary column, the column temperature was 120°, the inlet temperature was 250°, the detector temperature was 250° and the split ratio was 10∶1.Results: The results of TLC and PXRD proved the formation of inclusion complexes.The inclusion rate of menthol with β-CD from home and abroad was 25% and 47.9%, respectively.Conclusion: The method is simple, accurate and rapid, which can be used to determine the inclusion rate of β-CD from different sources.The results show that the inclusion effect of imported β-CD is better than that of domestic β-CD.

Monitoring real time polymorphic transformation of sulfanilamide by diffuse reflectance visible spectroscopy$ / 药物分析学报

This study investigated the development of a novel approach to surface characterization of drug poly-morphism and the extension of the capabilities of this method to perform ‘real time’ in situ measure-ments. This was achieved using diffuse reflectance visible (DRV) spectroscopy and dye deposition, using the pH sensitive dye, thymol blue (TB). Two polymorphs, SFN-β and SFN-γ, of the drug substance sul-fanilamide (SFN) were examined. The interaction of adsorbed dye with polymorphs showed different behavior, and thus reported different DRV spectra. Consideration of the acid/base properties of the morphological forms of the drug molecule provided a rationalization of the mechanism of differential coloration by indicator dyes. The kinetics of the polymorphic transformation of SFN polymorphs was monitored using treatment with TB dye and DRV spectroscopy. The thermally-induced transformation fitted a first-order solid-state kinetic model (R2 ? 0.992), giving a rate constant of 2.43 ? 10 ? 2 s ? 1.

Qualitative Detection for Polymorphs in Solid Pharmaceutical Preparations by PXRD / 医药导报

Objective To establish a method for qualitative identification of polymorphs in pharmaceutical solid preparations of active pharmaceutical ingredients ( API ) . Methods We obtained the powder diffraction patterns of the polymorphic drug substance like nimodipine and roxithromycin in solid preparation material and completed quantitative identification for polymorphs by the quantitative detection and using PXRD technology, deduction calculation through the powder X-ray diffraction and comparing with standard diagram. Results Through the analysis of nimodipine and roxithromycin which came from 27 batches of solid preparations from 11 different manufacturers, and comparing to the standard patterns of pure polymorphs, the quantitative identification of different crystalline states of API in pharmaceutical preparations had been established. Conclusion The qualitative detection method for polymorphs of API in pharmaceutical preparations by powder X-ray diffraction has wide applicability and high accuracy, which can be used to identify the polymorphism of API in solid preparation,and also used to control the quality of solid preparations commonly as a qualitative analysis method.

Charge-transfer interaction of drug quinidine with quinol, picric acid and DDQ：Spectroscopic characterization and biological activity studies towards understanding the drug-receptor mechanism / 药物分析学报

Investigation of charge-transfer (CT) complexes of drugs has been recognized as an important phenomenon in understanding of the drug-receptor binding mechanism. Structural, thermal, morpholo-gical and biological behavior of CT complexes formed between drug quinidine (Qui) as a donor and quinol (QL), picric acid (PA) or dichlorodicyanobenzoquinone (DDQ) as acceptors were reported. The newly synthesized CT complexes have been spectroscopically characterized via elemental analysis;infrared (IR), Raman, 1H NMR and electronic absorption spectroscopy; powder X-ray diffraction (PXRD);thermogravimetric (TG) analysis and scanning electron microscopy (SEM). It was found that the obtained complexes are nanoscale, semi-crystalline particles, thermally stable and spontaneous. The molecular composition of the obtained complexes was determined using spectrophotometric titration method and was found to be 1:1 ratios (donor:acceptor). Finally, the biological activities of the obtained CT complexes were tested for their antibacterial activities. The results obtained herein are satisfactory for estimation of drug Qui in the pharmaceutical form.