Characterization of Non-stoichiometric Hydration and the Dehydration Behavior of Sitafloxacin Hydrate

Abstract

Sitafloxacin (STFX) hydrate is a non-stoichiometric hydrate. The hydration state of STFX hydrate varies non-stoichiometrically depending on the relative humidity and temperature, though X-ray powder diffraction (XRPD) of STFX hydrate was not affected by storing at low and high relative humidities. The detailed properties of crystalline water of STFX hydrate were estimated in terms of hygroscopicity, thermal analysis combined with X-ray powder diffractometry, crystallography and density functional theory (DFT) calculation. STFX hydrate changed the water contents continuously and reversibly from an equivalent amount of dihydrate through that of sesquihydrate depending on the relative humidity at 25°C. Thermal analysis and X-ray powder diffraction (XRPD) simultaneous measurement also revealed that STFX hydrate dehydrated into a hydrated state equivalent to monohydrate by heating up to 100°C, whereas XRPD patterns were slightly affected. This indicated that the crystal structure of STFX hydrate was retained at the dehydration level of monohydrate. Single-crystal X-ray structural analysis showed that two STFX molecules and four water molecule sites were contained in an asymmetric unit. STFX molecules formed a channel structure where water molecules were included. At the partially dehydrated state, at least two of four water molecules were considered to be disordered in occupancy and/or coordinates. Insight into the crystal structure of STFX hydrate stored at low and high relative humidities and geometry of the hydrogen bond were helpful to estimate the origin of non-stoichiometric hydration of STFX hydrate.

Powder Structure Analysis of Vapochromic Quinolone Antibacterial Agent Crystals

“…[28][29][30][31] In fact, other quinolone antibacterial agents showing dehydration/hydration or polymorphism were reported. [32][33][34][35] Notably, color changes in APIs due to dehydration/hydration could potentially be used as a quality control method. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 7…”

Usage of Powder XRD Technique for Material Characterization and Analysis of Portland Cement

“…Finer crystallites are prone to react faster (or to react better as catalysts). Assessment of crystallite shape (in case of anisotropic peak size broadening) Lattice parameters and hence metallic contents can be accurately determined [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”

“…The purity of a sample can be accessed by diffraction pattern (Figure 1) by taking into consideration the proportion and composition of impurities present. PXRD is the prime requisite for differentiating the crystalline sample ( Figure 2) from semi-crystalline like in polymer like cotton and amorphous materials like phenol-formaldehyde complex resin ( Figure 3) [1][2][3][4][5][6][7][8].XRD is helpful in qualitative and quantitative phase abundance analysis. It can identify the polymorph and determine the phase abundance to classify the cement and correlating the performance with composition [9][10][11][12][13][14][15].…”

“…The purity of a sample can be accessed by diffraction pattern (Figure 1) by taking into consideration the proportion and composition of impurities present. PXRD is the prime requisite for differentiating the crystalline sample ( Figure 2) from semi-crystalline like in polymer like cotton and amorphous materials like phenol-formaldehyde complex resin ( Figure 3) [1][2][3][4][5][6][7][8].…”

Structural Studies of a Non‐Stoichiometric Channel Hydrate Using High Resolution X‐ray Powder Diffraction, Solid‐State Nuclear Magnetic Resonance, and Moisture Sorption Methods

“…Hydrates are commonly used solid forms in pharmaceutical development and have attracted much attention from pharmaceutical researchers . A compound may form polymorphic hydrates or multiple hydrates at different hydrated states.…”