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The emergence of TKX-50, an energetic ionic salt with a high enthalpy of formation and low sensitivity, has opened a new path for the development of high-energetic, insensitive composite explosives. However, due to the poor interfacial binding properties of TKX-50 with conventional binders, there is a lack of effective guidance for the design of TKX-50 based composite explosives. To address the above issues, the interactions between carboxymethyl cellulose acetate butyrate (CMCAB) and other binders with explosives TKX-50/HMX were compared using the molecular dynamics method. Based on the simulations, TKX-50/HMX/CMCAB-based polymer-bonded explosives (PBXs) were prepared with CMCAB as binder, which displays a high binding energy (Ebind) with TKX-50 and high cohesive energy density (CED), and the effect of TKX-50 content on the performance of PBXs was investigated. The physical properties of PBXs, specifically the morphology, mechanical sensitivity, and thermal conductivity, were analyzed by SEM, sensitivity apparatus, and thermal conductivity meter, respectively. The specific heat capacity (Cp) and non-isothermal decomposition temperature of PBXs were tested by DSC, and then the corresponding thermal kinetic parameters were analyzed to evaluate their thermal safety. The adiabatic thermal decomposition processes of PBXs were tested using an ARC instrument. The decomposition mechanism and kinetics were also explored to further analyze their thermal stability and thermal safety under adiabatic conditions. The computer code EXPLO5 was used to predict the detonation parameters of PBXs. The results showed that CMCAB and TKX-50 displayed favorable interfacial bonding properties, and TKX-50 can be bonded with HMX to form a molding powder with a desirable morphology and safety profile. The TKX-50 in PBXs effectively improves the mechanical sensitivity and thermal safety of PBX and has a significant effect on the detonation performance of PBX. This research demonstrates a novel method suitable for screening and investigating high-energetic insensitive explosive systems compatible with TKX-50. [ABSTRACT FROM AUTHOR]

The energetic ion salt, TKX-50, has attracted great interests in the field of energetic materials due to its advantages of high enthalpy of formation, low sensitivity and low toxicity. However, the large aspect ratio and poor surface adhesion performance of its crystal are inconducive to the safe use and interfacial bonding for the preparation of composite energetic materials. To solve these problems, we introduced an anionic polymer, carboxymethyl cellulose acetate butyrate (CMCAB), as the crystal control agent and surface modifier for the recrystallization of TKX-50 by the anti-solvent method. The effects of CMCAB on the morphology, internal structure, surface elemental composition, mechanical sensitivity, specific heat capacity (C p) and thermal stability of TKX-50 were investigated. It was found that the morphologies of the TKX-50 recrystallized in the anti-solvents containing CMCAB were better with lower aspect ratios and narrower particle size distributions. A discontinuous CMCAB coating layer was formed on the crystal surfaces due to the electrostatic interaction between CMCAB and TKX-50, resulting in the CMCAB@TKX-50 complex. The coating degree and surface modification were more significant with the increase of CMCAB concentration. The CMCAB coating reduced the friction sensitivity of TKX-50 by 12–38%, meanwhile, the impact sensitivities of CMCAB@TKX-50 prepared at different CMCAB concentrations remained at the low levels of 4–12%. The DSC analysis revealed that the C p of CMCAB@TKX-50 was generally higher than that of TKX-50. The bigger the crystals of CMCAB@TKX-50, the greater the C p and the higher the thermal stability. The peak decomposition temperature of the first stage, the activation energy (E a) and pre-exponential factor (A) of CMCAB@TKX-50 were generally higher than those of TKX-50, suggesting better thermal stability and safety of CMCAB@TKX-50 than TKX-50. The CMCAB@TKX-50 prepared in our work not only shows superior safety performance, but also is well compatible with the traditional binder, cellulose acetate butyrate (CAB). The good dissolution properties of CMCAB make CMCAB@TKX-50 more suitable for the preparation of polymer-bonded explosives (PBX), which can promote the application of TKX-50 in PBX. [Display omitted] • CMCAB was used as the crystal control agent and surface modifier for TKX-50. • The interaction between CMCAB and TKX-50 changes the crystal growth mode of TKX-50. • The surface adhesion performance of TKX-50 crystals was improved by CMCAB. • CMCAB@TKX-50 showed lower friction sensitivity and impact sensitivity than TKX-50. • CMCAB@TKX-50 showed better thermal stability and safety than TKX-50. [ABSTRACT FROM AUTHOR]

Naringenin (Nar) is an important bioactive flavonoid with poor organic solubility and oral bioavailability. It is highly promising for treatment of conditions including diabetes, hyperlipidemia, and hepatitis C infection. Amorphous solid dispersion (ASD) of Nar is an appealing way to enhance its solubility, and carboxylated cellulose esters are attractive polymers for this purpose because of their ability to stabilize drugs against crystallization in both solid and solution phases, while restricting drug release to the pH of the small intestine (ca. 6.8). We demonstrate that ASDs of Nar can be formed using such carboxylated cellulose derivatives as cellulose acetate adipate propionate (CAAdP), carboxymethylcellulose acetate butyrate (CMCAB) and hydroxypropylmethylcellulose acetate succinate (HPMCAS). We compare Nar solution concentrations and release profiles from these cellulosic ASDs to those from pure crystalline Nar, and to Nar ASD in poly(vinylpyrrolidinone) (PVP). We show that all polymers in this study form ASDs with Nar, that the PVP ASDs release Nar at both gastric (1.2) and small intestine (6.8) pH, and that the cellulosic polymers release Nar selectively at neutral pH. Solution concentrations of Nar are significantly enhanced from these ASDs. These preliminary studies indicate that HPMCAS, CAAdP, and CMCAB are practical ASD polymers for Nar due to their ability to generate and stabilize high solution concentrations, and their pH-triggered drug release. [ABSTRACT FROM AUTHOR]

Resveratrol is a highly biologically active phytoalexin, found in many plant materials that are common elements of the human diet, such as grapes, nuts, and red wine. The therapeutic or disease preventative potential of this natural polyphenolic antioxidant has been limited in part due to its poor aqueous solubility and low oral bioavailability. We hypothesized that solid dispersion of resveratrol (Res) in cellulose derivative matrices might afford amorphous dispersions, from which supersaturated Res solutions would be produced in the human gastrointestinal (GI) tract, resulting in higher Res bioavailability. We carried out structure-property studies employing cellulose esters with a range of physical characteristics but possessing features suitable for use in amorphous solid dispersions: carboxymethylcellulose acetate butyrate (CMCAB), hydroxypropylmethylcellulose acetate succinate (HPMCAS) and cellulose acetate adipate propionate (CAAdP). The cellulose derivative results were compared with those of a negative control, pure crystalline Res, and a positive control, Res/poly(vinylpyrrolidinone) (PVP). Solid dispersions were characterized by powder X-ray diffraction (XRPD), modulated differential scanning calorimetry (MDSC), nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR) of solid dispersions. HPMCAS and PVP solid dispersions afforded faster and more complete Res release at pH 6.8; however Res is also released from PVP matrices at pH 1.2. The carboxyl-containing cellulose derivatives release Res to only a small extent at pH 1.2. This combination of solution and solid phase stabilization against crystallization, and pH-triggered drug release makes these cellulose esters attractive candidates for Res bioavailability enhancement. [ABSTRACT FROM AUTHOR]

Abstract: Amorphous solid dispersions (ASD) of quercetin (Que) in cellulose derivative matrices, carboxymethylcellulose acetate butyrate (CMCAB), hydroxypropylmethylcellulose acetate succinate (HPMCAS), and cellulose acetate adipate propionate (CAAdP) were prepared with the goal of identifying an ASD that effectively increased Que aqueous solution concentration. Crystalline quercetin and Que/poly(vinylpyrrolidinone) (PVP) ASD were evaluated for comparison. Powder X-ray diffraction (XRPD) and differential scanning calorimetry (DSC) were used to examine the crystallinity of ASDs, physical mixtures (PM) and quercetin. ASDs were amorphous up to 50wt% Que. Que stability against crystallization and solution concentrations from these ASDs were significantly higher than those observed for physical mixtures and crystalline Que. PVP stabilizes against both Que degradation and recrystallization; in contrast, these carboxylated cellulose derivatives inhibit recrystallization but release Que slowly. PVP ASDs afforded fast and complete drug release, while ASDs using these three cellulose derivatives provide slow, incomplete, pH-triggered drug release. [Copyright &y& Elsevier]

Abstract: Structurally varied, carboxyl-containing cellulose derivatives were evaluated for their ability to form amorphous solid dispersions (ASD) with ellagic acid (EA), in order to improve the solubility of this high-melting, poorly bioavailable, but highly bioactive natural flavonoid compound. ASDs of EA with carboxymethylcellulose acetate butyrate (CMCAB), cellulose acetate adipate propionate (CAAdP), and hydroxypropylmethylcellulose acetate succinate (HPMCAS) were prepared, and EA dissolution from these ASDs was compared with that from pure crystalline EA and from EA/poly(vinylpyrrolidinone) (PVP) solid dispersions (SD). Polymer/drug mixtures were characterized by powder X-ray diffraction (XRPD), modulated differential scanning calorimetry (MDSC), nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR). The XRPD and FT-IR results indicated that EA was amorphous in solid dispersions with EA concentration up to 25wt%. The stability against crystallization and solution concentrations of EA from these solid dispersions were significantly higher than those observed for physical mixtures and pure crystalline EA. HPMCAS stabilized EA most effectively, among the polymers tested, against both chemical degradation and recrystallization. The relative ability to solubilize EA from ASDs at pH 6.8 was PVP≫HPMCAS≫CMCAB. EA dissolves from ASD in PVP quickly and completely (maximum 92%) at pH 6.8, but EA is also released from PVP at pH 1.2, and then crystallizes rapidly. Therefore PVP is not a practical candidate for EA ASD. In contrast, the cellulose derivative ASDs show very slow EA release at pH 1.2 (<4%) and faster but still incomplete drug release at pH 6.8 (maximum 35% for HPMCAS SD). The pH-triggered drug release from HPMCAS ASD makes HPMCAS a practical choice for EA solubility enhancement. [Copyright &y& Elsevier]