Interplay of Aging and Lot-to-Lot Variability on the Physical and Chemical Properties of Excipients: A Case Study of Mono- and Diglycerides.

The present study investigates the chemical composition governing the physical properties of mono- and diglycerides (MDGs) at the microstructural level, as a function of aging and lot-to-lot variability. The physical structure of the MDG plays a vital role in ameliorating the emulsion stability and is widely explored in diverse research horizons related to the pharmaceutical, cosmetic, and food industries. In an effort to understand the mechanism of emulsion stabilization, physical properties were extensively evaluated in selective commercial lots to determine if there is a correlation between the chemical composition of MDG and physical properties. The solid state of the MDG samples with different aging profiles was characterized using X-ray scattering, differential scanning calorimetry, attenuated total reflection-Fourier transform infrared spectroscopy, and NMR relaxometry. Moreover, the kinetic aspect of solid-state transformation was also evaluated via treating MDG samples with a heat-cool cycle. The chemical composition of MDGs was quantified using a quantitative NMR (qNMR) method. Interestingly, the X-ray scattering results demonstrated a change in the MDG polymorphic form and an increase in the %ß content as a function of aging. The increase in the %ß content led to the formation of rigid crystal structures of MDG, as evident from the NMR relaxometry. Chemical quantification of isomeric composition revealed chemical composition change as a potentially critical factor responsible for the altered physical structures of MDG with respect to aging and lot-to-lot variability. The findings correlated the solid-state transformation with the change in the chemical composition of the MDG as a combined effect of aging and lot-to-lot variability. This work serves as a basis to better understand the interdependency of the physicochemical properties of MDG. Furthermore, the present work can also be used as guidance for setting up the specifications of MDG, as per the required polymorphic form for a multitude of applications.

Quantitative Chemical Profiling of Commercial Glyceride Excipients via 1H NMR Spectroscopy.

Glycerides are the main components of oils, and fats, used in formulated products in the food and cosmetic industry as well as in the pharmaceutical product industry. However, there is limited literature available on the analysis of the chemical composition of glycerides. The lack of a suitable analytical method for complete chemical profiling of glycerides is one of the bottlenecks in understanding and controlling the change in chemical composition during processing, formulation, and storage. Thus, the aim of the present study is to develop a calibration-free quantitative proton nuclear magnetic resonance (qHNMR) method for the simultaneous quantification of different components of glycerides. The qHNMR method was developed for the quantification of mono-, di-, and triglycerides; their positional isomers; free fatty acids; and glycerol content. The accuracy, precision, and robustness of the developed method were evaluated and were found suitable for the quantitative analysis of five batches of marketed excipient. The study demonstrates the potential of qHNMR method for the quantification of different components of glycerides in various marketed products. The method has the ability to identify the variability of glycerides among different batches and suppliers in terms of chemical composition and also to discern the changes during storage.

Myeloperoxidase-responsive materials for infection detection based on immobilized aminomethoxyphenol.

There is a strong need for simple and fast diagnostic tools for the detection of wound infection. Immune system-derived enzymes like myeloperoxidase are efficient biomarkers for wound infection that emerge in the early stage infection process. In this study, 5-amino-2-methoxyphenol was functionalized with alkoxysilane to allow visual detection of MPO on carrier materials, for example, in test strips. Indeed, MPO activity was visually detectable in short time in wound background. Oxidation of the substrate was followed spectrophotometrically and proved via HPLC. LC-ESI TOF and NMR analyses unveiled the reaction mechanism and a dimeric reaction product responsible for the visualization of MPO activity. The substrate specificity and sensitivity toward MPO detection was proved and tests with infected wound fluids were successfully performed. The study demonstrates the suitability of the novel MPO substrate for the detection of wound infection and the covalent immobilization on diagnostic carrier materials. Biotechnol. Bioeng. 2016;113: 2553-2560. © 2016 Wiley Periodicals, Inc.

Biocatalyzed approach for the surface functionalization of poly(L-lactic acid) films using hydrolytic enzymes.

Poly(lactic acid) as a biodegradable thermoplastic polyester has received increasing attention. This renewable polyester has found applications in a wide range of products such as food packaging, textiles and biomedical devices. Its major drawbacks are poor toughness, slow degradation rate and lack of reactive side-chain groups. An enzymatic process for the grafting of carboxylic acids onto the surface of poly(L-lactic acid) (PLLA) films was developed using Candida antarctica lipase B as a catalyst. Enzymatic hydrolysis of the PLLA film using Humicola insolens cutinase in order to increase the number of hydroxyl and carboxylic groups on the outer polymer chains for grafting was also assessed and showed a change of water contact angle from 74.6 to 33.1° while the roughness and waviness were an order of magnitude higher in comparison to the blank. Surface functionalization was demonstrated using two different techniques, (14) C-radiochemical analysis and X-ray photoelectron spectroscopy (XPS) using (14) C-butyric acid sodium salt and 4,4,4-trifluorobutyric acid as model molecules, respectively. XPS analysis showed that 4,4,4-trifluorobutyric acid was enzymatically coupled based on an increase of the fluor content from 0.19 to 0.40%. The presented (14) C-radiochemical analyses are consistent with the XPS data indicating the potential of enzymatic functionalization in different reaction conditions.

Fast Blue RR-Siloxane Derivatized Materials Indicate Wound Infection Due to a Deep Blue Color Development.

There is a strong need for simple and fast methods for wound infection determination. Myeloperoxidase, an immune system-derived enzyme was found to be a suitable biomarker for wound infection. Hence, alkoxysilane-derivatized Fast Blue RR was immobilized via simple hydrolytic polymerization. The resulting enzyme-responsive siloxane layers were incubated with myeloperoxidase, wound fluid or hemoglobin. The reaction was monitored via HPLC measurements and the color development quantified spectrophotometrically. Myeloperoxidase was indeed able to oxidize immobilized Fast Blue RR leading to a blue colored product. No conversion was detected in non-infected wound fluids. The visible color changes of these novel materials towards blue enable an easy distinction between infected and non-infected wound fluids.

Laccase catalyzed covalent coupling of fluorophenols increases lignocellulose surface hydrophobicity.

This work presents for the first time the mechanistic evidence of a laccase-catalyzed method of covalently grafting hydrophobicity enhancing fluorophenols onto Fagus sylvatica veneers. Coupling of fluorophenols onto complex lignin model compounds guaiacylglycerol beta-guaiacyl ether and syringylglycerol beta-guaiacyl ether was demonstrated by LC-MS and NMR. Laccase-mediated coupling increased binding of 4-[4-(trifluoromethyl)phenoxy]phenol (4,4-F3MPP) and 4-(trifluoromethoxy)phenol (4-F3MP) to veneers by 77.1% and 39.2%, respectively. XPS studies showed that laccase-catalyzed grafting of fluorophenols resulted in a fluorine content of 6.39% for 4,4-F3MPP, 3.01% for 4-F3MP and 0.26% for 4-fluoro-2-methylphenol (4,2-FMP). Grafting of the fluorophenols 4,2-FMP, 4-F3MP and 4,4-F3MPP led to a 9.6%, 28.6% and 65.5% increase in hydrophobicity, respectively, when compared to treatments with the respective fluorophenols in the absence of laccase, in good agreement with XPS data.