Scanning electron microscopy and X-ray energy dispersive spectroscopy – useful tools in the analysis of pharmaceutical products

Effects of nano zinc oxide and nano chitosan on the taste masking paracetamol granules

OBJECTIVE

The purpose of this study is to investigate the taste masking of Paracetamol granules in the range of 250-850 µm, coated by two nanocomposites prepared from Eudragit® E100, nanozinc oxide, and nanochitosan, respectively, from 1 to 5% by the weight of the granules.

METHODS

In this study, Paracetamol granules were coated in several formulas with two different types of nanocomposites (polymeric and mineral) on two sizes of granules to reduce bitter taste and with the FBC method and pH-sensitive polymers (Eudragit® E100).

RESULTS

The effect of nanoparticles (Nano zinc oxide and Nanochitosan) on taste-masking Paracetamol was studied with dissolution-coated granules in vitro by simulating in the oral (pH 6.8) range. Based on the results of the studies, the rate of drug release was confirmed by the taste test, and the formulated granule with 5% nano-chitosan (F14) had the best bitter taste mask function of all samples. These results were also confirmed by scanning electron microscopy (SEM) analysis, which showed a smoother and more stable surface than the samples obtained from other formulations.

CONCLUSION

In the comparison of the release of two types of nanocomposites in the dissolution test, it was shown that the type B granules of Paracetamol's 5% nano-chitosan-coated granule (F14) were released 99% less than Paracetamol's 5% nano-ZnO-coated granule (F11). and Paracetamol's 1% nano-chitosan-coated granule (F12) was released 91% less than Paracetamol's 1% nano-ZnO-coated granule (F9). The results showed that nano-chitosan-coated granules have better coverage of bitter taste instead of nano-ZnO.

Characterization of Pharmaceutical Tablets by X-ray Tomography

Solid dosage forms such as tablets are extensively used in drug administration for their simplicity and large-scale manufacturing capabilities. High-resolution X-ray tomography is one of the most valuable non-destructive techniques to investigate the internal structure of the tablets for drug product development as well as for a cost effective production process. In this work, we review the recent developments in high-resolution X-ray microtomography and its application towards different tablet characterizations. The increased availability of powerful laboratory instrumentation, as well as the advent of high brilliance and coherent 3rd generation synchrotron light sources, combined with advanced data processing techniques, are driving the application of X-ray microtomography forward as an indispensable tool in the pharmaceutical industry.

A review on the applicability of adsorption techniques for remediation of recalcitrant pesticides

Pesticide has revolutionised the agricultural industry by reducing yield losses and by enhancing productivity. But indiscriminate usage of such chemicals can negatively impact human health and ecosystem balance as certain pesticides can be recalcitrant in nature. Out of some of the suggested sustainable techniques to remove the pesticide load from the environment, adsorption is found to be highly efficient and can also be implemented on a large scale. It has been observed that natural adsorption that takes place after the application of the pesticide is not enough to reduce the pesticide load, hence, adsorbents like activated carbon, plant-based adsorbents, agricultural by-products, silica materials, polymeric adsorbents, metal organic framework etc are being experimented upon. It is becoming increasingly important to choose adsorbents which will not leave any secondary pollutant after treatment and the cost of production of such adsorbent should be feasible. In this review paper, it has been established that certain adsorbent like biochar, hydrochar, resin, metal organic framework etc can efficiently remove pesticides namely chlorpyrifos, diazinon, 2,4-Dichlorophenoxyacetic Acid, atrazine, fipronil, imidacloprid etc. The mechanism of adsorption, thermodynamics and kinetic part have been discussed in detail with respect to the pesticide and adsorbent under discussion. The reason behind choosing an adsorbent for the removal of a particular pesticide have also been explained. It is further highly recommended to carry out a cost analysis before implementing an absorbent because inspite of its efficacy, it might not be cost effective to use it for a particular type of pesticide or contaminant.

Magnesium stearate surface coverage on tablets and drug crystals: Insights from SEM-EDS elemental mapping

Scanning electron microscopy-based energy dispersive X-ray spectroscopy (SEM-EDS) is proposed as a versatile tool for quantifying surface area coverage (SAC) by magnesium stearate (MgSt) on pharmaceutical tablets and particles. Our approach involved fast elemental mapping and subsequent SAC quantitation by image analysis. The study was conducted using a multi-component system, but the particle-level mapping was limited to active pharmaceutical ingredient (API) crystals. For both tablets and API particles, the calculated SAC against MgSt loading afforded a positive linear correlation over the range of MgSt levels examined in this work. On the tablet surface, MgSt was found to be preferentially concentrated at or in the close vicinity of grain boundaries, supporting the idea of compression-driven migration and relocation of MgSt within the tablet. On the particle surface, only discrete aggregates of MgSt were observed, as opposed to the widely accepted phenomenon of the formation of a thin lubricant film around host particles. The selection of proper SEM-EDS operating conditions and the challenges confronted in particle surface mapping are discussed in detail.

The Use of Novel, Rapid Analytical Tools in the Assessment of the Stability of Tablets—A Pilot Analysis of Expired and Unexpired Tablets Containing Nifuroxazide

In the analysis of finished pharmaceutical products, numerous innovative analytical techniques are often used, i.e., Raman spectroscopy, scanning electron microscopy, computer microtomography, directional hemispherical reflectance, and hyperspectral analyses. These techniques allow for the identification of changes in solid phases. Many advantages over other techniques can be attributed to these techniques, e.g., they are rapid, non-destructive, and comprehensive. They allow for the identification of changes occurring in solid phases. However, the above-mentioned methods are still not standard procedures in pharmaceutical research. The present study aimed to assess the possible usefulness of total directional hemispherical reflectance (THR), hyperspectral imaging, and computer microtomography to evaluate the stability of tablets containing nifuroxazide during storage. In the study, expired and unexpired coating tablets containing nifuroxazide (n = 10 each) were analyzed. In addition, four unexpired tablets were stored at 40°C over 3 months (stressed tablets). Reflectance was determined with seven wavelength bands from 335 nm to 2500 nm using an SOC-410 Directional Hemispherical Reflectometer (Surface Optics Corporation, San Diego, CA, USA). A Specim IQ hyperspectral camera (Spectral Imaging Ltd., Oulu, Finland) was used with a wavelength range of 400–1030 nm. Tablets were also scanned using X-ray microtomography (Phoenix vǀtomeǀx, GE Sensing & Inspection Technologies GmbH, Wunstorf, Germany). The results indicated that total reflectance was lower in expired tablets than in unexpired tablets in all spectral bands, except for 700–1100 nm and 1700–2500 nm. In turn, the stressed tablets showed higher THR values than expired tablets in all spectral bands, except for 1000–1700 nm. In addition, hyperspectral analysis of the homogeneity of the tablets, as well as X-ray microtomographic analysis of tablet density and coating thickness, indicated that these parameters differed significantly between the analyzed tablets.

Synthesis, Characterization, and Intrinsic Dissolution Studies of Drug-Drug Eutectic Solid Forms of Metformin Hydrochloride and Thiazide Diuretics

The mechanochemical synthesis of drug–drug solid forms containing metformin hydrochloride (MET·HCl) and thiazide diuretics hydrochlorothiazide (HTZ) or chlorothiazide (CTZ) is reported. Characterization of these new systems indicates formation of binary eutectic conglomerates, i.e., drug–drug eutectic solids (DDESs). Further analysis by construction of binary diagrams (DSC screening) exhibited the characteristic V-shaped form indicating formation of DDESs in both cases. These new DDESs were further characterized by different techniques, including thermal analysis (DSC), solid state NMR spectroscopy (SSNMR), powder X-ray diffraction (PXRD) and scanning electron microscopy–energy dispersive X-ray spectroscopy analysis (SEM–EDS). In addition, intrinsic dissolution rate experiments and solubility assays were performed. In the case of MET·HCl-HTZ (χ_MET·HCl = 0.66), we observed a slight enhancement in the dissolution properties compared with pure HTZ (1.21-fold). The same analysis for the solid forms of MET·HCl-CTZ (χ_MET·HCl = 0.33 and 0.5) showed an enhancement in the dissolved amount of CTZ accompanied by a slight improvement in solubility. From these dissolution profiles and saturation solubility studies and by comparing the thermodynamic parameters (ΔH_fus and ΔS_fus) of the pure drugs with these new solid forms, it can be observed that there was a limited modification in these properties, not modifying the free energy of the solution (ΔG) and thus not allowing an improvement in the dissolution and solubility properties of these solid forms.

Homogeneity of amorphous solid dispersions - an example with KinetiSol®

KinetiSol^® is a high-shear, fusion-based technology capable of producing stable amorphous solid dispersions (ASDs) without the assistance of solvent. KinetiSol^® has proven successful with multiple challenging BCS class II and IV drugs, where drug properties like thermal instability or lack of appreciable solubility in volatile solvents make hot melt extrusion or spray drying unfeasible. However, there is a necessity to characterize the ASDs like those made by the KinetiSol^® process, in order to better understand whether KinetiSol^® is capable of homogeneously dispersing drug throughout a carrier in a short (<40 s) processing time. Our study utilized the high melting point, BCS class II drug, meloxicam, in order to evaluate the degree of homogeneity of 1, 5, and 10% w/w KinetiSol^®-processed samples. Powder blend homogeneity and content uniformity were evaluated, and all samples demonstrated a meloxicam concentration % relative standard deviation of ≤2.0%. SEM/EDS was utilized to map elemental distribution of the processed samples, which confirmed KinetiSol^®-processed materials were homogeneous at a 25 µm² area. Utilizing Raman spectroscopy, we were able to verify the amorphous content of the processed samples. Finally, we utilized ssNMR ¹H spin-lattice relaxation measurement to evaluate the molecular miscibility of meloxicam with the polymer at 1% w/w drug load, for the first time, and determined the processed sample was highly miscible at ∼200 nm scale. In conclusion, we determined the KinetiSol^® process is capable of producing ASDs that are homogeneously and molecularly well-dispersed drug-in-polymer at drug concentrations as low as 1% w/w.