Analysis of impurities by high-performance thin-layer chromatography with Fourier transform infrared spectroscopy and UV absorbance detection in situ measurement: chlordiazepoxide in bulk powder and in tablets

Anti-EGFR-mAb and 5-Fluorouracil Conjugated Polymeric Nanoparticles for Colorectal Cancer

BACKGROUND

Due to the higher intake of junk food and unhealthy lifestyle, the percentage of U.S. adults aged 50 to 75 years who were up-to-date with colorectal cancer screening increased 1.4 percentage points, from 67.4% in 2016 to 68.8% in 2018. This represents an additional 3.5 million adults screened for colorectal cancer. This is a severe concern of this research, and an attempt was made to prepare a target-specific formulation that could circumvent chemotherapy-related compilation and improvise higher cellular uptake. The fundamental agenda of this research was to prepare and develop Anti-EGFR mAb and 5-Fluorouracil (5-FU) fabricated polymeric nanoparticles for colorectal cancer.

OBJECTIVE

The main objective of this research was to prepare and evaluate more target specific formulation for the treatment of colorectal cancer. PLGA and PEG-based polymeric nanoparticles are capable of preventing opsonization via the reticuloendothelial system. Hence, prepared polymeric nanoparticles are capable of higher cellular uptake.

METHODS

The Poly(d,1-lactide-co-glycolide) (PLGA) and Polyethylene Glycol (PEG) were combined utilizing the ring-opening polymerization method. The presence of PEG prevents opsonization and distinguished blood concentration along with enhanced targeting. The presence of PLGA benefits in the sustained release of polymeric formulations. The optimized formulation (5-FU-PLGA- PEG-NP) was lyophilized using 4% trehalose (cryoprotectants) and conjugated with Anti- EGFR mAb on its surface to produce Anti-EGFR-5-FU-PLGA-PEG-NP; the final formulation, which increases target specificity and drug delivery system of nanoparticles.

RESULTS

The spherical shaped optimized formulation, 5-FU-PLGA-PEG-NP-3 was found to have higher percentage drug entrapment efficacy (71.23%), higher percentage drug content (1.98 ± 0.34%) with minimum particles size (252.3nm) and anionic zeta potential (-31.23mV). The IC₅₀ value of Anti-EGFR-5-FU-PLGA-PEG-NP was 1.01μg/mL after 48 hours incubation period in the HCT 116 cell line, indicating higher anticancer effects of the final formulation.

CONCLUSION

From the outcomes of various experiments, it was concluded that Anti-EGFR-5-FUPLGA- PEG-NP has biphasic drug release kinetics, higher cellular uptake and higher cytotoxicity. Therefore, anti-EGFR-5-FU-PLGA-PEG-NP holds excellent potential for drug delivery to EGFR positive colorectal cancer cells.

Analytical methods for determination of benzodiazepines. A short review

Benzodiazepines (BDZs) are generally commonly used as anxiolytic and/or hypnotic drugs as a ligand of the GABAA-benzodiazepine receptor. Moreover, some of benzodiazepines are widely used as an anti-depressive and sedative drugs, and also as anti-epileptic drugs and in some cases can be useful as an adjunct treatment in refractory epilepsies or anti-alcoholic therapy. High-performance liquid chromatography (HPLC) methods, thin-layer chromatography (TLC) methods, gas chromatography (GC) methods, capillary electrophoresis (CE) methods and some of spectrophotometric and spectrofluorometric methods were developed and have been extensively applied to the analysis of number of benzodiazepine derivative drugs (BDZs) providing reliable and accurate results. The available chemical methods for the determination of BDZs in biological materials and pharmaceutical formulations are reviewed in this work.

Near infrared spectroscopy, cluster and multivariate analysis hyphenated to thin layer chromatography for the analysis of amino acids

A method based on near-infrared spectroscopy (NIRS) was developed for the rapid and non-destructive determination and quantification of solid and dissolved amino acids. The statistical results obtained after optimisation of measurement conditions were evaluated on the basis of statistical parameters, Q-value (quality of calibrations), R(2), standard error of estimation (SEE), standard error of prediction (SEP), BIAS applying cluster and different multivariate analytical procedures. Experimental optimisation comprised the selection of the highest suitable optical thin-layer (0.5, 1.0, 1.5, 2.0, 2.5, 3.0 mm), sample temperature (10-30 degrees C), measurement option (light fibre, 0.5 mm optical thin-layer; boiling point tube; different types of cuvettes) and sample concentration in the range between 100 and 500 ppm. Applying the optimised conditions and a 115-QS Suprasil cuvette (V = 400 microl), the established qualitative model enabled to distinguish between different dissolved amino acids with a Q-value of 0.9555. Solid amino acids were investigated in the transflectance mode, allowing to differentiate them with a Q-value of 0.9155. For the qualitative and quantitative analysis of amino acids in complex matrices NIRS was established as a detection system directly onto the plate after prior separation on cellulose based thin-layer chromatography (TLC) sheets employing n-butanol, acetic acid and distilled water at a ratio of 8:4:2 (v/v/v) as an optimised mobile phase. Due to the prior separation step, the established calibration curve was found to be more stable than the one calculated from the dissolved amino acids. The found lower limit of detection was 0.01 mg/ml. Finally, this optimised TLC-NIRS method was successfully applied for the qualitative and quantitative analysis of L-lysine in apple juice. NIRS is shown not only to offer a fast, non-destructive detection tool but also to provide an easy-to-use alternative to more complicated detection methods such as mass spectrometry (MS) for qualitative and quantitative TLC analysis of amino acids in crude samples.

New sorbent for HPTLC--FTIR in situ determination of impurities in flurazepam

An efficient HPTLC--UV/FTIR coupling procedure is presented for the separation and rapid identification of flurazepam hydrochloride and its related substances in bulk powder and capsules. An optimized mobile phase was developed for the separation on specialized plates for HPTLC--FTIR in situ measurement containing a proportion of 50% magnesium tungstate. The proposed procedure shows several advantages to the related compound test of the pharmacopoeia, e.g. baseline separation of the known impurities and detection of the substances as peaks in the UV, Gram-Schmidt or window chromatograms. Furthermore, unambiguous identification is obtained by postrun extraction of the DRIFT spectra and comparison with reference spectra in the library. Quantification of the related compounds was carried out densitometrically. This method shows that the current resurgence of interest in modern instrumental TLC is rightful based on the flexibility and efficiency of this analytical method.

Planar chromatography at the turn of the century

An overview of the state-of-the-art of modern thin-layer chromatography (planar chromatography) is presented with emphasis on the complementary features of thin-layer and column liquid chromatographic separations. The reasons for selecting thin-layer chromatography for a particular analysis are identified by its attributes: a disposable stationary phase; simultaneous parallel separations; static detection free of time constraints; storage device for chromatographic information; all sample components are observed in the chromatogram. Future prospects for improved separation performance in TLC using zone refocusing, forced flow and electroosmotic flow methods are discussed as well as increasing zone capacity by using two-dimensional development and coupling to column chromatographic methods. Advances in coupling thin-layer chromatography with spectroscopic methods for structural elucidation are also considered. Finally, some predictions are made for how thin-layer chromatography will be practiced in the future.