Absorption Modulation Research Articles

Absorption modulation of quasi-BIC in Si–VO2 composite metasurface at near-infrared wavelength

Bound states in the continuum (BIC) have attracted great attention in nanophotonics in the past few years. The metasurface with inverted symmetry breaking exhibits high Q resonance through quasi-BIC (Q-BIC), which realizes light modulation, sensing and nonlinear generation. In this work, a symmetry-broken Si–VO2 composite metasurface is studied and modulate near-infrared light absorption in Q-BIC mode. First, a L-shaped Si metasurface with broken C4v symmetry is designed, which realizes the transition from BIC to Q-BIC and shows strong circular dichroism. Later, phase-change material VO2 is integrated into the L-shaped Si metasurface. By changing the ambient temperature, the Si–VO2 composite metasurface shows distinct light absorption characteristics, including insensitivity to incident angle and a maximum absorption modulation of up to 210%. The results show that VO2 can effectively modified Q-BIC resonator to realize the modulation absorption of near-infrared light.

Green HPTLC - Densitometric approach for quantitation of Ruxolitinib in bulk and marketed formulation

Background: This paper describes the development of HPTLC method for the quantitative determination of Ruxolitinib in bulk and tablet dosage form using a systemic approach. A. simple, precise, accurate and specific high performance thin layer chromatographic method has been developed and validated for the Ruxolitinib in bulk and marketed formulation. Methods: The solvent system was 8.0:2.0:0.05 v/v/v of chloroform, methanol, and formic acid. This system was found to give compact spots for Ruxolitinib (Rf value of (0.71±0.02) Densitometric analysis of Ruxolitinib was tested in the absorbance mode at 236nm. Results: The developed method produced linear results with R2 = 0.998 for a range of 100 - 600ng/band. The accuracy of the method was determined at 80, 100, and 120% level. The % recoveries were found to be 100.01%, 99.13%, and 99.82% which are within the limit of 99% to 101%. The LOD and LOQ were found to be 8.19 ng/band and 25.06ng/band indicating the sensitivity of the method. Using the developed method, it was found that intraday and interday RSD values were less than 2%. The method was also found to be robust as indicated by the % RSD values less than 2%. Conclusion: The present method was validated according to the ICH guidelines and it is applied successfully for the determination of Ruxolitinib in tablets.

Semi-embedded slot waveguide electro-optic modulator.

Electro-optic modulators are essential devices on silicon photonic chips in modern optical communication networks. This paper presents a compact, low-loss electro-optic modulator. The modulation efficiency is greatly improved by embedding the lower half of the slot waveguide into the buried oxide layer and inserting graphene at the junction. The interaction of graphene with an optical field in a waveguide is studied using the finite element method. The functions of phase modulation and absorption modulation are realized by changing the gate voltage to change the chemical potential of graphene. The semi-embedded slot waveguide optical modulator has a length of 50µm. After simulation verification, it can be used as an electro-absorption modulator and can achieve a modulation depth of 26.38dB and an insertion loss of 0.60dB. When used as an electro-refractive modulator, it can be realized with a linear change of phase from zero to π; the total insertion loss is only 0.59dB. The modulator has a modulation bandwidth of 79.6GHz, and the energy consumption as electro-absorption and electro-refraction modulation are 0.51 and 1.92pj/bit, respectively. Compared with common electro-optic modulators, the electro-optic modulator designed in this paper has a higher modulation effect and also takes into account the advantages of low insertion loss and low energy consumption. This research is helpful for the design of higher-performance optical communication network devices.

Evidence for the Beneficial Effects of Brazilian Native Fruits and Their By-Products on Human Intestinal Microbiota and Repercussions on Non-Communicable Chronic Diseases-A Review.

Non-communicable chronic diseases (NCDs) are the most widespread cause of mortality worldwide. Intestinal microbiota balance can be altered by changes in the abundance and/or diversity of intestinal microbiota, indicating a role of intestinal microbiota in NCD development. This review discusses the findings of in vitro studies, pre-clinical studies and clinical trials on the effects of Brazilian native fruits, their by-products, as well as their bioactive compounds on human intestinal microbiota and NCD. The major bioactive compounds in Brazilian native fruits and their by-products, and the impacts of their administration on outcomes linked to intestinal microbiota modulation are discussed. Mechanisms of intestinal microbiota affecting NCD could be linked to the modulation of absorption and energy balance, immune and endocrine systems, and inflammatory response. Brazilian native fruits, such as acerola, açaí, baru, buriti, guava, jabuticaba, juçara, and passion fruit, have several bioactive compounds, soluble and insoluble fibers, and a variety of phenolic compounds, which are capable of changing these key mechanisms. Brazilian native fruits and their by-products can help to promote positive intestinal and systemic health benefits by driving alterations in the composition of the human intestinal microbiota, and increasing the production of distinct short-chain fatty acids and phenolic metabolites, thereby enhancing intestinal integrity and homeostasis. Evidence from available literature shows that the modulatory impacts of Brazilian native fruits and their by-products on the composition and metabolic activity of the intestinal microbiota could improve several clinical repercussions associated with NCD, reinforcing the influence of intestinal microbiota in extra-intestinal outcomes.

Multiplexing of bias-controlled modulation modes on a monolithic III-nitride optoelectronic chip.

III-nitride optoelectronic chips have tremendous potential for developing integrated computing and communication systems with low power consumption. The monolithic, top-down approaches are advantageous for simplifying the fabrication process and reducing the corresponding manufacturing cost. Herein, an ultraviolet optical interconnection system is investigated to discover the way of multiplexing between emission and absorption modulations on a monolithic optoelectronic chip. All on-chip components, the transmitter, monitor, waveguide, modulator, and receiver, share the same quantum well structure. As an example, two bias-controlled modulation modes are used to modulate video and audio signals in the experiment presented in this Letter. The results show that our on-chip optoelectronic system works efficiently in the near ultraviolet band, revealing the potential breadth of GaN optoelectronic integration.

Comparative HPTLC study for simultaneous determination of ivabradine and metoprolol using UV and fluorescence detectors

New, simple, accurate, sensitive and validated high performance thin layer chromatographic (HPTLC) method coupled with UV absorbance mode and fluorescence (FL) detectors which were used for simultaneous determination of ivabradine (IVA) and metoprolol (MET) in their bulk and pharmaceutical dosage form using TLC silica 60 F254 plates and non-fluorescent TLC silica gel 60 plates. The developing system was chloroform: methanol: formic acid: ammonia (8.5:1.5:0.2:0.1, v/v). Desnitometric analysis in UV absorbance mode was set at λ = 275 nm. While, fluorescence mode was performed with excitation at 260 nm for quantitative simultaneous determination of IVA and MET using optical filter K320. The retention factors values were 0.45 ± 0.05 and 0.89 ± 0.01 of IVA and MET, respectively. UV absorbance mode, linearity was 50.0–600.0 ng/band for IVA and 50.0–900.0 ng/band for MET. For fluorescence mode, the linearity ranges were 18.0–400.0 ng/band and 50.0–550.0 ng/band for IVA and MET; respectively. ICH guidelines were followed in respect to linearity and range, accuracy, precision and selectivity, limit of detection (LOD), limit of quantitation (LOQ) and robustness. The analytical eco-scale, green analytical procedure index (GAPI) and analytical greenness metric tools were used to assess the suggested method. The quantitative proposed method results showed there was no statistically significant difference at 95% confidence when compared to the reported method of high performance liquid chromatography (HPLC).

Spacecraft smart radiation device with near-zero solar absorption based on cascaded photonic crystals

Smart radiation device (SRD) for spacecraft based on thermochromic material vanadium dioxide (VO2) attracts increasing interest due to its ability of self-adaptive emission regulation. However, the spacecraft SRD is constrained by the high solar absorption at a high temperature and low emission tunability in practical applications. In this paper, a SRD is proposed for spacecraft thermal control, which consists of a solar reflector based on cascaded photonic crystals and a thermal emitter (VO2/BaF2/Ag). By cascading four photonic crystals with photonic band gaps for different central wavelengths, the total reflection range of the SRD in the solar radiation band is broadened. It is found that the SRD can realize near-zero solar absorption and high emission modulation depth, simultaneously. Though optimizing the thicknesses of the VO2 and BaF2, the emission modulation depth can reach 0.69, and the solar absorption can reduce to 0.08. In addition, the physical mechanism is studied by the distribution of the electric field. It is proved that the near-zero solar absorption originates from the broadband total reflection of the cascaded photonic crystals. The phase transition properties of VO2 and the difference in inherent losses at high and low temperatures result in high emission modulation depth. Besides, the low solar absorption and high emission modulation depth performances of the SRD can remain excellent when the angle of incidence is small than 46° regardless of the transverse electric wave or transverse magnetic wave. This work not only provides a new idea for designing SRDs, but also is expected to accelerate the development of intelligent thermal control of spacecraft.

POTENTIAL HERB-DRUG INTERACTION OF DECALEPIS HAMILTONII VIA P-GP MEDIATED PHARMACOKINETIC INTERACTION WITH FEXOFENADINE IN RATS: AN IN SITU AND IN VIVO STUDY

Objective: The objective of this study was to investigate the influence of Decalepis hamiltonii (D. hamiltonii), a traditional plant used in herbal medicine, on the intestinal absorption and pharmacokinetics of fexofenadine, a substrate of P-glycoprotein (P-gp), in rats. Methods: In situ intestinal perfusion tests were conducted to assess the intestinal permeability of fexofenadine. P-gp ATPase activity was also evaluated to understand the modulatory effects of D. hamiltonii on P-gp. An in vivo pharmacokinetic investigation was performed by administering oral fexofenadine to rats. Results: The in situ study results revealed that the effective permeation (Peff) of fexofenadine was significantly diminished (p<0.001***) in aqueous extract of D. hamiltonii (AREDH, 200 mg/kg p. o.) pretreated group compared to normal control indicating modulation in absorption. Further, there was significant augmentation (p<0.01**) of P-gp ATPase activity in AREDH pretreated group (200 mg/kg p. o.) compared normal control indicating P-gp inductive potential of D. hamiltonii. Pharmacokinetic study results revealed that the peak plasma concentration (Cmax) and the area under the concentration-time curve (AUC) of fexofenadine was significantly downregulated (p<0.001***) in AREDH pretreated group (200 mg/kg p. o.) compared to the normal control group indicating the compromised absorption and bioavailability. However, no significant changes were observed in fexofenadine half-life (T1/2 k10), time to reach peak plasma concentration (Tmax), or elimination rate constant (k10). Conclusion: In conclusion, D. hamiltonii significantly reduced the oral bioavailability of fexofenadine by promoting P-gp-mediated drug efflux during intestinal absorption. This suggests that the modulatory characteristics of D. hamiltonii may lead to herb-drug interactions when taken in combination with xenobiotics, emphasizing the importance of considering such interactions in clinical practice and further research.

A Switchable A-T-A Rasorber With Polarization Selectivity and High Roll-Off Characteristics

Switchable rasorber has attracted a great deal of interest in recent years due to its in-band shielding ability. In this work, a methodology for designing a switchable rasorber with high roll-off and polarization selection characteristics is proposed. The device can be switched between rasorber, polarization selection and absorber modes, and composes of two resistive layers (a passive and an active resistive layer) and a frequency selective surface (FSS). Transmission zeros (TZs) are introduced in the FSS design to improve the roll-off characteristic of its transmission band. The PIN diodes on the active resistive layer and FSS can be independently controlled in the orthogonal polarizations to realize the polarization selectivity. The simulation results indicate that the device exhibits a 27.5% fractional transmission bandwidth (3.42 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sim$</tex-math></inline-formula> 4.51 GHz) under rasorber mode. In addition, the fractional absorption bandwidth is as large as 142.9% (1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sim$</tex-math></inline-formula> 6 GHz) under absorber mode. A prototype is fabricated and measured to validate the proposed design methodology. This work is promising for designing metamaterials (MMs) with excellent flexibility and high performance.

Environmentally Friendly Analytical Methods for Quantitative Measurement of Sofosbuvir in Pharmaceutical Formulations: Comparison of HPTLC and UV Spectrophotometric Approaches

For the quantitative measurement of sofosbuvir (SFR) in pharmaceutical formulation, high-performance thin-layer chromatographic (HPTLC) and environmentally friendly UV spectrophotometric approaches have been developed. HPTLC stationary phases were silica gel 60 F₂₅₄-coated aluminium plates. Toluene, chloroform, and ethanol were mixed 4:4:1 v/v/v. This mobile phase produced tiny spots of SFR with Rf 0.30±0.01. SFR was densitometrically analysed at 267nm in absorbance mode. Peak area showed great linearity (r2 =0.998) in the dilution range of 100–800ng/spot. A solvent combination of methanol and water was utilised for the UV spectrophotometric technique. First, a stock solution of SFR was made in methanol, and then it was diluted further in water. Absorption maxima were observed at 261nm for the SFR standard solution. Beer-law Lambert's was followed by the SFR at an r2 value of 0.999 at 10-50ng/mL. Both methods met ICH standards for precision, LOD, LOQ, accuracy and specificity. Statistical study validated the methods as reliable and accurate for the estimation of the SFR. The established procedures can be applied to the regular analysis of SFR drugs and pharmaceuticals.

Honeycomb-like bamboo powders-derived porous carbon with low filler loading, high-performance microwave absorption

Nowadays, the problem posed by electromagnetic wave pollution to electronic devices and biological systems is of serious concern. To create a microwave absorber, component and structural modulation is crucial. Biomass-derived porous carbon is a potential material for microwave absorption applications due to the characteristics of lightweight, high specific surface area, and significant dielectric loss. In this study, by examining the impact of various KOH concentrations on the pore structure, bamboo powders with an 80-mesh size were used as a raw material to create honeycomb-like bamboo powders-derived porous carbon (BPDPC) materials. The activation mechanism of the BPDPC material is also explained. Based on the electromagnetic parameters, the sample BPDPC-4 impregnated with 4 mol/L KOH has a maximum effective absorption bandwidth (RL ≤ −10 dB) of 4.76 GHz at a matching thickness of 2.0 mm, covering 11.54–16.30 GHz and a minimum reflection loss (RLmin) of −40.99 dB at a matching thickness of 2.2 mm at 5 wt% ultra-low filler loading. Due to polarization loss, conduction loss, and the mutually beneficial effects of multiple electromagnetic wave reflection and scattering, the superior wave absorption performance is explained. This work also serves as a reference for investigating porous carbon generated from biomass.

Effect of ion intercalation and electrochemisorption on nonlinear optical absorption of MoO3: A comparative study of six different ions

Electrochemical modulation of nonlinear optical (NLO) absorption has recently garnered significant attention. In this work, we demonstrate the effective modulation of the third-order NLO absorption of layered molybdenum trioxide (MoO3) by cation intercalation. Upon application of different negative voltages to samples in different electrolytes, we observe varying degrees of enhancement in MoO3’s nonlinear absorption corresponding to different cations and different electrochemical processes. Cation intercalation of H[Formula: see text], Li[Formula: see text], Na[Formula: see text], K[Formula: see text], and Mg[Formula: see text] is found to be more effective in enhancing the nonlinear absorption of MoO3 than electrochemisorption of Al[Formula: see text] cations. Notably, Li[Formula: see text] intercalation leads to the most significant performance improvement, with an enhancement of 11.6 times and a nonlinear absorption coefficient of [Formula: see text][Formula: see text]cm[Formula: see text]GW[Formula: see text]. This improvement is ascribed to the increasing number of defect states in MoO3 during ion intercalation, which strengthens its saturation absorption behavior. Our work provides valuable insights into the electrically controlled NLO performance of MoO3 and can be applied to other similar materials.

Excitons dynamic modulation by tailoring size of high-entropy Mo0.64W0.36S2 alloy

Two-dimensional transition metal disulfides with tailored optical response are vital to demonstrate versatile optoelectronic devices and nanophotonic elements. In this work, using transient absorption spectroscopy in conjunction with density functional theory calculations, we demonstrate ultrafast excitons absorption modulation via tailoring the size of a transition-metal dichalcogenide alloy Mo0.64W0.36S2 nanosheet. As the size of the nanosheet increases from 9 ± 5 to 190 ± 121 nm, peak positions of the A and B excitons vary from 666 to 675 nm and 626 to 638 nm, respectively. Furthermore, the decay lifetimes of A excitons slow down from 1.16 to 1.84 ps when the size changes from 9 ± 5 to 190 ± 121 nm. It is shown that the exciton diffusion and decay properties can be modulated by the components and structure modulation, which is beneficial for the optimal design and optimization of optoelectronic devices.

Influence of saturable absorber parameters on the hybrid mode-locking performance of fiber lasers

In this paper, we numerically study the influence of saturable absorber parameters, namely, modulation depth, recovery time, and saturation energy, on the performance of an ultrafast fiber laser that is mode-locked by a hybrid scheme of a saturation absorber (SA) and a nonlinear polarization rotation (NPR). Maps of mode-locked states related to intracavity wave-plates are created to evaluate the operation of hybrid mode-locking under different modulation depths of the SA. Along with the improvement of modulation depth of the SA, the mode-locked pulse results from a combination effect of the SA and NPR. The numerical analysis reveals that the SA parameters can significantly impact the pulse profile, peak power, and operation state. Moreover, they can also impact the selection of NPR mode-locked points, resulting in variation in stable single pulse output. A higher modulation depth can suppress the unstable multiple pulses’ operation and convert them into harmonic mode-locked pulses. The obtained results indicate that the selection of appropriate SA parameters can effectively improve the output characteristics of hybrid mode-locked fiber lasers.

Single- and two-photon absorption induced all-optical control of gallium selenide integrated silicon nitride photonic devices in the 700–800 nm wavelength range

In this work, we report single- and two-photon absorption (TPA) induced transmission and resonance modulation in a multilayer gallium selenide (GaSe) integrated silicon nitride (Si3N4) waveguide and ring resonator operating in the 700–800 nm wavelength range. Intensity dependent saturable absorption at low optical powers followed by TPA at higher power levels in GaSe integrated Si3N4 waveguides is observed at 785 nm pulsed laser excitation. A TPA coefficient of 0.117 cm/GW for the GaSe–Si3N4 composite waveguide and a three-photon absorption coefficient of 7.876 × 10−6 cm3/GW2 for the bare Si3N4 waveguide are extracted from intensity dependent transmission measurements. The single-photon absorption process induced by a blue laser incident on the multilayer GaSe transferred on top of the Si3N4 ring resonator is used for all-optical resonance tuning through the free-carrier refraction effect. A strong blue shift of the resonance by ∼12.3 pm/mW combined with resonance broadening is observed due to the free-carrier induced refractive index and absorption modulation. The TPA in the GaSe integrated Si3N4 ring resonator is also shown to result in a blue shift of the resonances excited using a 785 nm pulsed laser. This work demonstrates the all-optical control of 2D material integrated Si3N4 guided-wave structures operating in the shorter near-infrared wavelength range with potential applications in integrated quantum photonics, miniaturized sensing devices, and biomedical imaging.

Velocity and Direction Adjustment of Actuated Droplets Using the Standing Wave Ratio of Surface Acoustic Waves (SAW)

Droplet actuation using surface acoustic wave (SAW) technology has recently been widely employed in “lab-on-a-chip” applications. In this article, SAWs generated by interdigital transducers (IDTs) were used to actuate microdroplets, where their velocity and direction could be adjusted by changing only the excitation phase shift, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">θ</i> , of the voltage applied to the two IDTs. Specifically, the equation of the vibration of the mixed traveling surface acoustic waves (TSAWs) and standing surface acoustic waves (SSAWs) formed on the substrate surface operating in the exciter–exciter mode has been reported by the authors. An analytical expression for the acoustic standing wave ratio has been derived and given as a function of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">θ</i> and the spatial phase difference. It can be seen from the expression that the directions of the TSAWs will be opposite to each other, in the range of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">θ</i> given by (0, π) and (π, 2π), and the component of the TSAWs can be adjusted by changing <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">θ</i> in each direction. Following the theoretical analysis discussed here, two IDTs have been excited to generate a mixture of TSAWs and SSAWs. A series of experiments was carried out to control the velocity and direction of the actuated droplets, by changing only <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">θ</i> . In addition, an experiment performed to compare the techniques shows that the upper limit of the velocity of the actuated droplets can be significantly increased using the exciter–exciter mode, showing that it has the potential to be an alternative method to the traditional exciter–absorber mode.

Bitter Is Better: Wild Greens Used in the Blue Zone of Ikaria, Greece.

The current study reports an ethnobotanical field investigation of traditionally gathered and consumed wild greens (Chorta) in one of the five so-called Blue Zones in the world: Ikaria Isle, Greece. Through 31 semi-structured interviews, a total of 56 wild green plants were documented along with their culinary uses, linguistic labels, and locally perceived tastes. Most of the gathered greens were described as bitter and associated with members of Asteraceae and Brassicaceae botanical families (31%), while among the top-quoted wild greens, species belonging to these two plant families accounted for 50% of the wild vegetables, which were consumed mostly cooked. Cross-cultural comparison with foraging in other areas of the central-eastern Mediterranean and the Near East demonstrated a remarkable overlapping of Ikarian greens with Cretan and Sicilian, as well as in the prevalence of bitter-tasting botanical genera. Important differences with other wild greens-related food heritage were found, most notably with the Armenian and Kurdish ones, which do not commonly feature many bitter greens. The proven role of extra-oral bitter taste receptors in the modulation of gastric emptying, glucose absorption and crosstalk with microbiota opens new ways of looking at these differences, in particular with regard to possible health implications. The present study is also an important attempt to preserve and document the bio-cultural gastronomic heritage of Chorta as a quintessential part of the Mediterranean diet. The study recommends that nutritionists, food scientists, and historians, as well as policymakers and practitioners, pay the required attention to traditional rural dietary systems as models of sustainable health.

Terahertz Metamaterial Waveguide with I-Shaped Resonators for Phase and Absorption Modulation

In terahertz communication systems, amplifiers and other components can induce non-linear distortion in terms of amplitude and phase, resulting in system performance degradation. This paper presents a terahertz metamaterial waveguide to mitigate amplitude and phase distortions in some terahertz systems. A simple method based on free-space analysis is proposed for designing metamaterial waveguides in an enclosed space. The quasi-periodic metamaterial structures, which feature I-shaped resonant patterns, are integrated onto the inner walls of rectangular waveguides. The phase and amplitude of electromagnetic waves within the waveguide can be modulated by varying the dimensions and number of these resonators. Utilizing the effective medium theory and the equivalent circuits, the metamaterial waveguide’s phase and absorption modulation mechanisms are analyzed. Based on the proposed structure, a metamaterial waveguide with I-shaped resonators is designed and fabricated, and its abilities to modulate the phase and absorption of terahertz waves around 0.2 THz are demonstrated.

Development and Validation of Stability Indicating HPTLC Method for Determination of Donepezil Hydrochloride and its related substances in Bulk Drug and Pharmaceutical Dosage Form

Context: A new, simple, selective, and affordable HPTLC technique for the analysis of donepezil hydrochloride (DH) and its associated compounds was developed and verified in accordance with ICH guidelines. Method: Donepezil Hydrochloride and Related Substances were densitometrically analyzed in the absorbance mode at 320 nm. The stationary phase was 60 F—254 silica gel pre-coated on aluminium TLC plates. Butanol, water, and glacial acetic acid were the components of the mobile phase (4:5:1, v/v/v). Result: It was discovered that this method provides compact places for DH (RF 0.53± 0.03) .Testing for stability indicators (force degradation) was done in acidic and alkaline conditions, as well as with dry heat and photodegradation. The degradation products were clearly distinguished from the pure drug by their markedly differing RF values. For Validation of method linearity, precision, robustness, limit of detection (LOD), limit of quantification (LOQ), ruggedness, and accuracy parameters are verified. LOD and LOQ were found to be 80.85 and 245 ng per spot, respectively, and linearity was found in the range 400-1200 ng per spot with a considerably high value of the correlation coefficient r2 = 0.999 is found. A 0.43% coefficient of variance is discovered. Conclusion: The approach was repeatable and specific for estimating donepezil hydrochloride and related compounds, according to statistical analysis Donepezil Hydrochloride can be quantified even when there are degraded products and related compounds present. It is commercially available for the estimation of related compounds and Donepezil hydrochloride.

Development and validation of high‐performance thin layer chromatographic method for simultaneous quantitation of novel combination perindopril erbumine and moxonidine hydrochloride

AbstractThe primary purpose of the present study was to develop and validate a high‐performance thin‐layer chromatography method for quantitatively determining an anti‐hypertensive agent, perindopril erbumine, and moxonidine hydrochloride in bulk and synthetic mixture. The densitometric procedure was performed on aluminum thin‐layer chromatography plates pre‐coated with silica gel 60F254, employing a combination of dichloromethane: toluene: methanol: ammonia (7:1:2:0.1 v/v/v/v) as the mobile phase. The thin‐layer chromatography scanner was operated in absorbance mode at a wavelength of 223 nm to evaluate densitograms. The linearity of the method was established in the range of 1000–5000 ng/band for perindopril erbumine and 40–200 ng/band for moxonidine hydrochloride; the correlation coefficient (r2) was 0.9993 and 0.9983, respectively. The values of a limit of detection (186.06 and 3.51 ng/band, respectively, for perindopril erbumine and moxonidine hydrochloride) and limit of quantification (620.23 and 11.73 ng/band, respectively, for perindopril erbumine and moxonidine hydrochloride) have demonstrated the sensitivity of the developed method. The reported process was precise in both intra‐day and inter‐day analysis; the percentage relative standard deviation of peak area was less than 2% and has an accuracy within 100 ± 2%. The developed method has the potential to quantify perindopril erbumine and moxonidine hydrochloride from its synthetic mixture without any interference from other components or in quality control laboratories.