Tablet Content Research Articles

The –NO2 vibrational spectra of metronidazole for analytical method development using Fourier Transform Infrared compared to the UV-VIS spectrophotometry

This study aimed to develop a green method in analyzing metronidazole compound using Fourier Transform Infrared (FTIR) and to ensure that this method is suitable to be done for tablet content determination, and then was compared to the established spectrophotometry ultraviolet-Visible (UV-Vis). Both methods were compared in terms of analysis parameters, effectiveness, and cost required. The experiment was started by screening to find the best spectra was performed, supported by derivation mode to increase the specificity. After that, the method was developed by tests its validation parameters, and then it was applied for tablet content determination. All observation results were compared to an established spectrophotometry UV-VISVis, which also has been verified concurrently. As a result, metronidazole showed a specific spectrum of -NO2 at 1388.5-1338.36 cm-1, which is not interfered by matrices. The calibration curve yielded revealed the correlation regression (r) = 0.99985. All validation parameter requirements can be fulfilled by this method, which had the limit of detection and limit of quantification of 0.36 ppm and 1.19 ppm, respectively. As the comparison to UVVis spectrophotometry, in terms of effectiveness, the FTIR method is relatively more practical and more straightforward, it was evidenced by the shorter processing time than the counterpart. In terms of cost, the FTIR method also required a relatively less cost. Besides, it is more environmentally friendly due to the absence of solvent usage.

AN AN STUDY OF ANALGESIC ACTIVITY OF HAFFNER’S TAIL CLIP METHOD ON ALBINO WISTAR RATS OF SOME POLYHERBAL FORMULATION

Objective: Herbal drugs are more beneficial better than aspirin because this is an herb so no side effect this drug and it is easy to collect or use to as herbal drugs. Words are inadequate to describe the motivation for my work given to my beloved guide. I would like to add special thanks to my guide Gauravbilwal, for their guidance, support, and encouragement.
 Purpose (Hypothesis): The main purpose of this article pays to attention for herbal drugs because they are naturally old effective drugs. As well as, Ayurveda treatment is very older effective technique.
 Design/Method: Haffner gave to this technique of determining analgesic are around in 1929.
 Procedure: This technique according to tail if clipped with any object and tightly or will be compression generation of pain in the tail as well as mice starting to bite that portion of its tail, and could evaluate and recorded the response how much it bites tail quickly or in potential.
 
 Using this simple yet important marvel, we may apply the drug to be evaluated and record the response whether it bites tail quickly or in potential.
 If given drugs have analgesic likely, then rat will not bite its tail so frequently.
 Mice that do not show any response within 15 s will reject from the experiment.
 
 Results: The found in analgesic activity of additional compounds test to significant on tail flick test than acetic acid-induced test and thus it appears that the test compounds inhibit predominantly the peripheral pain mechanism. The results of the study indicate that the extracts of polyherbal plants of analgesic activity by reducing the abdominal constriction significantly and may supposed to have a possible role in inhibition of cyclooxygenase in the prostaglandin pathways (p****<0.0001, ***0.0001, *0.05).
 Conclusion: The present study showed the significant analgesic effect of both aqueous and alcoholic at 400 mg/kg doses in albino rats, we reported for the 1st time analgesic effect of different plants (Curcuma longa, Colchicaceae, Colocynthis, Withania somnifera, and Achyranthes aspera) in Haffner’s tail clip models. Aspirin has each uncoated effervescent tablet content are acetylsalicylic acid I.P. 325 mg. Finally summarized in this article represent a most effective results of herbal drugs equalized allopathic drugs without any other side effect. Hence, this is very usefully combination of Ayurveda drugs.

Green analytical chromatographic assay method for quantitation of cyclobenzaprine in tablets, spiked human urine and in-vitro dissolution test

Cyclobenzaprine hydrochloride, a skeletal muscle relaxant has been determined using an ecofriendly micellar HPLC method in its pure form and tablets. The chromatographic determination was performed using C8 monolithic column (100mm×4.6mm i.d., 5μm particle size) and micellar eluent which was composed of sodium dodecyl sulfate (0.15M), n-propanol (15%), 0.02M orthophosphoric acid (pH 4.5) and 0.3% triethylamine using UV detection of effluent was set at 225nm. The calibration plot showed good linearity over concentration range from 2-40μg/mL. The assay results were statistically validated for linearity, accuracy, precision and specificity according to ICH guidelines. Additionally, regarding USP guidelines, the uniformity of tablets content and in-vitro dissolution test of the tablets was tested using the proposed method. Simple and rapid applicability of the developed method allowed determination of the drug in its pure and tablet dosage forms. Moreover, the major advantage of micellar HPLC technique is to determine the drug in biological fluids without prior extraction steps. Depending on this, the estimation of cyclobenzaprine in spiked human urine was so simple without traditional tedious procedures. The proposed method offers the advantages of sensitivity and simplicity in addition to short analysis time which didn't exceed 6 minutes.

Silver Amalgam Tubular Detector Combined with Platinum Auxiliary Electrode for Electrochemical Measurements in Flow Systems

AbstractA new type of tubular detector with platinum auxiliary electrode inside the silver amalgam tube (TD+AuxE) was proposed, fabricated, tested and compared with a typical silver amalgam tubular detector developed earlier. Non‐stop‐flow differential pulse voltammetric anodic stripping method (AS‐DPV) and amperometric method in a glucose oxidase biosensor arrangement were tested. Both detectors were applied for AS‐DPV detection in flow systems for the first time. Solutions of zinc and cadmium cations were used as the testing species for voltammetry, and detection of oxygen concentration was used for amperometry. All these experiments require application of highly negative potentials, which is possible to realize with detectors made of silver solid amalgam. The proposed combination of TD+AuxE provides a much greater current response than the arrangement with three individual electrodes. All relevant parameters were optimized for the developed TD+AuxE. The simple and fast measuring protocol for the determination of the zinc content in commercial food supplement tablets has been developed.

Comparison between integrated continuous direct compression line and batch processing – The effect of raw material properties

There is a current trend in pharmaceutical manufacturing to shift from traditional batch manufacture to continuous manufacturing. The purpose of this study was to test the ability of an integrated continuous direct compression (CDC) line, in relation to batch processing, to achieve consistent tablet quality over long processing periods for formulations with poor flow properties or with a tendency to segregate. The study design included four industrially relevant formulations with different segregation indices and flow properties induced through different grades of the Active Pharmaceutical Ingredient (API), paracetamol, and major filler as well as varying the amount of API. The performance metrics investigated were content, uniformity of content, tablet weight, and tablet strength. The overall process stability over time was significantly improved with the CDC line as compared to the batch process. For all the formulations with a high API content, the CDC line provided better or equal uniformity of content and tablet weight as compared to batch. The CDC line was especially efficient in providing a stable content and tablet weight for poorly flowing formulations containing the standard, cohesive, grade of API. The only formulation that performed better in the batch process was the formulation with a low API content. Thus, for this formulation, the batch process achieved lower variation in tablet content since maintaining a low feed rate for the API proved challenging in the CDC line. In addition, some of the API became stuck in the CDC line between feeding and tableting, most likely at the funnel in the mixer inlet, highlighting the need for properly designed interfaces between units. The insensitivity of the CDC line towards poor flow indicates that one could use direct compression at high drug load compositions of poorly flowing powder blends that could not be processed via batch manufacturing.

Microfluidic Extractive Crystallization for Spherical Drug/Drug-Excipient Microparticle Production

Granulation is a common manufacturing step for pharmaceutical drug products, which improves powder flowability, compactibility, and ensures tablet content uniformity. Granules of uniform content can conventionally be challenging to obtain due to powder segregation and mixing issues prior to granulation. Spherical crystallization—a method where drug crystals are directly formed into spherical granules—is a promising way to overcome issues with mixing and form granules with uniform content. However, a common challenge of existing quasi emulsion solvent diffusion or solvent extraction methods for spherical crystallization involving miscible solvents in stirred batch vessels is the coarse control over particles sizes, as they are sensitive to multiple scale-up factors (mixing efficiency, impeller and vessel geometry, inlet configuration). This limits the method in terms of content uniformity, which in turn limits the extent to which granules with tunable dissolution profiles can be created. Here, we propose a...

Formulation Development and Evaluation of Poorly Water Soluble Gliclazide Tablet Containing Aerosil 380 as Carrier

The core objective of the current work was to improve dissolution rate of poorly water-soluble anti-diabetic drug gliclazide by solid dispersions (SDs) technique using fumed silica particles Aerosil 380 as carrier into compressed tablets. Different FGA-1, FGA-2, FGA-3 (Formulated Gliclazide Aerosil; weight ratio, 1:1) and FPG-1, FPG-2 (Formulated Plain Gliclazide) tablet batches were formulated, prepared, evaluated and characterized. All the findings of pre-compression factors were found to be satisfactory and post-com- pression parameters revealed good mechanical integrity and good uniformity in all formulations. All the formulated tablets satisfied the compendia limits of weight variation, friability and the disintegration time. Among all formulations, FGA-3 was optimized based on in vitro drug release findings, disintegration time, hardness and other quality attributes. The percent of drug release from the formulated FGA tablets containing gliclazide loaded aerosil is about 3 fold higher when compared with the tablets formulated and prepared with plain gliclazide (FPG) and the tested commercial brands in first 60 minutes. There was no significant change noted in the drug content and drug release pattern in the FGA tablets batches when stored in 40℃ and 75% RH for three months. It was thus concluded that SDs formulations of gliclazide could be successfully used to design and develop a solid dosage form of the drug, which would have significant benefits over the existing commercial brands.

Understanding Compression-Induced Amorphization of Crystalline Posaconazole.

Process-induced phase transformations (PIPTs) of active pharmaceutical ingredients (APIs) can alter APIs' physicochemical properties and impact performance of pharmaceutical drug products. In this study, we investigated compression-induced amorphization of crystalline posaconazole (POSA), where the impact of mechanical stresses and excipients on amorphization were explored. 19F solid-state NMR (ssNMR) was utilized to detect and quantify amorphous content in the compressed tablets, and finite element analysis (FEA) was conducted to understand stress distributions in the compression process. Both applied macroscopic axial stress and shear stress were found to be important to amorphization of crystalline POSA. Punch velocity, an important compression process parameter, had negligible effect on amorphization up to 100 mm/s. Two diluents, microcrystalline cellulose (MCC) and dibasic calcium phosphate anhydrous (DCPA), and one lubricant, magnesium stearate (MgSt), were evaluated for their impact on amorphization in this study. It was found that both MCC and DCPA significantly enhanced amorphization of POSA at a low drug loading (5% w/w). The 1% (w/w) blended lubricant effectively reduced the amorphous content in MCC-POSA tablets; however, it had minimal effect on either neat POSA or DCPA-POSA tablets. Drug loading, or excipient concentration, was demonstrated to have a significant impact on the extent of amorphization. These observed excipient effects support the important role of interparticulate stresses in amorphization of crystalline POSA.

Application of Box-Behnken design and desirability function in the optimization of spectrophotometric method for the quantification of WADA banned drug: Acetazolamide

Experimental design approach was used to optimize the experimental factors in developing a spectrophotometric method for quantification of acetazolamide using N-bromosuccinimide (NBS) as a reagent. In this method, a known excess of NBS was mixed with acetazolamide in acid medium and the unreacted NBS was treated with methyl orange which was monitored at 513 nm. The effects of critical factors such as volumes of 5.60 × 10−4 mol L−1 NBS, 0.5 mol L−1 HCl, 4.2 × 10−2 mol L−1 KBr and 1.53 × 10−4 mol L−1 methyl orange on the absorbance were analysed and these factors were optimized using Box-Behnken design (BBD) and desirability function. The calibration curve was linear in the range of 6–18 μg mL−1 with a correlation coefficient of 0.9999. The detection limit was 0.023 μg mL−1. The method was used to quantify the acetazolamide content in commercial tablets and urine samples. The percentage recoveries of acetazolamide in urine samples were found to vary from 96.22–96.39%.

Process analytical technology for continuous manufacturing tableting processing: A case study

The use of Near Infrared Spectroscopy (NIRS) as a fast and non-destructive technique was employed for the control and monitoring of the tableting step during a continuous manufacturing process.Two NIRS methods were optimized in order to in-line control the blend uniformity in the tablet feed frame and the API concentration of freshly pressed tablets prior the ejection. The novelty of this work first lies in the acquisition speed of NIR spectra reaching up to 70,000 tablets/h. Partial Least Square (PLS) regression was used as chemometric tool for the computation that resulted in excellent predictive calibration results. A coefficient of correlation (r) value of 0.99 was obtained for both probes. The root mean square error of calibration (RMSEC) and the root mean square error of prediction (RMSEP) were respectively 1.8% and 1.8% for active content in the tablet feeder and 2.2% and 2.3% for the tablet content. In addition, calibration performance and robustness of the methods were evaluated. Moreover several qualitative methods were proposed to monitor the tableting process in different stages of development (single wavelength, Principal Component Analysis, and Independent Component Analysis). In early phase development, the requirement/quality of the input material is not established yet; hence the use of a qualitative approach allows to confirm the suitability of the PAT methodology for in-process material monitoring & control. Later, the qualitative approach constitutes the foundation for the quantitative approach when input materials are fixed and larger production size occurs. The proposed strategy is a performant PAT tool for continuous manufacturing and a step forward to real time release.

A “Large-N” Content Uniformity Process Analytical Technology (PAT) Method for Phenytoin Sodium Tablets

Accurate assessment of tablet content uniformity is critical for narrow therapeutic index drugs such as phenytoin sodium. This work presents a near-infrared (NIR)-based analytical method for rapid prediction of content uniformity based on a large number of phenytoin sodium formulation tablets. Calibration tablets were generated through an integrated experimental design by varying formulation and process parameters, and scale of manufacturing. A partial least squares model for individual tablet content was developed based on tablet NIR spectra. The tablet content was obtained from a modified United States Pharmacopeia phenytoin sodium high-performance liquid chromatography assay method. The partial least squares model with 4 latent variables explained 92% of the composition variability and yielded a root mean square error of prediction of 0.48% w/w. The resultant NIR model successfully assayed the composition of tablets manufactured at the pilot scale. For one such batch, bootstrapping was applied to calculate the confidence intervals on the mean, acceptance value, and relative SD for different sample sizes, n = 10, 30, and 100. As the bootstrap sample size increased, the confidence interval on the mean, acceptance value, and relative SD became narrower and symmetric. Such a ‘large N’ NIR-based process analytical technology method can increase reliability of quality assessments in solid dosage manufacturing.

Quantitative screening of the pharmaceutical ingredient for the rapid identification of substandard and falsified medicines using reflectance infrared spectroscopy.

The World Health Organization suggests that approximately 10% of medicines worldwide are either falsified or substandard with higher figures in low and middle income countries. Such poor quality medicines can seriously harm patients and pose a threat to the economy worldwide. This study investigates attenuated total reflectance-fourier transform infrared (ATR-FTIR) spectroscopy as a simple and rapid method for determination of drug content in tablet dosage forms. Paracetamol was used as the model pharmaceutical ingredient. Spectra of standard mixtures of paracetamol with different excipients formed the basis for multivariate PLS based quantitative analysis of simulated tablet content using different selected infrared absorbance bands. Calibration methods using ATR-FTIR were compared with the ATR-FTIR and conventional ultraviolet spectroscopic analyses of real tablet samples and showed that the paracetamol/microcrystalline cellulose mixtures gave optimum results for all spectral bands tested. The quantitative data for band 1524–1493cm-1 was linear (R2 ˃ 0.98; LOQ ≥ 10%w/w tablet). Global examples of paracetamol tablets were tested using this protocol and 12% of the tablet samples examined was identified as substandard. Each sample analysis was completed in just a few minutes. ATR-FTIR can therefore be used in the rapid screening of tablet formulations. The simplicity of the proposed method makes it appropriate for use in low and middle income countries where analytical facilities are not available.

Development and Robustness Verification of an At-Line Transmission Raman Method for Pharmaceutical Tablets Using Quality by Design (QbD) Principles

The purpose of the present study was to investigate the feasibility of developing a fast non-destructive at-line transmission Raman spectroscopy (TRS) method for core tablet potency and content uniformity (CU) as part of a real-time release testing (RTRt) control strategy. The effects of tablet hardness and weight (thickness), API particle size, and concentration were studied by using a novel experimental design called generalized subset designs (GSDs). A subset of 28 experiments plus three replicate center points were selected for a total of 31 experiments. Matrix effects included tablets with active pharmaceutical ingredient (API) at seven concentration levels (14 to 26%w/w), and API particle size (17 to 71 μm), tablet weight (275 to 328 mg), and tablet hardness (8 to 16 SCU) at two levels. Three calibration models were developed, by using partial least squares (PLS) and different preprocessing conditions (model nos. 1 to 3). In model no. 1, all matrix effects were excluded. This model showed high potency prediction errors (RMSEP of 10.0%). When all matrix variations were included in the multivariate calibration according to the GSD as shown in model nos. 2 and 3, the prediction accuracy was greatly improved (RMSEP 2.56 and 1.74% respectively). The statistical significance of the tablet weight, hardness, and API particle size in the %Recovery (TRS vs. the reference HPLC method) was investigated by using MODDE Pro (Sartorius Stedim Data Analytics). Statistically significant effects were identified if the calculated p value was ≤ 0.05. The main effect hardness, the cross-term hardness×particle size, and the quadratic term cal level×cal level showed to be statistically significant. However, these effects had a very small impact on tablet prediction accuracy (± 1.0%w/w) well within the intermediate precision of the method. A non-destructive TRS method for core tablet potency and CU was fully validated, following ICH Q2 and EMEA NIR guidelines. The applicability of the method to process development batches was demonstrated and compared to a previously developed and validated NIR method.

RAPID ASSAY DEVELOPMENT OF DICLOFENAC SODIUM COATED TABLET ASSAY USING FTIR COMPARED TO HPLC METHOD

Objective: A lot of coated tablet preparations of diclofenac have been marketed. This research aimed to develop and validate a quantitative analysis method for diclofenac sodium coated tablet using Fourier Transform Infrared (FTIR), which never reported.Methods: The quantification was done by measuring the sample spectra, which then was converted into its derivative. Areas under the curve (AUC) of the derivative spectrums were plotted against the concentrations; corresponding to the calibration graphic. Then, the validation method was carried out by evaluating the accuracy, precision, linearity, range, limit of detection (LOD), and limit of quantification (LOQ).Results: The results showed that diclofenac sodium had a specific peak within the wavenumber range of 1550-1605 cm-1. This area showed linearity to concentration within the range 0.1-1.0% w/w, with coefficient correlation of 0.9998. Recovery was found within 98-102% w/w. The intra and inter-day precision showed a coefficient of variance below 2%. The LOD and LOQ were 0.0127% and 0.0424% respectively. Further, a comparative study was performed, between this method and the compendia method using HPLC. The results showed that the measurement method using FTIR has an advantage in terms of time and cost.Conclusion: Based on all data, it is concluded that FTIR can be used as a valid alternative method. It is faster and more cost-effective for diclofenac sodium coated tablet content determination, compared to the compendia method.

HIV Stigma Reduction for Health Facility Staff: Development of a Blended- Learning Intervention.

Introduction: The effect of stigma on health and health inequity is increasingly recognized. While many medical conditions trigger stigmatization, the negative effects of HIV stigma are particularly well documented. HIV stigma undermines access, uptake, and adherence to both HIV prevention and treatment. People living with HIV face stigma in all aspects of their daily lives; however, stigma in the health system is particularly detrimental. A key component for health facility stigma-reduction interventions is participatory training of staff, often through several days of in-person training. Though this approach shows promise, it is time intensive and poses challenges for busy health facilities. In response, the DriSti study has developed a brief blended-learning approach to stigma reduction in Karnataka State, India. This paper describes the process and final content of the intervention development. The intervention is currently being tested. Final evaluation results will be published upon study completion.Methods: Grounded in behavior change strategies based on social cognitive theory principles that stress the importance of combining interpersonal interactions with specific strategies that promote behavior change, we used a three-phase approach to intervention development: (1) content planning—review of existing participatory stigma-reduction training activities; (2) story boarding—script development and tablet content production; and (3) pilot testing of tablet and in-person session materials.Results: The final intervention curriculum consists of three sessions. Two initial self-administered tablet sessions focus on stigma awareness, attitudes, fears of HIV transmission, and use of standard precautions. The third small group session covers the same material but includes skill building through role-play and testimony by a person living with HIV. A study team member administers the tablet sessions, explains the process, and is present throughout to answer questions.Conclusion: This paper describes the theoretical underpinning and process of developing the blended-learning curriculum content, and practical lessons learned.The approach covers three key drivers of HIV stigma—stigma awareness, fear of HIV transmission, and attitudes. Developing video content for the self-directed learning is complex, requires a diverse set of people and skills, and presents unexpected opportunities for stigma reduction. Co-facilitation of the in-person session by someone living with HIV is a critical component.

Determination of Optimum Drying Temperature Profile by Iterative Learning Control (ILC) Method to Obtain a Desired Moisture Content in Tablets

<p>The paper presents an industrial case study example to evaluate the performance of the linear time varying (LTV) perturbation model based iterative learning control (ILC) in a pilot scale batch system. The operating data based strategy applied here is based on utilizing the repetitive nature of batch processes to update the operating trajectories using process knowledge obtained from previous runs and thereby providing a convergent batch-to-batch improvement of the process performance indicator. The method was applied to determine the required drying temperature of Paracetamol granules to obtain desired moisture content at the end of the batch. After granulation operations, Paracetamol granules were dried in a fluid bed dryer in the pilot plant laboratory of GlaxoSmithKline Bangladesh Limited, Chittagong, Bangladesh. These results demonstrate the potential of the ILC approach for controlling batch processes without rigorous process models.</p><p>Chemical Engineering Research Bulletin 20(2018) 1-7</p>

The performance of derivate FTIR spectrophotometry method compared to colorimetry for tranexamic acid tablet content determination

Recently, FTIR reported has been established as a direct content determination for some tablet dosage forms. In the method, infrared transmittance spectra was converted into the derivated absorbance form. In this present research, the method’s performance was investigated to quantified tranexamic acid in its tablet dosage form directly. The result then was compared to the colorimetry, which has been developed by another researcher. Correlations between the two methods were analyzed using t-test. The good linearity was shown at concentration range of 0.5 - 1.75% w/w at the wave number of NH group. Furthermore, the recovery, intra- and inter-day precision also fulfilled the validation requirement. Meanwhile, LOD and LOQ of the method were 0.0531%w/w and 0.1770%w/w. These methods were compared with colorimetry has been established before. Afterwards, the t-test proved no significant difference of content determination yielded, between these two methods. In conclusion, FTIR can be used for quantify the content of tranexamic tablet, more accurately than colorimetry, which has been developed before. Moreover, FTIR method also has advantages such as easier, simpler, faster and cheaper than the colorimetry method. Â

GREEN METHOD FOR ACETAMINOPHEN AND IBUPROFEN SIMULTANEOUS ASSAY IN THE COMBINATION TABLET USING FTIR

Objective: The purpose of this study was to develop a green method for assay the tablet consists of a combination of acetaminophen (ACT)-ibuprofen (IBU). FTIR (Fourier Transform Infrared Spectroscopy), which is commonly used for qualitative analysis, was developed to measure the tablet contents, directly and quantitatively.Methods: Standard for ACT and IBU was respectively mixed with KBr crystal in varied and measured using FTIR. The transmission spectrum yielded later was converted into its absorbance-derivatized forms which then a calibration curve was composed using the data. Once validated, the analytical method was conducted on samples of the branded ACT-IBU combination tablet.Results: ACT had a specific wavenumber of a group N-H stretch, meanwhile IBU was represented by the C = O spectrum. These peaks then used for quantitative calculation basis levels respectively. The limits of detection and quantitation of ACT consecutively were % w/w and  w/w and IBU were % w/w and  w/w. Next; the method was carried out successfully to evaluate the content of sample tablet from the market.Conclusion: The analytical method of ACT-IBU was proven applicable and suitable for the quantitative purpose. The method shows meet with the expectation such as simple and easy to perform and reduce the use of solvents.

Development and Validation of High Performance Liquid Chromatography Method for Determination Atorvastatin in Tablet

Atorvastatin is the primary choice for dyslipidemia treatment. Due to patent expiration of atorvastatin, the pharmaceutical industry makes copy of the drug. Therefore, the development methods for tablet quality tests involving atorvastatin concentration on tablets needs to be performed. The purpose of this research was to develop and validate the simple atorvastatin tablet analytical method by HPLC. HPLC system used in this experiment consisted of column Cosmosil C18 (150 x 4,6 mm, 5 µm) as the stationary reverse phase chomatography, a mixture of methanol-water at pH 3 (80:20 v/v) as the mobile phase, flow rate of 1 mL/min, and UV detector at wavelength of 245 nm. Validation methods were including: selectivity, linearity, accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ). The results of this study indicate that the developed method had good validation including selectivity, linearity, accuracy, precision, LOD, and LOQ for analysis of atorvastatin tablet content. LOD and LOQ were 0.2 and 0.7 ng/mL, and the linearity range were 20 - 120 ng/mL.

In-Situ Measurement of Vitamin C Content in Commercial Tablet Products by Terahertz Time-Domain

Terahertz time-domain spectroscopy (THz-TDS) was applied to investigate the feasibility of in-situ measuring vitamin C content in commercial tablet products without any pretreatments. Characteristic absorption peaks of vitamin C were analyzed with quantum mechanical calculation to reveal the molecular origin of them. The peak appearing at 1.08 THz was then selected and tested for its suitability as a fingerprint signal for analyzing the vitamin C content in dietary supplement tablets. There are a couple of factors influencing THz absorbance other than concentration. Among those, the effects of tablet thickness and types of excipients in the tablet products were found to be significant, and were corrected with the calibration curve to determine vitamin C concentration in tablet forms. Furthermore, commercial tablet products in the market were analyzed using THz-TDS and the measured vitamin C contents were in good agreement with those determined using a reference method (high-performance liquid chromatography). Thus, our results suggest that THz-TDS can be used for the in-situ analysis of vitamin C in commercial tablet products.