Endoscopic transcanal coblation excision of glomus tympanicum: a novel technique

OBJECTIVE

To evaluate the feasibility of coblation in excision of glomus tympanicum tumors.

PATIENTS AND METHODS

A retrospective study carried out over 28 patients with types I and II glomus tympanicum tumors according to GLASSCOCK-JACKSON classification. Preoperative radiological and endocrinal evaluation were performed. All patients underwent endoscopic transcanal excision of their glomus tympanicum tumors using coblation.

RESULTS

None of the patients developed recurrence during the 1-year follow up period proved radiologically. None of the patients developed facial palsy postoperatively. Differences between preoperative and postoperative dizziness and taste disturbance were statistically non-significant. Tinnitus disappeared completely in 22 patients postoperatively. A statistically significant reduction in Tinnitus Handicap Inventory (THI) after surgery was found. Statistically significant reductions in postoperative air conduction (AC) threshold and air bone gap (ABG) were recorded while bone conduction (BC) threshold showed statistically non-significant change.

CONCLUSION

Coblation is an effective and safe tool in excision of glomus tympanicum tumors. Further studies comparing coblation with laser and piezosurgery are strongly recommended.

Endoscopic ossiculoplasty in traumatic conductive hearing loss with intact tympanic membrane: a five-year experience

BACKGROUND

Exploratory tympanotomy in cases of traumatic ossicular disruption with intact tympanic membrane is crucial for both diagnostic and therapeutic purposes. Performing this procedure using the endoscope is gaining popularity. Hence, this study aimed to demonstrate varieties of ossicular pathology and their management in our institution.

METHODS

A retrospective evaluation was conducted of 136 ears in patients with traumatic ossicular disruption with an intact tympanic membrane, who underwent endoscopic exploratory tympanotomy. A proposed algorithm was followed, to incorporate different traumatic ossicular possibilities. Assessment of hearing outcomes and surgical complications was performed six months post-operatively.

RESULTS

Incudostapedial dislocation was the most commonly encountered type of traumatic ossicular disruption (35.3 per cent). Air conduction threshold improved significantly following endoscopic ossiculoplasty, from 50.9 ± 6.35 dB pre-operatively to 22.35 ± 3.27 dB post-operatively, with successful air-bone gap closure.

CONCLUSION

Endoscopic ear surgery is effective in the diagnosis and management of challenging cases of post-traumatic ossicular disruption with an intact tympanic membrane.

Superior semicircular canal dehiscence: a radiological and clinical study

Aim

to assess radiologically the prevalence of SSCD with its clinical presentations and its relationship with age.

Methods

a prospective cohort study carried out on 200 consecutive patients (400 temporal bones). Radiological evaluation was performed using High Resolution Computed Tomography (HRCT) with measurement of thickness of bone covering superior semicircular canal (SCC), height and diameter of SSC.

Results

Two hundred patients (400 temporal bones) were involved. The mean thickness ± SD, the mean diameter ± SD and the mean height ± SD were 1.38 ± 0.80 mm, 0.94 ± 0.26 mm and 10.91 ± 2.39 mm respectively. The prevalence of SSCD and predehiscence were 1% and 14% respectively. The commonest symptom encountered was autophony (48.3%). When the SSC thickness, diameter and height were compared with the age of patients, statistically significant differences were detected. The highest diameter, lowest height and lowest thickness were found in patients aged from 54 to 72 years. Thickness of bony layer covering SSC was found to be the most validated measurement for differentiation between cases with positive and negative symptoms with the highest sensitivity and specificity.

Conclusion

The prevalence of SSCD and predehiscence varied among the studies. Autophony is the commonest symptom usually encountered. The condition is acquired rather than congenital. The thickness of bone covering SCC is the most validated measurement in differentiation between cases with positive and negative symptoms.

Predictors of effusion viscosity in otitis media with effusion: neutrophil lymphocyte ratio versus mean platelet volume

OBJETIVOS

comparar entre el índice de linfocitos neutrófilos (NLR) y el volume plaquetario medio (VPM) en la predicción de la viscosidad del derrame en otitis media con derrame. MATERIALES Y MéTODOS: Se incluyeron en el estudio 248 niños con derrame en el oído medio. Se evaluaron hemogramas completos (CBC) preoperatorios. Se registraron los valores de NLR y MPV. La viscosidad del derrame se evaluó durante la cirugía mientras se aspiraba el derrame después de la miringotomía. De esta forma se clasificaron 2 tipos de derrames; tipos serosos y mucoides.

RESULTADOS

se reportaron diferencias estadísticamente significativas en NLR y MPV entre los tipos serosos y mucoides. Los valores de corte de NLR y MPV para diferenciar entre derrames serosos y mucoides fueron 1,21 y 7,95 respectivamente. Cuando se compararon NLR y MPV, NLR pareció tener mayor sensibilidad, especificidad y precisión que MPV. CONCLUSIóN: NLR es superior a MPV como predictor de la viscosidad del derrame en otitis media con derrame. Ambos marcadores se consideran rentables y fiables para la evaluación de la viscosidad del derrame.

A Novel, Sustainable, and Eco-Friendly Spectrophotometric and Chemometric Approach for Determination of Severely Overlapped Spectrum via Unified Regression Equation: Greenness and Whiteness Assessment

BACKGROUND

Nebivolol and valsartan (VAL) in combination with each other successfully control blood pressure and improve hypertension patient outcomes.

OBJECTIVE

To develop and validate innovative, simple, and sustainable spectrophotometric methods for the simultaneous analysis of nebivolol and valsartan.

METHOD

The new modified difference amplitude modulation (MD-AM) method uses only unified regression equation and does not require any resolution techniques. Other different approaches were also applied for the determination of the same mixture including univariate and multivariate spectrophotometric methods. The multivariate methods were PLS and PCR, whereas the univariate methods were derivative ratio (DD1), ratio difference (RD), constant center (CC), constant center spectrum subtraction (CC-SS), constant value coupled with amplitude difference (CV-AD), advanced concentration value (ACV), and amplitude difference (AD). The proposed methods use a green solvent; thus, the environmental impact of the presented procedures was evaluated qualitatively and quantitatively using six well-known evaluation tools.

RESULTS

All methods were applied successfully for the analysis of the studied drugs in their bulk powder, pharmaceutical dosage form Byvalson®, and in vitro release at intestinal pH (7.4) using a USP dissolution tester. Results obtained were compared statistically with the reported method and with each other using a one-way ANOVA statistical test, and no significant differences were found.

CONCLUSIONS

All green and white analytical chemistry evaluation tools results confirm the safety, sustainability, and cost-effectiveness of the approaches, indicating that the methods are regarded green and sustainable. Results were agreeable, encouraging their applicability in quality control laboratories for dosage form and making these methods an eco-friendly substitute for the analysis of this combined dosage form and for evaluating the dissolution profile.

HIGHLIGHTS

For the first time, a severely overlapped spectrum was determined using a unified regression equation without the need of extended part or zero contribution regions by the novel method MD-AM. The proposed methods are the first study of in vitro dissolution profiling of nebivolol hydrochloride (NEB) and VAL and the first sustainable and green methods applied without compromising the analytical criteria.

Endoscopic stapedotomy: classic versus reversal technique

OBJECTIVES

To compare hearing outcome and surgical complications between endoscopic classic and reversal stapedotomies.

PATIENTS AND METHODS

A prospective single blinded randomized clinical study carried out on 60 patients with otosclerosis who were randomized into two groups; each containing 30 patients. Patients in group 1 underwent endoscopic classic stapedotomy. Patients in group 2 underwent endoscopic reversal stapedotomy. Both groups were compared as regards hearing outcome and surgical complications.

RESULTS

The difference in the hearing outcome between the two groups was statistically non-significant. Post-operative closure of the air bone gap (ABG) within 10 dB was attained in 76.67% and 80% of patients in groups 1 and 2, respectively. The differences in the surgical complications between the two studied groups were statistically non-significant.

CONCLUSION

Endoscopic classic and reversal stapedotomies are comparable to each other as regards hearing outcome and surgical complications. The authors recommend further studies with relatively larger sample size.

A refashioned foley catheter: novel cost-effective available stent in pediatric laryngotracheal reconstruction

PURPOSE

Pediatric laryngotracheal reconstruction (LTR) for laryngotracheal stenosis (LTS) mandates stenting in certain situations. This study presents a novel commercially available and cost-effective stent, a refashioned foley catheter.

METHODS

This prospective clinical study was performed on pediatric cases with LTS up to 8 years. The study was performed in a tertiary referral center. The selection of the proper foley catheter size for age was explained. The atraumatic insertion maneuver of the stent was also shown in detail in different situations of LTS. The endoscopic removal of the stent was also described. The mean follow-up was 6.45 ± 1.3 months.

RESULTS

The study included 31 cases using the refashioned foley catheter stents. The study included 17 males and 14 females with a mean age of 3.45 ± 1.09. Subglottic stenosis was the most common cause of LTR in the study (74.2%) cases. The mean duration of stenting was 40.5 ± 3.7 days. Decannulation was achieved in 96.8% of cases. No stent complications were encountered like stent migration, excess granulation tissue, intractable aspiration, or pressure necrosis.

CONCLUSION

The refashioned foley catheter is a novel, available, and inexpensive stent that can be utilized for LTR cases for pediatric LTS. The newly described stent is soft, pliable with atraumatic insertion and easy endoscopic removal with minimal complications.

Standardization and quantitative analysis of Araucaria Heterophylla extract via an UPLC-MS/MS method and its formulation as an antibacterial phytonanoemulsion gel

Skin infections are among the bacterial infections that present significant therapeutic challenges due to antibiotic resistance. Recently, herbal products clutched a significant attention as safe replacements for other medications but their low aqueous solubility and poor bioavailability are considered major challenges which could be circumvented via formulation. As a species of genera Araucaria, Araucaria Heterophylla possesses pharmacological activities such as antioxidant and antibacterial actions, and this study aimed to standardize the extract of the plant against 4ʹʹʹmethoxyamentoflavone (as a main component of the extract) through a validated UPLC-MS/MS method and evaluate its antibacterial activity, which was followed by loading the standardized extract into a nanoemulsion to form a phytonanoemulsion (PNE), where the design analysis and optimization were performed through a simplex lattice design. The optimized PNE (PNE 3) was then loaded into HPMC/Pluronic F-127 gel (in ratio 1:4) to sustain the release of the active constituent. The heightened penetrability of PNE 3 gel was visualized via confocal laser scanning microscopy, and its prolonged effect was proved thru an in vivo study conducted on male Wistar rats. A histopathological study revealed the safety of the formulation when applied topically. Thus, PNE gel could be a potentially broad-spectrum antibacterial drug delivery system.

In Vitro Dissolution Profile of Antihypertensive Mixture: Comparison between Multivariate Methods and Statistical and Graphical Representation of Different Univariate Spectrophotometric Data

Background

Triplixam is a new antihypertensive drug combination consisting of Perindopril, Amlodipine, and Indapamide which have a synergistic mechanism of action in combination with each other.

Objective

Comparative study of different spectrophotometric approaches used for the simultaneous determination of Perindopril, Indapamide, and Amlodipine in bulk powder and in dosage form Triplixam.

Methods

The methods include univariate and multivariate spectrophotometric methods depending on either mathematically calculation or graphically representation of data. For the univariate methods: Perindopril were resolved from other component using Constant multiplication followed by spectrum subtraction resolution technique then Two Base Point, AUC, Constant value, and Concentration value methods were applied. For both Amlodipine and Indapamide: Constant multiplication resolution technique was used then Constant value and Concentration value methods were applied. Concentration Value depends on graphical representation of data rather than statistical data. PLS and PCR chemometric assisted spectrophotometric techniques were also applied. The proposed methods are considered green alternative to the reported methods as the greenness of the proposed methods was evaluated qualitatively and quantitatively by four green analytical evaluation tools.

Results

The methods were applied for the analysis of the mixture in the pharmaceutical dosage form Triplixam, and in vitro release at intestinal pH (7.4) using a USP dissolution tester.

Conclusion

The proposed green analytical methods considered to be greener than the reported methods and simpler so could be used as alternative for routine analysis of the mixture in quality control laboratories for the reason of their accurate results beside minimum manipulation steps that reduced the error and time required of the analysis with no harmful effect on analyst health as well as the environment.

Highlights

The study was the first in vitro dissolution profiling of Perindopril, Amlodipine, and Indapamide. The developed methods were of excellent green methods without compromising the analytical criteria.

Kinetic degradation study for the first licenced anti-influenza polymerase inhibitor, baloxavir marboxil, using HPLC-MS

The first licensed polymerase inhibitor, baloxavir marboxil was recently approved for the treatment of influenza A and B viruses. Furthermore, there is growing interest in testing the antiviral activity of baloxavir marboxil against Coronavirus. Despite its critical clinical value, there is no information on the degradation products, pathways or kinetics of baloxavir marboxil under various stress conditions. In this study, a new HPLC-MS chromatographic method for accurately quantifying baloxavir marboxil in the presence of its degradation products was developed. A study of degradation kinetics revealed that acidic, thermal neutral, and photolytic degradation reactions have zero-order kinetics, whereas basic and oxidative degradation reactions have first-order kinetics. The structural characterization of baloxavir marboxil degradation products was performed by coupling the optimized HPLC method to the triple-quadrupole tandem mass spectrometer. The proposed approach was validated according to the International Council for Harmonisation Q2 (R1) requirements for accuracy, precision, robustness, specificity, and linearity. The proposed approach was successfully used to analyze baloxavir marboxil as raw material and its pharmaceutical dosage form, Xofluza®. This article is protected by copyright. All rights reserved.

Development and Validation of Stability-Indicating Assay Method for a Novel Oxazolidinone (PH-192) with Anticonvulsant Activity by Using UHPLC-QToF-MS

The treatment of seizure disorders with currently available pharmacotherapeutic agents is not optimal due to the failure of some patients to respond, coupled with occurrences of side effects. There is therefore a need for research into the development of new chemical entities as potential anticonvulsant agents, which are different structurally from the existing class of drugs. We recently identified a novel triazolyl-oxazolidinone derivative, PH-192, as a potential anticonvulsant agent. PH-192 demonstrated protection comparable to phenytoin against both chemically- and electrically-induced seizures in rodents with little or no central nervous system side effects. However, PH-192 did not exhibit protection beyond 30 min; therefore, we decide to investigate a stability-indicating assay of PH-192 in plasma and other solutions. A reliable and validated analytical method was developed to investigate the stability of PH-192 for 90 min in human plasma, acidic, basic, and oxidative conditions, using a Waters Acquity ultra high-performance liquid chromatography (UHPLC) system with a quaternary Solvent Manager (H-Class). A simple extraction method indicated that PH-192 was stable in human plasma after 90 min at 37 °C, with more than 90% successfully recovered. Moreover, stress stability studies were performed, and degradants were identified using LC-QToF-MS under acidic, basic, and oxidative simulated conditions.

Development of a multivariate model with desirability-based optimization for determination of atenolol and hydrochlorothiazide by eco-friendly HPLC method with fluorescence detection

Determination of a widely used antihypertensive combination of atenolol and hydrochlorothiazide was achieved by rapid and eco-friendly high-performance liquid chromatography method combined with fluorescence detection. The response surface methodology is conducive to the complete separation of the two drugs in a shorter analysis time. The separation of the mixture was achieved using an Inertsil C18 analytical column (150 × 4.6 mm, 5 µ). The mobile phase used was ethanol: potassium dihydrogen phosphate at pH 3 (65:35 v/v) and the flow rate was 0.7 mL/min. The fluorescence detector operated at excitation and emission wavelengths of 230 and 310 nm (atenolol) and 270 and 375 nm (hydrochlorothiazide). The linearity of the developed method covered a concentration of atenolol of 0.05-5 µg/mL and a concentration of hydrochlorothiazide of 0.02-1 µg/mL. The greenness of the developed method was evaluated by analytical eco-scale and the recently reported evaluation method, that is, green analytical procedure index, and it was found to be an excellent, sensitive, and green alternative to the reported methods. The developed method was validated according to the ICH guidelines and compared with the reference method. No significant difference was found in terms of accuracy.

Endoscopic transcanal attico-antrostomy versus endoscopic-assisted canal wall up mastoidectomy in management of localized cholesteatoma: a randomized clinical trial

OBJECTIVES

This study aims to compare results of endoscopic transcanal tympanoplasty with attico-antrostomy with endoscopic-assisted canal wall up mastoidectomy in treatment of cases of limited attic cholesteatoma.

MATERIALS AND METHODS

A prospective randomized single-blinded study involving 40 patients with limited attic cholesteatoma was conducted. Randomization of the patients into two groups was done; 20 patients are managed by endoscopic transcanal tympanoplasty with attico-antrostomy, while the other 20 patients are managed by endoscopic-assisted canal wall up mastoidectomy. Primary outcome is recidivism, while secondary outcomes include hearing results, operative time, pain score and associated complications.

RESULTS

Comparable recidivism rate was found in the two groups. The endoscopic-assisted canal wall up mastoidectomy group was associated with significantly longer duration of surgery and higher postoperative pain score. There was no significant difference between both the groups regarding hearing results and associated complications.

CONCLUSION

In localized attic cholesteatoma cases, endoscopic transcanal tympanoplasty with attico-antrostomy is a time-saving less-invasive reliable technique with good eradication results.

CLINICAL TRIAL REGISTRY

ClinicalTrials.gov (NCT04959539) "retrospectively registered" at 12/7/2021.

Determination of amlodipine and atorvastatin mixture by different spectrophotometric methods with or without regression equations

Four new, simple, and reproducible spectrophotometric methods were developed and validated for the simultaneous determination of Amlodipine (AML) and Atorvastatin (AT) in bulk powder and pharmaceutical dosage form. The four methods include two progressive and two successive resolution techniques. The two progressive methods are Absorbance Subtraction (AS) and Amplitude Modulation (AM), while the two successive methods are Constant Value (CV) and Concentration Value. In the Concentration Value method, the concentration of the drugs is determined from the graphical representation without the use of regression equations. Linearity range for the two progressive methods was from 5 μg/mL-35 μg/mL while for the two successive methods was from 5 μg/mL-55 μg/mL. The four methods were validated according to the ICH guidelines and were found to be accurate, precise, and selective. The methods were also applied for determination of the mixture in the marketed pharmaceutical dosage form. Results obtained were compared with reported methods. Also, One-way ANOVA statistical test was done between all the proposed spectrophotometric methods where no significant differences were found.

Univariate calibrations with or without chemometric assistance for determination of drugs lacking peak maxima in their zero-order profiles

Trandolapril has no sharp peak in its zero-order spectrum and therefore, it is difficult to be measured by direct spectrophotometry. In this manuscript, several univariate and multivariate spectrophotometric methods were developed and validated for determination of Trandolapril (TR) and Verapamil (VR) combination. The first method for measuring Trandolapril is Constant Multiplication-Spectrum Subtraction (CM-SS), where Trandolapril was measured at 210 nm in its zero-order curve after elimination of Verapamil spectrum. Second and third methods are two Base Points (2BP) and area under the curve (AUC) to measure Trandolapril concentration without depending on the shoulder peak. The fourth method for Trandolapril is Derivative Subtraction (DS) that utilizes the sharp peak appeared in the first order spectrum of Trandolapril. Verapamil was determined by two methods, Constant Multiplication (CM) and Derivative Subtraction-Constant Multiplication (DS-CM). Also, two multivariate methods were developed for measurement of the mixture, Partial Least Squares (PLS) and Principal Component Regression (PCR). All the developed methods were validated as per ICH guidelines and the results proved that the developed methods are accurate and selective. Moreover, a statistical comparison between the developed methods and a reference method was done. Also, One-way ANOVA statistical test was done between all the proposed univariate and multivariate spectrophotometric methods.

Response surface design as a powerful tool for the development of environmentally benign HPLC methods for the determination of two antihypertensive combinations: Greenness assessment by two green analytical chemistry evaluation tools

Interest in implementing green chemistry principles in analytical chemistry has grown dramatically in the past few years. The solvents used have the major influence on the greenness of the method. Most conventional high-performance liquid chromatography methods employed utilize solvents that are "hazardous for the environment". In the present study, two-factor three-level response surface design was exploited to develop eco-friendly chromatographic methods for two different mixtures. The first one was atorvastatin and amlodipine and the second one was amlodipine, perindopril, and indapamide. As it is nontoxic to the environment, ethanol was used as the organic modifier in the mobile phase. The separation of the first mixture was attained using phosphate buffer (pH 7)/ethanol (42:58 v/v), and the second mixture was fully resolved using phosphate buffer (pH 5)/ethanol (40:60 v/v). The use of high-performance liquid chromatography allows excellent resolution in a short run time, hence, less waste was produced. The greenness of the developed methods was assessed by two evaluation tools, namely, National Environmental Methods Index and analytical eco-scale, and found to be excellent green analytical methods. Moreover, the developed methods were compared with other reported methods regarding accuracy and greenness and were found to be perfect alternatives to reported methods for separation and quantification of the mixtures.

Comparative pharmacokinetics of trandolapril, its active metabolite, and verapamil in human plasma of Egyptian population using HPLC-MS/MS

Trandolapril and verapamil are commonly used antihypertensive drugs. However, there is a lack of available data on the change of their pharmacokinetics in patients with liver or kidney impairment and hence the need for dose adjustment. In this article, a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed and validated for the monitoring of trandolapril, its active metabolite trandolaprilat, and verapamil in human plasma of patients with renal impairment and/or liver insufficiency. The chromatographic separation was achieved on a Gemini C18 reversed phase column using a gradient elution mode with a run time of 10 minutes. The mobile phase consisted of a mixture of methanol and 2% acetic acid. The electrospray ionization MS/MS analysis was performed in multiple reaction monitoring (MRM) mode. The assay was validated as per Food and Drug Administration (FDA) guidelines for bioanalytical method validation and proved to be suitable for the determination of therapeutic drug levels in plasma. The inter-group changes in pharmacokinetic data were compared to that of healthy volunteers. The comparison showed a significant difference in the pharmacokinetic parameters between the studied groups. The presented results exhibit the benefits of the proposed assay as a validated analytical tool for the continuous drug monitoring.

Full spectrum and selected spectrum based chemometric methods for the simultaneous determination of Cinnarizine and Dimenhydrinate in laboratory prepared mixtures and pharmaceutical dosage form

Three chemometric methods namely, concentration residual augmented classical least squares (CRACLS), spectral residual augmented classical least squares (SRACLS) and partial least squares (PLS) were applied for the simultaneous quantitative determination of Cinnarizine and Dimenhydrinate in their binary mixtures. All techniques were applied with and without variable selection using genetic algorithm (GA) resulting in six models (CRACLS, GA-CRACLS, SRACLS, GA-SRACLS, PLS, GA-PLS). These models were applied for the simultaneous determination of the drugs in their laboratory prepared mixtures and pharmaceutical dosage form via handling their UV spectral data. It was found that GA based models are simpler and more robust than those built with the full spectral data. The proposed models were found to be simple, fast and require no preliminary separation steps; so they can be used for the routine analysis of this binary mixture in quality control laboratories.

Development and validation of different methods manipulating zero order and first order spectra for determination of the partially overlapped mixture benazepril and amlodipine: A comparative study

Three simple, selective, and accurate spectrophotometric methods have been developed and then validated for the analysis of Benazepril (BENZ) and Amlodipine (AML) in bulk powder and pharmaceutical dosage form. The first method is the absorption factor (AF) for zero order and amplitude factor (P-F) for first order spectrum, where both BENZ and AML can be measured from their resolved zero order spectra at 238nm or from their first order spectra at 253nm. The second method is the constant multiplication coupled with constant subtraction (CM-CS) for zero order and successive derivative subtraction-constant multiplication (SDS-CM) for first order spectrum, where both BENZ and AML can be measured from their resolved zero order spectra at 240nm and 238nm, respectively, or from their first order spectra at 214nm and 253nm for Benazepril and Amlodipine respectively. The third method is the novel constant multiplication coupled with derivative zero crossing (CM-DZC) which is a stability indicating assay method for determination of Benazepril and Amlodipine in presence of the main degradation product of Benazepril which is Benazeprilate (BENZT). The three methods were validated as per the ICH guidelines and the standard curves were found to be linear in the range of 5-60μg/mL for Benazepril and 5-30 for Amlodipine, with well accepted mean correlation coefficient for each analyte. The intra-day and inter-day precision and accuracy results were well within the acceptable limits.

Comparative study between univariate spectrophotometry and multivariate calibration as analytical tools for simultaneous quantitation of Moexipril and Hydrochlorothiazide

Three simple, accurate, reproducible, and selective methods have been developed and subsequently validated for the simultaneous determination of Moexipril (MOX) and Hydrochlorothiazide (HCTZ) in pharmaceutical dosage form. The first method is the new extended ratio subtraction method (EXRSM) coupled to ratio subtraction method (RSM) for determination of both drugs in commercial dosage form. The second and third methods are multivariate calibration which include Principal Component Regression (PCR) and Partial Least Squares (PLSs). A detailed validation of the methods was performed following the ICH guidelines and the standard curves were found to be linear in the range of 10-60 and 2-30 for MOX and HCTZ in EXRSM method, respectively, with well accepted mean correlation coefficient for each analyte. The intra-day and inter-day precision and accuracy results were well within the acceptable limits.

Comparative study between univariate spectrophotometry and multivariate calibration as analytical tools for quantitation of Benazepril alone and in combination with Amlodipine

Four simple, accurate, reproducible, and selective methods have been developed and subsequently validated for the determination of Benazepril (BENZ) alone and in combination with Amlodipine (AML) in pharmaceutical dosage form. The first method is pH induced difference spectrophotometry, where BENZ can be measured in presence of AML as it showed maximum absorption at 237nm and 241nm in 0.1N HCl and 0.1N NaOH, respectively, while AML has no wavelength shift in both solvents. The second method is the new Extended Ratio Subtraction Method (EXRSM) coupled to Ratio Subtraction Method (RSM) for determination of both drugs in commercial dosage form. The third and fourth methods are multivariate calibration which include Principal Component Regression (PCR) and Partial Least Squares (PLSs). A detailed validation of the methods was performed following the ICH guidelines and the standard curves were found to be linear in the range of 2-30μg/mL for BENZ in difference and extended ratio subtraction spectrophotometric method, and 5-30 for AML in EXRSM method, with well accepted mean correlation coefficient for each analyte. The intra-day and inter-day precision and accuracy results were well within the acceptable limits.