Solution Stability Studies Research Articles

Development and Validation of RP-HPLC Method using UV detection for Simultaneous quantification of Amlodipine besylate and Nebivolol hydrochloride in Fixed-dose combination tablets

Calcium channel blockers and beta blockers are the class of choice of drugs in treatment of hypertension and cardio vascular diseases. Such a fixed dose combination is viable to deal with the patients for whom monotherapy is not sufficient. A simple, responsive and productive high performance liquid chromatography method was designed and approved for simultaneous quantification of Amlodipine Besylate (AMB) and Nebivolol Hydrochloride (NBL) in tablet dosage form. In the developed method mobile phase comprised of a mixture of aqueous buffer (pH 6) and acetonitrile (55:45 v/v, respectively) at a flow rate of 1.5 ml/min. Chromatographic separation was achieved using Reverse-phase Kromasil 60-5-CN column, 250 × 4.6 mm (particle size 5 μm). Method was discovered specific as no obstruction of excipients peaks at the retention time of tablets was observed and demonstrated linearity in concentration range of 30.4-70.8 mcg/ml for AMB and 29.8-69.4 mcg/ml for NBL with R2> 0.999. Accuracy values for AMB and NBL was found to be 98.21-99.49% and 97.91-99.09%, respectively. Inter-day and intra-day precision was carried out and % RSD was found to be less than 2%. Robustness was performed to evaluate the results with slight variations in method and % RSD found to be less than 2%. Solution stability studies were conducted in normal conditions. Force degradation study was carried out using Photo-diode Array (PDA) detector and revealed that acid degradation in AMB and NBL was 7.12% and 1.88%, alkaline degradation was 9.61% and 0.05% and oxidative degradation was 8.50% and 1.59%, respectively.

Stability Indicating RP-HPLC Method for the Estimation of Impurities in Esomeprazole Gastro-Resistant Tablets by AQbD Approach

Abstract Background: Esomeprazole (ESO) gastro-resistant tablets (40 mg) are sold under the brand name, Zosa, which effectively manages conditions associated with the overproduction of gastric acid, including peptic ulcer disease and Zollinger-Ellison syndrome. The present study quantifies impurities in esomeprazole using advanced analytical techniques known as analytical quality by design with high-performance liquid chromatography. Methods: Buffer selection (pH 7.6) and mobile phase composition (75:25 v/v) were optimized utilizing a YMC C18 column (150 mm × 4.6 mm; particle size, 3 μm) with a flow rate of 1.0 mL/min. The analyte was monitored with a UV/PDA detector at a wavelength of 280 nm. The stability-indicating nature of the method was confirmed based on forced degradation studies. The method validation was performed per ICH guidelines. Linearity, specificity, limit of detection, limit of quantification, precision, accuracy, solution stability, and robustness parameters were validated. Results: All validation parameters were within an acceptable range. Excellent linearity with correlation coefficient values > 0.99 was achieved across the quantification limit. The solution stability study demonstrated no significant increase in percent impurity over a 24-h period. Analytical quality by design was instrumental in defining the design range for buffer pH and mobile phase composition, ensuring robust method performance. It was confirmed that 75% buffer solution, 25% acetonitrile, and pH 7.6 were the ideal conditions for determination of ESO impurities. Conclusion: The validated method provides a reliable tool for accurately quantifying impurities in ESO tablet formulations.

Cocrystals of Favipiravir: Improved Physicochemical Properties and Solution Stability Study

Cocrystals of Favipiravir: Improved Physicochemical Properties and Solution Stability Study

A Validated RP-HPLC Method for Simultaneous Assay Determination and UV-Spectrophotometric Method for Dissolution Estimation in Film-Coated Tablets Containing Cefixime and Clavulanic Acid

A simple and novel reverse phase high performance liquid chromatography (RP-HPLC) method was developed for the simultaneous assay estimation of film coated tablets incorporating clavulanic acid (CVA) and cefixime (CFX). Furthermore, the same method was also applied in order to assess the dissolution of CVA while a UV spectroscopic method was produced to examine the drug release of CFX. In this research, an analytical column used was C18 (4.6-mm × 25-cm); 5-μm. Moreover, the mobile phase was prepared by completely dissolving 3.408 gm of disodium hydrogen phosphate in 800 mL of water (HPLC grade), 200 mL methanol was added in (20:80 v/v) it and then finally pH was adjusted to 6.0 using orthophosphoric acid. In addition, flow rate, detecting wavelength, and run time were 1.0 mL/min, 220 nm, and 15 minutes, respectively. Furthermore, the maximum absorption of CFX was obtained at 288 nm thereby this wavelength was optimized for the dissolution estimation of CFX by UV spectroscopy. The validation parameters were validated according to the specifications and guidelines of the international conference on harmonization (ICH) prior to evaluating both assay and dissolution of CVA and CFX. In case of assay estimation, the findings of the linearity revealed a linear interrelation of concentration between 0.16 - 0.25 mg/mL for both CVA and CFX. Similarly, the calibration curve was linear between the concentration range of 0.03 – 0.045 mg/mL and 0.004 – 0.006 mg/mL, respectively for dissolution determination. Additionally, the value of LOD and LOQ of CVA for assay evaluation was obtained 0.011 and 0.033 μg, respectively. The accuracy of the developed method was assessed by determining recovery studies and the mean recovery of CVA and CFX obtained 99.35% and 100.50%, respectively at 100% spiked level for assay analysis. The repeatability evaluation for assay and dissolution demonstrated that the optimized method is precise within the appropriate range and the RSD% was observed lower than 2.0%. In addition, results of different validation parameters including study of solution stability were achieved within the suitable limit as well.

Forced degradation studies and development of RP-HPLC method for related substances of Tenofovir alafenamide in tablet dosage form

The development and validation of an easy and rapid stability-indicating RP-HPLC technique for Tenofovir alafenamide and its impurities. In this newly developed method, chromatographic separation of Tenofovir alafenamide and its impurities was achieved on an Inertsil ODS-3V C18 (250 mm x 4.6 mm, 5 μ) column. The impurities were extracted by a mixture of Mobile Phase A: buffer solution: Acetonitrile: Purified water (20:02:78) and Mobile Phase B: Solvent Mixture and Purified water (75:25), The injection volume was 20 μL, the column temperature was 40°C, the flow rate was 1 mL/min, and the detection was carried out at 262 nm. The retention time of Tenofovir alafenamide, PMPA, PMPA anhydrate, Phenyl PMPA and PMPA isopropyl alaninate were 56.24, 5.69, 8.71, 25.89 and 37.13 respectively. The Correlation Coefficient within the acceptance criteria is not less than 0.999. The evaluated concentrations for Tenofovir alafenamide and its impurities were in the range of 0.5–7.5 ppm. The average recovery value was in the range of 90.2–113.9%. Tenofovir alafenamide’s LOD and LOQ were determined to be 0.1 μg/mL and 0.5 μg/mL respectively. Tenofovir alafenamide solution degradation behaviour was assessed using solution stability studies. A new, accurate, and precise method has been developed, evaluated, and elevated for the detection of impurities in Tenofovir alafenamide tablet dosage form. The results obtained from the validation study established that this method is specific, reliable, precise and effective. As a result, the proposed strategy can serve as an alternate method to determine related substances in routine analysis of tablet dosage form.

Chromate Incarceration by Nanojars and Its Removal from Water by Liquid-Liquid Extraction.

The unprecedented liquid-liquid extraction of the dinegative chromate ion (CrO42-) from neutral aqueous solutions into aliphatic hydrocarbon solvents using nanojars as extraction agents is demonstrated. Transferring chromate from water into an organic solvent is extremely challenging due to its large hydration energy (ΔGh° = -950 kJ/mol) and strong oxidizing ability. Owing to their highly hydrophilic anion binding pockets lined by a multitude of hydrogen bond donor OH groups, neutral nanojars of the formula [cis-CuII(μ-OH)(μ-4-Rpz)]n (n = 27-33; pz = pyrazolate anion; R = H or n-octyl) strongly bind the CrO42- ion and efficiently transfer it from water into n-heptane or C11 - C13 isoalkanes (when R = n-octyl). The extracted chromate can easily be recovered from the organic layer by stripping with an aqueous acid solution. Electrospray ionization mass spectrometric, UV-vis and paramagnetic 1H NMR spectroscopic, X-ray crystallographic, and thermal stability studies in solution and chemical stability studies toward NH3, methanol, and Ba2+ ions are employed to explore the binding of the CrO42- ion by nanojars. Titration of carbonate nanojars [CO3 ⊂ {Cu(OH)(pz)}n]2- with H2CrO4 leads to anion exchange and the formation of chromate nanojars [CrO4 ⊂ {Cu(OH)(pz)}n]2-. Details of chromate binding by H-bonding based on single-crystal structures of (Bu4N)2[CrO4 ⊂ {Cu(OH)(pz)}28], four pseudopolymorphs of (Bu4N)2[CrO4 ⊂ {Cu(OH)(pz)}31], and also the methoxy-substituted derivative (Bu4N)2[CrO4 ⊂ {Cu31(OH)30(OCH3)(pz)31}] are presented.

DEVELOPMENT AND VALIDATION OF STABILITY INDICATING RP-HPLC METHOD FOR QUANTITATIVE ESTIMATION OF LENALIDOMIDE AND ITS IMPURITIES IN SOLID DOSAGE FORM

Highly sensitive RP-HPLC method has been developed for the determination and quantification of Lenalidomideimpurities in Lenalidomide liquid dosage formulations. Samples are analysed by means of reverse phase (RP-HPLC) usingstationary phase an Inertsil ODS-3V (150 x 4.6 mm, 3μm) and the mobile phase consists of two channels A and B;channel-A: pH 3.0 phosphate buffer and channel-B: Acetonitrile: water (90:10 v/v). The flow rate was 1.0 mL/min.The column temperature was maintained at 40°C and sample cooler temperature was maintained at 5°C, injectionvolume 20 μL and wavelength 210 nm. The developed HPLC method was validated with respect to specificity,precision, linearity, accuracy, solution stability and filter study. Validation study was compared as per ICH guideline.

Naphthoyl benzhydrazine-decorated binuclear arene Ru(II) complexes as anticancer agents targeting human breast cancer cells.

Breast cancer is the most dangerous type in women and its fatality rate has increased over the past decade. To develop more potent and target-specific breast cancer drugs, six arene ruthenium(II) complexes (1-6) containing naphthoyl benzhydrazine ligands (NL1-NL3) were synthesized and characterized by analytical and spectroscopic (infrared, UV-visible, NMR and HR-MS) methods. The SC-XRD analysis of 1 and 6 demonstrates the bis N^O bidentate binding nature of ligands to ruthenium ions and a pseudo-octahedral geometry around the Ru(II) ion. Solution stability studies using UV-Vis spectroscopy evidenced the instantaneous hydrolysis of the complexes to form monoaquated species in a solution of 1 : 9 (v/v) DMSO/phosphate buffer. All the complexes were screened for their in vitro antiproliferative activities against different human breast cancer cells, including MCF-7, SkBr3, MDA-MB-468, MDA-MB-231, and non-cancerous HEK-293 cells, by an MTT assay, and they displayed good cancer cell growth inhibitory capacity with low IC50 values. Notably, complexes 2 and 5 comprising methoxy and p-cymene groups exhibited excellent cytotoxicity towards SkBr3 cells compared to clinical drug cisplatin. AO-EB and HOECHST-33342 staining assays revealed apoptotic morphological changes in complex-treated cancer cells. Further, reactive oxygen species and mitochondrial membrane potential assays validated that the complexes induce apoptotic cell death via an intrinsic mitochondrial pathway with ROS production. In addition, the apoptotic induction and the quantification of late apoptosis were established with the aid of western blot and flow cytometry analysis, respectively.

DEVELOPMENT AND VALIDATION OF A NOVEL STABILITY INDICATING REVERSE PHASE HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC METHOD FOR RELATED SUBSTANCES AND ASSAY ANALYSIS OF MOLNUPIRAVIR DRUG SUBSTANCE AND DRUG PRODUCT

Molnupiravir, a broad-spectrum antiviral is an isopropyl ester prodrug of β-D-N4-hydroxycytidine. Molnupiravir targets RNA-dependent RNA-polymerase enzyme of the viruses. A new stability-indicating HPLC-method was developed to determine related substances and assay of molnupiravir. Separation was achieved by using Shim-pack GWS C18 column. The method was validated according to current ICH requirements. The calibration plot gave a linear relationship for all known analytes over the concentration range from LOQ to 200%. LOD and LOQ for all known analytes were found in 0.05-0.08 µg mL-1 and 0.12-0.20 µg mL-1, respectively, the mean recovery was found to be 97.79-102.44 %. Study showed that the method, results of robustness, solution stability studies are precise and within the acceptable limits. Molnupiravir was found to degrade in acid, alkali, and oxidative conditions, and was stable in thermal, moisture, and photolytic degradation condition. The method is simple, accurate, precise, and reproducible for routine purity analysis of drug-samples.

The nicotinamide ruthenium(II) complex induces the production of reactive oxygen species (ROS), cell cycle arrest, and apoptosis in melanoma cells

A set of new ruthenium complexes, [RuCl(NIC)(dppb)(4,4′-Me-bipy)]PF6 (C1), [RuCl(NIC)(dppb)(4,4′-Methoxy-bipy)]PF6 (C2), and [RuCl(NIC)(dppb)(5,5′-Me-bipy)]PF6 (C3), where NIC = 3-pyridinecarboxamide, 4,4′-Me-bipy = 4,4′-dimethyl-2,2′-bipyridine, 4,4′-Methoxy-bipy = 4,4′-dimethoxy-2,2′-bipyridine, and 5,5′-Me-bipy = 5,5′-dimethyl-2,2′-bipyridine were synthesized and characterized by elemental analysis, UV/Vis and infrared spectroscopy, 31P{1H},1H, 13C{1H} nuclear magnetic resonance (NMR), and cyclic voltammetry. In addition, the structure of [RuCl(NIC)(dppb)(4,4′-Me-bipy)]PF6 was confirmed by single crystal X-ray diffraction (XRD). The solution stability study of C1-C3 showed the formation of pyridine which was coordinated due to solvent protic attacked to nicotinamide, and an elimination reaction of a carbamate group was observed. C1-C3 interacted with DNA through intercalation, electrostatic forces of attraction, or hydrogen bonding. The complexes interacted, moderately and spontaneously, with HSA, mainly through Van der Waals and hydrogen bond interactions. An in vitro evaluation of the (C1-C3) complexes revealed a cytotoxicity against MCF-7, HepG2, A549, SK-MEL-147, WM1366, and CHL-1. A higher cytotoxicity was observed for compound (C3) against melanoma cell cancer (CHL-1). Moreover, the (C3) complex inhibited the clonogenic capacity and cell cycle progression of CHL-1 cells and induced apoptosis involving the production of reactive oxygen species (ROS). [RuCl(py)(dppb)(5,5′-Me-bipy)]PF6 presented a very close C3 cytotoxicity against melanoma cell cancer (CHL-1).

Bifunctionalized Polyoxotungstates: Dilacunary Keggin Clusters Incorporating FeIIIand Organoarsonate Constituents

Polyanions [{B-α-(OH)Fe2(PW10O37)}2{o-R–C6H4–AsO3)}2]12– (R = NH2 (1) and NO2 (2)) represent the first polyoxotungstates functionalized by both organoarsonates and FeIII. 1 and 2 comprise the rare dilacunary Keggin-type phosphotungstate {B-α-PW10O37}9– isomer that coordinates FeIII ions to form {B-α-FeIII2PW10} complexes linked into dimers via two organoarsonate groups. The title polyanions have been isolated as crystalline materials and fully characterized via single-crystal and powder X-ray diffraction, elemental analysis and IR and UV–vis spectroscopies, including solution stability studies. In addition, their electrochemical and magnetic properties have been characterized.

STEP TOWORDS THE FORMULATION OF INJECTABLE HYDROGEL: PREFORMULATION STUDIES OF TERIFLUNOMIDE

Purpose: The aim of formulation of this hydrogel is to treat the osteoarthritis which is one of the common inflammatory autoimmune disorders of joints. The use of conventional drugs like NSAIDs having various side effects.
 The aim of our research was to develop a formulation of injectable hydrogel containing teriflunomide. This study will be helps us for the development of stable, robust and therapeutically effective dosage form.
 Method: Solubility of Teriflunomaide was determined by using various solvents. By using infrared spectrum and absorption maxima the purity of sample was checked. With the help of UV spectrophotometer standard UV curve was developed. Drug excipients compatibility studies were performed using Fourier transform infrared spectroscopy, differential scanning colorimetry, partition coefficient and also short term drug solution stability studies were performed.
 Result: Teriflunomide is soluble in methanol & 0.1 N NaOH on the other hand poorly soluble in distilled water, phosphate buffer (pH 7.4) and 0.1 N HCl. Absorption maxima was observed at 292nm and infrared spectrum was showing the characteristic peaks. The standard curve obtained was linear with correlation coefficient below 1. Log P value obtained at 2.78 it confirms that teriflunomide is having both hydrophilic & hydrophobic nature. After the entire short term stability studies drug was found to be stable in short term stability studies.
 Conclusion: The studies like melting point, FTIR etc suggested that drug selected for the formulation was found to be pure. Partition coefficient values suggested that it is having both hydrophilic and hydrophobic nature. Results obtained from short term stability studies were suggested that drug is stable showing no degradation on phosphate buffer which confirmed by no shift of λ max.

A Validated RP-HPLC Method for Simultaneous Determination of Cefixime and Clavulanic Acid Powder in Pediatric Oral Suspension.

A new reverse phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the simultaneous estimation of pediatric oral powder formulation containing cefixime (CFX) and clavulanic acid (CVA). In this research, an analytical C18 (4.6 mm × 25 cm), 5 μm column was used for chromatographic separation with a mixture of methanol and water containing disodium hydrogen phosphate in ratio of 20 : 80 v/v as the mobile phase (pH 5.5 adjusted with orthophosphoric acid) at a flow rate of 1.0 mL/min. The detecting wavelength and run time were 220 nm and 15 min, respectively. Moreover, the column temperature was maintained at 30°C. The analytical method was validated prior to meeting the conditions specified by International Conference on Harmonization (ICH) and the parameters were specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision, robustness, and solution stability. The calibration curve was found to be linear between the concentration ranges of 0.024–0.036 mg/mL and 0.032–0.048 mg/mL for CFX and CVA, respectively. Furthermore, the LOD and LOQ of CFX were 0.0008 and 0.0025 μg/mL, respectively. Accordingly, LOD and LOQ of CVA were 0.0021 and 0.0065 μg/mL, respectively. The accuracy of the optimized method was examined by recovery studies and the mean recovery was observed to be 98.96% and 99.05% for CFX and CVA, respectively, at 100% spiked level. The repeatability testing for both standard and sample solutions revealed that the method is precise within the acceptable range and the %RSD of the precision was <2%. In addition, the findings of specificity, linearity, accuracy, precision, robustness, LOD, LOQ, and solution stability studies of both CFX and CVA were within the criteria of acceptable limit as well.

Supramolecular Incarceration and Extraction of Tetrafluoroberyllate from Water by Nanojars.

The previously unexplored noncovalent binding of the highly toxic tetrafluoroberyllate anion (BeF42-) and its extraction from water into organic solvents are presented. Nanojars resemble anion-binding proteins in that they also possess an inner anion binding pocket lined by a multitude of H-bond donors (OH groups), which wrap around the incarcerated anion and completely isolate it from the surrounding medium. The BeF4-binding propensity of [BeF4⊂{CuII(OH)(pz)}n]2- (pz = pyrazolate; n = 27-32) nanojars of different sizes is investigated using an array of techniques including mass spectrometry, paramagnetic 1H, 9Be, and 19F NMR spectroscopy, and X-ray crystallography, along with thermal stability studies in solution and chemical stability studies toward acidity and Ba2+ ions. The latter is found to be unable to precipitate the insoluble BaBeF4 from nanojar solutions, indicating a very strong binding of the BeF42- anion by nanojars. 9Be and 19F NMR spectroscopy allows for the unprecedented direct probing of the incarcerated anion in a nanojar and, along with 1H NMR studies, reveals the fluxional structure of nanojars and their inner anion-binding pockets. Single-crystal X-ray diffraction provides the crystal and molecular structures of (Bu4N)2[BeF4⊂{Cu(OH)(pz)}32], which contains a novel Cux-ring combination (x = 9 + 14 + 9), (Bu4N)2[BeF4⊂{Cu(OH)(pz)}8+14+9], and (Bu4N)2[BeF4⊂{Cu(OH)(pz)}6+12+10] and offers detailed structural parameters related to the supramolecular binding of BeF42- in these nanojars. The extraction of BeF42- from water into organic solvents, including the highly hydrophobic solvent n-heptane, demonstrates that nanojars are efficient binding and extracting agents not only for oxoanions but also for fluoroanions.

Iron (III)-mediated degradation of α-asarone and characterization of its major degradation products by UPLC-MS/MS and NMR.

α-Asarone, the main bioactive phytochemicals of Acorus species, is widely used in the treatment of respiratory disorders. The solution stability study of α-asarone was investigated in the presence of various metal ions. α-Asarone was found to be unstable in the presence of the metal ions Fe3+, Cu2+ and Al3+, in which the induction of Fe3+ was highly prone to the degradation of α-asarone. Thus, an iron (III)-mediated forced degradation study of α-asarone was carried out. One oxidative and four dimeric products were formed after the degradation of α-asarone. The complete mass fragmentation patterns for α-asarone and its degradation products (DPs) were established by UPLC-MS/MS in the positive ionization mode, and their structural confirmation was accomplished with 1H and 13C NMR. Then, the mechanistic pathways for the formation of all DPs were postulated. Finally, the oxidation degradation behavior and mechanism of α-asarone in the presence of oxidative stressors viz., hydrogen peroxide and azobisisobutyronitrile were explored.

Synthesis, Characterization, and Cytotoxicity of Morpholine-Containing Ruthenium(II) p-Cymene Complexes.

Morpholine motif is an important pharmacophore and, depending on the molecular design, may localize in cellular acidic vesicles. To understand the importance of the presence of pendant morpholine in a metal complex, six bidentate N,O-donor ligands with or without a pendant morpholine unit and their corresponding ruthenium(II) p-cymene complexes (1-6) are synthesized, purified, and structurally characterized by various analytical methods including X-ray diffraction. Complexes 2-4 crystallized in the P21/c space group, whereas 5 and 6 crystallized in the P1̅ space group. The solution stability studies using 1H NMR support instantaneous hydrolysis of the native complexes to form monoaquated species in a solution of 3:7 (v/v) dimethyl sulfoxide-d6 and 20 mM phosphate buffer (pH* 7.4, containing 4 mM NaCl). The monoaquated complexes are stable for at least up to 24 h. The complexes display excellent in vitro antiproliferative activity (IC50 ca. 1-14 μM) in various cancer cell lines, viz., MDA-MB-231, MiaPaCa2, and Hep-G2. The presence of the pendant morpholine does not improve the dose efficacy, but rather, with 2-[[(2,6-dimethylphenyl)imino]methyl]phenol (HL1) and its pendant morpholine analogue (HL3) giving complexes 1 and 3, respectively, the antiproliferative activity was poorer with 3. MDA-MB-231 cells treated with the complexes show that the acidic vesicles remain acidic, but the population of acidic vesicles increases or decreases with time of exposure, as observed from the dispersed red puncta, depending on the complex used. The presence of the 2,6-disubstituted aniline and the naphthyl group seems to improve the antiproliferative dose. The complex treated MDA-MB-231 cells show that cathepsin D, which is otherwise present in the cytosolic lysosomes, translocates to the nucleus as a result of exposure to the complexes. Irrespective of the presence of a morpholine motif, the complexes do not activate caspase-3 to induce apoptosis and seem to favor the necrotic pathway of cell killing.

Stability Indicating Method Development and Validation for Assay of Omeprazole Sodium for Injection by a Rapid RP-HPLC

Omeprazole,13 a member of proton pump inhibitor, used for the treatment of peptic ulcers, it supresses gastric acid secretion by inhibiting H+/K+ ATPase. A new fundamental, rapid and sensitive HPLC method was developed for the assay of Omeprazole sodium for injection. It was validated according to ICH and FDA guidelines 2. The HPLC analysis was performed on Dionex ultimate 3000 system equipped with C-18 (150cm*4.6mm) 5µ column, with a mixture of ammonium acetate and acetonitrile buffer in the ratio 65:35 v/v as the mobile phase at the wavelength (λ) 305nm. The total run time was 8 minutes. The calibration curve was linear for 50-150% range of the analytical concentration of 40mg/ml, r2 was found to be 0.9998. The precision was calculated and % RSD was 0.1 % and the recovery of omeprazole was within the range of 98-102%. Validation parameters like robustness, solution stability studies, specificity and forced degradation studies were performed and found to be within acceptance limits. As compared to other methods, this method was found to be more accurate, linear, precise and specific, with short run time. All the results were acceptable and confirmed that the method is suitable for its intended use in routine quality control analysis.&#x0D;

Fluorescence-based method for sensitive and rapid estimation of chlorin e6 in stealth liposomes for photodynamic therapy against cancer.

Chlorin e6 is a chlorine-based porphyrin containing photosensitizer mainly used for the therapy in cancers like neck and head, early-stage lung cancer, and topical skin cancers. The present study provides a comprehensive account of a highly sensitive, precise, and validated method for the quantification of chlorin e6 in its liposomal formulation. This method is based on the systemic study of the fluorescence action of chlorin e6 in acetonitrile solvent. This experiment follows the analytical method validation parameters as per the International Conference on Harmonization (ICH). Chlorin e6 molecule exhibits strong fluorescence at a wavelength of emission 665nm, upon excitation at a wavelength of excitation 400nm in acetonitrile. The linearity of the fluorescence concentration plot was observed over a concentration range of 50 to 1000ng/mL. The developed and validated method was successfully applied for the estimation of encapsulation efficiency in in-house developed stealth liposomes. Also, stock solution stability and photodegradation study of chlorin e6 were further conducted.

One-step solution synthesis and stability study of inorganic perovskite semiconductor Cs2SnI6

Inorganic perovskite semiconductor Cs2SnI6 is a promising solar light absorber material to replace its unstable organic-inorganic counterpart in perovskite solar cells. However, at present its synthesis method is still complex and expensive. Here we report a simple one-step solution method to synthesize the Cs2SnI6 powder, and then the effects of reactant type, reactant ratio and reaction solvent on the purity, crystallinity, optical and electrical properties, air and thermal stability of the Cs2SnI6 power were studied. We find that pure and crystalline Cs2SnI6 powder can be achieved in acetonitrile or anhydrous ethanol with a CsI:SnI2 ratio of 1:1, or with a CsI:SnI4 ratio of 3:2 (or 2:1). Cs2SnI6 film with better crystallinity usually has a stronger optical absorption, a lower carrier concentration, a higher carrier mobility, and a better air and thermal stablity. Optical absorption of Cs2SnI6 synthesized in anhydrous ethanol and acetonitrile keeps almost unchanged at the anneal temperature up to 150 °C.

An Orthogonal Approach for Determination of Acetamide Content in Pharmaceutical Drug Substance and Base-Contaminated Acetonitrile by GC and GC-MS External Method.

Acetamide is a potential genotoxic impurity; it should control in drug substance based on daily dosage level. It forms from base-contaminated acetonitrile and by-product of some drug substances. The available methods for acetamide in drug substance and water samples were determined by GC-MS using internal standard with critical procedures. These developed and validated methods can assist in evaluating the reaction between acetonitrile and different bases and also determine trace level acetamide in drug substances. The method development was initiated with DB-624, 30 m, 0.32 width and 1.0-μm column. The column was used to validate at the 600ppm TTC value. Similarly, the CP-SIL 5CB, 60 m, 0.32 width, the 5-μm column was used for the remaining TTC values. The validation study was performed for all TTC limits. The % RSD for precision at 600, 60, 20, 10 and 2.5ppm was <15%. The % recovery at all TTC level was in between the 70 and 130%. Solution stability study was performed up to the 24h. At 2.5ppm, the results were <15% variation from the initial value. The linearities from the 50 to 150% concerning TTC values were more than limit of 0.98 correlation coefficient. The limit of detection and limit of quantitation values were 0.4 to the 1.3ppm, respectively, for 2.5ppm TTC limit method.