Analytical Method Capable of Quantifying Eight Nitrosamine Impurities from Five Different Commercially Available Metformin Formulations with Glipizide, Glibenclamide, Gliclazide, Evogliptin, and Glimepiride by Ultra High Performance Liquid Chromatography Tripple Quadrupole Mass Spectrometry.

Metformin and its combinations are widely used to treat type 2 diabetes. The drugs commonly used in combination with Metformin are Glipizide, Glibenclamide, Gliclazide, Evogliptin, and Glimepiride. Combination therapy is preferred over monotherapy of Metformin in most diabetics. About eighteen pharmaceutical manufacturers have lately recalled metformin formulation batches from the U.S. market due to N-nitrosodimethylamine (NDMA) impurities based on the food and drug administration (USFDA) guideline "Control of Nitrosamine in Human Drugs." European Medicines Agency (EMA) and Health Canada have also established guidelines for nitrosamine impurities. Nitrosamines are well-known mutagenic impurities and probable human carcinogens found in pharmaceutical formulations. Thus, global regulatory agencies require pharmaceutical and formulation manufacturers to complete risk assessments for nitrosamine impurities for patient safety. Therefore, drug manufacturers must develop analytical techniques for monitoring trace nitrosamine impurities. Quantifying nitrosamine impurities in formulations requires modern equipment like LC-MS/MS and great intellect. The present study intends to give a single pre-packaged LC-MS/MS method parameters, including liquid chromatography and triple quadrupole mass spectrometer configuration. This method could quantify eight nitrosamine impurities from five different Metformin combinations (Metformin with Glipizide, Glibenclamide, Gliclazide, Evogliptin, and Glimepiride). The atmospheric pressure chemical ionisation (APCI) was used as an ionisation source, and the mass spectrometer was set to multiple reaction monitoring (MRM) mode for all eight nitrosamine impurities. A unified pre-packaged analytical setup allows analytical chemists to develop a reliable, sensitive, robust, and precise method for quantifying eight nitrosamine impurities from five different Metformin formulations of varying manufacturers. This analytical method saves time, money, and the environment using fewer pharmaceutical chemicals.

Development and validation of an analytical method for trace-level quantification of genotoxic nitrosamine impurities in losartan and hydrochlorothiazide fixed-dose combination tablets using ultra performance liquid chromatography triple quadrupole mass spectrometry.

RATIONALE: Since June 2018, globally large numbers of pharmaceuticals have been recalled due to the unexpected presence of nitrosamines. Beginning with the class of pharmaceuticals known as sartans, subsequent lines of inquiry included antidiabetic medicines, antihistamines, and antibiotics. A critical review of the U.S. Food and Drug Administration database reveals that the highest number of products recall due to the presence of unacceptable levels of nitrosamines were losartan potassium drug products and their coformulations with other drug substances. The problem can be mainly attributed to naively adopted approval revisions and the lack of sufficient current analytical technologies to detect those contaminants in time. In this work, we developed a specific, selective, accurate, precise, and robust ultra-performance liquid chromatography-triple quadrupole-mass spectrometry (UPLC-TQ-MS/MS) method for the estimation of eight genotoxic nitrosamine impurities in losartan and hydrochlorothiazide (HCTZ) tablets, which is the only fixed-dosage combination approved by the USFDA to treat hypertension. METHODS: All the nitrosamine impurities along with the drug substances were separated using an Agilent Pursuit XRs Ultra diphenyl column (150 × 2.0 mm, 2.8 µm) with mobile phase A (0.1% formic acid in water) and mobile phase B (0.1% formic acid in methanol) at a flow rate of 0.4 ml/min using the gradient elution program. The proposed method was validated per ICH (International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use) Q2 (R1) guidelines to ensure the method is suitable for its intended purpose. RESULTS: Limit of detection and limit of quantification were obtained in the range of 0.25-0.5 ng/mL, which was very low compared to levels specified by the USFDA, European Medicines Agency (EMA), and other regulatory authorities that ensure the sensitivity of the method in its entire life cycle. CONCLUSIONS: The developed method can be incorporated into an official monograph and applied for routine quality control analysis of losartan and HCTZ fixed-dose combination tablets.

Preparation and evaluation of sublingual tablets of zolmitriptan.

AIM: Zolmitriptan is a 5-HT receptor agonist (1B/1D). It is used in the acute treatment of migraine having low bioavailability about 40% orally due to hepatic first pass metabolism. The purpose of the present research was to formulate fast acting sublingual tablets of zolmitriptan. MATERIALS AND METHODS: Sublingual tablets were prepared using ispaghula husk powder, gellan gum, sodium alginate as super disintegrating polymers and citric acid, tartaric acid and camphor as permeation enhancers by direct compressible technique and evaluated for weight variation, thickness, friability, content uniformity, hardness, disintegration time, wetting time, in-vitro drug release, in-vitro and ex-vivo permeation study. Stability study of optimized formulation was performed as per ICH (International Conference on Harmonisation) guideline. RESULTS: The in-vitro disintegration time of the optimized formulation (D5) was 9 ± 2 s and all formulations showed 100% of dissolution within 6 ± 2 min. Formulation containing 4% of gellan gum (D5) showed highest disintegration and 2% of citric acid formulation (P3) showed highest permeation 88% within 30 min and ex-vivo permeation was 52% within 30 min. Optimized formulation was stable for 1 month during stability study as per ICH guideline. CONCLUSION: The sublingual tablet formulation gives better results using natural super disintegrant for fast onset of action.

Synthesis, antifungal activity, and QSAR studies of 1,6-dihydropyrimidine derivatives.

INTRODUCTION: A practical synthesis of pyrimidinone would be very helpful for chemists because pyrimidinone is found in many bioactive natural products and exhibits a wide range of biological properties. The biological significance of pyrimidine derivatives has led us to the synthesis of substituted pyrimidine. MATERIALS AND METHODS: With the aim of developing potential antimicrobials, new series of 5-cyano-6-oxo-1,6-dihydro-pyrimidine derivatives namely 2-(5-cyano-6-oxo-4-substituted (aryl)-1,6-dihydropyrimidin-2-ylthio)-N-substituted (phenyl) acetamide (C1-C41) were synthesized and characterized by Fourier transform infrared spectroscopy (FTIR), mass analysis, and proton nuclear magnetic resonance ((1)H NMR). All the compounds were screened for their antifungal activity against Candida albicans (MTCC, 227). RESULTS AND DISCUSSION: Quantitative structure activity relationship (QSAR) studies of a series of 1,6-dihydro-pyrimidine were carried out to study various structural requirements for fungal inhibition. Various lipophilic, electronic, geometric, and spatial descriptors were correlated with antifungal activity using genetic function approximation. Developed models were found predictive as indicated by their square of predictive regression values (r(2pred)) and their internal and external cross-validation. Study reveals that CHI_3_C, Molecular_SurfaceArea, and Jurs_DPSA_1 contributed significantly to the activity along with some electronic, geometric, and quantum mechanical descriptors. CONCLUSION: A careful analysis of the antifungal activity data of synthesized compounds revealed that electron withdrawing substitution on N-phenyl acetamide ring of 1,6-dihydropyrimidine moiety possess good activity.

Determination of galantamine hydrobromide in bulk drug and pharmaceutical dosage form by spectrofluorimetry.

AIM: To develop a simple, accurate, sensitive, rapid and precise method for the determination of galantamine hydrobromide in bulk drug and pharmaceutical dosage form. MATERIAL AND METHODS: The method employs wavelength detection and determination of galantamine hydrobromide at excitation wavelength 282 nm and emission wavelength 607 nm in a solution of simple distilled water. RESULT AND CONCLUSION: The method was found to be linear in the range of 2-14 µg/ml having r (2) = 0.9999. The mean accuracy was found to be 98.12% to 99.67%. The intraday and interday precision was found to be 0.18-0.35% and 0.13-0.46%, respectively. The limit of detection was found to be 0.29 µg/ml. The limit of quantification was found to be 0.89 µg/ml. The method was successfully applied for the determination of galantamine hydrobromide in bulk drug as well as pharmaceutical dosage form.

Formulation and evaluation of liquisolid compacts for olmesartan medoxomil.

Olmesartan medoxomil is an angiotensin type II receptor blocker, antihypertensive agent, administered orally. It is highly lipophilic (log P 5.5) and a poorly water-soluble drug with absolute bioavailability of 26%. The poor dissolution rate of water-insoluble drugs is still a major problem confronting the pharmaceutical industry. The objective of the present investigation was to develop liquisolid compacts for olmesartan medoxomil to improve the dissolution rate. Liquisolid compacts were prepared using Acrysol El 135 as a solvent, Avicel PH 102, Fujicalin and Neusilin as carrier materials, and Aerosil as coating material in different ratios. The interaction between drug and excipients was characterized by DSC and FT-IR studies, which showed that there is no interaction between drug and excipients. The powder characteristics were evaluated by different flow parameters to comply with pharmacopoeial limits. The dissolution studies for liquisolid compacts and conventional formulations were carried out, and it was found that liquisolid compacts with 80% w/w of Acrysol EL 135 to the drug showed significant higher drug release rates than conventional tablets. Amongst carriers used Fujicalin and Neusilin were found to be more effective carrier materials for liquid adsorption.

Preparation and Characterization of Self-Microemulsifying Drug Delivery System of Olmesartan Medoxomil for Bioavailability Improvement.

Olmesartan medoxomil (OLM) is an angiotensin II receptor blocker (ARB) antihypertensive agent administered orally that has absolute bioavailability of only 26% due to the poor aqueous solubility (7.75 µg/ml). The aim of the present investigation was to develop a self-microemulsifying drug delivery system (SMEDDS) to enhance the oral absorption of OLM. The solubility of OLM in various oils, surfactants, and cosurfactants was determined. Pseudoternary phase diagrams were constructed using Acrysol EL 135, Tween 80, Transcutol P, and distilled water to identify the efficient self-microemulsification region. Prepared SMEDDS was further evaluated for its emulsification time, drug content, optical clarity, droplet size, zeta potential, in vitro dissolution, and in vitro and ex vivo drug diffusion study. The optimized formulation S2 contained OLM (20 mg), Tween 80 (33%v/v), Transcutol P (33%v/v), and Acrysol EL 135 (34%v/v) had shown the smallest particle size, maximum solubility, less emulsification time, good optical clarity, and in vitro release. The in vitro and ex vivo diffusion rate of the drug from the SMEDDS was significantly higher than that of the plain drug suspension. It was concluded that SMEDDS would be a promising drug delivery system for poorly water-soluble drugs by the oral route.

Synthesis and screening of antibacterial and antifungal activity of 5-chloro-1,3-benzoxazol-2(3 h)-one derivatives.

BACKGROUND: An antibacterial is a substance that either kills bacteria or slows their growth. Antifungal are the agents that use drugs for treatment of fungal infections. 5-Chloro-1,3-benzoxazol-2(3 H)-one (5-Chloro Benzoxazolinone) contains an azole ring structure. Numbers of azole compounds are reported as antibacterial and antifungal agents. Benzoxazolinones naturally occur in plants. They play a role as defense compounds against bacteria, fungi, and insects. RESULTS: In this article, synthesis of six Benzoxazolinone derivatives with various substituents is presented. Benzoxazolinone substituted with p-aminobenzoic acids and sulphanilamide derivatives. The above both substituents are reported as potent antimicrobial agents. Attachment with azole leads to increase its potency. The other substituents are 2,4-dichlorobezylchloride. The same rings are found in miconazole and this may lead to increase its antifungal activity. Fluconazole also contains triazole moiety and triazole is having other numbers of activity like antimicrobial, anti-inflammatory, local anesthetic, antiviral, anticancer, antimalarial, etc. Here, there is a substitution for azole ring at 5-Chloro position which might increase antibacterial and antifungal activity. The synthesis and interpretation of six final compounds and three intermediates are presented in this article. Synthesis of 5-Chloro Benzoxazolinone derivatives substituted with Halogenated rings, sulfonated and benzylated derivatives and azole derivatives. There is a synthesis of P2A, P2B, P4A, P4B, P5A, and P6A compounds and their structures were characterized by UV-Visible, IR, MASS spectroscopy, and NMR spectroscopy. CONCLUSIONS: The antibacterial activity of all six compounds is measured against various Gram-positive and Gram-negative bacteria and against fungi. Compounds P4A and P4B have good antibacterial and antifungal activity, half of the Ampicillin and Cephalexin. P4A, P4B, P6A have good activity against Staphylococcus aureus and Escherichia coli. Compound P2B has good antifungal activity, half of the Miconazole against Candida albicans. P2A, P2B, P5A, P6A have almost equal antibacterial activity.

RP-HPLC method for simultaneous estimation of tenofovir disoproxil fumarate, lamivudine, and efavirenz in combined tablet dosage form.

BACKGROUND: A simple, precise, accurate, and rapid reverse phase-high performance liquid chromatography (RP-HPLC) method with UV-Visible detector has been developed and subsequently validated for the simultaneous determination of tenofovir disoproxil fumarate (TDF), lamivudine (LAMI), and efavirenz (EFV) in their combined tablet dosage form. MATERIALS AND METHODS: The separation was based on the use of a Kromasil C18 analytical column (150 × 4.6 mm, i.d., 5 µm). The mobile phase consisted of a mixture of 70 volumes of methanol and 30 volumes of 10 mM phosphate buffer (pH 5.0). The separation was carried out at 40°C temperature with a flow rate of 1 ml/min. RESULTS: Quantitation was achieved with UV detection at 254 nm, with linear calibration curves at concentration ranges of 1-6 µg/ml for TDF and LAMI and 2-12 µg/ml for EFV. The recoveries obtained were 99.46-101.36% for LAMI, 99.57-101.42% for TDF, and 99.96-100.87 for EFV. CONCLUSION: The method was validated according to International conference of harmonisation guidelines in terms of accuracy, precision, specificity, robustness, limits of detection and quantitation, and other aspects of analytical validation.

Development and validation of the liquid chromatography-tandem mass spectrometry method for quantitative estimation of candesartan from human plasma.

INTRODUCTION: A simple and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for estimation of candesartan in human plasma using the protein precipitation technique. MATERIALS AND METHODS: The chromatographic separation was performed on reverse phase using a Betasil C8 (100 × 2.1 mm) 5-µm column, mobile phase of methanol:ammonium tri-floro acetate buffer with formic acid (60:40 v/v) and flow rate of 0.45 ml/min. The protonated analyte was quantitated in positive ionization by multiple reaction monitoring with a mass spectrometer. The mass transitions m/z 441.2 → 263.2 and 260.2 → 116.1 were used to measure candesartan by using propranolol as an internal standard. RESULTS: The linearity of the developed method was achieved in the range of 1.2-1030 ng/ml (r(2) ≥ 0.9996) for candesartan. CONCLUSION: The developed method is simple, rapid, accurate, cost-effective and specific; hence, it can be applied for routine analysis in pharmaceutical industries.

Simultaneous analysis of eprosartan and hydrochlorothiazide in tablets by high-performance liquid chromatography.

OBJECTIVE: A simple, precise and accurate isocratic reversed phase (RP) column high-performance liquid chromatographic (HPLC) method has been developed for simultaneous analysis of eprosartan (EPR) and hydrochlorothiazide (HCT) in tablet formulations. MATERIALS AND METHODS: Isocratic RP-HPLC separation was achieved on phenomenex C18 column (250 × 4.6 mm i.d., 5 µm particle size) using mobile phase composed of 0.5% formic acid-methanol-acetonitrile [(80 : 25 : 20 v/v/v) pH, 2.80 ± 0.04] at a flow rate of 1.0 ml/min. The retention time for EPR and HCT was 7.69 ± 0.10 and 4.24 ± 0.09 minutes, respectively. The detection was performed at 272 nm. RESULTS: The method was linear in the concentration range of 60-600 µg/ml for EPR and 2.5-25 µg/ml for HCT with a correlation coefficient of 0.9992 and 0.9997, respectively. The repeatability for six samples was 0.53 and 0.61 % RSD for EPR and HCT, respectively. The accuracy (recovery) was found to be in the range of 99.46 to 100.61% for EPR and 99.06 to 100.93% for HCT, respectively. CONCLUSIONS: The method was validated and successfully used for determination of the drugs in tablets.

Floating matrix tablets of domperidone formulation and optimization using simplex lattice design.

The purpose of this research was to prepare a floating matrix tablet containing domperidone as a model drug. Polyethylene oxide (PEO) and hydroxypropyl methylcellulose (HPMC) were evaluated for matrix-forming properties. A simplex lattice design was applied to systemically optimize the drug release profile. The amounts of PEO WSR 303, HPMC K15M and sodium bicarbonate were selected as independent variables and floating lag time, time required to release 50% of drug (t50) and 80% of drug (t80), diffusion coefficient (n) and release rate (k) as dependent variables. The amount of PEO and HPMC both had significant influence on the dependent variables. It was found that the content of PEO had dominating role as drug release controlling factor, but using suitable concentration of sodium bicarbonate, one can tailor the desired drug release from hydrophilic matrixes. The linear regression analysis and model fitting showed that all these formulations followed Korsmeyer and Peppas model, which had a higher value of correlation coefficient (r). The tablets of promising formulation were found to be stable for 3 months under accelerated (40°C / 75% RH) stability testing.

Development and validation of a high-performance liquid chromatographic method for determination of eprosartan in bulk drug and tablets.

A simple, precise, and accurate isocratic RP-HPLC method was developed and validated for determination of eprosartan in bulk drug and tablets. Isocratic RP-HPLC separation was achieved on a Phenomenex C18 column (250 x 4.6 mm id, 5 microm particle size) using the mobile phase 0.5% formic acid-methanol-acetonitrile (80 + 25 + 20, v/v/v, pH 2.80) at a flow rate of 1.0 mL/min. The retention time of eprosartan was 7.64 +/- 0.05 min. The detection was performed at 232 nm. The method was validated for linearity, precision, accuracy, robustness, solution stability, and specificity. The method was linear in the concentration range of 10-400 microg/mL with a correlation coefficient of 0.9999. The repeatability for six samples was 0.253% RSD; the intraday and interday precision were 0.21-0.57 and 0.33-0.71% RSD, respectively. The accuracy (recovery) was found to be in the range of 99.86-100.92%. The drug was subjected to the stress conditions hydrolysis, oxidation, photolysis, and heat. Degradation products produced as a result of the stress conditions did not interfere with detection of eprosartan; therefore, the proposed method can be considered stability-indicating.

Chitosan superporous hydrogel composite-based floating drug delivery system: A newer formulation approach.

OBJECTIVE: In this study efforts have been made to design a drug delivery system based on a superporous hydrogel composite, for floating and sustained delivery of Ranitidine hydrochloride. MATERIALS AND METHODS: The characterization studies were performed by the measurement of apparent density, porosity, swelling studies, mechanical strength studies, and scanning electron microscopy studies. The prepared formulation was evaluated for buoyant behavior, in vitro drug release, kinetics of drug release, and stability. The release profile of Ranitidine hydrochloride was investigated by changing the release retardant polymer in the formulation. To ascertain the kinetics of drug release, the drug release profiles were fitted to mathematical models that included zero-order, first-order, Higuchi, Hixson-Crowell, Korsmeyer-Peppas, Weibull, and Hopfenberg models. RESULTS: Scanning electron microscopy images clearly indicated the formation of interconnected pores and capillary channels, and cross-linked Chitosan molecules were observed around the peripheries of the pores. The prepared drug delivery system floated and delivered the Ranitidine hydrochloride for about 17 hours. The in vitro drug release from the proposed system was best explained by the Korsmeyer-Peppas model. The values of the diffusion exponent in the Korsmeyer-Peppas model ranged between 0.47 ± 0.02 and 0.66 ± 0.02, which appeared to indicate a coupling of the diffusion and erosion mechanisms, anomalous non-Fickian transport. CONCLUSION: It was concluded that the proposed floating drug delivery system, based on the superporous hydrogel composite containing Chitosan as a composite material, is promising for stomach-specific delivery of Ranitidine hydrochloride.

In vitro evaluation of marketed antimalarial chloroquine phosphate tablets.

BACKGROUND & OBJECTIVES: The aim of the present study is to investigate the physicochemical equivalence of seven brands of tablets containing chloroquine phosphate, an antimalarial purchased from different retail pharmacy outlets. METHODS: The quality and physicochemical equivalence of seven different brands of chloroquine phosphate tablets were assessed. The assessment included the evaluation of uniformity of weight, friability, crushing strength, disintegration and dissolution tests as well as chemical assay of the tablets. RESULTS: All the seven brands of the tablets passed the British Pharmacopoeia (BP) standards for uniformity of weight, disintegration and crushing strength. One of seven brands failed the friability test. One of the brands did not comply with the standard assay of content of active ingredients. Dissolution test passes the pharmacopoeial standards for chloroquine phosphate tablets. There were no significant differences in the amounts of chloroquine phosphate released from the different brands. INTERPRETATION & CONCLUSION: Out of the seven brands of anti-malarial chloroquine phosphate tablets only one brand fails to meet BP quality specifications which shows constant market monitoring of new products to ascertain their equivalency to pharmacopoeial standards.