Various techniques for resolving overlapping ultraviolet spectra of combination pharmaceutical dosage forms containing hydroxychloroquine and paracetamol.

Ten novel spectrophotometric approaches were developed for the initial examination of the Hydroxychloroquine and Paracetamol medications. These procedures are straightforward, specific, easy to use, and provide exact and accurate results. The determination was conducted through the utilization of several approaches, including zero order (dual wavelength, zero crossing, advanced absorption subtraction and spectrum subtraction), derivative (first derivative of zero crossing), ratio (ratio difference, ratio derivative) and mathematical (bivariate, simultaneous equation, and Q-absorbance) techniques. After undergoing validation in accordance with ICH criteria, it was established that each of these methods achieved acceptable levels of precision, repeatability, robustness, and accuracy. The advantages and disadvantages of each method are demonstrated, and the proposed and reported methodologies were statistically compared.

Different methods for resolving overlapping UV spectra of combination medicinal dose forms of ciprofloxacin and metronidazole.

Four simple, specific, easy, precise and accurate spectrophotometric methods were developed for the first time to examine ciprofloxacin and metronidazole in combination, without having been separated beforehand by the developed methods. Ciprofloxacin and metronidazole were determined by utilizing advanced absorbance subtraction (AAS), spectrum subtraction, bivariate and ratio difference methods. Precision, repeatability, robustness, and accuracy were all determined to be within acceptable levels after each of these procedures underwent validation in accordance with ICH recommendations. Each method's benefits and drawbacks are illustrated, and the proposed and reported methodologies were statistically compared.

Quality by design approach for development and validation of a RP-HPLC method for simultaneous estimation of xipamide and valsartan in human plasma.

A new rapid, simple, and sensitive RP-HPLC method was carried out through applying Quality by Design approach for determination of xipamide and valsartan in Human plasma. Fractional factorial design was used for screening of four independent factors: pH, flow rate, detection wavelength, and % of MeOH. Analysis of variance (ANOVA) confirmed that flow rate and % of MeOH were only significant. Chromatographic conditions optimization was carried out through using central composite design. Method analysis was performed using BDS Hypersil C8 column (250 × 4.6 mm, 5 µm) and an isocratic mobile phase of MeOH and 0.05 M KH2PO4 buffer pH 3 (64.5:35.5, v/v) at 1.2 mL/min flow rate with UV detection at 240 nm and 10 µL injection volume. According to FDA guidelines, the method was then validated for the determination of the two drugs clinically in human plasma in respect of future pharmacokinetic and bioequivalence simulation studies. The standard curve was linear in the concentration range of 5-100 µg/mL for both drugs, with a determination coefficient (R2) of 0.999. Also, the average recoveries lied within the range from 99.89 to 100.03%. The proposed method showed good predictability and robustness.

Toxicity Profile and Pharmacokinetic Study of Antibiotic Mixtures, Gentamicin and Vancomycin, in Rat Plasma by Ecofriendly Liquid Chromatography Coupled Tandem Mass Spectrometry.

The global burden of bacterial infection and antimicrobial resistance increases the demand to associate more than one antibiotic to fight life-threatening bacteria. Therefore, there is a great necessity to develop simple and sensitive methods for routine analysis of clinical samples. Therapeutic drug monitoring, bioequivalence, and pharmacokinetic studies are essential to ensure drug efficiency and safety. Herein, therefore, the first ecofriendly liquid chromatography -tandem mass spectrometry (LC-MS/MS) method was developed and fully validated for simultaneous determination of a commonly combined antibiotic for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin (VCM) and gentamicin (GTM), in rat plasma after parenteral administration. VCM and GTM were extracted from plasma sample using acetonitrile (ACN)/0.1% TFA-induced protein precipitation followed by the separation on an Agilent Eclipse Plus ODS (3 mm × 100 mm, 3.5 µm) column using water-enriched mobile phase consisting of water containing 0.1% THF/ACN (85:15, v/v%) at flow rates of 0.30 mL min-1. The mass spectrometry parameters were optimized, and multiple reaction monitoring (MRM) in positive ion mode of two transitions was utilized for quantification of precursor to product ion at m/z 725.5 → 144 and 100.1 for VCM as [M + 2H]2+, 478.3 → 322.2 and 156.9 for GTM, and 586.3 → 162.9 and 425.3 for amikacin (AMK) internal standard, as [M + H]+. The current method has been validated as per U.S. FDA bioanalytical guidelines in terms of linearity, accuracy, precision, selectivity, recovery, matrix effects, and stability. The method was linear in the range of 1-2000 ng mL-1 and 1-1000 ng mL-1 with detection limits (S/N of 3) of 0.18 and 0.09 ng mL-1 for VCM and GTM, respectively. The selectivity and high sensitivity allow the current method to succeed in the study of pharmacokinetic parameters and drug-drug interaction between VCM and GTM after single-dose administration. VCM increased plasma clearance and elimination rate constant of GTM when coadministered and GTM also too. The change of serum chemistry analysis and significant elevation of creatinine and BUN indicate an alteration in kidney function in group III in those given the combined antibiotics. Our finding illustrated the nephrotoxicity of the two drugs when associated. The ecofriendly, simplicity, and rapidity of the current study made it a promising method for high-throughput biomonitoring in clinical samples.

HPLC Determination of Imidazoles with Variant Anti-Infective Activity in Their Dosage Forms and Human Plasma.

A suitable HPLC method has been selected and validated for rapid simultaneous separation and determination of four imidazole anti-infective drugs, secnidazole, omeprazole, albendazole, and fenbendazole, in their final dosage forms, in addition to human plasma within 5 min. The method suitability was derived from the superiority of using the environmentally benign solvent, methanol over acetonitrile as a mobile phase component in respect of safety issues and migration times. Separation of the four anti-infective drugs was performed on a Thermo Scientific® BDS Hypersil C8 column (5 µm, 2.50 × 4.60 mm) using a mobile phase consist of MeOH: 0.025 M KH2PO4 (70:30, v/v) adjusted to pH 3.20 with ortho-phosphoric acid at room temperature. The flow rate was 1.00 mL/min and maximum absorption was measured with UV detector set at 300 nm. Limits of detection were reported to be 0.41, 0.13, 0.18, and 0.15 µg/mL for secnidazole, omeprazole, albendazole, and fenbendazole, respectively, showing a high degree of the method sensitivity. The method of analysis was validated according to Food and Drug Administration (FDA)guidelines for the determination of the drugs, either in their dosage forms with highly precise recoveries, or clinically in human plasma, especially regarding pharmacokinetic and bioequivalence studies.

Different techniques for overlapped UV spectra resolution of some co-administered drugs with paracetamol in their combined pharmaceutical dosage forms.

Six simple, specific, accurate and precise spectrophotometric methods were developed for the first time analysis of some co-administered drugs with paracetamol in their mixture form without prior separation. Paracetamol & orphenadrine citrate were determined by using dual wavelength, bivariate, ratio difference, ratio derivative and mean centering of ratio spectra methods. Paracetamol & caffeine were determined by using ratio difference, ratio derivative and mean centering of ratio spectra methods. Paracetamol & diclofenac sodium were determined by using advanced absorption subtraction, ratio difference, ratio derivative and mean centering of ratio spectra methods. All of these methods were validated according to ICH guidelines where accuracy, precision, repeatability and robustness were found to be within the accepted limits. Advantages and limitations of each method are demonstrated and statistical comparison between the proposed methods was performed.

Developing a High-performance Liquid Chromatography Method for Simultaneous Determination of Loratadine and its Metabolite Desloratadine in Human Plasma.

BACKGROUND: Allergic diseases are considered as the major burden on public health with increased prevalence globally. Histamine H1-receptor antagonists are the foremost commonly used drugs in the treatment of allergic disorders. The target drug in this study, loratadine, belongs to this class of drugs and its biometabolite desloratadine which is also a non-sedating H1 receptor antagonist with anti-histaminic activity being 2.5 to 4 times greater than loratadine. This study aimed to develop and validate a novel isocratic Reversed-phase High-Performance Liquid Chromatography (RP-HPLC) method for rapid and simultaneous separation and determination of loratadine and its metabolite, desloratadine in human plasma. METHODS: The drug extraction method from plasma was based on protein precipitation technique. The separation was carried out on a Thermo Scientific BDS Hypersil C18 column (5µm, 250 x 4.60 mm) in a mobile phase of MeOH: 0.025M KH2PO4 adjusted to pH 3.50 using orthophosphoric acid (85: 15, v/v) at an ambient temperature. The flow rate was maintained at 1 mL/min and maximum absorption was measured using the PDA detector at 248 nm. RESULTS: The retention times of loratadine and desloratadine in plasma samples were recorded to be 4.10 and 5.08 minutes, respectively, indicating a short analysis time. Limits of detection were found to be 1.80 and 1.97 ng/mL for loratadine and desloratadine, respectively, showing a high degree of sensitivity of the method. The method was then validated according to FDA guidelines for the determination of the two analytes in human plasma. CONCLUSION: The results obtained indicate that the proposed method is rapid, sensitive in the nanogram range, accurate, selective, robust and reproducible compared to other reported methods.

An LC-MS/MS spectrometry method for the simultaneous determination of Rosuvastatin and Irbesartan in rat plasma: Insight into pharmacokinetic and drug-drug interaction studies.

The synergistic vascular protective effect of statins and angiotensin receptor blockers (ARBs) is well known, however, the pharmacokinetic interaction among these classes is yet to be understood and the necessity of developing analytical methods for their determination in vivo is gradually increased. Herein, first chromatographic separation coupled tandem mass spectrometric was developed and fully validated for simultaneous measurement of rosuvastatin (ROS) and irbesartan (IRB) in rat plasma after oral administration. The two analytes were extracted from plasma sample using acetonitrile-induced protein precipitation then separated on an Agilent Eclipse Plus ODS (4.6 × 100 mm, 3.5 µm) column by gradient elution using 6 mM ammonium formate/0.1% formic acid and ACN at a flow rate 0.4 mL min-1. Multiple reaction monitoring in positive ion mode was used for quantification of precursor to production at m/z 492.1 → 206.9 for IRB, 482.1 → 258.1 for ROS, and 409.2 → 238.2 for the internal standard, amlodipine (AML). Linearity was obeyed in the range of 1-10000 ng mL-1 and 1-5000 ng mL-1 with detection limits (S/N of 3) of 0.05 and 0.07 ng mL-1 for IRB and ROS, respectively. The current method was validated in terms of selectivity, recovery, accuracy, precision, matrix effects, and stability as per US-FDA bioanalytical guidelines. The application of our method reported her is the first to study pharmacokinetic interaction of IRB and ROS in rat plasma after a single oral dose. The area under the concentration-time curve (AUC), peak plasma concentrations (Cmax), half-life time (t1/2), and volume of distribution (Vd) of ROS and IRB were affected when the two drugs were co-administering. The current study provided a valuable tool for studying drug-drug interaction and might be useful for therapeutic drug monitoring and bioequivalence studies.

Developing a High-Performance Liquid Chromatography (HPLC) Method for Simultaneous Determination of Oxytetracycline, Tinidazole and Esomeprazole in Human Plasma.

A high performance liquid chromatography method had been developed and validated for rapid simultaneous separation and determination of three anti-helicobacter drugs, oxytetracycline (OXY), tinidazole (TIN) and esomeprazole (ESM) in human plasma within 6 minutes. Drugs extraction method from plasma was based on protein precipitation technique. Separation was carried out on a Equisil BDS C18 column (5 µm, 150 × 4.60 mm) using a mobile phase of acetonitrile: 0.025 M KH2PO4 (25: 75, v/v) adjusted to pH 3.50 with ortho-phosphoric acid at ambient temperature. The flow rate was 1 mL/min and maximum absorption was measured using Diode Array (DAD) detector at 285 nm. The retention times of OXY, TIN and ESM were recorded to be 2.68, 3.52 and 5.17 minutes, respectively, indicating a shorter analysis time. Limits of detection were also reported to be 0.10, 0.07 and 0.04 µg/mL for OXY, TIN and ESM, respectively, showing a high degree of the method sensitivity. The method was then validated according to FDA guidelines for the determination of the drugs clinically in human plasma specially regarding pharmacokinetic and bioequivalence studies.