Isocratic High-performance Liquid Chromatography Research Articles

Implantation of impressive chromatographic and built-in UV spectrophotometry approaches for sustainable Estimation of olopatadine and mometasone in pharmaceuticals; eco-scale and BAGI applications

The development of analytical methods that adhere to the principles of sustainable green chemistry is essential in the modern scientific arena. This research presents two novel methods for the concurrent quantification of olopatadine (OLO) and mometasone (MOM), targeting sustainable green chemistry principles in their raw materials, dosage forms and combined nasal spray formulations. The first method is a rapid isocratic high-performance liquid chromatography (HPLC) that achieves excellent resolution within 4min, with retention times of 2.37±0.1min for OLO and 4.05±0.1min for MOM. It features optimal sensitivity, with detection limits of 0.13µg/mL for OLO and 0.03µg/mL for MOM. It utilizes a cyano column with an isocratic mobile phase of acetonitrile and 0.1M OPA (50: 50, v/v), making it accessible to standard laboratory equipment. The second method is UV-visible spectrophotometry, which includes first-order derivative measurement (D1) and ratio derivative spectra (RDS) methods. These spectroscopic approaches provide linear response range of 0.2-20.0µg/mL for OLO and 4.0-40.0µg/mL for MOM, respectively serving as cost-effective alternatives for labs with limited resources. Validation results show high accuracy (98-102%) and precision (RSD < 2%). Green assessments using Eco-Scale indicate scores of 86 for HPLC and 100 for spectrophotometry, while the "blueness" concept via BAGI demonstrates strong sustainability with scores of 87.5 and 90. These methods effectively quantify OLO and MOM in their raw materials, different formulations and combined nasal spray, providing a sustainable and reliable approach for pharmaceutical analysis. This work is the first green assessment for the determination of OLO and MOM in pure drug and in the pharmaceutical formulations using less hazard solvent and simple technique.

Comparative Bioequivalence Studies of doxysam and doxycycline (Pfizer) by reversed phase HPLC.

Isocratic high performance liquid chromatography on reversed phase a (150x 4.6 mm I.D), 5 ?m ?-Bondapak RP-8 column (with acidic mobile phase allow the separation of doxcycycline hydrochloride with low detection limit of 0.2 µg/ml detected by UV set at 226 nm. The method was validated for Doxycycline between 0.156- to 5 µg/ml. The concentration of doxycycline was assessed in two single dose randomized crossover studies with intervals of one week between two period. In sera of 20 adults healthy male volunteers with average age of (42 + 10) year, body weight 48-85 kg, body height of (160-185cm) after a single dose of doxycycline hydrochoride 100 mg in form of capsules were orally administrated for both formulations. The blood samples (2ml) were drawn concomitantly from 0.5 – 24 hours. µg The pharmacokinetics parameter were obtained from the mean serum concentration measured at various sampling times for both formulations. The maximum peak concentration (Cmax) of doxycycline reference drug from Pfizer In serum was (3.1 +0.094 µg /ml) attained in 2 hrs. While the maximum concentration (Cmax) of test drug doxysam (2.8 +0.098 µg /ml) attained in about 2 hrs, both drug have long elimination time with half time of approximately (13 hrs.) Both test and reference drug were show no significant difference in pharmacokinetics parameters, so they were considered to be bioequivalent.

The Relation of Serum Vitamin C Concentrations with Alzheimer's Disease Mortality in a National Cohort of Community-Dwelling Elderly Adults.

The relation of vitamin C with Alzheimer's disease (AD) is equivocal. The aim of this study was to assess the relation of serum vitamin C levels with AD-related mortality, and to evaluate the threshold beyond which the potential benefits of higher serum concentrations of vitamin C for AD mortality ceases. The cohort consisted of 4504 adults aged ≥60 years enrolled in the National Health and Nutrition Examination Survey who had serum measures of vitamin C and no cognitive impairment at baseline (1988-1994) and were followed-up for mortality until 2019. Vitamin C was assayed from fasting blood samples using isocratic high-performance liquid chromatography. At baseline, the mean age of participants was 70 years, with 42.7% being men. At the end of follow-up (median: 15 years), the AD mortality rate was 2.4 per 1000 person-years. In the Cox regression models, compared to participants in the lowest tertile of serum vitamin C (<0.56 mg/dL), those in the highest tertile (>0.98 mg/dL) had a lower risk of AD mortality (hazard ratio: 0.44, 95% confidence intervals: 0.25-0.77) after adjusting for sociodemographic factors, behavior/lifestyle factors, prevalent health conditions, and dietary vitamin C intake. In dose-response analysis using restricted cubic splines, vitamin C concentrations beyond 2.3 mg/dL were associated with the elevated risk of AD-related mortality. The findings from this national sample of community-dwelling elderly adults suggest that higher levels of serum vitamin C are associated with slower AD disease progression, although levels beyond the normal reference values were associated with a higher risk of AD mortality.

A green perspective on simultaneous HPLC and UV spectrophotometric estimation of Udenafil and Dapoxetine hydrochloride in pharmaceutical formulations

A green perspective on simultaneous HPLC and UV spectrophotometric estimation of Udenafil and Dapoxetine hydrochloride in pharmaceutical formulations

Preformulation-Assisted Design of Ketorolac Tromethamine for Effective Ophthalmic Delivery.

Background: The eye is a highly protected organ from ocularly administered drugs; drug- and formulation-related factors contribute significantly to ocular bioavailability. There has been a growing interest in using nonsteroidal anti-inflammatory drugs in ophthalmology for treating postoperative pain, inflammation, and seasonal allergic conjunctivitis. A preformulation-assisted design boosts efficacy and reduces dose requirements. Methods: This work aims to study the preformulation characteristics of ketorolac tromethamine to improve ocular performance and future formulation development through developing an high-performance liquid chromatography (HPLC) stability-indicating assay, forced degradation under stress conditions, solubility, as well as partition and distribution coefficient measurements. An isocratic HPLC with diode array detector method was developed and validated. Accelerated degradation under different stressors (acid, alkali, heat, and oxidative) was studied. In addition, solubility, partition, and distribution were investigated at different pHs of 3.5-7.4. Results: The results indicated that the developed HPLC method was simple, rapid (retention time ≃3 min), sensitive, selective, robust, and stability indicating. The drug seems more chemically sensitive to acid degradation (∼30% and 40% of the drug was degraded under 0.1 M and 1 M HCl at 60°C for 24 h, respectively). Another significant degradation was recorded in the following order: Oxidative > alkali > heat (phosphate-buffered saline) > heat (distilled water). Being a weak ionizable drug, both water and lipid solubility, as measured through partition coefficients, it demonstrated pH-dependency. Conclusion: For the optimum balance of water and lipid solubility required for penetration through the lipophilic corneal epithelial barrier, ketorolac eye drops would be better formulated between pH 5.5 and 6.6 than being formulated at the physiological fluid pH 7.4, where the drug is extremely hydrophilic and less permeable.

Development and validation of high-performance liquid chromatography method for determination of clarithromycin in pharmaceutical tablets.

Clarithromycin is a very important macrolide antibiotic used to treat bacterial infections in human and veterinary medicine. This study reports the development and validation of cost-effective, simple, precise, accurate, and robust high-performance liquid chromatography (HPLC) for the determination of clarithromycin (CLA) in tablets. Reversed-phase chromatography was conducted using a standard column at 55°C with ultraviolet detection at 215nm. A mobile phase consisting of acetonitrile -2-methyl-2-propanol -potassium phosphate buffer was used at a flow rate of 1.0mL/min. The proposed method displayed good linearity, precision, accuracy, robustness, and specificity. The present HPLC was compared with capillary electrophoresis and bioassay methods and the results indicated that there was no significant difference between these methods. Moreover, the obtained results demonstrated the validity of the isocratic HPLC, which allows reliable quantitation of CLA in pharmaceutical samples. Thus, it can be used as a substitute alternative methodology for the routine quality control of this medicine, in situations where other methods are less accessible in the laboratory.

LC-MS Method Development and Optimization for Small Drug Analysis in Urine

Both amphetamine and methamphetamine are considered to be illegal chemicals, and hence, the purchase, possession, and use of these drugs is forbidden in many nations. Within the fields of forensic and clinical toxicology, there has been a recent uptick in the detection and quantification of illicit substances within urine samples. Objective: To detect and quantify both drugs in urine samples utilizing caffeine as an internal standard with an optimized liquid-liquid extraction procedure. Methods: An alternative rapid and efficient method of liquid chromatography – electron spray ionization – Tandem mass spectrometry (LC – ESI – TMS) was developed and optimized. The chromatographic separation was carried out using an isocratic high-performance liquid chromatography (HPLC) system, and the eluent that was applied was a mixture of 20% acetonitrile and 80% buffer with a pH of 2.6 that included 10mM ammonium acetate and 0.1% trifluoroacetic acid. The run duration was 9 minutes, and the detection was accomplished at 210 nm with a flow rate of 1 mL/min utilizing triple quadruple MSMS to validate ionic transitions following direct infusion and fragmentation of analytes. Results: An excellent linearity was seen in the calibration curves of amphetamine and methamphetamine in urine samples across the concentration range of 0-10 mg/L, with a regression coefficient of 0.91 and 0.97, respectively, for each of these substances. Conclusions: More compounds are able to be identified in urine as chromatographic techniques, such as high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS), continue to improve in terms of their sensitivity

Chemo- and enantio-selective reversed-phase HPLC analysis of rosuvastatin using a cellulose-based chiral stationary phase in gradient elution mode

A direct reversed-phase high-performance liquid chromatographic (HPLC) method was developed for determining the content of the enantiomeric impurity of the chiral statin rosuvastatin calcium salt (RSV) in commercial tablets. The baseline enantioseparation was achieved using the Lux Cellulose-2 column and a binary linear gradient of acetonitrile and trifluoroacetic acid 0.05% in an aqueous solution. The flow rate of the mobile phases and column temperature were set at 1.0mLmin-1 and 40°C, respectively. In comparison with the isocratic HPLC method reported in the European Pharmacopoeia (EP) monograph for RSV, the gradient elution method offered improved chemo-and enantio-selectivity and reduced analysis times. The limits of quantitation and detection of the enantiomeric impurity were found to be 0.15 and 0.05µgmL-1.

Ecofriendly chromatographic estimation of spasmolytic pharmaceutical mixture along with official toxic impurity, 3,5-dichloroaniline: Complete green profile appraisal.

Nowadays, Green Analytical Chemistry is widely applied to provide various analytical methods with eco-friendly procedures employing the least toxic, harmful reagents on humans and the environment without affecting the efficacy of the determination. Accordingly, two eco-friendly, accurate, and reliable high-performance thin-layer chromatography-densitometry and high-performance liquid chromatographic methods were established for the determination and separation of two antispasmodic drugs, namely phloroglucinol and trimethylphloroglucinol in their pure, combined dosage form along with phloroglucinol toxic impurity, 3,5-dichloroaniline. For high-performance thin-layer chromatography-densitometry, efficient separation was developed via utilizing the stationary phase of high-performance thin-layer chromatography silica gel 60 F254 plates and developing a system comprising of ethyl acetate-butanol-ammonia in the ratio of 8.0:2.0:0.2, by volume and scanning of the developed bands at 210.0nm. The subsequent method is isocratic high-performance liquid chromatography with diode array detection in which separation was successively attained using XTerra RP-C18 (250 × 4.6mm, 5μm) column as stationary phase and methanol-10.0mM phosphate buffer, pH 3.7±0.1 as mobile phase in the ratio of 75.0:25.0, v/v at flow rate 1.0ml/min and scanning at 220.0nm. The developed liquid chromatography methods were validated according to the International Council for Harmonization guidelines, and all results acknowledged their efficacy. Additionally, the proposed methods worked well for assessing the cited drugs in binary combined commercially available pharmaceutical formulation. The greenness profile of the present methods was assessed and estimated using various assessment tools, namely; Green Analytical Procedure Index, analytical eco-scale method, National Environmental Method Index in addition to Analytical GREEnness tool to evaluate the greenness of the provided methods with a statistical comparison between them to assess the more green ones.

Investigation of Intestinal Absorption and Excretion of Paracetamol in Streptozotocin-Induced Hyperglycemia.

The phenolic drug molecules can be metabolized, among others, by the small intestine’s enterocytes. The conjugation reactions (glucuronidation and sulfation) show great importance in these transformations, although the oxidation reactions can be significant. These processes are dependent on the substituents of the phenolic compounds or the reacting functional groups (hydroxyl or carboxyl). Pathologic conditions, e.g., permanent hyperglycemia and diabetes, can alter the activities of the conjugative and possibly the oxidative enzymes, thus forming a change in the metabolic pattern and eventually provoking oxidative stress. A rat intestinal perfusion model was used to investigate the way in which experimental hyperglycemia affects the paracetamol’s intestinal elimination and metabolism. Hyperglycemia was induced by the administration of streptozotocin. Two hundred and fifty µM paracetamol was used in the intestinal perfusion solution. For the quantitation of the paracetamol and its major metabolites in the intestinal perfusate, an isocratic high-performance liquid chromatography method with UV-Vis detection was developed. The results revealed that quantities of all of the measured metabolites (glucuronide, sulfate, cysteine, and mercapturic acid conjugates) increased as the effect of the streptozotocin-induced hyperglycemia also did. In the small intestine’s homogenate, the glutathione levels showed that there was a decrease in the hyperglycemia levels after the paracetamol administration. In contrast, the tissue levels of the cysteine were lower in the streptozotocin-induced hyperglycemia and increased after the administration of the paracetamol. The changes in the activity of the intestinal CYP 3A4, CYP 2E1, and cyclooxygenase (COX) enzymes were determined in the control and the hyperglycemic cases. Still, there was a significant observable enzyme activity elevation in the intestinal COX enzymes, but there was a decrease in the amount of activity of the intestinal CYP3A4 enzymes, and the CYP2E1 enzyme activity was practically changeless. The results on the cysteine levels in the intestinal homogenate, at least partly, can be explained by the regulation function of the cysteine during the occurrence of oxidative stress.

Development and validation of novel HPLC method for analytical evaluation of Lemborexant in tablet dosage form

A simple and novel isocratic high-performance liquid chromatography (HPLC) method was developed for quantitative determination of lemborexant in bulk as well as in its tablet dosage form. The developed HPLC method was validated as per ICH (Q2R1) guideline. The results of validation parameters indicate that developed HPLC method was specific, accurate, precise, rapid, reliable and reproducible. Therefore, it can be applied for routine quality control analysis of Lemborexant in bulk and tablet dosage form. Materials and Methods: The chromatographic separation was achieved on Thermoscientific BDS Hypersil (C18, 15 cm × 4.6 mm id, 5μ) column. The mobile phase consisting of buffer (triethylamine (0.1% v/v) adjusted to pH 3.0 with orthophosphoric acid) and acetonitrile in the ratio of (60:40) was passed through the column maintained at 40 °C with a flow rate of 1 ml/min. Approximately 20 µl of the solution was injected and the analyte was eluted at 265 nm. Results: The retention time of lemborexant was around 7.77 min. The percentage RSD of each parameter was found within the limit. The recovery of lemborexant was found to be 100.71%. LOD and LOQ values of lemborexant were found to be 0.54 µg/ml and 1.6 µg/ml respectively. The method was linear over the range of 10-70 µg/ml with a regression coefficient 0.9996. All the verification parameters were within the range according to ICH guidelines. Conclusion: The developed RP-HPLC method is economical, simple, and practical and useful in routine analysis of Lemborexant in bulk and tablet dosage form.

Transient Chemical Activation of Covalent Bonds for Healing of Kinetically Stable and Multifunctional Organohydrogels

Transient Chemical Activation of Covalent Bonds for Healing of Kinetically Stable and Multifunctional Organohydrogels

Validation method for determining enrofloxacin and tylosin levels in broiler liver, kidney, and muscle using high-performance liquid chromatography.

Background and Aim:Enrofloxacin and tylosin can be combined into an antibiotic formulation which is expected to have a broader range of antibacterial activity against various infections in broilers. Validation method analysis of the levels of these two active compounds needs to be done for future use in pharmacokinetic or residual studies. The present study aims to determine a suitable validation method of isocratic high-performance liquid chromatography (HPLC) to measure the concentration of antibiotic combinations in the broiler liver, kidney, and muscles.Materials and Methods:The combination of enrofloxacin and tylosin in the liver, kidney, and muscle was validated by HPLC method to find the procedures, processes, equipment, and systems used, consistently provides the appropriate results. The chromatography system consisted of an Octadecyl-silica column of 5 mm in diameter and 150 mm in length with a mobile phase of a mixture of 0.05 M monobasic sodium phosphate (pH 2.5) and acetonitrile (65:35 v/v). The solution was detected at a wavelength of 280 nm, 30°C, a flow rate of 1 mL/min, and an injection volume of 20 mL. The combination antibiotics powder was produced from PT Tekad Mandiri Citra, Bandung, Indonesia, and broiler tissues obtained from day-old chick broilers maintained for 30 days with free antibiotic feed.Results:Validation of a combination solution of enrofloxacin and tylosin shows the linearity values of enrofloxacin and tylosin in the liver, kidney, and muscles as r2=0.9988, r2=0.9999, r2=0.9997, r2=0.9989, r2=0.9978, and r2=0.9962. The accuracy and precision values of enrofloxacin in the liver, kidney, and muscles were 5.53, 6.23, and 6.93, respectively. The values of accuracy and precision of tylosin in the liver, kidney, and muscles were 10.43, 4.63, and 7.16%, respectively. The retention times for enrofloxacin and tylosin were 1.945-2.000 min and 4.175-4.342 min. The limit of detection (LOD) and limit of quantity (LOQ) values for enrofloxacin were 3.03 and 10.1 μg/g, respectively. In contrast, the LOD and LOQ values for tylosin were 9.05 and 30.17 μg/g, respectively.Conclusion:The value of linearity, accuracy, precision, specificity, and sensitivity of the combined solution of enrofloxacin and tylosin showed promising results.

Adulteration of the Herbal Weight Loss Products by the Illegal Addition of Synthetic Antiobesity Medications: A Pilot Study.

Background Some anorexic agents are used to fraudulent augmentation herbal weight loss formulations. This study was designed to evaluate the potential existence of illicit substances in 63 herbal weight loss formulations collected from local apothecaries in Hamadan, Iran. Methods The thin-layer chromatography method was applied for the primary screening of potential illicit substances in the samples. The positive samples were analyzed using an isocratic high-performance liquid chromatography method. Results The results showed that 26.98% of the samples contained 17.76 ± 6.02 mg/cap of sibutramine. Daily therapeutic dose intake of sibutramine is in the range of 5 to 15 mg daily. Conclusion Since apothecaries have advised consumers to take at least two capsules a day, it seems that the blood concentration of sibutramine will likely rise beyond the therapeutic concentration and become toxic. Therefore, the usage of such products could pose serious risks to consumers' health.

HPLC-UV method for quantification of favipiravir in pharmaceutical formulations

AbstractFavipiravir (FVP), a pyrazine analog, has shown antiviral activity against a wide variety of viruses. It is considered to be worth further investigation as a potential candidate drug for COVID-19. It is not officially available in any pharmacopoeia. A rapid, simple, precise, accurate, and isocratic high performance liquid chromatography (HPLC) method has been developed for routine quality control of favipiravir in pharmaceutical formulations. Separation was carried out by C18 column. The mobile phase was a mixture of 50 mM potassium dihydrogen phosphate (pH 2.3) and acetonitrile (90:10, v/v) at a flow rate of 1 mL min−1. The ultraviolet (UV) detection and column temperature were 323 nm, and 30 °C, respectively. The run time was 15 min under these chromatographic conditions. Excellent linear relationship between peak area and favipiravir concentration in the range of 10–100 μg mL−1 has been observed (r2, 0.9999). Developed method has been found to be sensitive (limits of detection and quantification were 1.20 μg mL−1 and 3.60 μg mL−1, respectively), precise (the interday and intraday relative standard deviation (RSD) values for peak area and retention time were less than 0.4 and 0.2%, respectively), accurate (recovery, 99.19–100.17%), specific and robust (% RSD were less than 1.00, for system suitability parameters). Proposed method has been successfully applied for quantification of favipiravir in pharmaceutical formulations.

HIGH-PERFORMANCE LIQUID CHROMATOGRAPHIC ESTIMATION METHOD FOR TRANSDERMAL DIFFUSION STUDY OF GRANISETRON

Objective: The study is aimed to develop a simple, isocratic and sensitive reversed-phase high-performance liquid chromatography method for the analysis of granisetron during transdermal permeation studies through porcine ear epithelium.&#x0D; Methods: A reversed-phase (C18) column was used with ultraviolet detection at 210 nm. Selected mobile phase contained 25% (v/v) of acetonitrile and 75% (v/v) of 0.25 mM potassium dihydrogen orthophosphate solution pH adjusted to 3.0 using 1% orthophosphoric acid solution.&#x0D; Results: Calibration curve showed good linearity over 0.1–30 μg/mL concentration range of porcine ear permeates in 80% ethanol and 20% water (blank permeates). The applicability of the method was demonstrated by the analysis of diffusion study samples of granisetron through porcine ear epithelium and the steady-state permeability flux (J) from ethanolic solution was found to be 4.707 µg/square cm/h.&#x0D; Conclusion: The developed method can be used in the analysis of diffusion study samples of granisetron transdermal formulations through the porcine ear epithelium.

Isocratic high-performance liquid chromatography (HPLC) for simultaneous quantification of curcumin and piperine in a microparticle formulation containing Curcuma longa and Piper nigrum

Poor bioavailability has been reported as a major challenge in the development of curcumin as a pharmaceutical agent. However, co-administration of curcumin with piperine has been shown to improve curcumin bioavailability. Therefore, to assure product control quality, an analytical method needs to be developed for the determination of curcumin and piperine content in a dosage form formulation. The objective of this study was to develop a simple isocratic reversed-phase HPLC (RP-HPLC) method to simultaneously quantify curcumin and piperine content in solid dispersion based microparticle formulation containing Curcuma longa and Piper nigrum extracts. The method was validated according to the International Council for Harmonization (ICH) guideline. Chromatographic separation of three curcuminoids and piperine could be achieved using acetonitrile-methanol-water of 65:5:35 %, at a flow rate of 1 mL/min and a wavelength of 353 nm for detection. Resolution (Rs) of 3.57 and 1.68 for piperine and curcumin, respectively, a theoretical plate number (N) > 8000 and a tailing factor (T) < 1.5 indicate a satisfactory separation of the compounds. The calibration curve was linear from 1.25-15 μg/mL and 2.5–30 μg/mL for piperine and curcumin, respectively, with the correlation coefficient of >0.999. The intra-day/inter-day accuracy and precision demonstrated a recovery of 99.54–101.50%/99.38–99.89% and 100.78–102.51%/101.15–102.47% with a Relative Standard Deviation (RSD) of 0.53–0.95%/0.13–1.44 % and 0.28–1.62%/0.46–1.14% for piperine/curcumin. The limit of detection (LOD) were 0.27 and 0.42 μg/mL, for piperine and curcumin, which reveals an adequate sensitivity. A solid dispersion based microparticle formulation containing C. longa and P. nigrum extracts confirmed the validity of the developed method as a recovery of 91.14% and 99.14% for piperine and curcumin, respectively. In conclusion, all the tested parameters confirm the precision, accuracy, and reliability of the method for the simultaneous analysis of curcumin and piperine within a microparticle formulation containing C. longa and P. nigrum extracts.

Rapid and simultaneous determination of dexamethasone and dexamethasone sodium phosphate using HPLC-UV: Application in microneedle-assisted skin permeation and deposition studies

Dexamethasone is a fluorinated derivative of the natural glucocorticoid, cortisone, with a very high systemic anti-inflammatory effect. In this study, a simple and rapid high performance liquid chromatography (HPLC) method was developed and validated to quantify dexamethasone and its prodrug dexamethasone sodium phosphate in skin permeation studies. The separation of both the compounds was achieved on a Vydac Denali C18 column(250×4.6mm, 5μm) with a mobile phase composed of 5mM ammonium acetate buffer-acetonitrile-methanol (43:32:25, v/v) at a flow rate of 0.9mL/min and UV detection at 240nm. The standard curves were found to be linear in the range from 0.5 to 100µg/mL for both the drugs and the method could successfully separate the drug peaks from interfering peaks of endogenous skin constituents. Accuracy values of both the drugs were within 98.60 to 108.60% (intra-day) and 98.70 to 107.20% (inter-day) and precision values were within 2% at the studied concentrations. The developed method was used to investigate the effect of microneedles on transdermal delivery of dexamethasone sodium phosphate. The hydrolysis of dexamethasone sodium phosphate to dexamethasone in the presence of rat skin homogenate and rat plasma was also evaluated to confirm the conversion that occurs during skin permeation and in the blood circulation. The skin permeation and deposition characteristics of microneedle-assisted diffusion were compared to those achieved by passive diffusion. The observed data demonstrated that transdermal permeation of dexamethasone is significantly enhanced with microneedle pretreatment of rat skin, showing a marked increase in flux and permeability coefficient, compared to passive diffusion. This simple isocratic HPLC method can, be effectively applied for the evaluation of skin permeation of topical/transdermal dexamethasone formulations.

Development and Standardization of Chromatographic Technique for Quantification of Bicalutamide in Pure and Pharmaceutical Dosage Forms

Background Bicalutamide BTM is a non-steroidal antiandrogen found to be available in various pharmaceutical dosage forms. Quantitative estimation of BTM is essential in the quality control laboratories of pharmaceutical industries.Objective The present research attempts to develop optimize and standardize chromatographic methodology for quantitative estimation of BTM in its pure and pharmaceutical dosage forms. Methodology The analysis was resolved by using a mobile phase acetonitrile methanol in the ratio of 6040 vv at a flow rate of 1 mlmin on an isocratic High Performance Liquid Chromatography HPLC system consisting of SPD-20 A20AV UV-VIS detector using C18 column at a wavelength of 275 nm. The developed method was subjected for standardization as per ICH guidelines. Results The retention time was found to be 4.7 minutes. The drug showed linear response between the concentration range from 10-100 mugmL. This method was found to be selective specific and precise with RSD Relative Standard Deviation less than 2.nbsp Conclusion The reported method was found to be simple precise and accurate for quantitative estimation of BTM in bulk and pharmaceutical dosage forms and can be employed for routine quality control analysis of BTM.

New liquid chromatography assays for simultaneous quantification of antihypertensives atenolol and valsartan in their dosage forms.

Nowadays, various single-pill combinations are used as the best choice in hypertension management. However, these pills made a high challenge to analysts in terms of quality control assays. We have developed three sensitive, selective, fast, simple, green, accurate, precise, and robust isocratic high-performance liquid chromatography methods for simultaneous determination of valsartan and atenolol in dosage forms. To find the appropriate high-performance liquid chromatography conditions for the separation of the examined drugs, various columns, isocratic mobile phase systems were tried, and successful attempts were performed. The used columns proved to be indispensably applicable and gave a shorter analysis time and peak symmetries. This reduction in total run time leads to low solvent consumption and makes all methods more economical. The linearity, accuracy, and precision remained within the acceptable limits. Therefore, all developed methods are suitable for the routine quality control analysis of any pharmaceutical preparation containing the two tested drugs with the proposed chromatographic methods advantages for checking quality during stability studies of their pharmaceutical preparations.