Physicochemical Stability of a Novel Tacrolimus Ophthalmic Formulation for the Treatment of Ophthalmic Inflammatory Diseases

Tacrolimus is an immunosuppressant used to treat a large variety of inflammatory or immunity-mediated ophthalmic diseases. However, there are currently no commercial industrial forms available that can provide relief to patients. Various ophthalmic formulations have been reported in the literature, but their stability has only been tested over short periods. The objective of this study was to evaluate the physicochemical stability of a preservative-free tacrolimus formulation (0.2 and 1 mg/mL) at three storage temperatures (5 °C, 25 °C and 35 °C) for up to nine months in a multidose eyedropper. Analyses performed were the following: visual inspection and chromaticity, turbidity, viscosity, size of micelles, osmolality and pH measurements, tacrolimus quantification by a stability-indicating liquid chromatography method, breakdown product research, and sterility assay. In an in-use study, tacrolimus quantification was also performed on the drops emitted from the eyedroppers. All tested parameters remained stable during the nine month period when the eyedrops were stored at 5 °C. However, during storage at 25 °C and 35 °C, several signs of chemical instability were detected. Furthermore, a leachable compound originating from a silicone part of the eyedropper was detected during the in-use assay. Overall, the 0.2 mg/mL and 1 mg/mL tacrolimus ophthalmic solutions were physicochemically stable for up to nine months when stored at 5 °C.

Development of a high-performance liquid chromatography method for simultaneously analyzing Guanosine 5’-monophosphate (GMP) and Inosine 5’-monophosphate (IMP) in food

This study aimed to develop a HPLC method to simultaneously analyze guanosine 5’-monophosphat (GMP) and inosine 5’-monophosphat (IMP) in food products. Sample preparation procedure was simple, fast. A C18 column (250 mm × 4.6 mm, 5 µm) was used as stationary phase, and a mixture of 10 mM potassium dihydrogen phosphate and 5 mM sodium heptanesulfonate was applied as mobile phase, and PDA detector at 250 nm. The method validation followed AOAC criteria. Selectivity, linearity (R2 > 0.999), recovery (IMP: 90.5 % - 102.8 %, GMP: 91.5 % - 103.9 %), repeatability (RSDR of IMP: 3.07 % and GMP: 2.83 %) were acceptable to determination GMP and IMP in food matrix under AOAC guidelines. LOD of GMP and IMP were of 2.32 and 2.77 mg/kg, respectively. This method was used to determination GMP, IMP in food products collected in Hanoi markets.

Solubility Studies and Validation of Lovastatin using High Performance Liquid Chromatography Method

This study aimed to determine the solubility of lovastatin (LV) in different oil, surfactant, and co-surfactant using the high-performance liquid chromatography method. LV was solubility studies in different vehicle. The different vehicle used almond oil, sunflower oil, oleic acid, olive oil, soybean oil, and corn oil, isoprophyl myristate, myoglyol, tween 80, tween 20, and cremophor R.H. 40, propylene glycol, and PEG 400. Each of them was added lovastatin until saturated. The mixtures were mixing, sonicating, putting in the water bath and standing for 24 hours, then centrifugated. Each of the aliquot 2 µL diluted with acetonitrile and determination of concentration lovastatin using HPLC, with detector ultraviolet at 237 nm. Before determinate LV validated, and curve calibration at range 2-16 µg/mL was made. This study using the HPLC method with detector UV 237 nm, Agilent C 18 (4.6 x 150 mm 5 µ) column, and acetonitrile: water (70:30 v/v) as mobile phase. Calibration curve of lovastatin at the range 2-16 µg/mL with linear regression 0.999. Accuracy and precision showed that. Lovastatin has high soluble in oleic acid, tween 80, and PEG 400.

A simple HPLC-UV Method for Therapeutic Drug Monitoring of Linezolid in human Plasma in low-resourced settings

OBJECTIVE: A high-performance liquid chromatography method for the estimation of Linezolid in human plasma was developed and validated. METHODS: Samples (100µµL) were deproteinized with acetonitrile and analyzed using LiChrospher 100, RP18e column with PDA detection at 254 nm. The flow rate of the isocratic mobile phase comprising of 0.1% formic acid in 1000 ml of water and acetonitrile in the ratio of 60:40 (v/v) was set at 1.0 ml/min. RESULTS: The calibration curve ranged from 0.50 to 20.0 µg/ml and was linear. The recovery ranged from 96% to 101%. The accuracy ranged from 98 to 101% and intra- and inter-day relative standard deviation was <4.58%. The method reliably eliminated interfering materials from plasma and R2 was 0.9973. The method described was applied to the determination of plasma LZD concentration in multi-drug-resistant tuberculosis patients who are treated with a dose of 600 mg LZD once daily. CONCLUSIONS: The developed method is suitable for determination of plasma LZD in routine care and considered feasible in less-resourced settings

Development of a high-performance liquid chromatography method to assess bisphenol F levels in milk

Bisphenol F (BPF) is a bisphenol A (BPA) analogue. As an endocrine disruptor, BPF shows a similar BPA hormonal activity and greater endocrine effects. To assess BPF levels in milk a selective method based on solvent extraction with acetonitrile, solid-phase extraction (SPE), high-performance liquid chromatography with fluorescence detection (HPLC-FD) system, was developed. The method showed high recovery values (from 97.60 to 107.16%), and good detection and quantification limits (LOD=0.03 μg/L; LOQ=0.1 μg/L). To validate the analytical method, quantitative analyses of n.20 milk samples of whole milk were preliminarily carried out applying a monitoring system based on the control of different stages of pasteurized whole milk processing at a dairy company. The proposed method is simple, sensitive, and might be suitable to detect BPF residues in milk processing. At the dairy company, the occurrence of BPF levels ranging from <LOQ to 2.956 μg/L was observed. Further analyses and better knowledge about the occurrence, toxicity, and exposure levels of BPF analogue in milk, particularly for vulnerable consumer categories, are needed.

POTENTIAL ANTIDIABETIC ACTIVITIES OF FRACTIONS FROM PURIFIED EXTRACT OF LAWSONIA INERMIS LEAVES IN ALLOXAN–INDUCED DIABETIC MICE

Objective: This research was conducted to determine the potential antidiabetic activity fractions of purified extract Lawsonia inermis leaves in mice (Mus musculus) and identification of the compound. Methods: The method included maceration, purification using ethanol and distilled water was followed by liquid-liquid extraction using ethyl acetate and magnesium sulfate as drying agents. Furthermore, the extract was analyzed using thin layer chromatography (TLC) for testing the purified extract. Fractionation using vacuum liquid chromatography, antidiabetic activity test of fractions at dose 100 mg/kgBW with alloxan induced and compound identification by Liquid Chromatography-Mass Spectrometry (LC-MS/MS) using HPLC connected to a Q-TOF spectrometer equipped with an ESI source, with Phenomenon column C8, and methanol with 0.3% formic acid as solvent. Results: The results showed that from the purification step of L. inermis leaves by vacuum liquid chromatography method, 7 fractions were obtained, i.e. A-G fractions. While the antidiabetic activity of fractions shown by decreasing blood sugar level in mice on the 15th day were 64, 75, 73, 73, 57, 45 and 67%, respectively. The identified compounds from each fraction were the ester groups namely 12-hydroxy-methyl abietate, 9,12-octadecadienoic acid (Z,Z)-(2,2-dimethyl-1,3-dioxolan-4-yl)methyl ester, dehydromorroniaglycone, and (E)-hexadecyl-ferulate; the steroid group namely siraitic acid E; phenylpropanoid groups namely umbelliferone and bletilol C, and the alkaloid groups namely moupinamide and valine. Conclusion: L. inermis leaves had activity in lowering blood sugar levels. LC-MS/MS analysis revealed the presence of ester groups, steroid groups, phenylpropanoid groups and alkaloid groups. The presence of these compounds mostly contribute to antidiabetic activity.