Development and validation of a dissolution test for meloxicam and pridinol mesylate from combined tablet formulation

Concurrent Determination of Pridinol, Diclofenac and Impurity A by HPLC-UV

A reversed-phase high-performance liquid chromatography method was developed and validated for the simultaneous determination of pridinol, diclofenac and diclofenac-related compounds in tablet formulations. The proposed method is also suitable for content uniformity determination, for dissolution test and for stability studies. Separation was achieved on a base-deactivated silica C8 column, using 50 mM phosphate buffer (pH 2.5) and methanol (40:60 v/v) as mobile phase, at a flow rate of 1.0 mL/min and column temperature of 40°C. Ultraviolet detection was made at 225 nm. The method was validated for specificity, accuracy, precision (intraday and interday levels) and linearity for each analyte. For diclofenac impurity A, sensitivity was also studied. The method showed specificity and linearity (R2: 0.999 for the three analytes) over the assessed concentration range (diclofenac: 2.5-75.0 μg/mL, pridinol: 2.0-60.0 μg/mL and impurity A: 1.25-5.0 μg/mL) and demonstrated good precision as reflected by the low coefficient of variation in all cases. Recovery rates obtained were 99.81, 100.58 and 100.96% for diclofenac, pridinol and impurity A respectively, and for all three analytes, the variances of the concentrations tested were equivalent. The detection and quantitation limits for impurity A were 0.078 and 0.261 μg/mL, respectively.

Evaluation of the effects of a novel exercise program in the treatment of low back pain in women working in a seated position: A randomized trial

BACKGROUND

Low back pain (LBP) in sedentary workers is an increasing problem. Hyperlordosis or hypolordosis of the lumbar spine may be one of the causes of LBP. Various exercise programs are used in the prevention of LBP, but they do not consider individualization for diagnosed hyperlordosis or hypolordosis of the lumbar spine.

OBJECTIVE

The purpose of this study was to evaluate the effect of the authors' original exercise program aimed at reducing hyperlordosis or increasing hypolordosis.

METHODS

Sixty women aged 26 to 40 working in a sedentary position participated in the study. The sagittal curvature and the range of motion of the lumbar spine flexion were measured with the Saunders inclinometer, and the level of LBP was evaluated using the VAS scale. Subjects were randomly divided into two groups that participated in a 3-month exercise program developed by the authors. The first group performed exercises adjusted to the diagnosed hyperlordosis or hypolordosis, and the second group performed the same exercises regardless of the lumbar lordosis angle. The study was conducted again after completing the exercises.

RESULTS

There was a statistically significant difference between the groups (p< 0.0001) in the level of pain, with better results in the group where individualized exercise was used - 60% of the participants reported complete absence of LBP. The lumbar lordosis angle was within normal limits in 97% of the subjects in the first group, and in 47% of the subjects in the second group.

CONCLUSION

The results of this study confirm the validity of using individualized exercises with regard to diagnosed hyperlordosis or hypolordosis of the lumbar spine in order to achieve better analgesic and postural correction effects.

Synthesis and characterization of meloxicam eutectics with mandelic acid and saccharin for enhanced solubility

Meloxicam (MLX) is a non-steroidal anti-inflammatory which is practically insoluble in water, requiring high concentrations to reach therapeutic levels and causing frequently gastrointestinal effects. In this way, the aim of this study was to synthesize two eutectic mixtures of MLX with mandelic acid (MND) and saccharin (SAC) by liquid-assisted grinding resulting in a multicomponent material with enhanced solubility. Mixtures were studied in different stoichiometric and eutectic point was found for each eutectic by Binary phase diagram and Tamman's triangle, with 0.33 molar fraction of MLX for SAC and MND. Eutectics were characterized by thermoanalytical techniques (TG-DSC, EGA, DSC, and DSC microscopy), infrared spectroscopy, and X-ray powder diffraction. Thermal behavior was studied and videos of the materials being heated were available. A polymorphic transition was discovered and studied for MLX-MND eutectic. Each new system was evaluated by solubility, dissolution, and hygroscopicity tests. Eutectics showed an increase in solubility of 1.7× (MLX-MND1), 3.1× (MLX-MND2), and 1.3× (MLX-SAC) with slower dissolution profile when compared with MLX. All new solid forms showed high hygroscopicity at 98% relative humidity with 27.9 and 58.9% increase in mass at day four for MLX-SAC and MLX-MND, deliquescence occurs at day 6. The experiments and analysis in this study help to understand the behavior of eutectics and evaluate them as an approach to modify properties in drugs.

Development of a Discriminative and Biorelevant Dissolution Test Method for Atorvastatin/Fenofibrate Combination with Appliance of Derivative Spectrophotometry

OBJECTIVES

Nowadays, the market is flooded with combinations of drugs in various dosage forms, but there is a lack of official methods to quantify them. A single dissolution test method for the analysis of combined dosage form is preferred for simplification of quality control testing.

MATERIALS AND METHODS

If the developed dissolution medium mimics the biorelevant and discriminating dissolution procedure for drug products with limited drug aqueous solubility it is a useful tool for qualitative forecasting of the in vivo behavior of formulations.

RESULTS

Dissolution profiles were evaluated for atorvastatin and fenofibrate in capsules, using a paddle-type United States Pharmacopeia dissolution apparatus in 900 mL of medium at 50 rpm and 37±0.5°C. The best medium was 900 mL of 0.5% w/v sodium lauryl sulfate. The cumulative % dissolution was more than 85% within 45 min for marketed tablets. The proposed dissolution test conditions have discriminative power, dissimilarity factor (f₁) values are low (12-16%), and similarity (f₂) factor values are also low (45-48%). Hence the use of 0.5% w/v sodium lauryl sulfate solution is justified.

CONCLUSION

The dissolution method was validated (% relative standard deviation <2). To quantify both drugs simultaneously, a second derivative spectrophotometric method was established (λ_max 281 nm and 296 nm, respectively, for atorvastatin and fenofibrate) in acetate buffer, pH 2.8 solution.

Development of dissolution test method for a telmisartan/amlodipine besylate combination using synchronous derivative spectrofluorimetry

The dissolution process is considered an important in vitro tool to evaluate product quality and drug release behavior. Single dissolution methods for the analysis of combined dosage forms are preferred to simplify quality control testing. The objective of the present work was to develop and validate a single dissolution test for a telmisartan (TEL) and amlodipine besylate (AML) combined tablet dosage form. The sink conditions, stability and specificity of both drugs in different dissolution media were tested to choose a discriminatory dissolution method, which uses an USP type-II apparatus with a paddle rotating at 75 rpm, with 900 mL of simulated gastric fluid (SGF without enzymes) as the dissolution medium. This dissolution methodology provided good dissolution profiles for both TEL and AML and was able to discriminate changes in the composition and manufacturing process. To quantify both drugs simultaneously, a synchronous first derivative spectrofluorimetric method was developed and validated. Drug release was analyzed by a fluorimetric method at 458 nm and 675 nm for AML and TEL, respectively. The dissolution method was validated as per ICH guidance.

Validation of Simultaneous Volumetric and HPLC Methods for the Determination of Pridinol Mesylate in Raw Material

Simple, sensitive, and economical simultaneous volumetric and HPLC methods for the determination of pridinol mesylate in raw material have been developed. The volumetric method is based on the reaction of pridinol with sodium lauryl sulphate in diluted sulphuric acid. Dimethyl yellow was used as indicator to detect the end point of the titration in aqueous/organic layer. The HPLC method for the determination of pridinol mesylate employs a reverse phase C18 column at ambient temperature with a mobile phase consisting of acetonitrile: 0.05 M potassium dihydrogen phosphate, pH adjusted to 5.0 (1 : 2, v/v). The flow rate was 0.8 mL/min. Quantitation was achieved with UV detection at 258 nm based on peak area. Both methods were found to be suitable for the quality control of pridinol mesylate in raw material.