Reduction of interferences in the analysis of Children's Dimetapp using ultraviolet spectroscopy data and target factor analysis

A calibration matrix has been developed and successfully applied to quantify actives in Children's Dimetapp®, a cough mixture whose active components suffer from heavy spectral interference. High-performance liquid chromatography/photodiode array instrument was used to identify the actives and any other UV-detectable excipients that might contribute to interferences. The instrument was also used to obtain reference data on the actives, instead of relying on the manufacturer's claims. Principal component analysis was used during the developmental stages of the calibration matrix to highlight any mismatch between the calibration and sample spectra, making certain that "apples" were not compared with "oranges". The prediction model was finally calculated using target factor analysis and partial least squares regression. In addition to the actives in Children's Dimetapp® (brompheniramine maleate, phenylephrine hydrogen chloride, and dextromethorphan hydrogen bromide), sodium benzoate was identified as the major and FD&C Blue #1, FD&C Red #40, and methyl anthranilate as minor spectral interferences. Model predictions were compared before and after the interferences were included into the calibration matrix. Before including interferences, the following results were obtained: brompheniramine maleate=481.3mgL^-1±134% RE; phenylephrine hydrogen chloride=1041mgL^-1±107% RE; dextromethorphan hydrogen bromide=1571mgL^-1±107% RE, where % RE=percent relative error based on the reference HPLC data. After including interferences, the results were as follows: brompheniramine maleate=196.3mgL^-1±4.4% RE; phenylephrine hydrogen chloride=501.3mgL^-1±0.10% RE; dextromethorphan hydrogen bromide=998.7mgL^-1±1.6% RE as detailed in Table 6.

A Critical Review of Physicochemical Properties and Analytical Methods Applied to Quantitative Determination of Ebastine

Allergic diseases are the most common conditions in children and the second most frequent in adults. Currently, there are two well-defined generations of antihistamines, those belonging to first generation, with inherent side effects such as drowsiness and anticholinergic effects. These side effects are often attributed to their high lipophilicity and high affinity for brain H1 receptors. The ebastine is a modern antihistaminic drug belongs to the second generation and has lower lipophilicity, which diminish the undesirable side effects. To ensure the quality, efficacy, safety, and effectiveness of ebastine drug products, efficient and reliable analytical methods are mandatory. Besides official compendial methods, alternative methods are often developed and used in quality control of pharmaceuticals as well as in pharmacokinetic studies. In this work, we present a critical review on characteristics, physicochemical properties, and analytical methods applied in the analysis of ebastine.

Simultaneous Liquid Chromatographic Determination of Ebastine with Two Sympathomimetic Drugs Using a Monolithic Column

Ebastine (EBS) has been assayed in its laboratory-prepared co-formulated tablets with either pseudoephedrine hydrochloride (PSU) or phenylephrine hydrochloride (PHR) using isocratic reversed-phase chromatography. Separation was conducted using a 50 mm × 4.6 mm i.d., Chromolith® SpeedROD RP-18 end-capped column at ambient temperature. A mobile phase composed of water:acetonitrile in a ratio of 25:75 having a pH of 3.2, has been utilized at 1 mL/min with UV detection at 254 nm for both EBS and PSU and 274 nm for PHR which in turn increased the sensitivity of the proposed method significantly. Symmetric well-separated peaks resulted in a short chromatographic run; <5 min. The proposed method was subjected to detailed validation procedures and proved to be highly sensitive as shown from limit of quantification values which were 4.7, 39.4 and 10.2 μg/mL for EBS, PSU and PHR, respectively. The proposed method was used to analyze EBS in its laboratory-prepared co-formulated tablets; the obtained results were comparable to those resulting from the reference method.

Using an innovative Quality-by-Design approach for development of a stability indicating UHPLC method for ebastine in the API and pharmaceutical formulations

A stability-indicating ultra high performance liquid chromatographic (UHPLC) method has been developed for purity testing of ebastine and its pharmaceutical formulations. Successful chromatographic separation of the API from impurities was achieved on a Waters Acquity UPLC BEH C18, 50 mm × 2.1 mm, 1.7 μm particle size column with gradient elution of 10 mM acetate buffer pH 6.2 and a mixture of acetonitrile/2-propanol (1:1) as the mobile phase. Incorporating Quality by Design (QbD) principles to the method development approach by using the chromatography modeling software DryLab4 allows the visualization of a "Design Space", a region in which changes to method parameters will not significantly affect the results as defined in the ICH guideline Q8 (R2). A verification study demonstrated that the established model for Design Space is accurate with a relative error of prediction of only 0.6%. The method was fully validated for specificity, linearity, accuracy and precision, and robustness in compliance to the ICH guideline Q2 (R1). The method was found to be linear in the concentration range from the quantification limit (LOQ) to 125% of the specification limit for ebastine and each of the impurities with correlation coefficients of not less than 0.999. The recovery rate was between 98.15 and 100.30% for each impurity. The repeatability and intermediate precision (RSD) were less than 3.2% for ebastine and each of the impurities. The robustness of the developed method was studied by varying the six parameters: gradient time, temperature, ternary composition of the eluent, flow rate and start and end concentration of the gradient at 3 levels (+1, 0, -1). The resulting 729 experiments were performed in silico from the previously constructed model for Design Space and showed that the required resolution of 2.0 can be reached in all experiments. To prove the stability-indicating performance of the method, forced degradation (acid and base hydrolysis, oxidation, photolytic and thermal stress conditions) of ebastine was carried out. Baseline separation could be achieved for all peaks of the impurities, the degradation products and the API. Total run time was only 4 min, which is an impressive 40-fold increase in productivity in comparison to the method published in the Ph. Eur. monograph and allowed purity testing of more than 360 samples per day.