Analysis of Diphenhydramine Hydrochloride and Naphazoline Hydrochloride in Presence of Methylene Blue in Eye Drops by Second Derivative Spectrophotometry

Application of multivariate chemometrics tools for spectrophotometric determination of naphazoline HCl, pheniramine maleate and three official impurities in their eye drops

This work is concerned with exploiting the power of chemometrics in the assay and purity determination of naphazoline HCl (NZ) and pheniramine maleate (PN) in their combined eye drops. Partial least squares (PLS) and artificial neural network (ANN) were the chosen models for that purpose where three selected official impurities, namely; NZ impurity B and PN impurities A and B, were successfully determined. The quantitative determinations of studied components were assessed by percentage recoveries, standard errors of prediction as well as root mean square errors of prediction. The developed models were constructed in the ranges of 5.0-13.0 μg mL-1 for NZ, 10.0-60.0 μg mL-1 for PN, 1.0-5.0 μg mL-1 for NZ impurity B and 2.0-14.0 μg mL-1 for two PN impurities. The proposed models could determine NZ and PN with respective detection limits of 0.447 and 1.750 μg mL-1 for PLS, and 0.494 and 2.093 μg mL-1 for ANN. The two established models were compared favorably with official methods where no significant difference observed.

Green Easily Implemented Spectrophotometric Methods for Concurrent Determination of Ephedrine Hydrochloride and Naphazoline Nitrate in Nasal Preparations Containing Methylparaben

BACKGROUND

Spectrophotometric resolution of a mixture of several drugs is considered a cheaper, simpler, and more versatile alternative compared to costly chromatographic instruments.

OBJECTIVE

The work aims to resolve the interfering spectra of ephedrine hydrochloride, naphazoline nitrate, and methylparaben in nasal preparations using smart spectrophotometric methods.

METHOD

In our work, derivative and dual-wavelength methods were combined to eliminate this interference, under the name of derivative dual-wavelength method. Other methods, namely successive derivative subtraction and chemometric analysis, were also able to eliminate this interference. The methods have proven their applicability as they follow the International Conference on Harmonization (ICH) requirements regarding repeatability, precision, accuracy, selectivity, and linearity. Eco-scale, GAPI, and AGREE tools were used to estimate the possible environmental effects of the methods.

RESULTS

Acceptable results for repeatability, precision, accuracy, selectivity, and linearity were obtained. Limit of detection (LOD) values were 2.2 for ephedrine and 0.3 for naphazoline. The correlation coefficients were above 0.999. The methods were proven to be safe for application.

CONCLUSIONS

The introduced methods are cheap and easily implemented compared to chromatographic techniques. They can be used in purity-checking of raw material and estimation of concentrations in market formulations. The replacement of the published chromatographic techniques with our developed methods is useful when needing to save money, effort, and time.

HIGHLIGHTS

The three components of a decongestant nasal preparation were determined using cheap, green, and versatile spectrophotometric methods that keep the advantages of chromatographic techniques, including accuracy, reproducibility, and selectivity.

A green TLC densitometric method for the simultaneous detection and quantification of naphazoline HCl, pheniramine maleate along with three official impurities

Impurity profiling of a pharmaceutical compound is now taking great attention during quality assessment of pharmaceuticals, as presence of small amount of impurities may affect safety and efficacy. In this work, a novel TLC chromatographic method coupled with densitometric detection was established for the simultaneous quantification of naphazoline HCl, pheniramine maleate and three of their official impurities, namely; naphazoline impurity B, pheniramine impurities; A & B. Chromatographic separation was carried out on TLC aluminum silica plates F254, as a stationary phase, using methanol: ethyl acetate: 33.0% ammonia (2.0: 8.0: 1.0, by volume), as a mobile phase. Plates were examined at 260.0 nm and International Council for Harmonisation (ICH) guidelines were followed for method’s validation. Important factors, such as; composition of mobile phase and detection wavelengths were optimized. Linearity was achieved over the ranges of 2.0–50.0 µg band⁻¹ for naphazoline, 10.0–110.0 µg band⁻¹ for pheniramine, 0.1–10.0 µg band⁻¹ for naphazoline impurity B and 2.0–50.0 µg band⁻¹ for both pheniramine impurities. The proposed method was assessed in terms of accuracy, precision and robustness where satisfactory results (recovery % ≈ 100% and RSD < 2) were obtained. The method was also applied for the simultaneous determination of naphazoline HCl and pheniramine maleate, in Naphcon-A^® eye drops, with respective recoveries of 101.36% and 100.94%. Method greenness was evaluated and compared to the reported HPLC one via environmental, health and safety tool. The developed method has much potential over the reported one of being simple, selective, economic and time saving for the analysis of the five cited compounds.

Determination of naphazoline HCl, pheniramine maleate and their official impurities in eye drops and biological fluid rabbit aqueous humor by a validated LC-DAD method

A simple RP-HPLC-DAD method was developed and validated, as per the ICH guidelines, for simultaneous determination of naphazoline HCl (NPZ) & pheniramine maleate (PHN) along with three of their official impurities. Chromatographic separation was performed on a hypersil ODS column (5 mm, 250-4.6 mm i.d.) with isocratic elution using phosphate buffer pH 6.0: acetonitrile (70 : 30, v/v) as mobile phase, at a flow rate of 1.0 mL min-1 and UV detection at 260.0 nm. The developed method was found to be linear over the concentration ranges of 5.00-45.00 μg mL-1 for NPZ and NPZ impurity B and 10.00-110.00 μg mL-1, 10-70 μg mL-1 and 10-120 μg mL-1 for PHN, and PHN impurity A and B, respectively, with correlation coefficient values <0.999 for the five cited compounds. The method was confirmed to be accurate, robust and precise with RSD >2.0%. LOD and LOQ values for the five cited compounds were calculated. Moreover, the method was also validated in rabbit aqueous humor as per the US food and drug administration (FDA) bioanalytical validation guidelines. Finally, the proposed method was applied for the analysis of the two drugs along with their impurities in dosage form and spiked aqueous humor samples.

Application of HPTLC with Densitometry for Evaluation of the Impact of External Factors on Contents of Diphenhydramine in Its Solutions

The subject of durability of drugs is a very important problem investigated by researches. The method of accelerated aging is very often used for stability testing. It involves the influence of temperature, humidity, and light exposure. The aim of this work is estimation of contents of diphenhydramine in its standard solutions undergoing the impact of external factors, that is, temperature and UV light. The standard solutions of diphenhydramine were prepared in distilled water. The analysis of contents of compound investigated was carried out by use of HPTLC. Adsorption thin layer chromatography was performed on aluminum HPTLC plates precoated with silica gel 60F₂₅₄ using mixture of ammonia, methanol, and ethyl acetate as mobile phase. The solutions investigated were exposed to UV light as well as being heated in 40°C. The contents of diphenhydramine were measured in initial solution and during experiment. The additional peaks on densitograms as well as changes in color of solution were observed as a result of exposure to UV light which can give information about new substances, degradation products of diphenhydramine, which were created during experiment.

Indirect atomic absorption determination of atropine, diphenhydramine, tolazoline, and levamisole based on formation of ion-associates with potassium tetraiodometrcurate

Ion-associate complexes of atropine sulphate (I), diphenhydramine HCl (II), tolazoline HCl (III) and levamisole HCl (IV) with potassium tetraiodomercurate were precipitated and their solubilities were studied as a function of pH, ionic strength and temperature. Saturated solutions of each ion-associate under the optimum precipitation conditions were prepared and the metal ion-content in the supernatant was determined. The solubility products were thus calculated at different temperatures. A new accurate and precise method using atomic absorption spectrometry for the determination of the investigated drugs in pure solutions and in pharmaceutical preparations is described. The drugs can be determined by the present method in the ranges 13.6--138.8, 5.6-58, 3.6--39.6 and 4.8--48 microg/ml solutions of I--IV, respectively.

Atomic emission spectrometric determination of ephedrine, cinchonine, chlorpheniramine, atropine and diphenhydramine based on formation of ion associates with ammonium reineckate

Ion-associate complexes of ephedrine HCl (I), cinchonine HCl (II), chlorpheniramine maleate (III), atropine sulphate (IV) and diphenhydramine HCl (V) with ammonium reineckate were precipitated and their solubilities were studied as a function of pH, ionic strength and temperature. Saturated solutions of each ion-associate under the optimum precipitation conditions were prepared and the Cr ion content in the supernatant was determined. The solubility products were thus elucidated at different temperatures. A new accurate and precise method using direct current plasma-atomic emission spectrometry for the determination of the investigated drugs in pure solutions and in pharmaceutical preparations is described. The drugs can determined by the present method in the ranges 1.6-52,2.64-85.8,3.12-101.4,5.52-180.4 and 2.72-75.85 microg/ml solutions of I, II, III, IV and V, respectively.

Determination of naphazoline in rat plasma using column liquid chromatography with ultraviolet detection

A sensitive (1 ng/mL) and rapid method for the determination of naphazoline in rat plasma is described. Following extraction, the compound is analysed by reversed phase high performance liquid chromatography and ultraviolet detection at 214 nm.