A rapid HPLC method for simultaneous determination of tretinoin and isotretinoin in dermatological formulations

A stability indicating RP-HPLC-UV assay method for the simultaneous determination of hydroquinone, tretinoin, hydrocortisone, butylated hydroxytoluene and parabens in pharmaceutical creams

Multicomponent drugs are medications that combine two or more active pharmaceutical ingredients in a single dosage form. These dosage forms improve the patient compliance, reduce the risk of drug interactions, and simplify dosing regimens. However, quality control of these multicomponent dosage forms can be challenging, especially if the final product contains four or more ingredients that are active (comprise stabilizers, preservatives, excipients, and other components). This problem can be more pronounced if the excipients can interfere with the analysis. In this work, a stability indicating assay method was developed and validated (according to the ICH International Guidelines) for the simultaneous determination of hydroquinone (HQ), tretinoin (TRT), hydrocortisone (HCA), butylated hydroxytoluene (BHT), methyl paraben (MP) and propyl paraben (PP) in commercially available pharmaceutical creams. The proposed method is based on gradient elution using X-Bridge C18 (150 × 4.6 mm, 5 µm) column with a flow rate of 1 mL/min. The linear ranges (μg/mL) were 240-560 for HQ, 24-56 for MP, 132-308 for HCA, 6-14 for PP, 12-28 for BHT, 6.6-15 for TRT. During the validation process, the intra- and interday precision and trueness (evaluated as recovery) were found to be below 2.0% and between 100-102%, respectively. System suitability tests (SST) allow validating the herein proposed procedure specifically for pharmaceutical and industrial applications. SST test shows that the reported procedure fulfill with the Guidelines, allowing excellent separation of the analytes with very sensitive, accurate (precise and true) and reproducible quantitation of each analytes. The method was successfully applied in forced degradation studies of the six analytes. Specifically, acid degradation slightly affected HCA and BHT (91% recovery), while alkaline degradation drastically reduced HCA recovery (5.5%) and moderately affected BHT (85%). Photodegradation primarily influenced TRT quantity, and oxidative degradation intensified the BHT peak (130%).

Environmentally friendly stability-indicating HPLC method for the determination of isotretinoin in commercial products and solubility samples

In this study, an environmentally friendly "high-performance liquid chromatography (HPLC)" assay to quantify isotretinoin (ITN) in commercial products and solubility samples is designed and verified. A Nucleodur reverse-phase C18 column was used as the stationary phase to identify ITN. The ecologically friendly mobile phase was composed of ethyl acetate and ethanol (50:50 v/v), and it was delivered at a flow rate of 1.0 mL/min. ITN was measured at 354 nm in wavelength. The current HPLC method had a determination coefficient of 0.9994 and was linear in the 0.2-80 μg/g range. The current protocol for ITN measurement was also rapid (retention time = 2.78 min), accurate (%recoveries = 98.60-101.52), precise (% uncertainties = 0.71-0.98), and sensitive. According to the AGREE methodology, the current procedure received an outstanding greenness profile with an AGREE score of 0.76. By determining ITN in commercial products and solubility samples, the applicability of the current approach was proven. ITN was discovered to be present in 98.43% and 100.84%, respectively, of commercial capsule brands A and B. The ITN's solubility in numerous eco-friendly solvents was successfully measured. Under different stress conditions, the current approach was able to distinguish between its degradation products, demonstrating its stability-indicating characteristics. These findings indicated that ITN in procured capsules and solubility samples might be regularly tested by the suggested approach.

Assay of Tretinoin using Safranine-O as a Chromogenic Reagent in Bulk and Dosage Forms

A new, economical and accurate analytical technique was developed for the assay of tretinoin (TTN) in bulk and formulations. While developing the method, it was found that the reaction was carried out due to the formation of ion-pair association complex involving the carboxyl group in the side chain of the TTN with safranine-O. The colored species formined was stable up to 60 minutes. The optical density of color species was measured at 520 nm. All the variables were optimized. The linearity range lies for the developed method within the concentration ranges of 2-10 μg mL-1.The linear correlation coefficient (r) and molar absorptivity (ϵmax)values were found as 0.9999 and 1.66 x 104 L mol–1cm–1. Percentage recoveries were found from 99.2 ± 1.8 to 100.2 ± 0.7.The method was validated as per ICH guidelines.

Application of LTA zeolite-modified electrode for sensitive detection of retinoic acid in tap water

An electrochemical method based on a Linde Type-A zeolite-modified glass carbon electrode (LTA/GCE) was introduced for the determination of retinoic acid (RA). LTA zeolite could be synthesized through a hydrothermal method and served as a commercial electrochemical sensor with high stability and sensitivity in electrochemical progress. The as-synthesized product was characterized by scanning electron microscopy (SEM), differential thermal analysis (DTA), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Under optimal conditions, a detection limit of 0.8 μM was obtained for RA with a linear range of 0.8-20.1 μM. This electrochemical method for determining RA was simpler and cheaper than previously reported methods. Furthermore, the modified electrode could be applied to the detection of RA in tap water, achieving a linear range of 1.4-15.0 μM with a detection limit of 1.4 μM and good recovery. The modified electrode designed by this method provided good selectivity, stability, and reproducibility for RA determination and reliable application for the analysis of RA in environmental water.

Simultaneous HPLC Determination of Clindamycin Phosphate, Tretinoin, and Preservatives in Gel Dosage Form Using a Novel Stability-Indicating Method

The most well-known, effective medicines for acne therapy are clindamycin phosphate and tretinoin. For the first time, we have developed and validated a reversed-phase HPLC stability-indicating technique for the detection of clindamycin phosphate (CLP), tretinoin (TRN), and two preservatives, methylparaben (MP) and imidazolidinyl urea (IU), simultaneously in this work. Most of the chromatographic conditions in the present study were optimized to achieve better separation. The best separation results were obtained using gradient elution on a C-18 (250 × 4.6 mm), 5 µm column, with a mobile phase consisting of solution A (1 mL/L ortho-phosphoric acid in water) and solution B (methanol), at a flow rate of 1.0 mL/min, with UV detection at wavelengths of 200 nm and 353 nm. Standard parameters such as system suitability, precision, accuracy, specificity, robustness, linearity, range, detection limit, quantification limit, and reagent stability were used to validate the developed technique. According to the standards of the International Council for Harmonization, all of the experimental parameters were found to be within allowable bounds (ICH). The simultaneous concentrations of clindamycin phosphate, tretinoin, methylparaben, and imidazolidinyl urea in pharmaceutical formulations were successfully determined using the suggested approach. The proposed RP-HPLC method detected no interfering peaks in the chromatogram. We may conclude from the data that the new RP-HPLC method can be utilized in pharmaceutical laboratories to simultaneously assess clindamycin phosphate, tretinoin, and two preservatives, methylparaben and imidazolidinyl urea, for both qualitative and quantitative analyses.

Mathematical filtration of quaternary mixture to the zero order spectra of its individual components

Simple accurate and precise validated UV spectrophotometric methods have been described here for the simultaneous determination of Tretinoin (TN) Eusolex (EX) Hydroquinone (HQ) & Hydrocortisone acetate (HC) in their dosage form. Simultaneous determination of these four drugs was a major challenge till now. Each spectrum was filtered alone to its zero-order absorption spectrum (D⁰) form getting spectra typical to each pure component separately. Four methods were applied depending upon constants obtained from extended regions of partially overlapped spectra in the zero or first derivative forms. The methods applied are constant multiplication coupled with spectrum subtraction method (CM-SS) derivative transformation coupled with spectrum subtraction method (DT-SS) constant value method (CV) and concentration value (conc.value) method. The partially overlapped spectra of TN and EX in the mixture were obtained by CM-SS in their zero-order form allowing direct measurement at their λ_max while the resolved binary mixture of HQ and HC obtained by SS; was determined by derivatization and transformed to their zero order by DT-SS. Also Ex and HQ concentrations were determined by the graphical representation of data only without regression equation by concentration value method and the results were compared to the conventional constant value method using a regression equation. The methods applied to the quaternary mixture under study were successfully applied for the simultaneous determination of the four drugs in synthetic mixtures and in their combined dosage form Tritospot® cream. Comparing the acquired results statistically together and to official methods demonstrated no significant difference.

Three Different Approaches Based on Derivative Ratio Spectra for Spectrophotometric Resolution of a Quaternary Mixture in Semisolid Dosage Form

BACKGROUND

Recent incorporated spectrophotometer software supporting mathematical methods was considered as an optimum key for the resolution of multicomponent mixtures.

OBJECTIVE

Several spectrophotometric techniques are introduced for the determination of mixtures of tretinoin (TN), hydroquinone (HQ), and fluocinolone acetonide (FA), in the presence of the preservative methyl paraben (MP), without any separation procedure, taking into consideration the presence of two minor components and the severe overlap of their spectra.

METHOD

Constant multiplication coupled spectrum subtraction resolved the quaternary mixture into the zero-order absorption spectrum of TN alone and a severely overlapped, ternary mixture of HQ, FA, and MP. Three approaches based on the derivative ratio spectra were applied to resolve this ternary, severely overlapped mixture: derivative ratio-zero-crossing point method, factorized derivative ratio method, and double divisor derivative ratio method.

RESULTS

The work was conducted over a concentration range of 1-10, 4-38, and 4-35 µg/mL, for TN, HQ, and FA, respectively. The results obtained were compared statistically to each other and to the official methods, showing no significant difference.

CONCLUSIONS

The proposed methods were successfully applied for the simultaneous determination of the three drugs in the presence of MP in synthetic mixtures and in their combined dosage form (Trimelasma® cream) with very good accuracy and precision.

HIGHLIGHTS

This was a comparative study between conventional and new methods for resolving ternary, severely overlapped mixtures. Mathematical manipulation steps and enrichment techniques aided accurate quantification of the minor components in mixtures.

Isotretinoin

Isotretinoin is chemically named as: (2Z, 4E, 6E, 8E)-3,7-Dimethyl-9-(2,6,6-trimethylcyclohex-1-enyl)nona-2,4,6,8-tetraenoic acid. It is an orally active retinoic acid derivative for the treatment of severe refractory nodulocystic acne. It acts primarily by reducing sebaceous gland size and sebum production, and as a result alters skin surface lipid composition. Using isotretinoin for 1-2mg/kg/day for 3-4 months produces 60%-95% clearance of inflammatory lesions in patients with acne. Doses as low as 0.1mg/kg/day have also proven successful in the clearance of lesions. Encouraging results have also been seen in small numbers of patients with rosacea, Side effects affecting the mucocutaneous system and raised serum triglyceride levels occur in most patients receiving isotretinoin. Isotretinoin is strictly contraindicated in women of childbearing potential. This profile discusses and explains names of isotretinoin, its physical and chemical characteristics. It also includes methods of preparation, thermal and spectral behavior, methods of analysis, and pharmacology.

Development of a stability-indicating UPLC method for determination of isotretinoin in bulk drug

A highly sensitive and rapid stability indicating ultra-performance liquid chromatographic (UPLC) method was developed for the quantification and identification of isotretinoin in bulk. Chromatographic separation was developed using a gradient elution in a reversed-phase system at flow rate of 0.5 ml/min with 12 min run time. The mobile phase was a gradient mixture of mobile phase A (contained a 30:70:0.5 mixture solution of methanol/purified water/glacial acetic acid) and mobile phase B (contained a 70:25:4.5:0.5 mixture solution of methanol/acetonitrile/purified water/glacial acetic acid). Eluents were monitored at 355 nm. The analytical method was validated for accuracy, precision, robustness, linearity, and forced degradation in accordance with the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) topic Q2 (R1) 'Validation of Analytical Procedures: Text and Methodology'. The method was linear over a concentration range of (1-7 µg/ml) with correlation coefficient of (r² > 0.9999). The accuracy was confirmed by calculating the % recovery which was found to be 100.0-101.6%. The RSD values obtained for repeatability and intermediate precision experiments were less than 2%. The limit of detection (LOD) was 0.12 µg/ml, while the limit of quantification (LOQ) was 0.38 µg/ml. The drug samples were exposed to different stressed conditions and the results showed that all degradation products were satisfactorily separated from each other and from the peak of the drug using the developed method. The proposed method can be used for the quantitative determination of isotretinoin with confidence.

Stability-indicating chromatographic determination of hydroquinone in combination with tretinoin and fluocinolone acetonide in pharmaceutical formulations with a photodegradation kinetic study

Stability indicating HPLC and TLC-densitometric methods for the determination of hydroquinone, tretinoin, fluocinolone acetonide, their degradation products and preservatives.

Derivative spectrophotometric method for simultaneous determination of clindamycin phosphate and tretinoin in pharmaceutical dosage forms

A derivative spectrophotometric method was proposed for the simultaneous determination of clindamycin and tretinoin in pharmaceutical dosage forms. The measurement was achieved using the first and second derivative signals of clindamycin at (¹D) 251 nm and (²D) 239 nm and tretinoin at (¹D) 364 nm and (²D) 387 nm.

The proposed method showed excellent linearity at both first and second derivative order in the range of 60–1200 and 1.25–25 μg/ml for clindamycin phosphate and tretinoin respectively. The within-day and between-day precision and accuracy was in acceptable range (CV<3.81%, error<3.20%). Good agreement between the found and added concentrations indicates successful application of the proposed method for simultaneous determination of clindamycin and tretinoin in synthetic mixtures and pharmaceutical dosage form.

Influence of High Shear Dispersion on the Production of Cellulose Nanofibers by Ultrasound-Assisted TEMPO-Oxidation of Kraft Pulp

Cellulose nanofibers can be produced using a combination of TEMPO, sodium bromide (NaBr) and sodium hypochlorite, and mechanical dispersion. Recently, this process has been the subject of intensive investigation. However, studies on the aspects of mechanical treatment of this process remain marginal. The main objective of this study is to evaluate the high shear dispersion parameters (e.g., consistency, stator-rotor gap, recirculation rate and pH) and determine their influences on nanocellulose production using ultrasound-assisted TEMPO-oxidation of Kraft pulp. All nanofiber gels produced in this study exhibited rheological behaviors known as shear thinning. From all the dispersion parameters, the following conditions were identified as optimal: 0.042 mm stator-rotor gap, 200 mL/min recycle rate, dispersion pH of 7 and a feed consistency of 2%. High quality cellulose gel could be produced under these conditions. This finding is surely of great interest for the pulp and paper industry.

Drug-cyclodextrin-vesicles dual carrier approach for skin targeting of anti-acne agent

In the present study attempt was made for preparation of isotretinoin-hydroxypropyl beta cyclodextrin (HP-beta-CD) inclusion complex and encapsulate this complex in elastic liposomes to study the effect of dual carrier approach on skin targeting of isotretinoin. The isotretinoin HP-beta-CD complex was prepared by freeze-drying method and characterized by IR spectroscopy. The drug and drug-CD complex loaded elastic liposomal formulation were prepared and characterized in vitro, ex-vivo and in vivo for shape, size, entrapment efficiency, no. of vesicles per cubic mm, in vitro skin permeation and deposition study, photodegradation and skin toxicity assay. The transdermal flux for different vesicular formulations was observed between 10.5 +/- 0.5 to 13.9 +/- 1.6 microg/cm(2)/h. This is about 15-21 folds higher than that obtained from drug solution (0.7 +/- 0.1 microg/cm(2)/h) and 4-5 folds higher than obtained with drug-CD complex solution (2.7 +/- 0.1 microg/cm(2)/h). The amount of drug deposit was found to increase significantly (p < 0.05) by cyclodextrin complexation (30.1 +/- 0.1 microg). The encapsulation of this complex in elastic liposomal formulation further increases its skin deposition (262.2 +/- 21 microg). The results of skin irritation study using Draize test also showed the significant reduction in skin irritation potential of isotretinoin elastic liposomal formulation in comparison to free drug. The results of the present study demonstrated that isotretinoin elastic liposomal formulation possesses great potential for skin targeting, prolonging drug release, reduction of photodegradation, reducing skin irritation and improving topical delivery of isotretinoin.

UVA is the major contributor to the photodegradation of tretinoin and isotretinoin: Implications for development of improved pharmaceutical formulations

The chemical stability of tretinoin (RA) and isotretinoin (13RA) in ethanol and dermatological cream preparations exposed to solar simulated light (SSL), UVA, and visible light has been studied. Photostability was monitored by an HPLC method that allowed simultaneous analysis of RA and 13RA, thus allowing photodegradation due to isomerization to other retinoids and photolysis to non-retinoid products to be monitored. Both retinoids undergo both isomerization and photolysis following SSL, UVA and visible light exposure but RA is more sensitive to photodegradation than 13RA. Degradation of both retinoids by photolysis is considerably greater in cream formulations than in ethanol and the photodegradation follows second order kinetics. Rate constants and half-lives for degradation of RA and 13RA in ethanol solution and cream preparations subjected to different light sources are reported. The UVA component of SSL is the major contributor to photodegradation. Since UVA penetrates deeply into skin, our results suggest that photodegradation of RA may contribute to the photosensitivity associated with RA therapy. Our studies suggest that development of improved formulations and the use of effective UVA sunscreens may reduce the side effects of RA therapy.