Development and validation of a stability-indicating RP-HPLC method to separate low levels of dexamethasone and other related compounds from betamethasone

Hydrogel Microneedles with Programmed Mesophase Transitions for Controlled Drug Delivery

Microneedle-based drug delivery offers an attractive and minimally invasive administration route to deliver therapeutic agents through the skin by bypassing the stratum corneum, the main skin barrier. Recently, hydrogel-based microneedles have gained prominence for their exceptional ability to precisely control the release of their drug cargo. In this study, we investigated the feasibility of fabricating microneedles from triblock amphiphiles with linear poly(ethylene glycol) (PEG) as the hydrophilic middle block and two dendritic side-blocks with enzyme-cleavable hydrophobic end-groups. Due to the poor formation and brittleness of microneedles made from the neat amphiphile, we added a sodium alginate base layer and tested different polymeric excipients to enhance the mechanical strength of the microneedles. Following optimization, microneedles based on triblock amphiphiles were successfully fabricated and exhibited favorable insertion efficiency and low height reduction percentage when tested in Parafilm as a skin-simulant model. When tested against static forces ranging from 50 to 1000 g (4.9-98 mN/needle), the microneedles showed adequate mechanical strength with no fractures or broken segments. In buffer solution, the solid microneedles swelled into a hydrogel within about 30 s, followed by their rapid disintegration into small hydrogel particles. These hydrogel particles could undergo slow enzymatic degradation to soluble polymers. In vitro release study of dexamethasone (DEX), as a steroid model drug, showed first-order drug release, with 90% released within 6 days. Eventually, DEX-loaded MNs were subjected to an insertion test using chicken skin and showed full penetration. This study demonstrates the feasibility of programming hydrogel-forming microneedles to undergo several mesophase transitions and their potential application as a delivery system for self-administration, increased patient compliance, improved efficacy, and sustained drug release.

A Fast, Validated UPLC Method Coupled with PDA-QDa Detectors for Impurity Profiling in Betamethasone acetate and Betamethasone phosphate Injectable Suspension and Isolation, Identification, Characterization of Two Thermal Impurities

For impurity profiling of betamethasone acetate and betamethasone phosphate injectable suspensions, a quick, verified stability indicating UPLC technique incorporating the detectors PDA-QDa had been established. This method with an analysis time of 12 min could able to separate all possible degradation impurities. Two of the thermal impurities have been identified in positive mode of detection by using QDa detector and isolated by using preparative HPLC. The method works at a flow rate of 0.5 mL/min in column: Poroshell 120 EC C18 (100 × 2.1) mm, 1.9 µm, maintained temperature precisely at 40 ºC. The M/Z values in ESI positive mode for the two new degradation impurities have been identified (M+H) as 393.22 (DP1), 363.17 (DP2) and confirmed by ¹H NMR. The approach was also verified in accordance with the rules of ICH Q2 (R1). From LOQ quantity value to 150 % quantity of specified concentration (2 % for betamethasone and 0.5 % for other impurities), the technique of UPLC-PDA-QDa was proven to be linear and accurate. Precision and ruggedness results showed ˂ 5 % RSD. Accuracy results showed more than 95 % recovery from LOQ till 150 % of impurity specification. This UPLC-PDA-QDa methodology was found specific, precise, stable and robust for quantification of all possible degradation impurities. The proposed method has been transferred to quality control laboratories to access the impurity profile during product storage.

Pharmaceutical impurity analysis by comprehensive two-dimensional temperature responsive × reversed phase liquid chromatography

In this study, the possibilities of temperature responsive × reversed phase liquid chromatography (TRLC × RPLC) are assessed in terms of pharmaceutical impurity analysis. Due to the increased peak capacity per unit time they offer, two-dimensional LC approaches are gaining relevance for the analysis of complex drug formulations. Because the latter depicts a larger predisposition for the occurrence of an increased number of impurities, current 1D-HPLC approaches often prove insufficient. Since many LC × LC methods are limited by modulation, solvent compatibility, orthogonality, and sensitivity issues, the combination of TRLC × RPLC is explored in this work for pharmaceutical impurity analysis. As this combination of a purely aqueous separation with RPLC allows for systematic and optimization-free refocusing in the second dimension, it opens possibilities for generic LC × LC requiring minimal to no method development, in this way overcoming a major perceived contemporary hurdle of LC × LC. The approach is demonstrated with a representative mixture of 17 solutes comprising 11 corticosteroids and 6 progestogens. Orthogonality and peak capacities were assessed on three RP core-shell column selectivities (Poroshell EC-C18, phenyl-hexyl and PFP). Although the TRLC × EC-C18 combination offered somewhat better orthogonality, the combination with the PFP column proved the best for the separation at hand. Depending on the composition of the mixture, the use of full, shifted, or segmented gradients allowed facile optimization of the separation. The developed platform allowed detection of the impurities at the 0.05% level compared to a selected main compound, while also opening up possibilities for analysis of formulations comprising two active ingredients.

Multivariate UV-Chemometric and HPLC-QbD Method for Simultaneous Estimation of Vardenafil and Dapoxetine in Active Pharmaceutical Ingredients and its Marketed Formulation

Background:

This manuscript focuses on Novel multivariate UV-chemometric method and HPLC-QbD method for simultaneous determination of Vardenafil (VR) and Dapoxetine (DP) in active pharmaceutical ingredient and their marketed formulation. To the best of our knowledge, there is no literature data on multivariate methods for the same.

Methods:

The spectrophotometric data were processed by CLS, PCR, PLS and MLR methods in order to determine the active substances, without prior separation from tablet marketed formulation. Analytical figures of merit, such as sensitivity, selectivity, analytical sensitivity, LOD, and LOQ were determined. In HPLC-QbD, four critical factors were selected after screening and boxbehnken design was applied for optimization. Twenty-five experiments were done, and a quadratic model was used for all response variables. Desirability plot, surface plot, design space, and three-dimensional plots were calculated.

Results:

For Chemometrics, wavelength range selected was 202 nm - 326 nm at 2 nm intervals, hence 59 wavelength points were selected in such a way that minimum RMSEC and RMSECV values were obtained at multiple wavelengths. HPLC-QbD optimized conditions were; Phenomenex C8 column (250 × 4.6 mm, 5 μm), acetonitrile: buffer (ammonium acetate buffer at pH 2.7 with acetic acid) (40:60, v/v) as a mobile phase at flow rate of 0.9 mL/min, 239 nm wavelength and 20°C temperature.

Conclusion:

The developed methods were validated and successfully applied for simultaneous determination of VR and DP in tablet dosage form. The results obtained by UV-Chemometric methods were statistically compared with an HPLC-QbD method, which concludes both the methods can apply for tablet analysis.

A Critical Review of Analytical Methods in Pharmaceutical Matrices for Determination of Corticosteroids

Corticosteroids are a class of hormones released by the adrenal cortex, which includes glucocorticoids and mineralocorticoids. Glucocorticoids have an important role in the metabolism of carbohydrates, proteins and calcium and effective anti-inflammatory and immunosuppressive activity. Due to their intense immunomodulatory and anti-inflammatory activity, glucocorticoids are used in the treatment of various inflammatory, malignant, allergic conditions such as rhinitis, asthma, dermatological, rheumatic, ophthalmic and neurological diseases, as well as after organ transplants. They are the most widely prescribed drugs in the world. The objective of this review is to provide an overview of the analytical methods in pharmaceutical matrices for determination of corticosteroids. In this study, the predominance of liquid chromatography methods for the analysis of corticosteroids from pharmaceutical products is evident for both liquid and semisolid dosage forms as well as for solids. The same can be said for topical, oral and parenteral formulations. Methods such as spectrophotometry are also used, but given the advantages of chromatographic methods such as better selectivity and sensitivity, they have become the choice for analysis of these drugs, however, most methods still do not meet the credentials of "green chemistry."

Testing the purity of spectral profiles: Finger-print resolution of complex matrices and extraction of absorbance signals

The application of spectrophotometric techniques has shown a tremendous development over the past few years, where it is possible to determine the concentrations of several components in complex matrix. A new feature will be introduced in this work where the application of spectrophotometric techniques will be enhanced to resolution and checking the purity of signals. The finger-print resolution "ratio subtraction method" (RSM) was coupled with the novel complementary method "unified constant subtraction" (UCS); in addition to the methods: extended ratio subtraction method (EXRSM), constant multiplication (CM) or "spectrum subtraction" (SS). These techniques were applied for the determination of the complex matrix of the binary mixture of chloramphenicol and dexamethasone. By applying official spectrophotometric methods, direct determination of the components was allowed with no need for validation procedures. The spectrophotometric techniques were successfully applied to the laboratory prepared mixtures and the combined dosage form where the purity of the extracted signals were tested by calculating the spectral contrast angle (θ) and the spectral ratio factor (SRF) where the results were compared to show the capability to recover pure spectral profiles and detect the presence of impurities. The proposed methods proved that spectrophotometric techniques can be used for identification and separation of signals, similar to chromatographic techniques.

Evaluation of a transtympanic delivery system in Mus musculus for extended release steroids

OBJECTIVE

The current investigation evaluated a novel extended release delivery system for treating inner ear diseases. The platform technology consists of a film forming agent (FFA) and microsphere component to localize and extend drug delivery within the ear.

STUDY DESIGN

Studies evaluated dissolution kinetics of microspheres with multiple encapsulates, testing of a variety of FFAs, and ability to localize to the round window membrane in mice in vivo.

SETTING

Studies were completed at Orbis Biosciences and The University of Kansas Medical Center.

SUBJECTS

In conjunction with in vitro characterization, an infrared dye-containing microsphere formulation was evaluated for round window membrane (RWM) localization and general tolerability in C57/BL6 Mus musculus for 35 days.

METHODS

In vitro characterization was performed using upright diffusion cells on cellulose acetate membranes, with drug content quantified by high performance liquid chromatography. Mus musculus dosing of infrared dye-containing microspheres was performed under anesthesia with a 27 GA needle and 2.0 μL injection volume RESULTS: In vitro dissolution demonstrates the ability of the FFA with microsphere platform to release steroids, proteins, peptides, and nucleic acids for at least one month, while necroscopy shows the ability of the FFA with dye-loaded microspheres to remain localized to Mus musculus RWM for the same period of time, with favorable tolerability.

CONCLUSIONS

Combining FFA and microsphere for localized drug delivery may enable cost-effective, extended release local delivery to the inner ear of new and existing small molecules, proteins, peptides, and nucleic acids.

Analytical investigation of different mathematical approaches utilizing manipulation of ratio spectra

This work represents a comparative study of different approaches of manipulating ratio spectra, applied on a binary mixture of ciprofloxacin HCl and dexamethasone sodium phosphate co-formulated as ear drops. The proposed new spectrophotometric methods are: ratio difference spectrophotometric method (RDSM), amplitude center method (ACM), first derivative of the ratio spectra (¹DD) and mean centering of ratio spectra (MCR). The proposed methods were checked using laboratory-prepared mixtures and were successfully applied for the analysis of pharmaceutical formulation containing the cited drugs. The proposed methods were validated according to the ICH guidelines. A comparative study was conducted between those methods regarding simplicity, limitations and sensitivity. The obtained results were statistically compared with those obtained from the reported HPLC method, showing no significant difference with respect to accuracy and precision.

Theoretically Guided Analytical Method Development and Validation for the Estimation of Rifampicin in a Mixture of Isoniazid and Pyrazinamide by UV Spectrophotometer

A simple, rapid, economic, accurate, and precise method for the estimation of rifampicin in a mixture of isoniazid and pyrazinamide by UV spectrophotometeric technique (guided by the theoretical investigation of physicochemical properties) was developed and validated. Theoretical investigations revealed that isoniazid and pyrazinamide both were freely soluble in water and slightly soluble in ethyl acetate whereas rifampicin was practically insoluble in water but freely soluble in ethyl acetate. This indicates that ethyl acetate is an effective solvent for the extraction of rifampicin from a water mixture of isoniazid and pyrazinamide. Computational study indicated that pH range of 6.0–8.0 would favor the extraction of rifampicin. Rifampicin is separated from isoniazid and pyrazinamide at pH 7.4 ± 0.1 by extracting with ethyl acetate. The ethyl acetate was then analyzed at λ_max of 344.0 nm. The developed method was validated for linearity, accuracy and precision according to ICH guidelines. The proposed method exhibited good linearity over the concentration range of 2.5–35.0 μg/mL. The intraday and inter-day precision in terms of % RSD ranged from 1.09 to 1.70% and 1.63 to 2.99%, respectively. The accuracy (in terms of recovery) of the method varied from of 96.7 ± 0.9 to 101.1 ± 0.4%. The LOD and LOQ were found to be 0.83 and 2.52 μg/mL, respectively. In addition, the developed method was successfully applied to determine rifampicin combination (isoniazid and pyrazinamide) brands available in Bangladesh.

Determination of midodrine hydrochloride via Hantzsch condensation reaction: a factorial design based spectrophotometric approach

An experimental design was adopted for determination of MD·HCl. The novelty of the current approach arises from being multivariate compared to traditional univariate techniques.

A comparative study of progressive versus successive spectrophotometric resolution techniques applied for pharmaceutical ternary mixtures

This work represents a comparative study of a novel progressive spectrophotometric resolution technique namely, amplitude center method (ACM), versus the well-established successive spectrophotometric resolution techniques namely; successive derivative subtraction (SDS); successive derivative of ratio spectra (SDR) and mean centering of ratio spectra (MCR). All the proposed spectrophotometric techniques consist of several consecutive steps utilizing ratio and/or derivative spectra. The novel amplitude center method (ACM) can be used for the determination of ternary mixtures using single divisor where the concentrations of the components are determined through progressive manipulation performed on the same ratio spectrum. Those methods were applied for the analysis of the ternary mixture of chloramphenicol (CHL), dexamethasone sodium phosphate (DXM) and tetryzoline hydrochloride (TZH) in eye drops in the presence of benzalkonium chloride as a preservative. The proposed methods were checked using laboratory-prepared mixtures and were successfully applied for the analysis of pharmaceutical formulation containing the cited drugs. The proposed methods were validated according to the ICH guidelines. A comparative study was conducted between those methods regarding simplicity, limitation and sensitivity. The obtained results were statistically compared with those obtained from the official BP methods, showing no significant difference with respect to accuracy and precision.

A comparative study of novel spectrophotometric methods based on isosbestic points; application on a pharmaceutical ternary mixture

This work represents the application of the isosbestic points present in different absorption spectra. Three novel spectrophotometric methods were developed, the first method is the absorption subtraction method (AS) utilizing the isosbestic point in zero-order absorption spectra; the second method is the amplitude modulation method (AM) utilizing the isosbestic point in ratio spectra; and third method is the amplitude summation method (A-Sum) utilizing the isosbestic point in derivative spectra. The three methods were applied for the analysis of the ternary mixture of chloramphenicol (CHL), dexamethasone sodium phosphate (DXM) and tetryzoline hydrochloride (TZH) in eye drops in the presence of benzalkonium chloride as a preservative. The components at the isosbestic point were determined using the corresponding unified regression equation at this point with no need for a complementary method. The obtained results were statistically compared to each other and to that of the developed PLS model. The specificity of the developed methods was investigated by analyzing laboratory prepared mixtures and the combined dosage form. The methods were validated as per ICH guidelines where accuracy, repeatability, inter-day precision and robustness were found to be within the acceptable limits. The results obtained from the proposed methods were statistically compared with official ones where no significant difference was observed.

A Rapid Reversed-Phase HPLC Method for Analysis of Trans-Resveratrol in PLGA Nanoparticulate Formulation

A rapid reversed-phase high performance liquid chromatography (RP-HPLC) method was developed for the determination of trans-resveratrol (t-RVT) in PLGA nanoparticle formulation. A new formulation of t-RVT loaded PLGA nanoparticles (NPs) with potential stealth properties was prepared by nanoprecipitation method in our laboratory. The desired chromatographic separation was achieved on a Phenomenex C18 column under isocratic conditions using UV detection at 306 nm. The optimized mobile phase consisted of a mixture of methanol: 10 mM potassium dihydrogen phosphate buffer (pH 6.8): acetonitrile (63 : 30 : 7, v/v/v) at a flow rate of 1 mL/min. The linear regression analysis for the calibration curves showed a good linear correlation over the concentration range of 0.025–2.0 μg/ml, with determination coefficients, R2, exceeding 0.9997. The method was shown to be specific, precise at the intraday and interday levels, as reflected by the relative standard deviation (RSD) values, lower than 5.0%, and accurate with bias not exceeding 15% and percentage recovery was found to be in the range between 94.5 and 101.2. The limits of detection and quantification were 0.002 and 0.007 μg/ml, respectively. The method was successfully applied for the determination of t-RVT encapsulation efficiency.

Optimization (central composite design) and validation of HPLC method for investigation of emtricitabine loaded poly(lactic-co-glycolic acid) nanoparticles: in vitro drug release and in vivo pharmacokinetic studies

The objective of the current study is to develop nanoparticles (NPs) drug delivery system of emtricitabine solely using poly(lactic-co-glycolic acid) (PLGA) and evaluate its in vitro and in vivo release performance by systematically optimized HPLC method using Formulation by Design (FbD). NPs were evaluated for in vitro release and in vivo absorption study. The desired chromatographic separation was achieved on a Phenomenex C18 (250 mm × 4.6 mm I.D., 5 μm) column, under isocratic conditions using UV detection at 280 nm. The optimized mobile phase consisted of a mixture of 40 mM phosphate dihydrogen phosphate buffer (pH 6.8), methanol, and 2% acetonitrile in a ratio of (83 : 15 : 2, v/v/v) at a flow rate of 1 mL/min. The linear regression analysis for the calibration curves showed a good linear correlation over the concentration range 0.040-2.0 μg/mL, with retention time of 4.39 min. An average encapsulation efficiency of 74.34% was obtained for NPs. In vitro studies showed zero-order release and about 95% drug being released within 15 days in PBS (pH 7.4). In conclusion, the proposed optimized method was successfully applied for the determination of in vitro and in vivo release studies of emtricitabine NPs.

Development and Validation of Stability-indicating HPLC Method for Betamethoasone Dipropionate and Related Substances in Topical Formulation

A gradient reversed phase HPLC method was developed and validated for analysis of betamethasone dipropionate, its related substances and degradation products, using Altima C(18) column (250×4.6 mm, 5 μm) with a flow rate of 1.0 ml/min and detection wavelength of 240 nm. The mobile phase A is a mixture of water, tetrahydrofuran and acetonitrile in the ratio of 90:4:6 (v/v/v) while mobile phase B is a mixture of acetonitrile, tetrahydrofuran, water and methanol in the ratio of 74:2:4:20 (v/v/v/v). The samples were analyzed using 20 μl injection volume and the column temperature was maintained at 50°. The limit of detection and limit of quantitation were found to be 0.02 μg/ml and 0.07 μg/ml, respectively. The stability-indicating capability of method was established by forced degradation studies and method demonstrated successful separation of drug, its related substances and degradation products. The method was validated as per the International Conference on Harmonization guidelines. The developed method is linear in the range of 0.07 to 200% of specification limits established for all the known related substances; betamethasone17-propionate, betamethasone 21-propionate, betamethasone 17-propionate-21-acetate (RSD <5, 2, 1%, respectively, r(2)=09991-0.9999 for sample concentration of 100 μg/ml). The method is sensitive, specific, linear, accurate, precise and stability indicating for the quantitation of drug, its related substances and other degradation compounds.