A stability-indicating reversed-phase high performance liquid chromatography method for simultaneous assay of two corticosteroids and estimation of their related compounds in a pharmaceutical injectable formulation

Simultaneous Determination of Esafoxolaner, Eprinomectin, Praziquantel, BHT and Their Related Substances in a Topical Finished Product by a Single Reversed-Phase High-Performance Liquid Chromatography Method

The topical product with three active pharmaceutical ingredients (APIs), namely, esafoxolaner, eprinomectin and praziquantel has demonstrated its efficacy in the treatment of cats with mixed infections with ectoparasites and nematodes and cestodes. A reversed-phase high-performance liquid chromatography (RP-HPLC) method has been developed and validated for assay and determination of related substances peaks of three APIs including the assay of antioxidant butylated hydroxytoluene (BHT) in the finished product. Analytes were separated on a short Zorbax SB-C18 column (50 × 4.6 mm I.D., 5 μm particle size, pore size: 80 Å) with gradient elution at 40 °C column temperature. Analytes were detected at 245 nm for praziquantel, esafoxolaner, eprinomectin and their degradation products. BHT and eprinomectin degradation product 8a-oxo-B1a were detected at 280 nm. All analytes of interest were adequately separated within 40 min. The assay for praziquantel, esafoxolaner, eprinomectin and BHT was conducted against their corresponding external reference standards. The related substances peaks of each API were determined by peak area and relative response factor against total peak area of their corresponding API peak in sample solution. This method has been demonstrated to be accurate, robust, specific and stability indicating.

Development and Validation of a Stability-Indicating Reversed-Phase HPLC Method for Assay and Estimation of Related Substances of Ivermectin in an Oral Paste

Ivermectin is a potent semi-synthetic antiparasitic drug used in veterinary medicine. A reversed-phase high performance liquid chromatography (HPLC) method has been developed and validated for the identification and assay of Ivermectin, including the identification and estimation of its related impurities in an oral paste. Analytes were separated using a gradient elution at a flow rate of 1.5 mL/min on a Zorbax Extend-C18 column (150 mm × 4.6 mm i.d., 3.5-μm particle size) maintained at 30 °C. The mobile phase was composed of water as mobile-phase A and acetonitrile/methanol (85/15, v/v) as mobile-phase B. Ultraviolet detection at 245 nm was employed to monitor the analytes. Limit of quantitation (LOQ) and limit of detection (LOD) of the method are 0.6 and 0.2 μg/mL, respectively. The validation results demonstrated excellent linearity of the method in the range of 0.1-150% of the analytical concentration (0.6 mg/mL) of the method. The stability-indicating capability of the method has been demonstrated by adequately separating the degradation products from the stress degraded samples of the oral paste as per method validation requirements prescribed in the current International Council for Harmonisation guidelines.

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.

Development and Validation of a Stability-Indicating Reversed-Phase High-Performance Liquid Chromatography (RP-HPLC) Method for Identification, Assay, and Estimation of Related Substances of Ivermectin Drug Substance

BACKGROUND

Ivermectin is a potent semi-synthetic antiparasitic drug used in veterinary medicine. It is widely used for the treatment of parasites.

OBJECTIVE

This study aimed to develop a stability-indicating reversed-phase HPLC (RP-HPLC) method for assay and identification of ivermectin including identification and estimation of its related substances in bulk drug substance batches of ivermectin.

METHOD

Ivermectin and its related substances were separated on an Ascentis Express C18 column (100 mm × 4.6 mm id, 2.7 µm particle size) maintained at 45°C (column temperature) on an HPLC system with gradient elution. The mobile phase was composed of water - acetonitrile (ACN; 50 + 50, v/v) as mobile phase A, and isopropanol - ACN (15 + 85, v/v) as mobile phase B. Analytes were detected with a detection wavelength of 252 nm and quantitated against an external reference standard of ivermectin with a quantitation limit of 0.1% of the target (analytical) concentration.

RESULTS

The HPLC method was able to separate all analytes of interest by gradient elution within 25 min. The method was validated according to the guidelines described in the International Conference on Harmonization guideline Q2(R1).

CONCLUSIONS

The HPLC method for assay of ivermectin and estimation of its related substances was successfully developed, validated, and demonstrated to be accurate, robust, specific, and stability indicating.

HIGHLIGHTS

The performance of the HPLC method is significantly faster and possesses a higher degree of selectivity. Implementation of this method for routine analysis in QC laboratories would save significant time, resources and solvents.

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."

Advancing USP compendial methods for fixed dose combinations: A case study of metoprolol tartrate and hydrochlorothiazide tablets

The current United States Pharmacopeia–National Formulary (USP–NF) includes more than 250 monographs of fixed dose combinations (FDCs), and some of them need to be updated due to incompleteness of impurity profiles and obsolescence of analytical methodologies. A case study of metoprolol tartrate and hydrochlorothiazide tablets is presented to summarize challenges encountered during the USP monograph modernization initiative of FDCs and to highlight an “adoption and adaptation” approach employed for method development. To this end, a single stability-indicating HPLC method was developed to separate the two drug substances and eight related compounds with resolution 2.0 or higher between all critical pairs. Chromatographic separations were achieved on a Symmetry column (C₁₈, 100 mm × 4.6 mm, 3.5 µm) using sodium phosphate buffer (pH 3.0; 34 mM) and acetonitrile as mobile phase in a gradient elution mode. The stability-indicating capability of this method has been demonstrated by analyzing stressed samples of the two drug substances. The developed HPLC method was validated for simultaneous determination of metoprolol tartrate and hydrochlorothiazide and relevant impurities in the tablets. Moreover, the developed method was successfully applied to the analysis of commercial tablet dosage forms and proved to be suitable for routine quality control use. The case study could be used to streamline USP's monograph modernization process of FDCs and strengthen compendial procedures.

Stability of a Parenteral Formulation of Betamethasone and Levobupivacaine

Background: The therapeutic management of syndromes presenting simultaneously pain and inflammation often requires the administration of anesthetic and corticosteroid drugs by epidural administration. In this article, we studied a mixture that combines betamethasone and levobupivacaine, which demonstrates prolonged analgesic effects. To our knowledge, the stability of such a mixture in epidural solution has not been examined. Objective: To evaluate the chemical, physical, and microbiological stability of an extemporaneously prepared mixture. Methods: A solution of betamethasone acetate 1 mg/mL, betamethasone phosphate 1 mg/mL, and levobupivacaine hydrochloride 0.83 mg/mL was prepared in saline. The components were analyzed by high-performance liquid chromatography for up to 270 days of storage, protected and exposed to light, at room temperature, and stored in the refrigerator and at 45°C. In addition, sterility, organoleptic properties, and pH of the admixture were monitored. Results: There are no significant differences between drug concentrations obtained at room temperature and at refrigerated temperature. The accelerated conditions (45°C) demonstrated different results among the actives: betamethasone acetate and levobupivacaine hydrochloride are affected while betamethasone phosphate remains stable. The stability of the mixture does not depend on light exposure. The validity period of the different components in the mixture was estimated as 120 days for betamethasone phosphate and 163 days for levobupivacaine hydrochloride; betamethasone acetate remained unchanged during 155 days. Conclusion: Analgesic mixtures of betamethasone and levobupivacaine can be stored at ambient temperature in polypropylene vials for up to 120 days at the studied concentrations. These data enable the rationalization of the centralized preparation in the hospital pharmacy.

Determination of Strong Acidic Drugs in Biological Matrices: A Review of Separation Methods

Strong acidic drugs are a class of chemical compounds that normally have high hydrophilicity and large negative charges, such as organophosphatic compounds and organosulphonic compounds. This review focuses on sample preparation and separation methods for this group of compounds in biological matrices in recent years. A wide range of separation techniques, especially chromatographic method, are presented and critically discussed, which include liquid chromatography (e.g., ion-pair and ion-exchange chromatography), capillary electrophoresis (CE), and other types. Due to the extremely low concentration level of target analytes as well as the complexity of biological matrices, sample pretreatment methods, such as dilute and shoot methods, protein precipitation (PP), liquid-liquid extraction (LLE), solid-phase extraction (SPE), degradation, and derivatization strategy, also play important roles for the development of successful analytical methods and thus are also discussed.

Testing the capability of a polynomial-modified gaussian model in the description and simulation of chromatographic peaks of amlodipine and its impurity in ion-interaction chromatography

In this paper, the capability of a polynomial-modified Gaussian model to relate the peak shape of basic analytes, amlodipine, and its impurity A, with the change of chromatographic conditions was tested. For the accurate simulation of real chromatographic peaks the authors proposed the three-step procedure based on indirect modeling of peak width at 10% of peak height (W0.1), individual values of left-half width (A) and right-half width (B), number of theoretical plates (N), and tailing factor (Tf). The values of retention factors corresponding to the peak beginning (k(B)), peak apex (k(A)), peak ending (k(E)), and peak heights (H0) of the analytes were directly modeled. Then, the investigated experimental domain was divided to acquire a grid of appropriate density, which allowed the subsequent calculation of W0.1, A, B, N, and Tf. On the basis of the predicted results for Tf and N, as well as the defined criteria for the simulation the following conditions were selected: 33% acetonitrile/67% aqueous phase (55 mM perchloric acid, pH 2.2) at 40°C column temperature. Perfect agreement between predicted and experimental values was obtained confirming the ability of polynomial modified Gaussian model and three-step procedure to successfully simulate the real chromatograms in ion-interaction chromatography.