A validated stability indicating DAD–HPLC method for determination of pentoxifylline in presence of its pharmacopeial related substances

Smart Multivariate Spectrophotometric Determination of Two Co-Administered Autoimmune Drugs; Sulfasalazine and Pentoxifylline; in Bulk and Spiked Human Plasma

BACKGROUND

Sulfasalazine and pentoxifylline are co-prescribed together to treat psoriasis and pemphigus vulgaris. Sulfasalazine is an anti-inflammatory, immunosuppressant, and antibiotic drug, while pentoxifylline is a vasodilator and immunosuppressant. The spectra of the two drugs and plasma suffer from severe overlap.

OBJECTIVE

This work aims to simultaneously determine sulfasalazine and pentoxifylline in their binary mixture and spiked human plasma by the assessment of their UV spectral data.

METHODS

Two model updated chemometric methods were established using principal component regression and partial least-squares regression models. The two models were validated in accordance with the U.S. Food and Drug Administration guidelines for bioanalysis and were applied for the determination of both drugs in synthetic mixtures or spiked human plasma.

RESULTS

Accuracy and precision were within the accepted limits. In addition, three different assessment methods were used to evaluate the environmental greenness of the proposed models.

CONCLUSION

The two updated models are simple, rapid, sensitive, and precise, and could be easily applied in QC laboratories for determination of sulfasalazine and pentoxifylline, without any preliminary separation steps or interference from plasma matrix.

HIGHLIGHTS

Two updated chemometric models called principlal component regression and partial least-squares regression were established for determination of sulfasalazine and pentoxifylline in spiked human plasma using UV spectrophotometric data.

Chemometrics Approaches in Forced Degradation Studies of Pharmaceutical Drugs

Chemometrics is the chemistry field responsible for planning and extracting the maximum of information of experiments from chemical data using mathematical tools (linear algebra, statistics, and so on). Active pharmaceutical ingredients (APIs) can form impurities when exposed to excipients or environmental variables such as light, high temperatures, acidic or basic conditions, humidity, and oxidative environment. By considering that these impurities can affect the safety and efficacy of the drug product, it is necessary to know how these impurities are yielded and to establish the pathway of their formation. In this context, forced degradation studies of pharmaceutical drugs have been used for the characterization of physicochemical stability of APIs. These studies are also essential in the validation of analytical methodologies, in order to prove the selectivity of methods for the API and its impurities and to create strategies to avoid the formation of degradation products. This review aims to demonstrate how forced degradation studies have been actually performed and the applications of chemometric tools in related studies. Some papers are going to be discussed to exemplify the chemometric applications in forced degradation studies.

Colloidal nanostructured lipid carriers of pentoxifylline produced by microwave irradiation ameliorates imiquimod-induced psoriasis in mice

Psoriasis is a chronic inflammatory disease occurring due to a large cascade of molecular and biological processes. Pentoxifylline (PTX) has a profound anti-inflammatory activity and is clinically indicated in the management of psoriasis. PTX is highly hydrophilic and thus is permeation-limited to exert its action on the psoriatic lesions. Colloidal nanostructured lipid carriers (NLCs) is a boon for dermal drug delivery, but incorporation of hydrophilic medicaments is not only difficult to be achieved but is accompanied by suboptimal loading, erratic drug release and time-consuming. The present study was designed to develop NLCs incorporating PTX using the recently explored thin lipid film based microwave assisted rapid technique. Prior to the formulation, the crystal structure of PTX was analyzed by molecular modeling. NLCs formed within 4 min having a size of <200 nm, PDI of <0.250 and a surface charge <-28 mV. PTX was loaded and encapsulated to an extent of 10% and 90% in the NLCs. The drug flux was 4.848 μg/cm²/h at the end of 24 h with a detection of 14% in the receptor fluid indicating a higher retention of PTX within the skin (>84%). In addition, the PTX loaded NLCs were tested against imiquimod-induced psoriasis in mouse model. Histological examinations clearly showed a higher levels of remodeling of the skin layers compared to disease control. These results justify NLCs to be a promising topical delivery system for PTX during psoriasis and can be rapidly produced without the requirement of complex equipment and conditions.

Simultaneous Determination of β-Cypermethrin and Its Metabolite 3-Phenoxybenzoic Acid in Microbial Degradation Systems by HPLC-UV

The wide use of pesticides in agriculture is necessary to guarantee adequate food production worldwide. However, pesticide residues have caused global concern because of their potential health risk to consumers. In this study, we could identify β-cypermethrin (β-CY) and its degradation product 3-phenoxybenzoic acid (3-PBA) by liquid chromatograph-mass spectrometry. Few studies on the simultaneous determination of β-CY and its metabolites have been carried out so far; hence, we established a high-performance liquid chromatography method to determine the concentrations of both β-CY and 3-PBA simultaneously in microbial degradation systems. In this study, a novel β-CY degrading strain, Bacillus licheniformis B-1, was isolated from a tea garden soil, utilizing β-CY as a growth substrate. Good linear relationships between β-CY and 3-PBA were observed and the concentrations of reference solutions were between 0.50 and 60.00 µg/mL. Satisfactory stability and intra- and interday precision were obtained. The limits of detection were 0.06 and 0.13 µg/mL for β-CY and 3-PBA, respectively, and the corresponding limits of quantification were 0.21 and 0.34 µg/mL, respectively. Spiking recoveries for β-CY varied from 98.38 to 105.80%, with relative standard deviations (RSDs) varying from 1.49 to 3.93%. Spiking recoveries for 3-PBA varied from 99.59 to 101.20%, with RSDs varying from 0.58 to 3.64%. The proposed method has advantages of simplicity, rapidity, high accuracy, good separation and reproducibility; thus, it is ideally suitable for simultaneous determination of β-CY and 3-PBA in microbial degradation systems.