Development of a liquid chromatographic method for the quantification of paromomycin. Application to in vitro release and ex vivo permeation studies

Nanoemulsions containing amphotericin b and paromomycin for the treatment of cutaneous leishmaniasis

Cutaneous leishmaniasis (CL) is a vector-borne disease characterized by skin lesions that can evolve into high-magnitude ulcerated lesions. Thus, this study aimed to develop an innovative nanoemulsion (NE) with clove oil, Poloxamer® 407, and multiple drugs, such as amphotericin B (AmB) and paromomycin (PM), for use in the topical treatment of CL.

METHODS

Droplet size, morphology, drug content, stability, in vitro release profile, in vitro cytotoxicity on RAW 264.7 macrophages, and antileishmanial activity using axenic amastigotes of Leishmania amazonensis were assessed for NEs.

RESULTS

After optimizing the formulation parameters, such as the concentration of clove oil and drugs, using an experimental design, it was possible to obtain a NE with an average droplet size of 40 nm and a polydispersion index of 0.3, and these parameters were maintained throughout the 365 days. Furthermore, the NE showed stability of AmB and PM content for 180 days under refrigeration (4 °C), presented a pH compatible with the skin, and released modified AmB and PM. NE showed the same toxicity as free AmB and higher toxicity than free PM against RAW 264.7 macrophages. The same activity as free AmB, and higher activity than free PM against amastigotes L. amazonensis.

CONCLUSION

It is possible to develop a NE for the treatment of CL; however, complementary studies regarding the antileishmanial activity of NE should be carried out.

High-Performance Liquid Chromatography Methods for Determining the Purity of Drugs with Weak UV Chromophores - A Review

High-performance liquid chromatography (HPLC) is one of the most useful techniques for the separation and determination of new drugs with a complex nature. The selection of an HPLC detector depends on the chemical nature of molecules, potential impurities, matrix of the sample, sensitivity, availability, and/or cost of the detector. HPLC methods with UV/Vis detectors are the most used and simple analytical procedures in pharmaceutical applications, but it is limited to compounds that possess a chromophore. Hence, this review provides an overview on the development of analytical methods for compounds with weak chromophores. The review described selected papers about HPLC based methods in the PubMed, Scopus, Semantic Scholar and ScienceDirect databases, basically between 2006 and 2023. Of the analytical studies, the HPLC methods with UV-Vis, FLD, CAD, ELSD, RID, ECD, CLND and MS detection were found. This study is a comparison of different types of detection that are described in scientific literature and are routinely used for compounds with weak chromophores. It is expected that this review will be helpful for scientists in the analytical development fields to improve research related to the drug candidates and to ensure its quality according to regulatory levels.

Highly sensitive liquid chromatographic method combined with online ion suppression to remove interfering anions and mass spectrometry for impurity profiling of paromomycin sulfate

A previously developed high-performance liquid chromatography method combined with pulsed amperometric detection allowed to separate many impurities of paromomycin. However, due to the presence of ion pairing agents and sodium hydroxide in the mobile phase, direct coupling to mass spectrometry for the identification of the chemical structures of the impurities was not an option. Indeed, ion suppression was encountered by trifluoroacetic acid and pentafluoroproponic acid in the mobile phase. A cation self-regenerating suppressor, which was originally designed for increasing analyte conductivity of ammonia and amines analysis in ion chromatography, was coupled between the liquid chromatography and ion trap-time of flight-mass spectrometry and almost all trifluoroacetic acid and pentafluoroproponic acid in the mobile phase was removed. The limit of detection of paromomycin in this integrated system improved significantly to 20 ng/ml (0.4 ng). The chemical structures of 19 impurities were elucidated and seven impurities were reported for the first time.

Genome-wide analysis reveals allelic variation and chromosome copy number variation in paromomycin-resistant Leishmania donovani

In the absence of adequate diagnosis and treatment, leishmaniasis remains a major public health concern on a global scale. Drug resistance remains a key obstacle in controlling and eliminating visceral leishmaniasis. The therapeutic gap due to lack of target-specific medicine and vaccine can be minimized by obtaining parasite's genomic information. This study compared whole-genome sequence of paromomycin-resistant parasite (K133PMM) developed through in vitro adaptation and selection with sensitive Leishmania clinical isolate (K133WT). We found a large number of upstream and intergenic gene variations in K133PMM. There were 259 single nucleotide polymorphisms (SNPs), 187 insertion-deletion (InDels), and 546 copy number variations (CNVs) identified. Most of the genomic variations were found in the gene's upstream and non-coding regions. Ploidy estimation revealed chromosome 5 in tetrasomy and 6, 9, and 12 in trisomy, uniquely in K133PMM. These contain the genes for protein degradation, parasite motility, autophagy, cell cycle maintenance, and drug efflux membrane transporters. Furthermore, we also observed reduction in ploidy of chromosomes 15, 20, and 23, in the resistant parasite containing mostly the genes for hypothetical proteins and membrane transporters. We chronicled correlated genomic conversion and aneuploidy in parasites and hypothesize that this led to rapid evolutionary changes in response to drug induced pressure, which causes them to become resistant.