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Currently, sample preparation is the most laborious part of the analytical process, requiring the most time and being susceptible to the most errors. In this context, numerous investigations have focused on the miniaturization of these techniques to reduce work time, costs, and errors. In this regard, microextraction by packed sorbent (MEPS) is a simple, fast, and robust sample preparation technique suitable for easy automation in several analytical systems and is applied to a wide variety of samples. Antibiotics are among the most commonly used drugs; however, their extensive and inappropriate use has garnered significant attention in the environment, human health, and food safety. This brief review is intended to provide an overview of recently reported antibiotic extraction methods based on MEPS, with a special interest in those applied to the analysis of biological, environmental, and food samples. In addition, the sample pretreatment step before extraction by the MEPS device was highlighted, as was the description of the sample-related steps within the MEPS procedure, such as extraction, washing, and elution.

Riolozatrione (RZ) is a diterpenoid compound isolated from a dichloromethane extract of the Jatropha dioica root. This compound has been shown to possess moderate antiherpetic activity in vitro. However, because of the poor solubility of this compound in aqueous vehicles, generating a stable formulation for potential use in the treatment of infection is challenging. The aim of this work was to optimize and physio-chemically characterize Eudragit® L100-55-based polymeric nanoparticles (NPs) loaded with RZ (NPR) for in vitro antiherpetic application. The NPs formulation was initially optimized using the dichloromethane extract of J. dioica, the major component of which was RZ. The optimized NPR formulation was stable, with a size of 263 nm, polydispersity index < 0.2, the zeta potential of –37 mV, and RZ encapsulation efficiency of 89 %. The NPR showed sustained release of RZ for 48 h with release percentages of 95 and 97 % at neutral and slightly acidic pH, respectively. Regarding in vitro antiherpetic activity, the optimized NPR showed a selectivity index for HSV-1 of ≈16 and for HSV-2 of 13.

There have been no reports of antifungal activity and composition of extracts from Thymus vulgaris, Rosmarinus officinalis or Origanum majorana from northeastern México. Antifungal activity of these oils against Trichophyton rubrum, Trichophyton tonsurans, Trichophyton mentagrophytes, Microsporum gypseum, Microsporum canis and Epidermophyton floccosum was measured by diffusion assay. Additionally, antibacterial and antioxidant activities were evaluated. Antibacterial activity against Staphylococcus aureus and Streptococcus pyogenes was examined by microdilution. Antioxidant activity was assessed by 2,2-difenil-1-picrilhidracil reduction test. The plant oils were characterized by both GC/MS and GC/FID. Oils of T. vulgaris and O. majorana showed growth inhibition activity against dermatophytes, especially T. vulgaris oil, which completely inhibited growth of all tested dermatophytes. The oils also showed bioactivity against bacteria, with minimum inhibitory concentration (MIC) values between 62.5 and 500 (xg/mL. The antioxidant activity of the oils was low, with effective concentration (EC50) values >250 µg/mL. The major components in the oils were as follows: T. vulgaris, o-cymene, γ-terpinene, thymol and carvacrol; R. officinalis, terpinen-4-ol and 1,8-cineole; O. majorana, terpinen-4-ol and thymol. [ABSTRACT FROM AUTHOR]

There have been no reports of antifungal activity and composition of extracts from Thymus vulgaris, Rosmarinus officinalis or Origanum majorana from northeastern México. Antifungal activity of these oils against Trichophyton rubrum, Trichophyton tonsurans, Trichophyton mentagrophytes, Microsporum gypseum, Microsporum canis and Epidermophyton floccosum was measured by diffusion assay. Additionally, antibacterial and antioxidant activities were evaluated. Antibacterial activity against Staphylococcus aureus and Streptococcus pyogenes was examined by microdilution. Antioxidant activity was assessed by 2,2-difenil-1-picrilhidracil reduction test. The plant oils were characterized by both GC/MS and GC/FID. Oils of T. vulgaris and O. majorana showed growth inhibition activity against dermatophytes, especially T. vulgaris oil, which completely inhibited growth of all tested dermatophytes. The oils also showed bioactivity against bacteria, with minimum inhibitory concentration (MIC) values between 62.5 and 500 μg/mL. The antioxidant activity of the oils was low, with effective concentration (EC50) values <250μg/mL. The major components in the oils were as follows: T. vulgaris, o-cymene, μ-terpinene, thymol and carvacrol; R. officinalis, terpinen-4-ol and 1,8-cineole; O. majorana, terpinen-4-ol and thymol.

The essential oils from Magnolia grandiflora and Chrysactinia mexicana leaves, and from Schinus molle leaves and fruit, were characterized by gas chromatography/flame-ionization detection and gas chromatography/mass spectrometry. Twenty-eight compounds from M. grandiflora leaves were identified (representing 93.6% of the total area of the gas chromatogram), with the major component being bornyl acetate (20.9%). Colorless and yellow oils were obtained from the C. mexicana leaves with 18 (86.7%) and 11 (100%) compounds identified, respectively. In both fractions, the principal component was sylvestrene (36.8% and 41.1%, respectively). The essential oils ofS. molle leaves and fruit were each separated into colorless and yellow fractions, in which 14 (98.2) and 20 (99.8%) compounds were identified. The main component was alpha-phellandrene in all fractions (between 32.8% and 45.0%). The M. grandiflora oil displayed antifungal activity against five dermatophyte strains. The oils from S. molle and M. grandiflora leaves had antimicrobial activity against Staphylococcus aureus and Streptococcus pyogenes, which cause skin infections that potentially may lead to sepsis. However, the antioxidant activities of all oils were small (half maximal effective concentration values >250 microg/mL).

Naproxen-loaded nanoparticles were used to prepare, in a one-step process, unilaminar films of Eudragit E-100 (EE-100), avoiding the use of organic solvents and assuring the homogeneity and molecular dispersion of the drug. Nanoparticle films (NP-F) and conventional films (CV-F, prepared by casting of methanolic solutions onto a Teflon disc) were assayed by their mechanical properties, skin adhesivity, and calorimetric studies to compare their behavior. Different proportions of plasticizer (triacetin) were included to evaluate the quality of the films. Film characterization included in vitro drug release studies through a cellulose membrane using Franz-type cells, and in vivo stratum corneum penetration experiments by the tape stripping technique. The results showed that NP-F were semi-transparent to transparent, suggesting a good compatibility between naproxen and EE-100. Differential calorimetric studies (DSC) confirmed a molecular dispersion of naproxen in the EE-100 matrix. Taking into account the mechanical properties of the films, a 20% triacetin concentration can be considered as optimal for both types of films. The in vitro release data obtained from both systems (NP-F and CV-F) followed the Higuchi's model for matrix systems, with the Fickian diffusion (t(0.5)) being the main release mechanism. Concerning the in vivo penetration studies, no statistical differences were found for the penetrated amount of naproxen across the stratum corneum and the depth of penetration for the two films and between the three contact times (2, 4, and 6 h). The films formulated from nanoparticle dispersions (NP-F) were shown to be effective for the transdermal administration of naproxen, and can be considered as an interesting alternative for the preparation of films with several technological advantages.