Research on the development of dissolving microneedles (DMNs) has focused on bolus drug delivery, with little attention on sustained release. Here, we evaluated the sustained release, absorption pattern, and effective drug permeation of a novel donepezil-loaded DMN patch through an in vivo investigation on rats. The applications of DMN patches to the shaved skin of rats for 1 week and 1 h were compared with oral donepezil administration to assess their sustained release capabilities. We used a validated liquid chromatography–tandem mass spectrometry method to quantify donepezil in the plasma. We found that the microneedle arrays effectively delivered donepezil across the skin, with dissolution observed within 1 h of application. Furthermore, skin irritation test showed that the patches produced no irritation response. The DMN arrays also effectively increased drug permeation and demonstrated sustained release and absorption of donepezil from DMN patches. These patches allow extended dosing intervals, reduced gastrointestinal adverse effects, and convenient self-administration to mitigate poor drug compliance, making them beneficial for the treatment of elderly patients with Alzheimer’s disease.

Rumex dentatus L. (Polygonaceae), also known as toothed dock or Aegean dock, is a medicinal plant with a high culinary value in addition to being used as an ethnomedicinal plant. This review focuses on the botanical, nutritional, phytochemical, and pharmacological activities of R. dentatus, as well as the future prospects for systematic investigations into these areas. R. dentatus has been subjected to scientific evaluation, which has confirmed its traditional uses and demonstrated a wide range of biological and pharmacological potentials, including antioxidant, anticancer, antifungal, antibacterial, anti-inflammatory, and other biological properties. Phytochemical analyses showed the presence of anthraquinones, chromones, flavonoids, and essential oils. As a result of this current review, the medicinal significance of R. dentatus has been confirmed, and future research on its unexplored aspects, such as the identification of pharmacologically active chemical constituents and related mechanisms and safety, may be stimulated, with the goal of developing it into a drug.

Rumex acetosa (R. acetosa) has been used in folk remedies for gastrointestinal disorders and cutaneous diseases. Rumex species, in particular, contain abundant anthraquinones. Anthraquinone glycosides and aglycones show different bioactive effects. However, information on the pharmacokinetics of anthraquinone glycosides is limited, and methods to quantify anthraquinone glycosides in plasma are rarely available. A simple and sensitive liquid chromatography-tandem mass spectrometric bioanalytical method for the simultaneous determination of both anthraquinone glycosides and their aglycones, including emodin, emodin-8-O-β-d-glucoside, chrysophanol, chrysophanol-8-O-β-d-glucoside, physcion, and physcion-8-O-β-d-glucoside , in a low volume of rat plasma (20 µL) was established. A simple and rapid sample preparation was employed using methanol as a precipitating agent with appropriate sensitivity. Chromatographic separation was performed on HPLC by using a biphenyl column with a gradient elution using 2 mM ammonium formate (pH 6) in water and 2 mM ammonium formate (pH 6) in methanol within a run time of 13 min. The anthraquinones were detected on triple-quadrupole mass spectrometer in negative ionization mode using multiple-reaction monitoring. The method was validated in terms of selectivity, linearity, accuracy, precision, recovery, and stability. The values of the lower limit of quantitation of anthraquinones were 1–20 ng/mL. The intra-batch and inter-batch accuracies were 96.7–111.9% and the precision was within the acceptable limits. The method was applied to a pharmacokinetic study after oral administration of R. acetosa 70% ethanol extract to rats at a dose of 2 g/kg.

Herbal drugs are widely used for the auxiliary treatment of diseases. The pharmacokinetics of a drug may be altered when it is coadministered with herbal drugs that can affect drug absorption. The effects of herbal drugs on absorption must be evaluated. In this study, we investigated the effects of Rumex acetosa (R. acetosa) extract on fexofenadine absorption. Fexofenadine was selected as a model drug that is a substrate of P-glycoprotein (P-gp) and organic anion transporting polypeptide 1A2 (OATP1A2). Emodine—the major component of R. acetosa extract—showed P-gp inhibition in vitro and in vivo. Uptake of fexofenadine via OATP1A2 was inhibited by R. acetosa extract in OATP1A2 transfected cells. A pharmacokinetic study showed that the area under the plasma concentration–time curve (AUC) of fexofenadine was smaller in the R. acetosa extract coadministered group than in the control group. R. acetosa extract also decreased aqueous solubility of fexofenadine HCl. The results of this study suggest that R. acetosa extract could inhibit the absorption of certain drugs via intervention in the aqueous solubility and the drug transporters. Therefore, R. acetosa extract may cause drug interactions when coadministered with substrates of drug transporters and poorly water-soluble drugs, although further clinical studies are needed.