Effect of pH on In Vitro Permeation of Ondansetron Hydrochloride Across Porcine Buccal Mucosa

Economical Voltammetric Sensor for Sensitive Rapid Determination of Ondansetron in the Presence of Opioid Antagonist Naltrexone

The electrochemical actions of ondansetron (OND) were investigated on the modified electrode with Polyvinyl Pyrollidone (PVP) and multi-walled carbon nanotube (MWCNTs). The oxidation peak current was enhanced to be doubled when compared to the bare electrode as a result of the synergistic effect of nanomaterial and cation-exchange polymer on the electron transfer rate. Following optimization of the experimental conditions, the Square Wave Voltammograms (SWV) method was employed to determine ondansetron in pharmaceutical formulations. Moreover, the modified electrode MWCNTs/PVP/CPE displayed high selectivity in the voltammetric measurements of ondansetron and co-administrated opioid antagonist drug naltrexone (NAL) with strong potential separation (422 mV). The response peak currents had a linear relationship with drug concentration in the range of (2.00–200.0 nmolL−1) with detection limits 430 pmolL−1 and 456 pmolL−1 for ondansetron and naltrexone, respectively. The electrode was successfully used to detect both medications electrochemically in human plasma samples.

Graphical abstract

Protection of bovine mammary epithelial cells by a nanoemulsion of the medicinal herb Achyrocline satureioides (Lam.) DC and its capacity of permeation through mammary epithelium

The low levels of toxicity and cytoprotective effect attributed to Achyrocline satureioides (Lam.) DC, a medicinal plant native to South America, are of interest for bovine mastitis therapy. This research paper reports the hypothesis that a nanoemulsion of macela extract (Achyrocline satureioides) exerts protective effects on bovine mammary alveolar cells -T (MAC-T) and increases the permeation of flavonoid compounds through mammary epithelium. Extract-loaded nanoemulsions (2.5 mg/ml) (NE-ML) (n = 4) were prepared using high-pressure homogenization with varying concentrations of flaxseed oil and Tween 80. Permeation and retention of free and nanoencapsulated quercetin, 3-O-methylquercetin and luteolin were performed on mammary glandular epithelium using Franz diffusion cells. The cell viability was evaluated on mammary epithelial cells (MAC-T lineage) using the MTT method (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) after exposure to loaded and blank nanoemulsions (NE-ML and NE-BL). Necrotic or apoptotic cell death was evaluated by flow cytometry after exposure to nanoemulsions (NE-ML and NE-BL). Subsequently, the cell death was assessed by previously treating MAC-T cells with NE-ML for 23 h, followed by exposure to H2O2 (2 mM) for 1 h. Higher permeation of quercetin and 3-O-methylquercetin in NE-ML was found compared to that of free extract with a final permeated amount of 50.7 ± 3.2 and 111.2 ± 0.6 μg/cm2 compared to 35.0 ± 0.6 and 48.9 ± 1.2, respectively. For NE-BL, the IC50 was at least 1.3% (v/v), while for the NE-ML, it was at least 2.6% (v/v). After exposure to NE-ML (5 and 1.2%, v/v), the percentage of apoptotic cells was reduced (±30%). For the H2O2 assay, the percentage of cells in necrosis was reduced by 40% after exposure to NE-ML1% (v/v) + H2O2 2 mM. The protective effects and increased permeation of macela nanoemulsion make this a promising new candidate for bovine mastitis therapy.

Permeability of Buccal Mucosa

The buccal mucosa provides an alternative route of drug delivery that can be more beneficial compared to other administration routes. Although numerous studies and reviews have been published on buccal drug delivery, an extensive review of the permeability data is not available. Understanding the buccal mucosa barrier could provide insights into the approaches to effective drug delivery and optimization of dosage forms. This paper provides a review on the permeability of the buccal mucosa. The intrinsic permeability coefficients of porcine buccal mucosa were collected. Large variability was observed among the published permeability data. The permeability coefficients were then analyzed using a model involving parallel lipoidal and polar transport pathways. For the lipoidal pathway, a correlation was observed between the permeability coefficients and permeant octanol/water partition coefficients (Kow) and molecular weight (MW) in a subset of the permeability data under specific conditions. The permeability analysis suggested that the buccal permeation barrier was less lipophilic than octanol. For the polar pathway and macromolecules, a correlation was observed between the permeability coefficients and permeant MW. The hindered transport analysis suggested an effective pore radius of 1.5 to 3 nm for the buccal membrane barrier.

On demand electrochemical release of drugs from porous reduced graphene oxide modified flexible electrodes

Despite the advantages of an electrochemical control of drug release, only a handful of electrochemical-based release systems have been developed so far.

Oral transmucosal drug delivery--current status and future prospects

Oral transmucosal drug delivery (OTDD) dosage forms have been available since the 1980s. In contrast to the number of actives currently delivered locally to the oral cavity, the number delivered as buccal or sublingual formulations remains relatively low. This is surprising in view of the advantages associated with OTDD, compared with conventional oral drug delivery. This review examines a number of aspects related to OTDD including the anatomy of the oral cavity, models currently used to study OTDD, as well as commercially available formulations and emerging technologies. The limitations of current methodologies to study OTDD are considered as well as recent publications and new approaches which have advanced our understanding of this route of drug delivery.

Optimization and characterization of chitosan films for transdermal delivery of ondansetron

The aim of this study was to develop novel transdermal films of ondansetron HCl with high molecular weight chitosan as matrix polymer and 2-(2-ethoxy-ethoxy) ethanol (Transcutol®) as plasticizer. In this context, firstly the physicochemical properties of gels used to formulate transdermal films were characterized and, physicochemical properties and bioadhesiveness of the transdermal films prepared with chitosan gels were assessed. The impact of three different types of terpenes, namely limonene, nerolidol and eucalyptol on in vitro skin permeation of ondansetron from transdermal films were also examined. ATR-FTIR measurements were performed to investigate the effects of the chitosan film formulations on in vitro conformational order of stratum corneum intercellular lipids after 24 h permeation study. The results showed that the chitosan gels consisting of Transcutol® as plasticizer and terpenes as penetration enhancer may be used to prepare transdermal films of ondansetron due to the good mechanical properties and bioadhesiveness of the transdermal films. Eucalyptol (1%) showed higher permeation enhancer effect than the other terpenes and control. ATR-FTIR data confirmed that finding in which eucalyptol induced a blue shift in the both CH₂ asymmetric and symmetric absorbance peak positions indicating increased lipid fluidity of stratum corneum.

In vitro and in vivo evaluation of chitosan buccal films of ondansetron hydrochloride

Buccal films of ondanstron hydrochloride were fabricated from mucoadhesive polymer, chitosan, and polyvinyl pyrrolidone (PVP K30) for the purpose of prolonging drug release and improving its bioavailability. All fabricated film formulations prepared were smooth and translucent, with good flexibility. The weight and thickness of all the formulations were found to be uniform. Drug content in the films ranged from 98 – 99%, indicating favorable drug loading and uniformity. The inclusion of PVP K30, a hydrophilic polymer, significantly reduced the bioadhesive strength and in vitro mucoadhesion time of the films, although the degree of swelling increased. In vitro drug release studies in simulated saliva showed a prolonged release of over five to six hours for all formulations, except C4, with 99.98% release in 1.5 hours. Kinetic analysis of the release data indicated that the best fit model with the highest correlation coefficient for all formulations was the Peppas model. In vivo studies, on selected films in rabbits, were conducted, to determine the pharmacokinetic parameters such as C_max, T_max, and AUC_0-∞, using model-independent methods with nonlinear least-squares regression analysis. The AUC and values of C_max of ondansetron hydrochloride were found to be significantly greater (P < 0.005) than the selected films C2 and C3, as compared to those from the oral solution, thereby confirming improved bioavailability via the buccal route. The T_max values were also significantly greater (P < 0.005), indicating the slower release of the drug from buccal films, thereby, providing prolonged effects. Good in vitro-in vivo correlation was observed with R² values exceeding 0.98, when the percentage of drug released was correlated with the percentage of drug absorbed.

Effect of experimental temperature on the permeation of model diffusants across porcine buccal mucosa

The influence of experimental temperature on the permeability of model diffusants across porcine buccal mucosa was investigated in vitro. The permeability increased significantly as the experimental temperature was increased in increments of approximately 7°C. It was observed that the apparent permeability and temperature were related by an exponential relationship that conformed to the Arrhenius equation. Diffusants with higher lipophilicities--buspirone and bupivacaine--had lower activation energies for diffusion when compared to hydrophilic diffusants--antipyrine and caffeine. The activation energy for diffusion of the model diffusants decreased linearly with increasing distribution coefficients across porcine buccal mucosa. The results suggested that the buccal mucosa acts as a stronger barrier to the diffusion of hydrophilic diffusants than the lipophilic ones. The log-linear relationship between permeability and temperature indicates that temperature should be carefully controlled in diffusion experiments. These results also point to the possibility of developing heat-generating buccal delivery devices, especially for hydrophobic diffusants.

Effects of OCT1 polymorphisms on the cellular uptake, plasma concentrations and efficacy of the 5-HT(3) antagonists tropisetron and ondansetron

After uptake into liver cells, the antiemetic drugs tropisetron and ondansetron undergo metabolic inactivation by cytochrome P450 2D6 (CYP2D6). We investigated whether the hepatic organic cation transporter 1 (OCT1; SLC22A1) mediates cellular uptake and whether common OCT1 loss-of-function polymorphisms affect pharmacokinetics and efficacy of both drugs. Both tropisetron and ondansetron inhibited ASP(+) uptake in OCT1-overexpressing HEK293 cells. Overexpression of wild-type, but not OCT1 loss-of-function variants, significantly increased tropisetron uptake. Correspondingly, patients with two loss-of-function OCT1 alleles had higher tropisetron plasma concentrations (n=59, P<0.04) and higher clinical efficacy (n=91, P=0.009) compared with carriers of fully active OCT1. Overexpression of OCT1 did not increase ondansetron uptake. Nevertheless, OCT1 genotypes correlated with pharmacokinetics (n=45, P<0.05) and clinical efficacy (n=222, P<0.02) of ondansetron, the effect size of OCT1 genotypes on pharmacokinetics and efficacy was greater for tropisetron than for ondansetron. In conclusion, in addition to the known effects of CYP2D6, OCT1 deficiency may increase efficacy of tropisetron and potentially of ondansetron by limiting their hepatic uptake.