Screening of venlafaxine hydrochloride for transdermal delivery: passive diffusion and iontophoresis

Venlafaxine HCl Encapsulated in Niosome: Green and Eco-friendly Formulation for the Management of Pain

The goal of this experimentation was to increase the cutaneous absorption of venlafaxine HCl (VFX) encapsulated in a niosome (venlasosme) produced by an ultrasonic approach. The impact of the cholesterol:surfactant (Chol:Surf) proportion was examined to modify the venlasosme properties. Photon correlation spectroscopy, powder X-ray diffraction (PXRD), SEM, DSC, and ATR-FTIR spectroscopy were utilized to investigate the solid-state and morphology of VFX in the venlasosme. The studies revealed that increasing the level of Chol in the venlasosme increased the size of the particles. Alterations in the Chol to surfactant ratios (when Chol decreased from 2.5 to 0%) caused the zeta potential enhancement from 7.37 ± 0.67 to 15.53 ± 1.47 mV. The venlasosme with the highest cholesterol concentration (2.5%) had the highest encapsulation efficiency (approximately 63%). PXRD results revealed that VFX in venlasosme was in the amorphous form. The levels of VFX in the cutaneous layers and the receiver compartment were higher for the venlasosme gel than for VFX simple gel in the cutaneous permeability study and showed no cutaneous irritancy in rats. Furthermore, the venlasosme gel demonstrated significant antinociceptive and anti-inflammatory responses when compared to the control groups (VFX simple gel and diclofenac gel). The topical administration of the venlasosme gel also considerably increased the tail-flick and hot-plate response time when compared to the VFX simple gel, control groups, and diclofenac gel (p < 0.05). These findings suggest that niosomes can improve VFX efficacy as an antinociceptive and anti-inflammatory substance by improving the medicaments delivery to the specified site.

Passive and iontophoretic transport of pramipexole dihydrochloride across human skin microchannels created by microneedles in vitro

Skin microchannels (MCs) created by microneedles (MNs) provide a promising route for enhancing transdermal drug delivery. This study investigated passive and iontophoretic transport of pramipexole dihydrochloride (PXCl) across skin MCs created by polymer MN patches made of 1:2 polymethyl-vinyl-ether-co-maleic acid (PMVEMA) to polyvinyl alcohol (PVA) ratio. Permeation studies were performed in vitro using excised human skin under the conditions of (i) "poke-and-patch" and "poke-and-release" delivery approaches with varying concentration of PXCl in the formulations, (ii) drug-loaded dissolving MN (DMN) and hydrogel-forming MN (HGMN) type patches and (iii) combination of MNs and iontophoresis. The results showed that DMN patch greatly enhanced transdermal delivery of PXCl for both "poke-and-patch" and "poke-and-release" approaches as compared with the conventional delivery method. PXCl flux mainly resulted from the contribution of MC pathway created in skin and increased with increasing drug amounts in the formulations. Compared to DMN patch, HGMN patch provided more linear sustained drug delivery over 72 h. Electromigration was the main mechanism of PXCl iontophoresis through MCs and flux enhancement was found to be larger for HGMN patch than DMN patch. These results demonstrated the potential application of MN patches individually or combined with iontophoresis as an alternative method for PXCl administration.

Transdermal Route: A Viable Option for Systemic Delivery of Antidepressants

The high rise in the population suffering from depression depicts the need for improved and highly effective treatment options for this condition. Efforts to develop existing drugs into user-friendly dosage forms with a number of advantages in major depressive states, including but not limited to: sustained drug release, reduced drug dosing frequency, improved tolerance and adherence, suitability for use in diverse populations and different treatment scenarios, as well as less central nervous system side effects are required. One such non-invasive drug delivery route that could provide the aforementioned benefits in the treatment of depression is the transdermal route. A number of conventional and emerging transdermal delivery strategies have been investigated for some potent antidepressants and results depict the potential of this route as a viable means for systemic delivery of therapeutically relevant doses of the tested agents, with Emsam®, the commercially available patch of selegiline, being an evidence for the same. The investigated approaches include the formulation of transdermal patches, use of vesicular drug carriers, pro-drug approach, microemulsification, chemical as well as physical enhancement technologies. This review provides a comprehensive account of the rationale, developments made till date, scope and future prospects of delivering antidepressants via the transdermal1 route of administration.

Stimuli-responsive In situ gelling system for nose-to-brain drug delivery

The diagnosis and treatment of neurological ailments always remain an utmost challenge for research fraternity due to the presence of BBB. The intranasal route appeared as an attractive and alternative route for brain targeting of therapeutics without the intrusion of BBB and GI exposure. This route directly and effectively delivers the therapeutics to different regions of the brain via olfactory and trigeminal nerve pathways. However, shorter drug retention time and mucociliary clearance curtail the efficiency of the intranasal route. The in situ mucoadhesive gel overthrow the limitations of direct nose-to-brain delivery by not only enhancing nasal residence time but also minimizing the mucociliary clearance and enzymatic degradation. This delivery system further improves the nasal absorption as well as bioavailability of drugs in the brain. The in situ mucoadhesive gel is a controlled and sustained release system that facilitates the absorption of various proteins, peptides and other larger lipophilic and hydrophilic moieties. Owing to multiple benefits, in situ gelling system has been widely explored to target the brain via nasal route. However, very few review works are reported which explains the application of in situ nasal gel for brain delivery of CNS acting moieties. Hence, in this piece of work, we have initially discussed the global statistics of neurological disorders reported by WHO and other reputed organizations, nasal anatomy, mechanism and challenges of nose-to-brain drug delivery. The work mainly focused on the use of different stimuli-responsive polymers, specifically thermoresponsive, pH-responsive, and ion triggered systems for the development of an effective and controlled dosage form, i.e., in situ nasal gel for brain targeting of bioactives. We have also highlighted the origin, structure, nature and phase transition behavior of the smart polymers found suitable for nasal administration, including poloxamer, chitosan, EHEC, xyloglucan, Carbopol, gellan gum and DGG along with their application in the treatment of neurological disorders. The article is aimed to gather all the information of the past 10 years related to the development and application of stimuli-responsive in situ nasal gel for brain drug delivery.

Antidepressants in a changing ocean: Venlafaxine uptake and elimination in juvenile fish (Argyrosomus regius) exposed to warming and acidification conditions

The presence of antidepressants, such as venlafaxine (VFX), in marine ecosystems is increasing, thus, potentially posing ecological and human health risks. The inherent mechanisms of VFX uptake and elimination still require further understanding, particularly accounting for the impact of climate change-related stressors, such as warming and acidification. Hence, the present work aimed to investigate, for the first time, the effects of increased seawater temperature (ΔT°C = +5 °C) and pCO₂ levels (ΔpCO₂ ∼1000 μatm, equivalent to ΔpH = -0.4 units) on the uptake and elimination of VFX in biological tissues (muscle, liver, brain) and plasma of juvenile meagre (Argyrosomus regius) exposed to VFX through two different exposure pathways (via water, i.e. [VFX ] ∼20 μg L^-1, and via feed, i.e. [VFX] ∼160 μg kg^-1 dry weight, dw). Overall, results showed that VFX can be uptaken by fish through both water and diet. Fish liver exhibited the highest VFX concentration (126.7 ± 86.5 μg kg^-1 and 6786.4 ± 1176.7 μg kg^-1 via feed and water exposures, respectively), as well as the highest tissue:plasma concentration ratio, followed in this order by brain and muscle, regardless of exposure route. Both warming and acidification decreased VFX uptake in liver, although VFX uptake in brain was favoured under warming conditions. Conversely, VFX elimination in liver was impaired by both stressors, particularly when acting simultaneously. The distinct patterns of VFX uptake and elimination observed in the different scenarios calls for a better understanding of the effects of exposure route and abiotic conditions on emerging contaminants' toxicokinetics.

Effect of terpenes on transdermal iontophoretic delivery of diclofenac potassium under constant voltage

OBJECTIVE

The aim of the study was to enhance the transdermal delivery of diclofenac potassium (DP) from hydrogels by constant voltage iontophoresis (CVI). The other objective was to establish the safety and efficacy of CVI in rats.

MATERIALS AND METHODS

Hydrogels of DP were developed using hydroxyethyl cellulose as matrix material and geraniol, l-menthol and thymol as iontophoretic efficiency enhancers (IEE). In vitro permeation of hydrogels under CVI (1.5 V) was performed in Franz diffusion cells across porcine skin. The ability of CVI to deliver therapeutic amount of DP in vivo was assessed in rat paw edema model.

RESULTS

CVI significantly (p < 0.05) increased the steady state flux of DP compared to the passive. The hydrogels containing geraniol and l-menthol enhanced the iontophoretic flux of DP by ∼4.75 and ∼4.49 fold, respectively compared to passive control. The in vivo studies indicated that CVI in combination with IEE, significantly reduced (p < 0.05) area under the curve (AUC) of % inflammation compared to passive treatment. An excellent correlation (r = 0.996) was noted between in vitro flux values and AUC of % inflammation.

CONCLUSION

The preclinical studies conclusively demonstrated that CVI in combination with IEE's such as geraniol or l-menthol has the potential to safely deliver therapeutic amounts of DP.

Effects of chemical and physical enhancement techniques on transdermal delivery of 3-fluoroamphetamine hydrochloride

The present study investigated the passive transdermal delivery of 3-fluoroamphetamine hydrochloride (PAL-353) and evaluated the effects of chemical and physical enhancement techniques on its permeation through human skin. In vitro drug permeation studies through dermatomed human skin were performed using Franz diffusion cells. Passive permeation of PAL-353 from propylene glycol and phosphate buffered saline as vehicles was studied. Effect of oleic acid, maltose microneedles, ablative laser, and anodal iontophoresis on its transdermal permeation was investigated. Infrared spectroscopy, scanning electron microscopy, calcein imaging, confocal laser microscopy, and histology studies were used to characterize the effects of chemical and physical treatments on skin integrity. Passive permeation of PAL-353 (propylene glycol) after 24h was found to be 1.03±0.17μg/cm². Microneedles, oleic acid, and laser significantly increased the permeation to 7.35±4.87μg/cm², 38.26±5.56μg/cm², and 523.24±86.79μg/cm² (p<0.05), respectively. A 548-fold increase in drug permeation was observed using iontophoresis as compared to its passive permeation from phosphate buffered saline (p<0.05). The characterization studies depicted disruption of the stratum corneum by microneedles and laser treatment. Overall, transdermal permeation of PAL-353 was significantly enhanced by the use of chemical and physical enhancement techniques.

Degradation of venlafaxine using TiO2/UV process: Kinetic studies, RSM optimization, identification of transformation products and toxicity evaluation

The photochemical degradation of the antidepressant drug venlafaxine (VNF) by UV/TiO₂ process was investigated in the present study. Prescreening experiments were conducted to study the effects of main parameters affecting the photocatalytic process. In addition, the effects and interactions of most influenced parameters were evaluated and optimized by using a central composite design model and a response surface methodology. Results indicated that VNF was quickly removed in all the irradiation experiments and its degradation was mainly affected by the studied variables (catalyst dose, initial VNF concentration and pH), as well as their interaction effects. Parallel to kinetic studies, the transformation products (TPs) generated during the treatment was investigated using LC coupled to low and high resolution mass spectrometry. Based on identification of the main TPs, tentative transformation pathways were proposed, including hydroxylation, demethylation and dehydration as major transformation routes. Τhe potential risk of VNF and its TPs to aqueous organisms was also investigated using Microtox bioassay before and during the processes. The obtained results showed an increment in the acute toxicity in the first stages and a continuously decreasing after then to very low values reached within 240min of the photocatalytic treatment, demonstrating that UV/TiO₂ can lead to the elimination of parent compound and the detoxification of the solution.

Effect of gel properties on transdermal iontophoretic delivery of diclofenac sodium

The aim of the study was to develop hydrogels and investigate the suitability for transdermal delivery of diclofenac sodium (DS) using constant voltage iontophoresis (CVI). Four batches of hydrogels of DS were developed using hydroxylethyl cellulose (HEC) as matrix material and terpenes as penetration enhancers. The hydrogels displayed a viscosity of ~1500 cps at a shear rate of 250 s-1 that was unlikely to change on minute shift in pH or temperature so that the iontophoretic transport would be unaffected. Moreover, the hydrogels were found to possess adequate conductivity at pH 7.4 to enable iontophoretic delivery of DS. In vitro studies indicated that passive transport of DS across porcine skin from hydrogels was comparable (p>0.05) to aqueous solution. The lead hydrogel (F1), containing geraniol was found to enhance the iontophoretic flux of DS by 5.16 fold at 1.5 V compared to passive control. In vivo studies in rats indicated that CVI on application of F1 significantly suppressed (p<0.001) carrageenan induced edema compared to passive treatment throughout the study.

Synergistic Effect and Mechanism of Cineole and Terpineol on In-vitro Transdermal Delivery of Huperzine A from Microemulsions

The aim of the present study was to investigate the influence and the mechanisms of cineole and terpineol on the in-vitro transdermal delivery of huperzine A from microemulsions, and their potential synergistic effect on the permeation enhancement. The transdermal delivery of huperzine A from microemulsions with different concentrations of cineole and terpineol through the rat abdominal skin was determined by Franz-type diffusion cells. The partition coefficient of huperzine A between the full thickness skin and microemulsion was determined. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) was carried out to analyze the effects of cineole and terpineol on the biophysical properties of the stratum corneum (SC) and the mechanisms of permeation enhancement. These results indicated that cineole and terpineol could synergistically increase the transdermal delivery of huperzine A from microemulsions through increasing the partition and diffusion coefficients of huperzine A. ATR-FTIR studies further validated the synergistic effect and revealed that the enhancing mechanisms were due to increasing the disorderliness and fluidity of SC lipid alkyl chains, disrupting the structure of keratin in SC, and extracting SC lipids. In conclusion, cineole and terpineol, acting synergistically to enhance the transdermal delivery of huperzine A from microemulsions, might provide an alternative permeation enhancer combination for the transdermal delivery of huperzine A.

5-Fluorouracil nanoparticles inhibit hepatocellular carcinoma via activation of the p53 pathway in the orthotopic transplant mouse model

Biodegradable polymer nanoparticle drug delivery systems provide targeted drug delivery, improved pharmacokinetic and biodistribution, enhanced drug stability and fewer side effects. These drug delivery systems are widely used for delivering cytotoxic agents. In the present study, we synthesized GC/5-FU nanoparticles by combining galactosylated chitosan (GC) material with 5-FU, and tested its effect on liver cancer in vitro and in vivo. The in vitro anti-cancer effects of this sustained release system were both dose- and time-dependent, and demonstrated higher cytotoxicity against hepatic cancer cells than against other cell types. The distribution of GC/5-FU in vivo revealed the greatest accumulation in hepatic cancer tissues. GC/5-FU significantly inhibited tumor growth in an orthotropic liver cancer mouse model, resulting in a significant reduction in tumor weight and increased survival time in comparison to 5-FU alone. Flow cytometry and TUNEL assays in hepatic cancer cells showed that GC/5-FU was associated with higher rates of G0-G1 arrest and apoptosis than 5-FU. Analysis of apoptosis pathways indicated that GC/5-FU upregulates p53 expression at both protein and mRNA levels. This in turn lowers Bcl-2/Bax expression resulting in mitochondrial release of cytochrome C into the cytosol with subsequent caspase-3 activation. Upregulation of caspase-3 expression decreased poly ADP-ribose polymerase 1 (PARP-1) at mRNA and protein levels, further promoting apoptosis. These findings indicate that sustained release of GC/5-FU nanoparticles are more effective at targeting hepatic cancer cells than 5-FU monotherapy in the mouse orthotropic liver cancer mouse model.

Transdermal delivery of venlafaxine hydrochloride: the effects of enhancers on permeation across pig ear skin

Venlafaxine representing a new class of antidepressants is a potent serotonin/ norepinephrine reuptake inhibitor. Transdermal delivery of venlafaxine hydrochloride (VHCl) may result in proper patient compliance by reducing the incidence of the undesirable GI problems generally associated with its plural oral dosing. The present study is an attempt to investigate the improvement of the transdermal flux of the hydrophilic VHCl by certain permeation enhancers viz. glycerin, urea, propylene glycol and mixture of propylene glycol and ethanol across pig ear skin. The cumulative drug release was the highest from the formulation F5 consisting of the mixture of propylene glycol and ethanol in sodium alginate gel with a load of 25% w/w VHCl with 96% permeation enhancement. The steady state flux observed with F5 was 0.203 mg cm^-2 hr and an area of 15.27 cm² would suffice to arrive at a required therapeutic concentration of VHCl in the blood.

The relevance of polymeric synthetic membranes in topical formulation assessment and drug diffusion study

Synthetic membranes are composed of thin sheets of polymeric macromolecules that can control the passage of components through them. Generally, synthetic membranes used in drug diffusion studies have one of two functions: skin simulation or quality control. Synthetic membranes for skin simulation, such as the silicone-based membranes polydimethylsiloxane and Carbosil, are generally hydrophobic and rate limiting, imitating the stratum corneum. In contrast, synthetic membranes for quality control, such as cellulose esters and polysulfone, are required to act as a support rather than a barrier. These synthetic membranes also often contain pores; hence, they are called porous membranes. The significance of Franz diffusion studies and synthetic membranes in quality control studies involves an understanding of the fundamentals of synthetic membranes. This article provides a general overview of synthetic membranes, including a brief background of the history and the common applications of synthetic membranes. This review then explores the types of synthetic membranes, the transport mechanisms across them, and their relevance in choosing a synthetic membrane in Franz diffusion cell studies for formulation assessment purposes.

In vitro and In vivo characterization of the transdermal delivery of sertraline hydrochloride Films

BACKGROUND AND THE PURPOSE OF THE STUDY

Sertraline hydrochloride is a selective serotonin reuptake inhibitor principally used in the treatment of major depressive disorder. To maintain the therapeutic plasma drug concentration of the drug for prolonged period, the transdermal drug delivery has been chosen as an alternative route of drug delivery. The pharmacokinetic properties of sertraline hydrochloride make it suitable for transdermal delivery. The purpose of the study was to investigate the effect of polymers and penetration enhancers on the transdermal delivery of the drug in order to improve its therapeutic efficacy.

METHODS

In the preparation of films, Eudragit RL 100, Eudragit RS 100, hydroxy propyl methyl cellulose (HPMC) and ethyl cellulose were used as polymers. The films were characterized for thickness, tensile strength, drug content, moisture uptake, moisture content, water vapor transmission rate and drug release. The films exhibiting higher rates of drug release were subjected to study the effect of oleic acid and propylene glycol as penetration enhancers on skin permeation of sertraline hydrochloride. In vivo and skin irritation studies were performed for the optimized film.

RESULTS

Films containing Eudragit RL 100, Eudragit RL 100 and HPMC showed the highest drug release of 94.34% and 96.90% respectively in a period of 42 hrs. The release data fitted into kinetic equations, yielded zero-order and fickian mechanism of drug release. There was a two-fold increase in skin permeation of sertraline hydrochloride in the presence of penetration enhancers in the film. The physical evaluation indicated the formation of smooth, flexible and translucent films. No skin irritation occurred on rabbit skin and the infrared studies showed the compatibility of the drug with the formulation excipients. The in vivo study revealed a constant plasma concentration of drug for long periods and the films containing penetration enhancers had achieved adequate plasma levels of the drug.

CONCLUSIONS

The obtained results indicated the feasibility for transdermal delivery of sertraline hydrochloride using eudragit RL 100 and HPMC.