Transdermal delivery of angiotensin II receptor blockers (ARBs), angiotensin-converting enzyme inhibitors (ACEIs) and others for management of hypertension

Application of Biomaterials in the Development of Hydrogel-Forming Microneedles Integrated with a Cyclodextrin Drug Reservoir for Improved Pharmacokinetic Profiles of Telmisartan

Telmisartan (TEL) is a promising antihypertensive agent among other angiotensin receptor blockers. However, its oral application is limited by its poor water solubility. This study presents the successful utilization of biomaterial-based hydrogel-forming microneedles integrated with a direct compressed tablet reservoir (HFMN-DCT) for the transdermal delivery of telmisartan in the treatment of hypertension. The combination of PVP, PVA, and tartaric acid was used in the HFMN formulation. A range of cross-linking temperatures and times were employed to optimize the characteristics of the HFMN. The HFMN exhibited excellent swelling capacity, mechanical strength, and insertion properties. Additionally, the poorly soluble characteristic of TEL was improved by the inclusion complex formulation with β-cyclodextrin (βCD). Phase solubility analysis showed an Ap-type diagram, indicating a higher-order complex between TEL and βCD, with respect to βCD. A ratio of TEL:βCD of 1:4 mM demonstrates the highest solubility enhancement of TEL. The inclusion complex formation was confirmed by FTIR, XRD, DSC, and molecular docking studies. A significantly higher release of TEL (up to 20-fold) from the inclusion complex was observed in the in vitro release study. Subsequently, a DCT reservoir was developed using various concentrations of sodium starch glycolate. Essentially, both the HFMN and DCT reservoir exhibit hemocompatibility and did not induce any skin irritation. The optimized combination of the HFMN-DCT reservoir showed an ex vivo permeation profile of 83.275 ± 2.405%. Notably, the proposed system showed superior pharmacokinetic profiles in the in vivo investigation using male Wistar rats. Overall, this study highlights the potential of HFMN-DCT reservoir systems as a versatile platform for transdermal drug delivery applications.

Engineering nanosystems for transdermal delivery of antihypertensive drugs

To control hypertension, long-term continuous antihypertensive therapeutics are required and five classes of antihypertensive drugs are frequently involved, including diuretics, β-blockers, calcium channel blockers, angiotensin II receptor blockers, and angiotensin-converting enzyme inhibitors. Although with demonstrated clinical utility, there is still room for the improvement of many antihypertensive drugs in oral tablet or capsule dosage form, in terms of reducing systemic side effects and first-pass hepatic drug uptake. Meanwhile, nanocarrier-mediated transdermal drug delivery systems have emerged as a powerful tool for various disease treatments. With benefits such as promoting patient compliance for long-time administration, enhancing skin permeability, and reducing systemic side effects, these systems are reasonably investigated and developed for the transdermal delivery of multiple antihypertensive drugs. This review aims to summarize the literature relating to nanosystem-based transdermal antihypertensive drug delivery and update recent advances in this field, as well as briefly discuss the challenges and prospects of engineering transdermal delivery nanosystems for hypertension treatment.

Nanotechnology-Based Strategies for Extended-Release Delivery of Angiotensin Receptor Blockers (ARBs): A Comprehensive Review

There has been a significant shift in the perception of hypertension as an important contributor to the global disease burden. Approximately 6 % and 8 % of pregnancies are affected by hypertension, which can adversely affect the mother and the fetus. Furthermore, a hypertensive individual is at increased risk of developing kidney disease, arterial hardening, eye damage, and strokes. Using angiotensin receptor blockers (ARBs) is widespread in treating hypertension, heart failure, coronary artery disease, and diabetic nephropathy. Despite this, some ARBs have limited use due to their poor oral bioavailability and water solubility. To tackle this, a variety of nanoparticle (NP)-based systems, such as polymeric NPs (i. e., dendrimers), polymeric micelles, polymer-drug conjugates, lipid NPs, nanoemulsions, self-emulsifying drug delivery systems (SEDDS), solid lipid NPs (SLNs), nanostructured lipid carriers (NLCs), carbon-based nanocarriers, inorganic NPs, and nanocrystals, have been recently developed for efficient delivery of losartan, Valsartan (Val), Olmesartan (OLM), Telmisartan (TEL), Candesartan, Eprosartan, Irbesartan, and Azilsartan to target cells. This review article provides a literature-based comparison of the various classes of ARBs, their mechanisms of action, and an overview of the nanoformulations developed for ARB delivery and successfully applied to managing hypertension, diabetic complications, and other conditions.

Microneedles and Their Application in Transdermal Delivery of Antihypertensive Drugs-A Review

One of the most cutting-edge, effective, and least invasive pharmaceutical innovations is the utilization of microneedles (MNs) for drug delivery, patient monitoring, diagnostics, medicine or vaccine delivery, and other medical procedures (e.g., intradermal vaccination, allergy testing, dermatology, and blood sampling). The MN-based system offers many advantages, such as minimal cost, high medical effectiveness, comparatively good safety, and painless drug application. Drug delivery through MNs can possibly be viewed as a viable instrument for various macromolecules (e.g., proteins, peptides, and nucleic acids) that are not efficiently administered through traditional approaches. This review article provides an overview of MN-based research in the transdermal delivery of hypertensive drugs. The critical attributes of microneedles are discussed, including the mechanism of drug release, pharmacokinetics, fabrication techniques, therapeutic applications, and upcoming challenges. Furthermore, the therapeutic perspective and improved bioavailability of hypertensive drugs that are poorly aqueous-soluble are also discussed. This focused review provides an overview of reported studies and the recent progress of MN-based delivery of hypertensive drugs, paving the way for future pharmaceutical uses. As MN-based drug administration bypasses first-pass metabolism and the high variability in drug plasma levels, it has grown significantly more important for systemic therapy. In conclusion, MN-based drug delivery of hypertensive drugs for increasing bioavailability and patient compliance could support a new trend of hypertensive drug delivery and provide an alternative option, overcoming the restrictions of the current dosage forms.

Improved transdermal delivery of valsartan using combinatorial approach of polymeric transdermal hydrogels and solid microneedles: an ex vivo proof of concept investigation

Valsartan (VAL) is used as a first-line agent to treat hypertension. However, VAL exhibits poor absorption and low bioavailability when administrated orally. To overcome these issues, VAL transdermal gel was developed in this study, where Carbopol was used as the gel matrices. Additionally, solid microneedles (Dermaroller^®) with various needle lengths were combined with transdermal gel to improve its permeation across the stratum corneum as a skin barrier. Developed formulations were further evaluated for various parameters, including pH, viscosity, spreadability, extrudability, gel strength, drug content, ex vivo permeation, in vitro release, occlusivity, and hemolysis. The results showed that all formulations exhibited desired physical characteristics without any potential to cause toxicity. Moreover, this approach showed that using microneedles could significantly enhance the permeation of VAL up to 3 folds compared to untreated skin. The use of microneedles 1.5 mm was found to be the optimum combination to improve VA permeation without affecting skin integrity. As much as 1.69 ± 0.004 mg of VAL permeated after 8 h. Finally, it could be concluded that this work had successfully developed a new approach for VALS drug delivery and could potentially show a significant impact on the treatment of hypertension. Further in vivo work should be considered.

Changes in Pharmacokinetics and Pharmacodynamics of Losartan in Experimental Diseased Rats Treated with Curcuma longa and Lepidium sativum

The current study investigated “pharmacodynamics and pharmacokinetics interactions” of losartan with Curcuma longa (CUR) and Lepidium sativum (LS) in hypertensive rats. Hypertension was induced by oral administration of L-NAME (40 mg/kg) for two weeks. Oral administration of CUR or LS shows some substantial antihypertensive activity. The systolic blood pressure (SBP) of hypertensive rats was decreased by 7.04% and 8.78% 12 h after treatment with CUR and LS, respectively, as compared to rats treated with L-NAME alone. LS and CUR display the ability to potentiate the blood pressure-lowering effects of losartan in hypertensive rats. A greater decrease in SBP, by 11.66% and 13.74%, was observed in hypertensive rats treated with CUR + losartan and LS + losartan, respectively. Further, both the investigated herbs, CUR and LS, caused an increase in plasma concentrations of losartan in hypertensive rats. The AUC0-t, AUC0-inf and AUMC0-inf of losartan were increased by 1.25-fold, 1.28-fold and 1.09-fold in hypertensive rats treated with CUR + losartan. A significant (p < 0.05) increase in AUC0-t (2.41-fold), AUC0-inf (3.86-fold) and AUMC0-inf (8.35-fold) of losartan was observed in hypertensive rats treated with LS + losartan. The present study affirms that interactions between CUR or LS with losartan alter both “pharmacokinetics and pharmacodynamics” of the drug. Concurrent administration of losartan with either CUR or LS would require dose adjustment and intermittent blood pressure monitoring for clinical use in hypertensive patients. Additional investigation is necessary to determine the importance of these interactions in humans and to elucidate the mechanisms of action behind these interactions.

AGTR1 blocker attenuates activation of Tenon's capsule fibroblasts after glaucoma filtration surgery via the NF-κB signaling pathway

Activation of Tenon's capsule fibroblasts limits the success rate of glaucoma filtration surgery (GFS), the most efficacious therapy for patients with glaucoma. Angiotensin type 1 receptor (AGTR1) is involved in tissues remodeling and fibrogenesis. However, whether AGTR1 is involved in the progress of fibrogenesis after GFS is not fully elucidated. The aim of this study was to investigate the role of an AGTR1 in scar formation after GFS and the potential anti-fibrosis effect of AGTR1 blocker. AGTR1 expression level was increased in subconjunctival tissues in a rat model of GFS and transforming growth factor-beta 2 (TGF-β2)-induced human Tenon's capsule fibroblasts (HTFs). AGTR1 blocker treatment suppressed TGF-β2-induced HTF migration and α-smooth muscle actin (α-SMA) and fibronectin (FN) expression. AGTR1 blocker treatment also attenuated collagen deposition and α-SMA and FN expression in subconjunctival tissues of the rat model after GFS. Moreover, AGTR1 blocker decreased TGF-β2-induced P65 phosphorylation, P65 nuclear translocation, and nuclear factor kappa B (NF-κB) luciferase activity. Additionally, BAY 11-7082 (an NF-κB inhibitor) significantly suppressed HTF fibrosis. In conclusion, our results indicate that AGTR1 is involved in scar formation after GFS. The AGTR1 blocker attenuates subconjunctival fibrosis after GFS by inhibiting the NF-κB signaling pathway. These findings indicate that targeting AGTR1 is a potential approach to attenuate fibrosis after GFS.

From Angiotensin II to Cyclic Peptides and Angiotensin Receptor Blockers (ARBs): Perspectives of ARBs in COVID-19 Therapy

The octapeptide hormone angiotensin II is one of the most studied peptides with the aim of designing and synthesizing non-peptide mimetics for oral administration. To achieve this, cyclizations at different positions within the peptide molecule has been a useful strategy to define the active conformation. These studies on angiotensin II led to the discovery of Sarmesin, a type II angiotensin II antagonist, and the breakthrough non-peptide mimetic Losartan, the first in a series of sartans marketed as a new generation of anti-hypertensive drugs in the 1990s. Angiotensin II receptor blockers (ARBS) and angiotensin I converting enzyme inhibitors (ACEI) were recently reported to protect hypertensive patients infected with SARS-CoV-2. The renin–angiotensin system (RAS) inhibitors reduce excess angiotensin II and increase antagonist heptapeptides alamandine and aspamandine which counterbalance angiotensin II and maintain homeostasis and vasodilation.

A Study on the Mechanism of Milkvetch Root in the Treatment of Diabetic Nephropathy Based on Network Pharmacology

Diabetic nephropathy (DN) is one of the most common complications of diabetes mellitus. Owing to its complicated pathogenesis, no satisfactory treatment strategies for DN are available. Milkvetch Root is a common traditional Chinese medicine (TCM) and has been extensively used to treat DN in clinical practice in China for many years. However, due to the complexity of botanical ingredients, the exact pharmacological mechanism of Milkvetch Root in treating DN has not been completely elucidated. The aim of this study was to explore the active components and potential mechanism of Milkvetch Root by using a systems pharmacology approach. First, the components and targets of Milkvetch Root were analyzed by using the Traditional Chinese Medicine Systems Pharmacology database. We found the common targets of Milkvetch Root and DN constructed a protein-protein interaction (PPI) network using STRING and screened the key targets via topological analysis. Enrichment of Gene Ontology (GO) pathways and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were analyzed. Subsequently, major hubs were identified and imported to the Database for Annotation, Visualization and Integrated Discovery for pathway enrichment analysis. The binding activity and targets of the active components of Milkvetch Root were verified by using the molecular docking software SYBYL. Finally, we found 20 active components in Milkvetch Root. Moreover, the enrichment analysis of GO and KEGG pathways suggested that AGE-RAGE signaling pathway, HIF-1 signaling pathway, PI3K-Akt signaling pathway, and TNF signaling pathway might be the key pathways for the treatment of DN; more importantly, 10 putative targets of Milkvetch Root (AKT1, VEGFA, IL-6, PPARG, CCL2, NOS3, SERPINE1, CRP, ICAM1, and SLC2A) were identified to be of great significance in regulating these biological processes and pathways. This study provides an important scientific basis for further elucidating the mechanism of Milkvetch Root in treating DN.

Access to Cyanoimines Enabled by Dual Photoredox/Copper-Catalyzed Cyanation of O-Acyl Oximes

An efficient strategy for the synthesis of pharmaceutically important and synthetically useful cyanoimines, as well as cyanamides, has been described. This strategy is enabled by dual photoredox/copper-catalyzed cyanation of O-acyl oximes or O-acyl hydroxamides. This state of the art protocol for cyanoimines and cyanamides features readily available starting materials, mild reaction conditions, good functional group tolerance, and operational simplicity. The resultant cyanoimines can be transformed into structurally diverse and functionally important N-containing heterocycles.

Potential pharmacodynamic and pharmacokinetic interactions of Nigella Sativa and Trigonella Foenum-graecum with losartan in L-NAME induced hypertensive rats

The objective of this investigation was to study whether Nigella Sativa and Trigonella Foenum-graecum, could modulate the losartan pharmacodynamic (PD) and pharmacokinetic (PK) in experimental L-NAME induced hypertensive rats. For in vivo study, the systolic blood pressure (SBP) of rats was measured by the “tail-cuff system” after the treatment of rats with herb alone and herb + losartan in hypertensive rats. The SBP of rats treated with L-NAME + losartan also recorded. For the PK study, blood samples were obtained for up to 12 h to determine the concentrations of the drug, and various PK parameters were calculated. The data displayed that the SBP was significantly (p < 0.05) decreased in the rats when administered with L-NAME + N. Sativa or L-NAME + T. Foenum-graecum in contrast to the rats administered with L-NAME alone. A more prominent decline (p < 0.05) in SBP was detected in rats administered with L-NAME + N. Sativa + losartan and L-NAME + T. Foenum-graecum + losartan. In a PK study, higher losartan C_max and AUC_0-t were noted in rats treated with N. Sativa + losartan and T. Foenum-graecum + losartan, although the difference was not significant in contrast to the control group. This study proposed that the interaction between N. Sativa & losartan and T. Foenum-graecum & losartan could take place on concurrent administration; consequently, the dose of losartan may need to be accustomed when they are utilized simultaneously.

Lipid Vesicles and Nanoparticles for Non-invasive Topical and Transdermal Drug Delivery

The delivery of drugs, via different layers of skin, is challenging because it acts as a natural barrier and exerts hindrance against molecules to permeate into or through it. To overcome such obstacles, different noninvasive methods, like vehicle-drug interaction, modifications of the horny layer and nanoparticles have been suggested. The aim of the present review is to highlight some of the non-invasive methods for topical, diadermal and transdermal delivery of drugs. Special emphasis has been made on the information available in numerous research articles that put efforts in overcoming obstacles associated with barrier functions imposed by various layers of skin. Advances have been made in improving patient compliance that tends to avoid hitches involved in oral administration. Of particular interest is the use of lipid-based vesicles and nanoparticles for dermatological applications. These particulate systems can effectively interact and penetrate into the stratum corneum via lipid exchange and get distributed in epidermis and dermis. They also have the tendency to exert a systemic effect by facilitating the absorption of an active moiety into general circulation.

Development of an optimized avanafil-loaded invasomal transdermal film: Ex vivo skin permeation and in vivo evaluation

Avanafil (AVA) is a recent FDA approved selective phosphodiesterase type 5 inhibitor used for oral treatment of erectile dysfunction. The oral bioavailability of the drug is challenged by its reduced water solubility, considerable presystemic metabolism, and altered absorption in the presence of food. Accordingly, this work aimed to surmount the aforementioned challenges through the development of optimized nanosized AVA invasomes with enhanced transdermal delivery. AVA invasomes were prepared according to a Box-Behnken experimental design to explore the impact of the following formulation factors: phospholipid % (X₁), ethanol % (X₂), terpene % (X₃), and terpene type (X₄) on vesicle size (Y₁) and entrapment efficiency (Y₂). The three numerical variables were used at three levels, while the categorical variable was used at two levels. The optimized formulation with vesicular size of 109.92 nm and entrapment efficiency of 96.98% was incorporated into a hydroxypropyl methyl cellulose-based transdermal film and characterized for its ex vivo permeation behavior and in vivo performance in rats. The optimized AVA invasomal film showed enhanced ex vivo permeation with an enhancement factor of 2.514 and a more than four-fold increase in relative bioavailability compared to the raw AVA film. These results provide insight into the capability of the optimized invasomal film to enhance the transdermal permeation and bioavailability of AVA.

Efficacy of aliskiren supplementation for heart failure : A meta-analysis of randomized controlled trials

BACKGROUND

Aliskiren might be beneficial for heart failure. However, the results of various studies are controversial. We conducted a systematic review and meta-analysis to explore the efficacy of aliskiren supplementation for heart failure.

METHODS

PubMed, Embase, Web of Science, EBSCO, and the Cochrane Library databases were systematically searched. Randomized controlled trials (RCTs) assessing the efficacy of aliskiren for heart failure were included. Two investigators independently searched for articles, extracted data, and assessed the quality of included studies. The meta-analysis was performed using the random-effect model.

RESULTS

Five RCTs comprising 1973 patients were included in the meta-analysis. Compared with control interventions in heart failure, aliskiren supplementation was found to significantly reduce NT-proBNP levels (standardized mean difference [SMD] = -0.12; 95% CI = -0.21 to -0.03 pg/ml; p = 0.008) and plasma renin activity (SMD = -0.66; 95% CI = -0.89 to -0.44 ng/ml.h; p < 0.00001) while increasing plasma renin concentration (SMD = 0.52; 95% CI = 0.30-0.75 ng/l; p < 0.00001); however, it demonstrated no significant influence on BNP levels (SMD = -0.08; 95% CI = -0.31-0.15 pg/ml; p = 0.49), mortality (RR = 0.97; 95% CI = 0.79-1.20; p = 0.79), aldosterone levels (SMD = -0.09; 95% CI = -0.32-0.14 pmol/l; p = 0.44), adverse events (RR = 3.03; 95% CI = 0.18-49.51; p = 0.44), and serious adverse events (RR = 1.34; 95% CI = 0.54-3.33; p = 0.53).

CONCLUSION

Aliskiren supplementation was found to significantly decrease NT-proBNP levels and plasma renin activity and to improve plasma renin concentration in the setting of heart failure.

Development and biological evaluation of vesicles containing bile salt of telmisartan for the treatment of diabetic nephropathy

The aim of present study was to develop and evaluate vesicles containing bile salt formulation of telmisartan for the treatment of diabetic nephropathy. Different vesicles containing bile salt formulations were developed by varying ratios of soybean phosphatidylcholine and sodium deoxycholate. Prepared formulations were characterized for their size, polydispersity index, zeta potential, morphology and entrapment efficiency. Further, the renoprotective outcome of optimized formulation was studied in streptozotocin-induced diabetic nephropathy rat model. Results of the present study demonstrated that the average vesicles size, polydispersity index, zeta potential and entrapment efficiency were found to be in the range of 64.98 ± 1.40 to 167.60 ± 6.46 nm, 0.02 ± 0.04 to 0.31 ± 0.01, -24.30 ± 1.39 to -42.60 ± 6.67 mV and 29.68 ± 1.08% to 77.21 ± 0.52%, respectively. Further, the best chosen formulation F4 presented vesicles size, polydispersity index, zeta potential and entrapment efficiency of 64.98 ± 1.40 nm, 0.24 ± 0.02, -35.40 ± 1.48 mV and 77.21 ± 0.52%, respectively. In addition, formulation F4 improved the biological indices in streptozotocin-induced diabetic nephropathy in rats. It was concluded that prepared formulation exerts a valuable results on diabetic nephropathy and it may be a potential pharmaceutical dosage form for the treatment of diabetic nephropathy.

Formulation and characterization of novel soft nanovesicles for enhanced transdermal delivery of eprosartan mesylate

The objective of the present work was to formulate, optimize and evaluate the potential of novel soft nanovesicles i.e. nano-transfersomes, containing eprosartan mesylate (EM) for transdermal delivery. Nano-transfersomes of EM were developed using Phospholipon 90G, Span 80 (SP) and sodium deoxycholate (SDC) and characterized for vesicle size, shape, entrapment efficiency, in vitro skin permeation study and confocal laser scanning microscopy. The optimized nano-transfersomes formulation showed vesicles size of 108.53 ± 0.06 nm and entrapment efficiency of 63.00 ± 2.76%. The optimized nano-transfersomes provided an improved transdermal flux of 27.22 ± 0.29 µg/cm²/h with an enhancement ratio of 16.80 over traditional liposomes through Wistar rat skin. Confocal laser microscopy of rat skin treated with the optimized formulation showed that the formulation was eventually distributed and permeated deep into the rat skin. The present investigation has shown that the nature and concentration of surfactants (edge activators) influence immense control on the characteristics of nano-transfersomes. It was concluded that the developed nano-transfersomes surmount the limitation of low penetration ability of the traditional liposomes across the rat skin. Improved drug delivery presented by nano-transfersomes establishes this system as an encouraging dosage form for the delivery of EM via skin route.

Design, formulation and optimization of novel soft nano-carriers for transdermal olmesartan medoxomil delivery: In vitro characterization and in vivo pharmacokinetic assessment

Olmesartan is a hydrophobic antihypertensive drug with a short biological half-life, and low bioavailability, presents a challenge with respect to its oral administration. The objective of the work was to formulate, optimize and evaluate the transdermal potential of novel vesicular nano-invasomes, containing above anti-hypertensive agent. To achieve the above purpose, soft carriers (viz. nano-invasomes) of olmesartan with β-citronellene as potential permeation enhancer were developed and optimized using Box-Behnken design. The physicochemical characteristics e.g., vesicle size, shape, entrapment efficiency and skin permeability of the nano-invasomes formulations were evaluated. The optimized formulation was further evaluated for in vitro drug release, confocal microscopy and in vivo pharmacokinetic study. The optimum nano-invasomes formulation showed vesicles size of 83.35±3.25nm, entrapment efficiency of 65.21±2.25% and transdermal flux of 32.78±0.703 (μg/cm(2)/h) which were found in agreement with the predicted value generated by Box-Behnken design. Confocal laser microscopy of rat skin showed that optimized formulation was eventually distributed and permeated deep into the skin. The pharmacokinetic study presented that transdermal nano-invasomes formulation showed 1.15 times improvement in bioavailability of olmesartan with respect to the control formulation in Wistar rats. It was concluded that the response surfaces estimated by Design Expert(®) illustrated obvious relationship between formulation factors and response variables and nano-invasomes were found to be a proficient carrier system for transdermal delivery of olmesartan.

Alternative Roles of STAT3 and MAPK Signaling Pathways in the MMPs Activation and Progression of Lung Injury Induced by Cigarette Smoke Exposure in ACE2 Knockout Mice

Inflammation-mediated abnormalities in the renin-angiotensin system (RAS) and expression of matrix metalloproteinases (MMPs) are implicated in the pathogenesis of lung injury. Angiotensin converting enzyme II (ACE2), an angiotensin converting enzyme (ACE) homologue that displays antagonist effects on ACE/angiotensin II (Ang II) axis, could also play a protective role against lung diseases. However, the relationship between ACE2 and MMPs activation in lung injury is still largely unclear. The purpose of this study is to investigate whether MMPs activity could be affected by ACE2 and which ACE2 derived signaling pathways could be also involved via using a mouse model with lung injury induced by cigarette smoke (CS) exposure for 1 to 3 weeks. Wild-type (WT; C57BL/6) and ACE2 KO mice (ACE2^-/-) were utilized to study CS-induced lung injury. Increases in the resting respiratory rate (RRR), pulmonary immunokines, leukocyte infiltration and bronchial hyperplasia were observed in the CS-exposed mice. Compared to WT mice, more serious physiopathological changes were found in ACE2^-/- mice in the first week of CS exposure. CS exposure increased pulmonary ACE and ACE2 activities in WT mice, and significantly increased ACE in ACE2^-/- mice. Furthermore, the activity of pulmonary MMPs was decreased in CS-exposed WT mice, whereas this activity was increased in ACE2^-/- mice. CS exposure increased the pulmonary p-p38, p-JNK and p-ERK1/2 level in all mice. In ACE2^-/- mice, a significant increase p-STAT3 signaling was detected; however, no effect was observed on the p-STAT3 level in WT mice. Our results support the hypothesis that ACE2 deficiency influences MMPs activation and STAT3 phosphorylation signaling to promote more pulmonary inflammation in the development of lung injury.

Invasomes of isradipine for enhanced transdermal delivery against hypertension: formulation, characterization, and in vivo pharmacodynamic study

Context Isradipine is an effective calcium channel blocker used in the management of hypertension. It undergoes extensive first pass metabolism and has low oral bioavailability. Hence we attempted to develop isradipine-loaded invasomes. Objective The purpose of this work was to prepare and characterize invasomes carrier for isradipine, and to evaluate the optimized formulation obtained for pharmacodynamic study. Materials and methods Isradipine-loaded invasomes were prepared by conventional thin layer evaporation technique using Phospholipon® 90G, β-citronellene (terpene) and ethanol. Prepared formulations were characterized in terms of size, size distribution, morphology, entrapment efficiency, and antihypertensive activity. Results and discussion It was observed that prepared isradipine-loaded invasomes delivers ameliorated flux, reasonable entrapment efficiency, and more effectiveness for transdermal delivery. The optimized formulation presented the particle size of 194 ± 18 nm, entrapment efficiency (88.46%), and attained mean transdermal flux of 22.80 ± 2.10 μg/cm²/h through rat skin. Confocal laser scanning microscopy revealed an enhanced permeation of Rhodamine-Red-loaded isradipine invasomes to the deeper layers of the rat skin. During antihypertensive study, the treatment group showed a substantial and constant decrease in blood pressure, for up to 24 h. The isradipine invasomes formulation was found to be effective, with a 20% reduction in blood pressure by virtue of better permeation through Wistar rat skin. Conclusion It was concluded that the developed isradipine invasomes accentuate the transdermal flux and the results obtained encouraged the use of the isradipine-loaded invasomes as the formulation for the potential management of hypertension.

The application of anethole, menthone, and eugenol in transdermal penetration of valsartan: Enhancement and mechanistic investigation

CONTEXT

The main barrier for transdermal delivery is the obstacle property of the stratum corneum. Many types of chemical penetration enhancers have been used to breach the skin barrier; among the penetration enhancers, terpenes are found as the most highly advanced, safe, and proven category.

OBJECTIVE

In the present investigation, the terpenes anethole, menthone, and eugenol were used to enhance the permeation of valsartan through rat skin in vitro and their enhancement mechanism was investigated.

MATERIALS AND METHODS

Skin permeation studies of valsartan across rat skin in the absence and the presence of terpenes at 1% w/v, 3% w/v, and 5% w/v in vehicle were carried out using the transdermal diffusion cell sampling system across rat skin and samples were withdrawn from the receptor compartment at 1, 2, 3, 4, 6, 8, 10, 12, and 24 h and analysed for drug content by the HPLC method. The mechanism of skin permeation enhancement of valsartan by terpenes treatment was evaluated by Fourier transform infrared spectroscopy (FTIR) analysis and differential scanning calorimetry (DSC).

RESULTS

All the investigated terpenes provided a significant (p < 0.01) enhancement in the valsartan flux at a concentration of 1%, and less so at 3% and 5%. The effectiveness of terpenes at 1% concentration was in the following order: anethole > menthone > eugenol with 4.4-, 4.0-, and 3.0-fold enhancement ratio over control, respectively. DSC study showed that the treatment of stratum corneum with anethole shifted endotherm down to lower melting point while FTIR studies revealed that anethole produced maximum decrease in peak height and area than other two terpenes.

CONCLUSION

The investigated terpenes can be successfully used as potential enhancers for the enhancement of skin permeation of lipophilic drug.