Targeting Hypertension: A Review on Pathophysiological Factors and Treatment Strategies.

Hypertension is one of the primary causes of cardiovascular diseases and death, with a higher prevalence in low- and middle-income countries. The pathophysiology of hypertension remains complex, with 2% to 5% of patients having underlying renal or adrenal disorders. The rest are referred to as essential hypertension, with derangements in various physiological mechanisms potentially contributing to the development of essential hypertension. Hypertension elevates the risk of cardiovascular disease (CVD) events (coronary heart disease, heart failure, and stroke) and mortality. First-line therapy for hypertension is lifestyle change, which includes weight loss, a balanced diet that includes low salt and high potassium intake, physical exercise, and limitation or elimination of alcohol use. Blood pressure-lowering effects of individual lifestyle components are partially additive, enhancing the efficacy of pharmaceutical treatment. The choice to begin antihypertensive medication should be based on the level of blood pressure and the existence of a high atherosclerotic CVD risk. First-line hypertension treatment includes a thiazide or thiazide-like diuretic, an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker, and a calcium channel blocker. Addressing hypertension will require continued efforts to improve access to diagnosis, treatment, and lifestyle interventions.

Formulation Strategies for Enhancing Pharmaceutical and Nutraceutical Potential of Sesamol: A Natural Phenolic Bioactive.

Natural plants and their products continue to be the major source of phytoconstituents in food and therapeutics. Scientific studies have evidenced the benefits of sesame oil and its bioactives in various health conditions. Various bioactives present in it include sesamin, sasamolin, sesaminol, and sesamol; among these, sesamol represents a major constituent. This bioactive is responsible for preventing various diseases including cancer, hepatic disorders, cardiac ailments, and neurological diseases. In the last decade, the application of sesamol in the management of various disorders has attracted the increasing interest of the research community. Owing to its prominent pharmacological activities, such as antioxidant, antiinflammatory, antineoplastic, and antimicrobial, sesamol has been explored for the above-mentioned disorders. However, despite the above-mentioned therapeutic potential, its clinical utility is mainly hindered owing to low solubility, stability, bioavailability, and rapid clearance issues. In this regard, numerous strategies have been explored to surpass these restrictions with the formulation of novel carrier platforms. This review aims to describe the various reports and summarize the different pharmacological activities of sesamol. Furthermore, one part of this review is devoted to formulating strategies to improve sesamol's challenges. To resolve the issues such as the stability, low bioavailability, and high systemic clearance of sesamol, novel carrier systems have been developed to open a new avenue to utilize this bioactive as an efficient first-line treatment for various diseases.

Formulation, Characterization, Anti-Inflammatory and Cytotoxicity Study of Sesamol-Laden Nanosponges.

Sesamol (SES) possesses remarkable chemotherapeutic activity, owing to its anti-inflammatory and antioxidant potential. However, the activity of SES is mainly hampered by its poor physicochemical properties and stability issues. Hence, to improve the efficacy of this natural anti-inflammatory and cytotoxic agent, it was loaded into ß-cyclodextrin nanosponges (NS) prepared using different molar ratios of polymer and crosslinker (diphenyl carbonate). The particle size of SES-laden NS (SES-NS) was shown to be in the nano range (200 to 500 nm), with a low polydispersity index, an adequate charge (-17 to -26 mV), and a high payload. Field emission scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy were used to characterize the bioactive-loaded selected batch (SES-NS6). This batch of nanoformulations showed improved solubilization efficacy (701.88 µg/mL) in comparison to bare SES (244.36 µg/mL), polymer (ß-CD) (261.43 µg/mL), and other fabricated batches. The drug release data displayed the controlled release behavior of SES from NS. The findings of the egg albumin denaturation assay revealed the enhanced anti-inflammatory potential of SES-NS as compared to bare SES. Further, the cytotoxicity assay showed that SES-NS was more effective against B16F12 melanoma cell lines than the bioactive alone. The findings of this assay demonstrated a reduction in the IC50 values of SES-NS (67.38 µg/mL) in comparison to SES (106 µg/mL). The present investigation demonstrated the in vitro controlled release pattern and the enhanced anti-inflammatory and cytotoxic activity of SES-NS, suggesting its potential as a promising drug delivery carrier for topical delivery.

Miconazole nitrate bearing ultraflexible liposomes for the treatment of fungal infection.

Miconazole nitrate is a widely used antifungal agent, but its use in topical formulations is not efficacious because deep seated fungal infections are difficult to treat with conventional topical formulation. Miconazole nitrate loaded ultraflexible liposomes have been prepared and their topical performance has been compared with conventional liposomes containing miconazole nitrate. Various ultraflexible liposomal formulations were prepared and extensively characterized for vesicular shape, size, entrapment efficiency, degree of deformability and in-vitro skin permeation through rat skin. Higher rate of drug transfer across the skin with ultraflexible liposomal formulations of miconazole nitrate suggests that the drug in its lipo-solubilized state might have gained facilitated entry into the tough barrier consisting of subcutaneous. In-vivo study showed better antifungal activity as compared to traditional liposomes and plain drug solution. This was confirmed through fluoroscence microscopy. It is concluded that prepared ultraflexible liposomes can facilitate improved and localized drug action in the skin, thus providing a better option to deal with deep seated skin problems.

Targeting of efavirenz loaded tuftsin conjugated poly(propyleneimine) dendrimers to HIV infected macrophages in vitro.

HIV infected macrophages are considered as reservoirs for spreading the virus in AIDS patients. Tuftsin not only binds specifically to the mononuclear phagocytic cells but also enhances their natural killer activity. The purpose of this study is to explore the targeting potential and anti-HIV activity of efavirenz (EFV) loaded, tuftsin conjugated 5th generation poly(propyleneimine) dendrimers (TuPPI) in vitro. Tuftsin was chemically conjugated to 5th generation poly(propyleneimine) dendrimers (PPI). The entrapment efficiency of PPI and TuPPI were found to be 37.43+/-0.3% and 49.31+/-0.33%, respectively. TuPPI was found to slow down and prolong the in vitro release of EFV upto 144h against PPI, which releases the drug completely within 24 h. TuPPI possessed negligible cytotoxicity as compared to that of PPI. The cellular uptake of TuPPI was found to be 34.5 times higher than that of the free drug in first 1 h and was significantly higher in HIV infected macrophages than that of uninfected cells. TuPPI was found to reduce the viral load by 99% at a concentration of 0.625 ng/ml, which is due to the enhanced cellular uptake, reduced toxicity and the inherent anti-HIV activity of TuPPI.

Poly(propyleneimine) dendrimer and dendrosome mediated genetic immunization against hepatitis B.

The purpose of the present research work is to explore the potential of dendrosomes in genetic immunization against hepatitis B. Plasmid DNA encoding pRc/CMV-HBs[S] (5.6 kb), encoding the small region of the hepatitis B surface antigen, was complexed with 5th generation poly(propyleneimine) dendrimer (PPI) in different ratios. Transfection of CHO cells revealed that a ratio of 1:50 for pDNA:PPI was optimum for transfection. Results of cytotoxicity studies showed that the toxicity of PPI-DNA complex was significantly (p<0.05) higher for PPI 75 and PPI 100 as compared to the other PPI-DNA complexes. PPI 50 was employed for preparation of dendrosomes by reverse phase evaporation method. The dendrosomal formulation DF3 was found to possess optimum vesicle size, zeta potential and entrapment efficiency. In vitro production of HBsAg in CHO cells showed that DF3 possess maximum transfection efficiency. In vivo immunization studies were carried out by giving a single intramuscular injection of 10 microg of plasmid DNA (pDNA) or its dendrimeric or dendrosomal formulation to female Balb/c mice, followed by estimation of total IgG, IgG(1), IgG(2a), IgG(2b), biweekly. DF3 was found to elicit maximum immune response in terms of total IgG and its subclasses under study as compared to PPI 50 and pDNA at all time points. Animals immunized with DF3 developed very high cytokine level. Higher level of IFN-gamma suggests that the immune response was strictly Th1 mediated. Our observations clearly prove the superiority of dendrosomes over PPI-DNA complex and pDNA for genetic immunization against hepatitis B.

Radiolabeling, pharmacoscintigraphic evaluation and antiretroviral efficacy of stavudine loaded 99mTc labeled galactosylated liposomes.

The study was aimed to optimize radiolabeling with 99mTc, to determine the antiretroviral activity and to study the biodistribution of 99mTc labeled galactosylated liposomes loaded with stavudine. Liposomes were prepared using reverse-phase evaporation method followed by extrusion through 200nm polycarbonate membranes. The galactosylated liposomes were assessed for in vitro ligand-specific activity and the aggregation of galactosylated liposomes was found to increase as lectin concentration was increased from 5microg/ml to 30microg/ml. Free stavudine and stavudine loaded plain and galactosylated liposomes were radiolabeled with 99mTc by direct labeling method using stannous chloride as a reducing agent. Labeling method was optimized for stannous chloride quantity to achieve maximum labeling efficiency >95%. Antiretroviral activity was determined using human immunodeficiency virus-1 (HIV) infected MT2 cell line. A dose-dependent inhibition of p24 production was observed upon treatment of HIV-1 infected MT2 cells with stavudine loaded liposomes and galactosylated liposomes. Scintigraphic imaging and quantitative biodistribution of 99mTc labeled drug and liposomes showed that liposomal formulations were better taken up by the liver and spleen. Free drug solution was cleared from the blood. Further, a significantly higher (P<0.05) liver and spleen retention was observed over a period of 24h in case of galactosylated liposomes as compared to free drug and plain liposomes. Reduced uptake of the galactosylated liposomes in bone and higher and prolonged accumulation in mononuclear phagocyte system (MPS)-rich organs indicates the excellent potential of this formulation in the treatment of HIV infection.

Stability study of stavudine-loaded O-palmitoyl-anchored carbohydrate-coated liposomes.

The purpose of this study was to evaluate the physicochemical stability of carbohydrate-anchored liposomes. In the present study, carbohydrate (galactose, fucose, and mannose) was palmitoylated and anchored on the surface of positively charged liposomes (PL). The stabilities of plain neutral liposomes (NL), PL, and O-palmitoyl carbohydrate-anchored liposomes were determined. The effects of storage conditions (4 degrees C +/- 2 degrees C, 25 degrees C +/- 2 degrees C/60% +/- 5% relative humidity [RH], or 40 degrees C +/- 2 degrees C/75% +/- 5% RH for a period of 10, 20, and 30 days) were observed on the vesicle size, shape, zeta potential, drug content, and in vitro ligand agglutination assay by keeping the liposomal formulations in sealed amber-colored vials (10-mL capacity) after flushing with nitrogen. The stability of liposomal formulations was found to be temperature dependent. All the liposomal formulations were found to be stable at 4 degrees C +/- 2 degrees C up to 1 month. Storage at 25 degrees C +/- 2 degrees C/60% +/- 5% RH and 40 degrees C +/- 2 degrees C/75% +/- 5% RH adversely affected uncoated liposomal formulations. Carbohydrate coating of the liposomes could enhance the stability of liposomes at 25 degrees C +/- 2 degrees C/60% +/- 5% RH and 40 degrees C +/- 2 degrees C/75% +/- 5% RH.

Investigations on biodistribution of technetium-99m-labeled carbohydrate-coated poly(propylene imine) dendrimers.

The purpose of this work was to study the biodistribution pattern of the fifth generation of poly(propylene imine) dendrimer (PPI-5.0G)-based carbohydrate (mannose and lactose)-coated glycodendrimers in mice so as to explore the potential of these systems as drug carriers. Plain dendrimers were synthesized and coated with carbohydrates following the reported procedures. The formulations were labeled with radioactive technetium (sodium pertechnetate; 99mTcO4-) and characterized for labeling efficiency as well as in vitro and in vivo stability of the labeled complexes. The blood clearance study was performed in female New Zealand rabbits. The periodic in vivo biodistribution profile of the formulations was investigated in female Balb/c mice. The dendrimeric formulations were labeled with 95% labeling efficiency. The labeled complexes were found to be stable in vitro (97% to 98% stability) and in vivo (89% to 94% stability). All the formulations were cleared rapidly from circulation; clearance of mannose-coated poly (propylene imine) dendrimer (M-PPI) and lactose-coated poly(propylene imine) dendrimer (L-PPI) was faster than PPI-5.0G. All the formulations accumulated in liver to a significant extent, but only those with terminal carbohydrate moieties were retained for a longer period. Significant accumulation of PPI-5.0G and M-PPI was observed in kidneys as against very less activity in the case of L-PPI. Rapid clearance of the dendrimers was in accordance with the earlier reports. Higher and prolonged retention of M-PPI and L-PPI in liver was attributed to lectin-carbohydrate interactions. Lesser accumulation of L-PPI in kidneys was suggestive of its lesser excretion. This observation can be explained on the basis of the molecular weight of L-PPI, which was greater than the threshold of glomerular excretion. In general, it was observed that the carbohydrate-coated dendrimers were distributed in liver to a significant extent. This information could serve as a useful platform in designing carbohydrate-coated dendrimers for selective delivery of bioactive agents to liver.

Poly (propyleneimine) dendrimer based nanocontainers for targeting of efavirenz to human monocytes/macrophages in vitro.

Cells of the mononuclear phagocytic system, in particular monocytes/macrophages (Mo/Mac) serve as a reservoir for human immunodeficiency virus (HIV) and are believed to be responsible for its dissemination throughout the body and especially into the brain. Treatment of HIV infection, therefore, must reach these cells in addition to the lymphocytes. The purpose of the present study is to develop poly(propyleneimine) (PPI) dendrimer-based nanocontainers for targeting of efavirenz (EFV) to Mo/Mac. Fifth generation PPI dendrimer, t-Boc-glycine conjugated PPI dendrimer (TPPI) and mannose conjugated dendrimers were synthesized and characterized. While the haemolytic activity and cytotoxicity of PPI dendrimer was found to be very high, the toxicity of t-Boc-glycine conjugated dendrimer and mannose conjugated dendrimers were found to be negligible. The entrapment efficiency of mannose conjugated dendrimer was found to be 47.4%, followed by that of PPI dendrimer (32.15%) and t-Boc-glycine conjugated dendrimer (23.1%). The in vitro drug release profile shows that while PPI dendrimer releases the drug by 24 h, the dendrimer-based nanocontainers prolong the release rate up to 144 h (83 +/- 0.4% in case of t-Boc-glycine conjugated dendrimer and 91 +/- 0.3% in mannose conjugated dendrimer). The cellular uptake of EFV was found to be both concentration and time dependent. Significant increase in cellular uptake of EFV by Mo/Mac cells were observed in case of mannose conjugated dendrimer which is 12 times higher than that of free drug and 5.5 times higher than that of t-Boc-glycine conjugated dendrimer. While mannose conjugated dendrimer was taken up by the lectin receptors of the cells, phagocytosis of t-Boc-glycine conjugated dendrimer might be responsible for its enhanced uptake. Results suggest that the proposed carriers hold potential to increase the efficacy and reduce the toxicity of antiretroviral therapy.

Reduced hepatic toxicity, enhanced cellular uptake and altered pharmacokinetics of stavudine loaded galactosylated liposomes.

The aim of the present investigation was to reduce the hepatic toxicity, enhance the cellular uptake and alter the pharmacokinetics of stavudine using galactosylated liposomes. beta-D-1-Thiogalactopyranoside residues were covalently coupled with dimyristoyl phosphatidylethanolamine, which was then used to form liposomes. The galactosylated liposomal system was assessed for in vitro ligand-specific activity. The drug release from liposomes was studied by dialysis method. Ex vivo cellular uptake study was performed using liver parenchymal cells harvested from male albino rats. Changes in hematological parameters, hepatic enzymes, hepatomegaly, plasma and tissue distribution of the formulations (free stavudine solution, uncoated liposomal and galactosylated liposomes) were determined using albino rats. Percent cumulative drug release in 24h was low (34.8+/-2.6%). Enhanced hepatic cellular d4T uptake (27.96+/-2.41pg d4T/million cells) was seen in case of galactosylated liposomal d4T. Galactosylated liposomes maintained a significant level of d4T in tissues rich in galactose specific receptors and had a prolonged residence (11.44+/-1.25h) in the body resulting in enhanced half-life of d4T (23.07+/-1.25h). This formulation did not show either hematological or hepatic toxicity. Galactosylation of liposomes alter the biodistribution of encapsulated drug thereby delivering the drug to cells bearing galactose specific receptors.

Elastic liposomes mediated transdermal delivery of an anti-hypertensive agent: propranolol hydrochloride.

One major problem encountered in transdermal drug delivery is the low permeability of drugs through the skin barrier. In the present investigation ultradeformable lipid vesicles, that is, elastic liposomes were prepared incorporating propranolol hydrochloride for enhanced transdermal delivery. Elastic liposomes bearing propranolol hydrochloride were prepared by conventional rotary evaporation method and characterized for various parameters including vesicles shape and surface morphology, size and size distribution, entrapment efficiency, elasticity, turbidity, and in vitro drug release. In vitro flux, enhancement ratio (ER), and release pattern of propranolol hydrochloride were calculated for transdermal delivery. In vivo study conducted on male albino rats (Sprague Dawley) was also taken as a measure of performance of elastic liposomal, liposomal, and plain drug solution. The better permeation through the skin was confirmed by confocal laser scanning microscopy (CLSM). Results indicate that the elastic liposomal formulation for transdermal delivery of propranolol hydrochloride provides better transdermal flux, higher entrapment efficiency, ability as a self-penetration enhancer and effectiveness for transdermal delivery as compared to liposomes.

Investigations on the toxicological profile of functionalized fifth-generation poly (propylene imine) dendrimer.

Dendrimers have generated tremendous interest in the field of drug delivery. Despite indications of their utility as drug carriers, the inherent cytotoxicity associated with polycationic dendrimers acts as a limiting factor to their clinical applications. Many functionalization strategies have been adopted to mask peripheral amines in order to overcome this limitation. The object of the present investigation was to evaluate the effect of functionalization on the toxicological profile of fifth-generation poly(propylene imine) dendrimer (PPI-5.0G). Four forms of functionalized dendrimers, including protected glycine and phenylalanine, and mannose and lactose functionalized poly(propylene imine) (PPI) dendrimer, were synthesized as prospective drug carriers. These dendrimeric systems were evaluated for haemolytic toxicity, cytotoxicity, immunogenicity and haematological parameters. PPI-5.0G demonstrated a positive charge-based time- and concentration-dependent toxicity profile. Functionalization greatly improved the toxicity profile of the parent dendrimer. Hence it is proposed that these functionalized forms of PPI dendrimer have great potential as bio-compatible drug vehicles.

Ethinylestradiol-loaded ultraflexible liposomes: pharmacokinetics and pharmacodynamics.

This study aimed to develop ultraflexible liposomes as an alternative to the oral route, which would enhance the bioavailability and reduce the toxicity of ethinylestradiol. Ultraflexible liposomes of ethinylestradiol using an optimized concentration of surfactants were prepared and characterized in vitro. The effect of surfactant type under non-occlusive conditions on transdermal permeability was assessed. A histopathological study was performed to assess the action of ethinylestradiol on the uterus and ovaries. The pharmacokinetics of free ethinylestradiol (following single oral administration and one day of application to the skin), ultraflexible liposomal ethinylestradiol and non-flexible liposomal ethinylestradiol were studied in female Sprague-Dawley rats. Insignificant differences in size between the ultraflexible liposomal formulations containing optimized concentrations of different surfactants were observed. Ultraflexible liposomes can penetrate through pores much smaller than their own diameter. The transdermal permeability of lipophilic surfactant was greater than that of hydrophilic surfactant. The release of ethinylestradiol from the proposed formulation through rat skin was found to be constant. The histopathological study showed that the ultraflexible liposomal transdermal drug delivery system for ethinylestradiol provided effective contraception by follicular cell lysis, depletion of zona granulosa and ova, and by increasing the uterine mucosal and endometrial proliferation. Encapsulation of ethinylestradiol in ultraflexible liposomes modified the pharmacodynamics and pharmacokinetics of the contraceptive agent, resulting in a marked improvement in bioavailability and optimized therapy.

Reduced hematopoietic toxicity, enhanced cellular uptake and altered pharmacokinetics of azidothymidine loaded galactosylated liposomes.

In order to target liposomes to the lectin receptors present on macrophages, galactosylated liposomes were prepared and characterized in vitro. O-palmitoylgalactose (OPG) for liposomal coating was synthesized by esterification of galactose with palmitoyl chloride. The galactose binding Ricinus communis lectin was employed as a model system for the determination of in vitro ligand binding capacity. Cellular drug uptake studies were performed using alveolar macrophages. Hematological changes, bone marrow toxicity, plasma and tissue distribution study of free, uncoated plain liposomal and galactosylated liposomal encapsulated azidothymidine (AZT) were determined following a bolus intravenous injection in Sprague-Dawley rats. Lectin (R. communis) carbohydrate interaction has been utilized for the effective delivery of AZT entrapped in galactosylated vesicles. Aggregation of galactosylated liposomes increased as lectin concentration was increased from 5 to 30 microg/ml. Cellular uptake of galactosylated liposomal formulation was maximum. No hematological toxicity was observed even after 10 days in case of galactosylated vesicle entrapped AZT. This formulation maintained a significant level of AZT in tissues rich in galactose specific receptors and had a prolonged residence in the body resulting in enhanced half-life of AZT. Conclusively, galactosylated liposomes are the potential candidate for targeted drug delivery and are anticipated to be promising in the treatment of AIDS6.

Stavudine-loaded mannosylated liposomes: in-vitro anti-HIV-I activity, tissue distribution and pharmacokinetics.

Cells of the mononuclear phagocyte system (MPS) are important hosts for human immunodeficiency virus (HIV). Lectin receptors, which act as molecular targets for sugar molecules, are found on the surface of these cells of the MPS. Stavudine-loaded mannosylated liposomal formulations were developed for targeting to HIV-infected cells. The mannose-binding protein concanavalin A was employed as model system for the determination of in-vitro ligand-binding capacity. Antiretroviral activity was determined using MT-2 cell line. Haematological changes, tissue distribution and pharmacokinetic studies of free, liposomal and mannosylated liposomal drug were performed following a bolus intravenous injection in Sprague-Dawley rats. The entrapment efficiency of mannosylated liposomes was found to be 47.2 +/- 1.57%. Protein-carbohydrate interaction has been utilized for the effective delivery of mannosylated formulations. Cellular drug uptake was maximal when mannosylated liposomes were used. MT2 cells treated continuously with uncoated liposomal formulation had p24 levels 8-12 times lower than the level of free drug solution. Further, the mannosylated liposomes have shown p24 levels that were 14-20 and 1.4-2.3 times lower than the level of free drug and uncoated liposomal formulation treatment, respectively. Similar results were observed when infected MT2 cells were treated overnight. Stavudine, either given plain or incorporated in liposomes, led to development of anaemia and leucocytopenia while mannosylated liposomes overcame these drawbacks. These systems maintained a significant level of stavudine in the liver, spleen and lungs up to 12 h and had greater systemic clearance as compared with free drug or the uncoated liposomal formulation. Mannosylated liposomes have shown potential for the site-specific and ligand-directed delivery systems with desired therapeutics and better pharmacological activity.