Exploring the Therapeutic Potential of Anti-VEGF Drugs for the Management of Diabetic Retinopathy: An Overview.

The discovery of antivascular endothelial growth factor medications has resulted in a substantial change in diabetic retinopathy treatment. The most common cause of diabetic retinopathy blindness is Diabetic Macular Edema. The pathophysiology of Diabetic Macular Edema is thought to include the well-known pro-angiogenic and pro-permeability factor vascular endothelial growth factor. Over the past decade, drugs that impede the functions of vascular endothelial growth factors have established themselves as a standard-of-care treatment for a range of ocular ailments and improved patients' clinical results with diabetic retinopathy and Diabetic Macular Edema, and their frequency has grown exponentially with the introduction of these agents Pegaptanib, Ranibizumab, and Aflibercept which are approved for ophthalmic indications, while Bevacizumab is used off-label. These medications delivered intravitreally have halted the vascular development of diabetic retinopathy. Various randomized trials have proven that antivascular endothelial growth factor medication is safe and effective in preserving vision. Following an extensive period of preclinical development aimed at enhancing and defining its biological impacts, these drugs were shown in clinical trials to be effective in treating diabetic retinopathy and other ophthalmic conditions. Data from various sources suggest that Pegaptanib, Ranibizumab, and Aflibercept are costly, while Bevacizumab is cost-effective, and in low and middle-income nations, it is thus a desirable therapy choice. However, issues with compounding, counterfeiting, and off-label usage restrict its availability in many nations. The pharmacology, pharmacokinetics, pharmacodynamics, adverse effects, and contraindications of antivascular endothelial growth factor agents are discussed, and the results of clinical trials evaluating their efficacy are summarized.

Combination therapy of vanillic acid and oxaliplatin co-loaded in polysaccharide based functionalized polymeric micelles could offer effective treatment for colon cancer: A hypothesis.

Colon cancer is characterised by the persistent change in bowel habits due to the formation of polyps (cancerous) in the inner lining of the colon. Clinically, there are several anticancer drugs available to treat colon cancer. Oxaliplatin (third generation platinum drug) is widely prescribed anticancer drug due to its broad range anticancer properties and low toxicities over cisplatin and carboplatin. Currently, use of oxaliplatin as adjuvant chemotherapy represents a standard care for the treatment of advanced colon cancer. Despite this, its rapid degradation in systemic circulations upon administration, lack of tumor specificity, and low bioavailability limits its anticancer potential. On the other hand, vanillic acid (VA) has shown anticancer potential in colon cancer by targeting mTOR/Ras pathway, HIF-1α inhibition, NF-ĸB, and Nrf2 that regulate cell growth, cell survival, proliferation and adaptation to cancer microenvironment. Normal oral delivery of these two drugs offers non-specific drug release in gastrointestinal tract that leads to unwanted toxicity and very less amount of drug become available for colonic site. Therefore, loading of these two drugs in polysaccharide based functionalized polymeric micelles (FPMs) can offer selective targeting at colonic site and could offer better therapeutic efficacy at much lesser doses of drugs. Therefore, a new hypothesis has been proposed that the combination of vanillic acid with oxaliplatin co-loaded in FPMs could provide colon targeting ability with enhanced potency and safety profile by targeting multiple pathways than current adjuvant chemotherapies available in the market for the treatment of colon cancer.

Fail-safe nano-formulation of prodrug of sulfapyridine: Preparation and evaluation for treatment of rheumatoid arthritis.

Aim of the present study was to give a second life to the long-abandoned drug, sulfapyridine (SP) for its anti-arthritic potential by design of nano-vesicular delivery system. For this, intra-articular delivery of its liposomal formulation was tried. As the prepared formulation exhibited rapid drug leakage, an arthritis responsive prodrug of SP showing lability towards synovial enzymes was synthesized to exploit the over-expression of arthritis specific enzymes. Prodrug (SP-PD) exhibited better retention in liposomes as compared to the drug, preventing its escape from synovium. Hydrolysis of SP-PD in human plasma and synovial fluid indicated its high susceptibility to enzymes. The liposomes of SP-PD exhibited larger mean size, less PDI and higher zeta potential as compared to those for SP liposomes. In arthritic rats, prodrug liposomes were found to reverse the symptoms of inflammation, including the levels of biochemical markers. Liposomes of bio-responsive prodrug, therefore, offer a revolutionary approach in the treatment of rheumatoid arthritis.

Opening eyes to therapeutic perspectives of bioactive polyphenols and their nanoformulations against diabetic neuropathy and related complications.

Introduction: Diabetic neuropathy (DN) is one of the major complications arising from hyperglycaemia in diabetic patients. In recent years polyphenols present in plants have gained attention to treat DN. The main advantages associated with them are their action via different molecular pathways to manage DN and their safety. However, they failed to gain clinical attention due to challenges associated with their formulation development such as lipophilicity,poor bioavailability, rapid systemic elimination, and enzymatic degradation.Area covered: This article includes different polyphenols that have shown their potential against DN in preclinical studies and the research carried out towards development of their nanoformulations in order to overcome aforementioned issues.Expert opinion: In this review various polyphenol based nanoformulations such as nanospheres, self-nanoemulsifying drug delivery systems, niosomes, electrospun nanofibers, metallic nanoparticles explored exclusively to treat DN are discussed. However, the literature available related to polyphenol based nanoformulations to treat DN is limited. Moreover, these experiments are limited to preclinical studies. Hence, more focus is required towards  development of nanoformulations using simple and single step process as well as inexpensive and non-toxic excipients so that a stable, scalable, reproducible and non-toxic formulation could be achieved and clinical trials could be initiated.

Impact of solidification on micromeritic properties and dissolution rate of self-nanoemulsifying delivery system loaded with docosahexaenoic acid.

Development of self-nanoemulsifying drug delivery systems (SNEDDS) of docosahexaenoic acid (DHA) is reported with the aim to achieve enhanced dissolution rate. The optimized composition of liquid SNEDDS (L-SNEDDS) formulation was Labrafil M1944 CS, 47% v/v Tween 80, 27% v/v Transcutol P, and 0.1% v/v DHA. L-SNEDDS were solidified using Syloid XDP 3150 as solid porous carrier. The droplet size, polydispersity index, zeta potential, percentage drug loading, and cloud point for L-SNEDDS were found to be 43.51 ± 1.36 nm, 0.186 ± 0.053, -19.20 ± 1.21 mV, 93.23 ± 1.71, and 88.60 ± 2.54 °C, respectively. Similarly, for solid SNEDDS (S-SNEDDS) the above parameters were found to be 57.32 ± 1.87 nm, 0.261 ± 0.043, -16.60 ± 2.18 mV, 91.23 ± 1.88, and 89.50 ± 1.18 °C, respectively. The formulations (L-SNEDDS, S-SNEDDS powder, and S-SNEDDS tablet) showed significant (p<.05) improvement in dissolution rate of drug in 0.1 N HCl (pH 1.2) and phosphate buffer (pH 6.8) as compared to unprocessed DHA. In both the dissolution media, the dissolution rate was found more that 85% in 90 min. Absence of drug precipitation, phase separation, and turbidity during thermodynamic stability studies indicated that the developed SNEDDS were stable. Hence, it was concluded that SNEDDS have offered sufficient stability as well as dissolution rate of DHA.

Modified apple polysaccharide capped gold nanoparticles for oral delivery of insulin.

The study entailed formulation of gold nanoparticles (AuNPs) upon reduction of chloroauric acid by modified apple polysaccharide (MAP). AuNPs were conjugated with insulin (INS) for its oral delivery to treat type 1 diabetes mellitus (DM). The size of MAP conjugated AuNPs loaded with INS was 124 ± 8.55 nm with zeta potential -10.5 ± 0.54 mV. The animal study carried out in streptozotocin induced rat model revealed that AuNPs conjugated insulin (AuNPs-INS) in high dose caused 3.36 folds decrease in blood glucose level in 240 min, whereas, orally administered INS failed to decrease the blood glucose level. The 28-day study also revealed better improvement in body weight, lipid profile, urea, creatinine and liver parameters in AuNPs-INS (high dose) for which the observed value was close with respect to intraperitoneally administrated insulin followed by medium dose of AuNPs-INS, low dose of AuNPS-INS, AuNPs alone and modified apple polysaccharide.

Gold nanoparticles: New routes across old boundaries.

In recent years, gold nanoparticles have emerged as unique non-invasive drug carriers for targeting drugs to their site of action. Their site specificity has helped in increasing drugs' efficacy at lower dose as well as reduction in their side effects. Moreover, their excellent optical properties and small size offer their utilization as diagnostic tools to diagnose tumors as well as other diseases. This review focuses on various approaches that have been used in last several years for preparation of gold nanoparticles, their characterization techniques and theranostic applications. Their toxicity related aspects are also highlighted. Gold nanoparticles are useful as theranostic agents, owing to their small size, biocompatible nature, size dependent physical, chemical and optical properties etc. However, the challenges associated with these nanoparticles such as scale up, cost, low drug payload, toxicity and stability have been the major impediments in their commercialization. The review looks into all these critical issues and identifies the possibilities to overcome these challenges for successful positioning of metallic nanoparticles in market.

A three-pronged formulation approach to improve oral bioavailability and therapeutic efficacy of two lipophilic drugs with gastric lability.

The aim of present study was to co-administer curcumin (CRM) liquisolid pellets and coated duloxetine hydrochloride (DXH) pellets in rats to treat neuropathic pain (NP) associated with chronic constriction injury (CCI). To formulate liquisolid pellets of CRM, it was first dissolved in Tween-80 and then adsorbed on the porous surface of MCC PH102 and Syloid XDP that were used as carrier and coating materials, respectively. Central composite design was used to optimize the liquisolid formulation. The results of powder X-ray diffraction studies, differential scanning calorimetry, and scanning electron microscopy showed complete solubility of drug in Tween-80 followed by its complete adsorption on the porous surface of Syloid XDP and MCC PH102. Both DXH and liquisolid CRM powders were converted into pellets using extrusion-spheronization. DXH pellets were further coated with Eudragit S100 to bypass the gastric pH. About 32.31-fold increase in dissolution rate of CRM present in liquisolid formulation was observed as compared to its unprocessed form. Similarly, the dissolution profile in 0.1 N HCl for Eudragit S100-coated DXH showed complete protection of drug for 2 h and complete release after its introduction in buffer medium (0.2 M phosphate buffer pH 6.8). he pharmacokinetic studies carried out on rats revealed 7.3-fold increase in bioavailability of CRM present in liquisolid pellets and 4.1-fold increase in bioavailability of DXH present in coated pellets was observed as compared to their unprocessed pellets. This increase in bioavailability of drugs caused significant amelioration of CCI-induced pain in rats as compared to their unprocessed forms. The histological sections showed better improvement in regeneration of nerve fibers in rats.

A Novel Three-pronged Approach for Colon Delivery of Sulfasalazine: Concomitant Use of pH- Responsive, Microbially Triggered Polymers and Liquisolid Technology.

OBJECTIVE: A major challenge in targeting orally administered drugs to colon is their passage through the long gastrointestinal path comprising highly variant conditions in terms of pH, viscosity, gut motility and microbial flora. Approaches to pH controlled release and microbially triggered release have proved to be successful in achieving colon targeting only to a partial extent. METHODS: In an attempt to improve targeting, both these approaches have been combined together with the approach of liquisolid technology which, hitherto, remains unexplored for colon targeting. The combination of these three approaches is being reported for the first time to achieve colon targeting along with a burst release of a Biopharmaceutical Classification System (BCS) Class IV drug at the target site. pH controlled polymer, Eudragit® S-100 was used to prevent the release of sulfasalazine in the gastric region while microbially triggered polymers, pectin and guar gum were used to ferry the system through the intestinal region. RESULTS: Liquisolid formulation was designed to provide a burst release of sulfasalazine in colon on the digestion of polysaccharide coating. CONCLUSION: The results support the premise that the combination of pH sensitive, microbially triggered polymers and liquisolid formulation technique appears to be a pragmatic approach for colonic delivery of orally administered drugs.

Stable Co-crystals of Glipizide with Enhanced Dissolution Profiles: Preparation and Characterization.

Present study deciphers preparation of co-crystals of lipophilic glipizide by using four different acids, oxalic, malonic, stearic, and benzoic acids, in order to achieve enhanced solubility and dissolution along with stability. All co-crystals were prepared by dissolving drug and individual acids in the ratio of 1:0.5 in acetonitrile at 60-70°C for 15 min, followed by cooling at room temperature for 24 h. FT-IR spectroscopy revealed no molecular interaction between acids and drug as the internal structure and their geometric configurations remain unchanged. Differential scanning calorimetry revealed closer melting points of raw glipizide and its co-crystals, which speculates absence of difference in crystallinity as well as intermolecular bonding of the co-crystals and drug. PXRD further revealed that all the co-crystals were having similar crystallinity as that of raw glipizide except glipizide-malonic acid co-crystals. This minor difference in the relative intensities of some of the diffraction peaks could be attributed to the crystal habit or crystal size modification. SEM revealed difference in the crystal morphology for all the co-crystals. Micromeritic, solubility, dissolution, and stability data revealed that among all the prepared co-crystals, glipizide-stearic acid co-crystals were found superior. Hence, it was concluded that glipizide-stearic acid co-crystals could offer an improved drug design strategy to overcome dissolution and bioavailability related challenges associated with lipophilic glipizide.

Oxaliplatin immunohybrid nanoparticles in vitro synergistic suppression evaluation in treatment of colorectal cancer.

In the present study, we have investigated the enhanced synergistic and apoptotic activity of immunohybrid nanoparticles encapsulating oxaliplatin and covalently conjugated with TRAIL (Apo-2L/CD-253). Time-dependent cytotoxicity activity of nanoparticles was determined by MTT assay in HT-29 cells. Nuclear morphological changes and assessment of apoptotic ratio was analyzed by DAPI (4'6-diamidino-2-phenylindole) staining and annexin-propidium iodide (PI) assay. Cell-cycle analysis of oxaliplatin in HT-29 cell was analyzed by flow cytometry at 72 h. Furthermore, molecular mechanisms related to oxaliplatin-induced anticancer activity was explored by western blot analysis. Our study revealed appreciable time-dependent cytotoxicity, apoptotic, and synergistic activity of oxaliplatin immunohybrid nanoparticles.

Novel anionic polymer as a carrier for CNS delivery of anti-Alzheimer drug.

Natural and plant-based polymers could be used for control release of drugs and also helps in targeting drug to the site of action. The main objective of present work was to check the feasibility of plant-based, namely, mango gum polymeric nanoparticles (NPs) as a carrier for central nervous system (CNS) delivery using model drug donepezil (DZP). The NPs were prepared by modified ionic gelation method and emulsion cross-linking method. Zeta sizer results showed that the diameter of NPs was about 90-130 nm. The polymeric DZP-loaded NPs were almost spherical in shape, as revealed by transmission electron microscopy (TEM). On increasing concentration of NPs suspension from 50 µg/ml to 5000 µg/ml there was no significant increase in % hemolysis. In vivo studies showed that brain targeting was achieved. So on the basis of above results, the extracted water soluble fraction of mango gum is a suitable candidate for brain delivery in the form of nanoformulations.

Oxaliplatin immuno hybrid nanoparticles for active targeting: an approach for enhanced apoptotic activity and drug delivery to colorectal tumors.

Tumor necrosis factor related apoptosis inducing ligand (TRAIL) proved to be a promising new target for colorectal cancer treatment. Elevated expression of TRAIL protein in tumor cells distinguishes it from healthy cells, thereby delivering the drug at the specific site. Here, we formulated oxaliplatin immunohybrid nanoparticles (OIHNPs) to deliver oxaliplatin and anti-TRAIL for colorectal cancer treatment in xenograft tumor models. The polymeric chitosan layer binds to the lipid film with the mixture of phospholipids by an ultra sound method followed by conjugating with thiolated antibody using DSPE-PEG-mal3400, resulting in the formation of OIHNPs. The polymer layer helps in more encapsulation of the drug (71 ± 0.09%) with appreciable particle size (95 ± 0.01 nm), and lipid layer prevents degradation of the drug in serum by preventing nanoparticle aggregation. OIHNPs have shown a 4-fold decrease in the IC50 value compared to oxaliplatin in HT-29 cells by the MTT assay. These immuno-nanoparticles represent the successful uptake and internalization of oxaliplatin in HT-29 cells rather than in MCF-7 cells determined by triple fluorescence method. Apoptotic activity in vitro of OIHNPs was determined by the change in the mitochondria membrane potential that further elevates its anti-tumor property. Furthermore, the conjugated nanoparticles can effectively deliver the drug to the tumor sites, which can be attributed to its ability in reducing tumor mass and tumor volume in xenograft tumor models in vivo along with sustaining its release in vitro. These findings indicated that the oxaliplatin immuno-hybrid nanoparticles would be a promising nano-sized active targeted formulation for colorectal-tumor targeted therapy.

Formulation and optimization of oxaliplatin immuno-nanoparticles using Box-Behnken design and cytotoxicity assessment for synergistic and receptor-mediated targeting in the treatment of colorectal cancer.

Conventional chemotherapy majorly lacks clinical application attributed to its inspecificity, adverse effects and inability to penetrate into tumor cells. Hence, the aim of the study was to prepare oxaliplatin solid lipid nanoparticles (OP-SLN) by microemulsion method optimizing it by Box-Behnken design and then covalently conjugated to TRAIL (CD-253) monoclonal antibody (TR-OP-SLN) for targeting colorectal cancer cells. The optimized OP-SLN3 has shown an appreciable particle size (121 ± 1.22 nm), entrapment efficiency (78 ± 0.09%) and drug loading (32 ± 1.01%). Fluorescence study and the Bradford assay further confirmed the binding of the protein. A 1.5-fold increase in cytotoxicity of immuno-nanoparticles (4.9 µM) was observed.

Effect of co-administration of probiotics with polysaccharide based colon targeted delivery systems to optimize site specific drug release.

Significant clinical success of colon targeted dosage forms has been limited by their inappropriate release profile at the target site. Their failure to release the drug completely in the colon may be attributed to changes in the colonic milieu because of pathological state, drug effect and psychological stress accompanying the diseased state or, a combination of these. Alteration in normal colonic pH and bacterial picture leads to incomplete release of drug from the designed delivery system. We report the effectiveness of a targeted delivery system wherein the constant replenishment of the colonic microbiota is achieved by concomitant administration of probiotics along with the polysaccharide based drug delivery system. Guar gum coated spheroids of sulfasalazine were prepared. In the dissolution studies, these spheroids showed markedly higher release in the simulated colonic fluid. In vivo experiments conducted in rats clearly demonstrated the therapeutic advantage of co-administration of probiotics with guar gum coated spheroids. Our results suggest that concomitant use of probiotics along with the polysaccharide based delivery systems can be a simple strategy to achieve satisfactory colon targeting of drugs.

Intranasal therapeutic strategies for management of Alzheimer's disease.

Alzheimer's disease (AD) is a chronic and progressive age-related irreversible neurodegenerative disorder that represents 70% of all dementia with 35 million cases worldwide. Successful treatment strategies for AD have so far been limited, and present therapy is based on cholinergic replacement therapy and inhibiting glutamate excitotoxicity. In this context, role of neuroprotective drugs has generated considerable interest in management of AD. Recently, direct intranasal (IN) delivery of drug moieties to the central nervous system (CNS) has emerged as a therapeutically viable alternative to oral and parenteral routes. IN delivery bypasses the blood-brain barrier by delivering and targeting drugs to the CNS along the olfactory and trigeminal neural pathways which are in direct contact with both the environment and the CNS. In an attempt to understand how neurotherapeutics/nanoparticulate delivery systems can be transported from the nose to the CNS, the present review sets out to discuss the mechanism of transport from nose to brain. The aim of this review is to discuss and summarize the latest findings of some of the major studies on IN drug delivery in AD models, with a focus on the potential efficacy of neuroprotective treatments.

Optimization of curcumin nanoemulsion for intranasal delivery using design of experiment and its toxicity assessment.

The objective of the study was to optimize curcumin nanoemulsion for intranasal delivery using design of experiment. Box-Behnken design was constructed using oil, surfactant and co-surfactant concentration as independent variables and their affect on response y1 (globule size) and y2 (zeta potential) were studied. The ANOVA test identified the significant factors that affected the responses. For globule size, percentage of oil, surfactant and co-surfactant were identified as significant model terms whereas for zeta potential, oil and co-surfactant were found to be significant. Critical factors affecting the responses were identified using perturbation and contour plots. The derived polynomial equation and contour graph aid in predicting the values of selected independent variables for preparation of optimum nanoemulsion with desired properties. Further, 2(4) factorial design was used to study influence of chitosan on particle size and zeta potential. The formulations were subjected to in vitro cytotoxicity using SK-N-SH cell line and nasal ciliotoxicity studies. The developed formulations did not show any toxicity and were safe for intranasal delivery for brain targeting. In vitro diffusion studies revealed that nanoemulsions had a significantly higher release compared to drug solution. Ex vivo diffusion studies were carried out using sheep nasal mucosa fixed onto Franz diffusion cells. Mucoadhesive nanoemulsion showed higher flux and permeation across sheep nasal mucosa.

Modulation of cerebral malaria by curcumin as an adjunctive therapy

Cerebral malaria is the most severe and rapidly fatal neurological complication of Plasmodium falciparum infection and responsible for more than two million deaths annually. The current therapy is inadequate in terms of reducing mortality or post-treatment symptoms such as neurological and cognitive deficits. The pathophysiology of cerebral malaria is quite complex and offers a variety of targets which remain to be exploited for better therapeutic outcome. The present review discusses on the pathophysiology of cerebral malaria with particular emphasis on scope and promises of curcumin as an adjunctive therapy to improve survival and overcome neurological deficits.

Modulation of cerebral malaria by curcumin as an adjunctive therapy.

Cerebral malaria is the most severe and rapidly fatal neurological complication of Plasmodium falciparum infection and responsible for more than two million deaths annually. The current therapy is inadequate in terms of reducing mortality or post-treatment symptoms such as neurological and cognitive deficits. The pathophysiology of cerebral malaria is quite complex and offers a variety of targets which remain to be exploited for better therapeutic outcome. The present review discusses on the pathophysiology of cerebral malaria with particular emphasis on scope and promises of curcumin as an adjunctive therapy to improve survival and overcome neurological deficits.

Influence of formulation parameters on dissolution rate enhancement of glyburide using liquisolid technique.

The aim of this study was to investigate the use of liquisolid technique in improving the dissolution of glyburide in a solid dosage form. This study was designed to evaluate the effects of different formulation variables, i.e. type of non-volatile liquid vehicles and drug concentrations, on drug dissolution rates. The liquisolid tablets were formulated with Propylene glycol, as liquid vehicle. Microcrystalline cellulose was used as a carrier material, silica as a coating material and croscaremellose as a disintegrant. In vitro drug dissolution profiles of the liquisolid formulations were studied and compared with direct compressed non-micronized and micronized tablets of glyburide using USP II, paddle apparatus at 50 rpm for 60 min using 900 ml of 0.05 M Phosphate Buffer, pH 7.5. The stability studies showed that the dissolution profiles of liquisolid tablets prepared with propylene glycol were not affected by ageing significantly, as f2 value found between aged and fresh samples was 51.92. Differential scanning calorimetry revealed that the drug has got solubilized in the liquid vehicle. This was further supported by the powder X-ray diffraction studies of pure drug and the liquisolid powder system. It can be concluded that it is possible to load poorly soluble drug into liquisolid tablets by addition of PVP to the liquid vehicle. This is valuable for the preparation of liquisolid tablets of poorly soluble drugs. The liquisolid tablets prepared with PVP showed a remarkably improved dissolution rate in comparison with DC tablet and other formulations.