Antimicrobials from endophytes as novel therapeutics to counter drug-resistant pathogens.

The rapid increase in antimicrobial resistance (AMR) projects a "global emergency" and necessitates a need to discover alternative resources for combating drug-resistant pathogens or "superbugs." One of the key themes in "One Health Concept" is based on the fact that the interconnected network of humans, the environment, and animal habitats majorly contribute to the rapid selection and spread of AMR. Moreover, the injudicious and overuse of antibiotics in healthcare, the environment, and associated disciplines, further aggravates the concern. The prevalence and persistence of AMR contribute to the global economic burden and are constantly witnessing an upsurge due to fewer therapeutic options, rising mortality statistics, and expensive healthcare. The present decade has witnessed the extensive exploration and utilization of bio-based resources in harnessing antibiotics of potential efficacies. The discovery and characterization of diverse chemical entities from endophytes as potent antimicrobials define an important yet less-explored area in natural product-mediated drug discovery. Endophytes-produced antimicrobials show potent efficacies in targeting microbial pathogens and synthetic biology (SB) mediated engineering of endophytes for yield enhancement, forms a prospective area of research. In keeping with the urgent requirements for new/novel antibiotics and growing concerns about pathogenic microbes and AMR, this paper comprehensively reviews emerging trends, prospects, and challenges of antimicrobials from endophytes and their effective production via SB. This literature review would serve as the platform for further exploration of novel bioactive entities from biological organisms as "novel therapeutics" to address AMR.

Overcoming Acquired Drug Resistance to Cancer Therapies through Targeted STAT3 Inhibition.

Anti-neoplastic agents for cancer treatment utilize many different mechanisms of action and, when combined, can result in potent inhibition of cancer growth. Combination therapies can result in long-term, durable remission or even cure; however, too many times, these anti-neoplastic agents lose their efficacy due to the development of acquired drug resistance (ADR). In this review, we evaluate the scientific and medical literature that elucidate STAT3-mediated mechanisms of resistance to cancer therapeutics. Herein, we have found that at least 24 different anti-neoplastic agents-standard toxic chemotherapeutic agents, targeted kinase inhibitors, anti-hormonal agents, and monoclonal antibodies-that utilize the STAT3 signaling pathway as one mechanism of developing therapeutic resistance. Targeting STAT3, in combination with existing anti-neoplastic agents, may prove to be a successful therapeutic strategy to either prevent or even overcome ADR to standard and novel cancer therapies.

Exploring the potential of minoxidil tretinoin liposomal based hydrogel for topical delivery in the treatment of androgenic alopecia.

Purpose: Androgenic alopecia (AGA) is a condition of progressive hair loss and involves follicular miniaturization triggered mainly due to varying levels of androgen besides environmental and genetic factors, which may also play some role. Minoxidil (MXD) has been considered as most effective therapeutic moiety to treat this disorder. Another drug Tretinoin (TRET) is known for its comedolytic activity and is reported to enhance percutaneous absorption of MXD. Presently both these drugs are being utilized for treatment of androgenic alopecia (AGA) in solution form which poses several problems in terms of poor solubility of drug, frequency of application and side effects.Materials and methods: Current work investigates liposomal hydrogel system for simultaneous delivery of MXD and TRET to overcome the limitations of existing formulation. Successful development of liposomes was commenced by thin film hydration method and various parameters affecting desired characteristics like size, morphology, entrapment efficiency; stability and ex vivo permeation were optimized. The formulated liposomes were further characterized for various physicochemical properties and evaluated for in vivo irritancy study in animals.Results and discussion: Results suggested prepared liposomes to be stable, homogenous and capable to hold both the drugs within. Association with hydrogel enhanced the permeation of MXD through skin ex vivo but TRET retained on the skin. Liposome loaded hydrogel was found to be non-irritant to skin.Conclusion: Overall developed system showed potential for effective and simultaneous delivery of both the drugs.

Fast dissolving electrospun polymeric films of anti-diabetic drug repaglinide: formulation and evaluation.

Objective: Repaglinide is a well-known FDA approved drug from category of meglitinide; used for the treatment of diabetes. However, its use is limited because of its poor water solubility which leads to erratic drug absorption. Present work focuses on formulation and evaluation of polyvinyl alcohol (PVA)-polyvinyl pyrrolidone (PVP) nanofibers to counter this problem of poor water solubility.Significance: Prepared nanofibers with hydrophilic polymers were expected to tackle the problem of poor water solubility.Methods: Nanofibers were prepared by electrospinning technique with the optimization of parameters affecting final product. Further prepared formulation was characterized using various techniques.Results: Successful development of drug loaded nanofibers was commenced utilizing electrospinning technique. Further casted film of same polymeric blend was prepared and compared with nanofibers. Optimized nanofibers showed an average diameter of 600-800 nm with smooth surface morphology. Prepared nanofibers and casted film was analyzed in terms of surface morphology, mechanical strength, solid state of drug present, effects of hydrogen bond formation and drug release profile. Results from the glucose tolerance test suggested both the formulations to be having better control over glucose levels as compared to free drug.Conclusion: Overall developed nanofibers presented themselves to be potential drug delivery candidates for drugs having poor water solubility.

Nanocrystal-based drug delivery system of risperidone: lyophilization and characterization.

OBJECTIVE: In the present work nanocrystal-based formulation of risperidone (RIS) was proposed to overcome solubility issue of RIS, while lyophilization technique was used effectively, for conversion of RIS nanosuspension to solid state. SIGNIFICANCE: RIS nanosuspension was developed and stabilized with a combination of polycaprolactone and Pluronic® F-68 as stabilizers. With focus on critical parameters like nature of cryoprotectants and effect of eutectic temperature on properties of nanosuspension, the suitability of lyophilization technique in improving the physical stability of prepared nanosuspension was also evaluated. Additionally, the developed nanocrystals were also assessed for their solid states properties. METHODS: Various process parameters affecting average particle size and polydispersity index (PDI), viz. drug to surfactant ratio, solvent to anti-solvent ratio, stirring speed, type of stabilizer were optimized. Assessment of lyophilization as a suitable solidification technique (for conversion to powder form) was done with selective cryoprotectants (trehalose dihydrate and sorbitol). RESULTS: The formulation was found to be stable at 4 °C for 3 months with size, PDI and zeta potential of 214 ± 3.4 nm, 0.120, and -10.2 ± 0.90 mV, respectively. Release profile of developed nanosuspension showed cumulative % release of ∼90% in initial 10 h whereas the value for the unprocessed drug was ∼11% in same time frame. CONCLUSIONS: These findings suggest that developed formulation was able to enhance water solubility of the drug effectively and can be potentially used in the management of psychotic disorders.

Antifungal effects of tulsi, garlic, cinnamon and lemongrass in powder and oil form on Candida albicans: An in vitro study.

INTRODUCTION: The use of plants for treating diseases is as old as the human species. Medicinal plants have been a major source of therapeutic agents for alleviation and cure of diseases. OBJECTIVES: The objective of the study was to evaluate and compare the antifungal activity of garlic, cinnamon, lemongrass and tulsi in powder and oil form at different concentrations on Candida albicans. MATERIALS AND METHODS: Powder and oil of garlic, cinnamon, lemongrass and Tulsi dissolved in inert solvent dimethyl formamide to obtain different concentration. Stock solution of different concentration was inoculated on Petri plates containing C. albicans and incubated at 30°C for 48 h. The inhibition zones were measured in millimeters using Vernier caliper. The collected data were analyzed using statistical test like mean value and one-way analysis of variance. RESULTS: Maximum zone of inhibition for the C. albicans was 42 mm at concentrations of 50% for the oil of lemongrass; followed by cinnamon 40 mm, garlic 24 mm and tulsi 20 mm. The P value obtained 0.050, 0.040, 0.036 and 0.031 were found to be statically significant for C. albicans at 20%, 30%, 40% and 50% concentrations of the various oil preparations, respectively. The P value obtained 0.043, 0.033, 0.032 and 0.027 were found to be statically significant for C. albicans at 20%, 30%, 40% and 50% concentrations of various plant powder, respectively. CONCLUSIONS: Lemongrass and cinnamon oil shows best antifungal effect against C. albicans as compared to garlic and tulsi. Compared to powder preparations, the oil preparations are better to inhibit the growth and higher the concentrations, greater the zone of inhibition seen in all the plant extracts and in oil.

Tumor microenvironment targeted nanotherapeutics for cancer therapy and diagnosis: A review.

Recent findings suggest that the cellular and extracellular materials surrounding the cancerous cells from an atypical tumor microenvironment (TM) play a pivotal role in the process of tumor initiation and progression. TM comprises an intricate system involving diverse cell types including endothelial cells, pericytes, smooth muscle cells, fibroblasts, various inflammatory cells, dendritic cells, and cancer stem cells (CSCs). The TM-forming cells dynamically interact with the cancerous cells through various signaling mechanisms and pathways. The existence of this dynamic cellular communication is responsible for creating an environment suitable for sustaining a reasonably high cellular proliferation. Presently, researchers are showing interest to use these TM conditions to mediate effective targeting measures for cancer therapy. The use of nanotherapeutics-based combination therapy; stimuli-responsive nanotherapeutics targeting acidic pH, hypoxic environment; and nanoparticle-induced hyperthermia are some of the approaches that are under intense investigation for cancer therapy. This review discusses TM and its role in cancer progression and crosstalk understanding, opportunities, and epigenetic modifications involved therein to materialize the capability of nanotherapeutics to target cancer by availing TM. STATEMENT OF SIGNIFICANCE: This article presents various recent reports, proof-of-concept studies, patents, and clinical trials on the concept of tumor microenvironment for mediating the cancer-specific delivery of nanotechnology-based systems bearing anticancer drug and diagnostics. We highlight the potential of tumor microenvironment; its role in disease progression, opportunities, challenges, and allied treatment strategies for effective cancer therapy by conceptual understanding of tumor microenvironment and epigenetic modifications involved. Specifically, nanoparticle-based approaches to target various processes related to tumor microenvironment (pH responsive, hypoxic environment responsive, targeting of specific cells involved in tumor microenvironment, etc.) are dealt in detail.

Comparative evaluation of fish oil and butter oil in modulating delivery of galantamine hydrobromide to brain via intranasal route: pharmacokinetic and oxidative stress studies.

The present study investigates the role of fish oil (FO)- and butter oil (BO)-enriched microemulsion-based system of galantamine hydrobromide (GH), an anti-Alzheimer drug, for its potential role in brain permeation enhancement and neuroprotection against oxidative stress. Microemulsion (ME)-based system of GH was prepared using water phase titration. The prepared ME was characterized by several physicochemical parameters like particle size, polydispersity index, and ex vivo drug permeation. Cell-based oxidative stress assays and pharmacokinetic studies were performed using C6 glial cell lines, and Sprague Dawley rats, respectively. The optimized ME comprised 5.3% v/v of Capmul MCM EP (as oil),15.8% v/v of Tween-80 (as surfactant), 5.3% v/v of Transcutol P (as co-surfactant), and 73.6% v/v of water (as aqueous phase). The addition of FO and BO resulted in a slight increase in the droplet size and decrease in transparency of ME. Cell-based anti-oxidative stress assays (glutathione assay, nitrite assay, and lipid peroxidation assay) showed the efficacy of formulation in the order of ME, BO ME, and FO ME, respectively. A similar trend was also observed in in vivo animal studies, wherein GH FO ME showed a comparatively higher percentage of drug reaching the brain when administered by intranasal route than by IV route. The study concluded the potential benefits of co-administering FO- and BO-enriched microemulsion is not only enhancing the permeation of drugs across BBB but also improving efficacy against lipopolysaccharide-induced oxidative stress. Graphical abstract.

Fatty acids as essential adjuvants to treat various ailments and their role in drug delivery: A review.

Since the discovery of fatty acids, a niche has been carved for their vital role as adjuvants in drug delivery and as treatment for various diseases. The literature has repeatedly described the essential role of various fatty acids in treating a wide range of diseases and disorders, from central nervous system diseases to wound healing. The use of fatty acids has expanded to many horizons and in recent decades they have gained importance as drug delivery adjuvants in addition to their auxiliary benefits in treating various diseases. Although fatty acids aid in solving both formulation-based and therapeutic challenges to our knowledge, they have never been viewed as dual agents in modern scientific literature. The aim of this review was to provide this perspective and combine the very discreet literature about fatty acids, which includes their role as therapeutic adjuvants and drug delivery agents. It gives insights on the use of fatty acids in treating the diseases of the eye, skin, central nervous system, viral diseases, and so on. The review further discusses how the structure of fatty acids plays an important role in therapeutic activity and affects formulation stability.

A bird's eye view of nanoparticles prepared by electrospraying: advancements in drug delivery field.

Recent analysis of the published data reveals the increasing importance of nanotechnology in the field of drug delivery, especially due to easy modulation of drug release and targeting effect. Various conventional methods including nanoprecipitation, spray drying, solvent evaporation, supercritical fluid extraction and ionotropic gelation are well-explored for lab-scale production of nanoparticles and present their own advantages and limitations. Electrospraying a variant of electrospinning is a method based on the processing of polymeric solutions/melt under high electrical voltage to produce particles of desired nature; post optimization of process parameters. This technique is comparatively newer one presenting itself as a competent alternative for the production of polymeric nanoparticles. Owing to its simplicity and flexibility electrospraying can be used to generate particulate material with meticulous structure, size and morphology; providing advantages of controlled release, improved dissolution rate, taste masking of drug candidates and many more. There is very less literature offering pertinent information about the production of nanoparticles by electrospraying technique as most of them deal with materialistic parameters only. This creates a void in learning and understanding of this novel technique for production of nanoparticles encapsulating drug candidates. Also there is a need of exploration in terms of drug release. Present article will provide an overview of electrospraying based production of nanoparticles for controlled and customized drug delivery, to fill this gap. Basic principle, instrumental set-up, advantages and limitations of electrospraying technique over other conventional nanoparticle production techniques and critical process parameters affecting nanoparticle properties is dealt in detail. Brief description of various polymeric nanoparticles (Polymers of natural as well as synthetic origin) with numerous case studies is given providing vast knowledge of drug encapsulation and modulated release patterns in correlation to polymer type used, structure and morphology of nanoparticles produced.

Comparative evaluation of electrospraying and lyophilization techniques on solid state properties of Erlotinib nanocrystals: Assessment of In-vitro cytotoxicity.

INTRODUCTION: Erlotinib is a well known FDA approved drug from category of tyrosine kinase inhibitors; used for the treatment of lung cancer. However its use is limited because of its poor water solubility. OBJECTIVE: The aim of present work was to improve solubility by developing a stable nanocrystal based drug delivery system of ERL with the aid of sodium lauryl sulfate as potential stabilizer and to carry out comparative evaluation of electrospraying and lyophilization as solidification techniques on its solid state properties. EXPERIMENTAL: Nanocrystal formulation was developed with antisolvent precipitation method having particle size, polydispersity index and zetapotential of 232.4±4.3nm, 0.162 and -9.82mV respectively. Further comparative evaluation of lyophilization and electrospraying was commenced as potential solidification techniques and solid powder matrix obtained from both the solidification techniques were compared in terms of size after re-dispersion (260±4.8 and 329±5.2nm respectively), particle morphology, surface area (0.984±0.11 and 0.341±0.05m2/g respectively), pore volume (0.0014 and 0.0009cc/g respectively), solid state of drug present and % drug release (~100% and ~78% respectively in 600min). In vitro cytotoxicity studies shared that obtained formulation was having reduced IC50 values in comparison to drug. Further intracellular reactive oxygen species production was found to be higher for formulation treated cells when compared to free drug. Overall developed formulation was found to be potential drug delivery system for lung cancer therapy.

Parenteral nanosuspensions: a brief review from solubility enhancement to more novel and specific applications.

Advancements in in silico techniques of lead molecule selection have resulted in the failure of around 70% of new chemical entities (NCEs). Some of these molecules are getting rejected at final developmental stage resulting in wastage of money and resources. Unfavourable physicochemical properties affect ADME profile of any efficacious and potent molecule, which may ultimately lead to killing of NCE at final stage. Numerous techniques are being explored including nanocrystals for solubility enhancement purposes. Nanocrystals are the most successful and the ones which had a shorter gap between invention and subsequent commercialization of the first marketed product. Several nanocrystal-based products are commercially available and there is a paradigm shift in using approach from simply being solubility enhancement technique to more novel and specific applications. Some other aspects in relation to parenteral nanosuspensions are concentrations of surfactant to be used, scalability and in vivo fate. At present, there exists a wide gap due to poor understanding of these critical factors, which we have tried to address in this review. This review will focus on parenteral nanosuspensions, covering varied aspects especially stabilizers used, GRAS (Generally Recognized as Safe) status of stabilizers, scalability challenges, issues of physical and chemical stability, solidification techniques to combat stability problems and in vivo fate.

Electrospun polymeric nanofibers: New horizons in drug delivery.

Nanofibers obtained using electrospinning technique are being used since ages especially in fields of textile industry, sensors, filters, protective clothing and tissue engineering. Their use as drug delivery system is an emerging platform in the field of pharmaceuticals and now-a-days formulation scientists are paying great attention to the technology due to several advantages prime being easy modulation of drug release profile depending upon the properties of polymer/polymeric blends/other materials used. Although there are several reports citing the use of antibiotics-loaded nanofibers as wound dressing materials and as antimicrobial therapy in periodontics; still there is a good scope of expanding the horizon for its application in newer ailments. This article reviews various aspects related to loading and release of drug as such or in nano-particulate form to polymeric nanofibers by taking critical process parameters (CPPs) for electrospinning and critical material attributes (CMAs) into account. Commercially available products and electrospinning technologies are described in brief along with some of the patents related to their use as drug delivery systems. The main focus of this review is applicability of drug/drug nanoparticle loaded nanofibers in the management of diseases/disorders related to the brain, eye, ear, cardiovascular system, lungs and oral cavity. Use in diseases with higher mortality rates like diabetes, Acquired immunodeficiency syndrome (AIDS) and cancer is also described in brief.

Nanocrystal Based Drug Delivery System: Conventional and Current Scenario.

BACKGROUND: Most of the chemical substances which emerge out as potential drug candidates (Active Pharmaceutical Ingredients) are either weak acids or weak bases. The poor aqueous solubility of these drug substances is a common concern. Several R&D centers are focused on developing suitable, economic, simpler and more feasible solubility enhancement techniques for increasing the solubility and thereby bioavailability of such drug substances. Nanocrystals are one of the preferred approaches for solubility enhancement in the last few decades. METHODS: Nanocrystal as a solubility enhancement approach is widely explored and discussed by many researchers. Despite being the most simple and feasible technique, nanocrystal formulation has its own limitations. The present review enlightens some novel technologies which can overcome disadvantages of conventionally well-established bottom-up and top-down techniques used for nanocrystal formulation. Results/Applications: The present review summarizes and also highlights the correlation between some novel findings like reduction in the melting point of drug and nanocrystal formulation. The review also includes a special section emphasizing on the patents granted in the field of nanocrystals. The review includes more than ten patents focusing on several aspects of nanocrystal formulations as manufacturing methods, formulation components and conventional and novel applications of nanocrystals in new and hybrid forms. Aspects related to advantages of nanocrystals over other formulation approaches, targeting (Active and Passive) through nanocrystal formulations and issues related to nanotoxicity are also reviewed and discussed in the present article. CONCLUSION: The findings, research outcomes and patents related to nanocrystal formulations, reported in the present review confirm the potential of the stated system as a drug delivery tool. The review emphasizes on the urge for further exploration required in the area of nanocrystal system for enhancing its efficiency as a drug delivery and a diagnostic tool.

Surface Engineered Dendrimers in siRNA Delivery and Gene Silencing.

BACKGROUND: Therapeutic efficacy of dreadful diseases like cancer, HIV (Human Immunodeficiency Virus) can be enhanced by delivering molecules which regulate function at gene level rather than at receptor level. Silencing RNA is one such approach recently used to silence target gene expressed diseases; and thereby reduce target protein levels. Many of the non-viral vectors are proved to act as carriers for silencing RNA. Dendrimers being one of them have less size, low poly dispersibility index, water solubility, multivalence, and easy surface modification. Many such surface modifications have been carried out to improve the delivery potential of small interfering RNA (siRNA) modified dendrimers compared to simple plain dendrimers. METHODS: Dendrimer was taken as a core whose surface was modified with fluorine, amino acids, phosphate, lipids, folate, specific antibody or RGD (Arg-Gly-Asp). The purpose of these modifications was to increase the therapeutic siRNA efficiency, lower the toxicity and improve the targeting potential of dendrimers. RESULTS: Fluorinated dendrimers have highest electronegativity and highest siRNA loading capacity. Amino acid functionalized dendrimers are made up of endogenous amino acids which improve biocompatibility of dendrimer and endosomal escape. Carbosilane dendrimers increase the gene transfection ability of tissues to be treated. Phosphate dendrimers having hydrophobic backbone and hydrophilic surface increase the permeability towards targeted tissue. Lipid based dendrimer causes endosomal escape and improves the permeability of dendrimers. Targeting of specific tissues is achieved by coupling dendrimer with folate, RGD and specific antibody, thereby reducing off target effect. CONCLUSION: Thus, surface modified dendrimers render a complete pack which offers increased siRNA loading, increased transfection and permeability, efficient targeting, endosomal escape and protecting siRNA from degradation by RNase and other such enzymes. The objective of this manuscript is to provide different approaches currently available for surface modifications of dendrimers and their overall effect on transfection ability of siRNA to target tissues.