Ankur Bhardwaj

Stimuli-responsive hydrogels in drug delivery and tissue engineering

Abstract Hydrogels are the three-dimensional network structures obtained from a class of synthetic or natural polymers which can absorb and retain a significant amount of water. Hydrogels are one of the most studied classes of polymer-based controlled drug release. These have attracted considerable attention in biochemical and biomedical fields because of their characteristics, such as swelling in aqueous medium, biocompatibility, pH and temperature sensitivity or sensitivity towards other stimuli, which can be utilized for their controlled zero-order release. The hydrogels are expected to explore new generation of self-regulated delivery system having a wide array of desirable properties. This review highlights the exciting opportunities and challenges in the area of hydrogels. Here, we review different literatures on stimuli-sensitive hydrogels, such as role of temperature, electric potential, pH and ionic strength to control the release of drug from hydrogels.

Nanotechnology: A magic bullet for HIV AIDS treatment

Abstract Human immunodeficiency virus (HIV) infection has become devastating in last a few years. Nearly 7400 new infection cases are coming every day. Highly active antiretroviral therapy (HAART), which involves combination of at least three antiretroviral (ARV) drugs, has been used to extend the life span of the HIV-infected patients. HAART has played an important role to reduce mortality rate in the developed countries but in the developing countries condition is still worst with millions of people being infected by this disease. For the improvement of the situation, nanotechnology-based drug system has been explored for the HIV therapeutics. Nanosystems used for HIV therapeutics offer some unique advantage like enhancement of bioavailability, water solubility, stability, and targeting ability of ARV drugs. Main nanotechnology-based systems explored for HIV therapeutics are liposomes, nanoparticles, niosomes, polymeric micelles, and dendrimers. Present manuscript reviews conventional method of HIV therapeutics and recent advances in the eld of nanotechnology-based systems for treatment of HIV-AIDS.

Development and characterization of ligand-appended liposomes for multiple drug therapy for pulmonary tuberculosis

Abstract Tuberculosis (TB) remains one of the oldest and deadliest diseases in the current scenario. The intracellular organism Mycobacterium tuberculosis, which mainly resides in mononuclear phagocytes, is responsible for tuberculosis in humans. A few therapies are available for the treatment of tuberculosis but they have many hurdles. To overcome these hurdles, a combination of chemotherapeutic agent-loaded vesicular systems have been prepared to overcome tuberculosis. To investigate the role of novel drug delivery systems for the treatment of pulmonary tuberculosis, ligand appended liposomals have been developed. In the present study, drug-loaded, ligand-appended liposomes and their DPI (Dry Powder Inhaler) forms have been prepared and characterized using various in vitro and in vivo parameters. The prepared ligand-appended liposomal formulation showed good entrapment efficiency, prolonged drug release, improved recovery of drugs from the target site, and proved to be more suitable for use as DPI, justifying their potential for improved drug delivery. Thus we tried our best by our project to reduce the national burden of tuberculosis, which is still a global health challenge.

Development and characterization of nanoemulsion as carrier for the enhancement of bioavailability of artemether

Abstract The present study aimed to develop a kinetically stable nanoemulsion of artemether with improved solubility, stability and oral bioavailability. Nanoemulsion was prepared by ultrasonication technique using internal oil phase (consisted of the drug dissolved in coconut oil and span 80) and external phase (comprising tween 80 and ethanol dissolved in water). The formulations were optimized using various parameters like percentage transmittance, refractive index, drug content, viscosity, zeta potential and release rate. Stability studies were conducted for a period of 90 days using stability chambers. In vivo studies of the developed formulations were conducted on Wistar rats and data were analyzed statistically. The nanoemulsion as observed under transmission electron microscope were found to be spherical in shape with an average size of 79.0 nm and a zeta potential of −15 mV which indicated of good electrokinetic stability of nanoemulsion . Nanoemulsion was found to be clear and transparent in appearance with a percentage transmittance of 98.2. Refractive index of 1.32 of the nanoemulsion indicated the isotropic nature of the drug. Release rate of the drug from the nanoemulsion formulation was found to be quite significant (P < 0.001) as compared to the plain drug. In vivo oral bioavailability of the nanoemulsion formulation was found to be 2.6-fold higher than the plain drug (˜ 40%) as observed from pharmacokinetic studies. Thus it was observed that nanoemulsion proved itself as a promising alternate for improving the bioavailability of artemether.

Eradication of superficial fungal infections by conventional and novel approaches: a comprehensive review

Abstract During the last two decades, the occurrence of fungal infections either superficial or systemic has been increasing. Moreover, fungal infections become more difficult to treat when they show coupling with immunogenic diseases like AIDS. Superficial fungal infections are associated with skin, nail and eye and are less prominent to systemic infection. However, it may be dangerous if not treated properly. It is usually observed that conventional formulations including cream, powder, gels etc. are used to treat skin fungal infections even for the deep seated fungal infections. However, these formulations show various side-effects on the application site like burning, redness and swelling. Further, due to the immediate release of drug from these formulations they can stimulate the immune system of body generating high impact allergic reactions. Deep seated fungal infections like invasive aspergillosis and invasive candidiasis may be more difficult to treat because the drug released from conventional topical formulation can not reach at the target site due to the low penetration capacity. Similarly, in case of fungal infection of nail and eye, conventional formulations show problem of less bioavailability. Thus, to overcome the drawbacks of conventional therapy a lot of research works have been carried out to develop novel formulations of antifungal drugs to deliver them superficially. Novel formulations explored for the skin delivery of antifungal drugs include liposomes, niosomes, ethosomes, microemulsions, nanoparticles, microspheres and micelles. These formulations show extended or sustained release of drug, minimizing the side effect on application site, enhancing bioavailability and reducing the dosing frequency. Further, these formulations also show penetration into the deep skin to treat invasive fungal infections. Novel formulations explored in treatment of fungal infections of eye are liposomes and nanoparticles and whether for nail fungal infections microemulsions are the choice. In present article, we have discussed about conventional treatment of superficial fungal infection and their comparison with the novel drug delivery systems.

Pulmonary delivery of antitubercular drugs using spray-dried lipid–polymer hybrid nanoparticles

The present study aimed to develop lipid–polymer hybrid nanoparticles (LPNs) for the combined pulmonary delivery of isoniazid (INH) and ciprofloxacin hydrochloride (CIP HCl). Drug-loaded LPNs were prepared by the double-emulsification solvent evaporation method using the three-factor three-level Box–Behnken design. The optimized formulation had a size of 111.81 ± 1.2 nm, PDI of 0.189 ± 1.4, and PDE of 63.64 ± 2.12% for INH-loaded LPN, and a size of 172.23 ± 2.31 nm, PDI of 0.169 ± 1.23, and PDE of 68.49 ± 2.54% for CIP HCl-loaded LPN. Drug release was found to be sustained and controlled at lower pH and followed the Peppas model. The in vitro uptake study in alveolar macrophage (AM) showed that uptake of the drugs was increased significantly if administered in the form of LPN. The stability study proved the applications of adding PLGA in LPN as the polymeric core, which leads to a much more stable product as compared to other novel drug delivery systems. Spray drying was done to produce an inhalable, dry, powdered form of drug-loaded LPN. The spray-dried (SD) powder was equally capable of producing nano-aggregates having morphology, density, flowability and reconstitutibility in the range ideal for inhaled drug delivery. The nano aggregates produced by spray drying manifested their aerosolization efficiency in terms of the higher emitted dose and fine particle fraction with lower mass median aerodynamic diameter. The in vivo study using pharmacokinetic and pharmacodynamic approaches revealed that maximum internalization efficiency was achieved by delivering LPN in SD powdered forms by pulmonary route.

Development and Characterization of Glucose Sensitive Hydrogels for the Treatment of Diabetes Mellitus

Development of stimuli-sensitive hydrogels for the delivery of drug involves the development of matrices that are glucose-sensitive and have strong sensing properties so that the developed system can sense the level of glucose and release the medicament in response to blood glucose level. In the present study an attempt has been made to develop a glucose sensitive hydrogel system which modulates the release of an anti-diabetic drug in response to the blood glucose level in the body. The hydrogel system was prepared by gas foaming technique using chitosan and polyvinyl alcohol (PVA) as polymer and glutaraldehyde as cross-linking agent. Metformin was used as a drug candidate because of its short biological half life (6.25±0.5 hrs). The prepared glucose sensitive hydrogel system has characterized using different parameters. It was observed that hydrogel swelled and deswelled reversibly depending on the pH and glucose sensitivity of the medium and has suitable mechanical properties. In-vitro results showed that the enzymatically immobilized hydrogel was sensitive to both pH and glucose for effective release of drug. It was found that higher the concentration of glucose in the medium, higher the amount of drug released from the hydrogel. In vivo results showed that glucose oxidase leads to reduction in blood glucose level in response to variable glucose concentration in the body thus achieving the desired therapeutic levels in the body . The present study showed that glucose sensitive hydrogels not only are efficient in controlling the physiological blood glucose level but also provide for a sustained and controlled release of drugs having short biological half life.

Development and characterization of floating spheroids of atorvastatin calcium loaded NLC for enhancement of oral bioavailability

Objective: The obejctive of the present study was to investigate the potential use of floating spheroids of Atorvastatin Calcium (ATS) Loaded nanostructured lipid carriers (NLCs). Materials and Methods: The final formula of floating spheroids was optimized on the basis of shape (spherical), diameter (0.47 mm), lag time (20 s), and floating time (> 32 h). Results: The results were further confirmed by different pharmacokinetic parameters—it was observed that the developed optimized floating ATS spheroid-loaded NLCs formulation has significantly improved relative bioavailability, that is, 3.053-folds through oral route in comparison to marketed formulation.

Stimuli-sensitive Systems-an emerging delivery system for drugs

Abstract Objectives: Development of controlled and sustained drug delivery system (DDS) remains a great thrust of human beings for the successful delivery of drugs due to various drawbacks of existing systems. In order to overcome these drawbacks, various stimuli-sensitive DDSs were developed in the recent years. Key findings: Stimuli are a state of responsiveness to sensory stimulation or excitability. Stimuli sensitive systems are those systems which deal with the changes in the physiology of body with respective to the environment changes. These systems may be very beneficial for the controlled and sustained delivery of drug in the body if proper work would be carried out on these types of systems. Controlled drug delivery became the standard criteria in modern pharmaceutical product design and an intensive research is still going on in achieving much better drug product with features like effectiveness, reliability, and safety. Many changes like photo and light, temperature, pH, ion, glucose, and redox affect the release of drug from the delivery system. These stimuli-sensitive systems are used for various purposes in various forms like in parenteral, ocular, peroral, rectal, vaginal, nasal, dermal and transdermal drug delivery. Summary: Various literature surveys revealed that stimuli-sensitive DDSs can be explored as a potential tool for the delivery of a variety of macromolecules that are not effectively delivered by conventional techniques.

Pulmonary Delivery of Anti-Tubercular Drugs Using Ligand Anchored pH Sensitive Liposomes for the Treatment of Pulmonary Tuberculosis

BACKGROUND Mycobacterium tuberculosis (M. TB) remains the prime cause of bacterial mortality and morbidity world-wide. Therefore, effective delivery and targeting of drug to the cellular tropics is essentially required to generate significant results for tuberculosis treatment. The aim of the present study was to develop and characterize ligand anchored pH sensitive liposomes (TPSL) as dry powder inhaler for the targeted delivery of drugs in the target site i.e. lungs. METHOD Ligand anchored PSL (TPSL) was prepared by thin film hydration for the combined delivery of Isoniazid (INH) and Ciprofloxacin HCl (CIP HCl) using 4-aminophenyl-α-D mannopyranoside (Man) as surface functionalized ligand and characterized using different parameters. RESULTS It was observed that size of the ligand anchored liposomes (TPSL) was slightly more than the non-ligand anchored liposomes (PSL). Drug release was studied at different pH for 24 hrs and it was observed that liposomes exhibited slow release at alkaline pH (58-64%) as compared to macrophage pH (81-87%) where it increased dramatically due to the destabilization of pH sensitive liposome (PSL). In vitro cellular uptake study showed that much higher concentration was achieved in the alveolar macrophage using ligand anchored liposomes as compared to its counterpart. In vivo study showed that maximum drug accumulation was achieved in the lung by delivering drug using ligand anchored PSL as compared to conventional PSL. CONCLUSION It was concluded that ligand anchored pH sensitive liposome is one of the promising systems for the targeted drug therapy in pulmonary tuberculosis.