Pollen grains as a novel microcarrier for oral delivery of proteins.

Oral delivery of proteins and peptides is a challenge due to their degradation in the stomach. To overcome this challenge, ragweed (Ambrosia elatior) pollen grains were engineered to serve as protective microcapsules. A matrix comprising of Eudragit L100-55, an enteric polymer was deposited on the inner surfaces of ragweed pollens to protect the encapsulated protein from gastric degradation and to achieve pH-dependent release in the intestine. The Eudragit L100-55 matrix was formed without use of organic solvents so that solvent-induced damage to protein molecules could be prevented. To demonstrate the concept, bovine serum albumin (BSA) a model protein was used. A matrix of Eudragit L100-55 embedded with BSA was prepared in ragweed pollens by optimizing their respective concentrations for maximizing BSA loading in the matrix. The ability of this optimized formulation to protect BSA in simulated gastric acid fluid was evaluated. Release studies in simulated gastric fluid (pH 1.2) showed minimal BSA release from the ragweed-Eudragit L100-55 formulation. Analysis of BSA retained in the formulation after its exposure to gastric fluid confirmed that the residual BSA had not denatured. Release studies in the simulated intestinal fluid (pH 6.8) showed that ragweed pollen offered additional controlled release mechanism within the first few hours of release by virtue of their solid wall. In conclusion, upon use of a protein-friendly solvent for Eudragit L100-55, proteins could be encapsulated in ragweed pollen without denaturing them, and the resulting formulation exhibited selective release of the proteins at intestinal pH suggesting that the ragweed pollen grain-based formulation could be promising for oral delivery of proteins.

Bio-functionalization of grade V titanium alloy with type I human collagen for enhancing and promoting human periodontal fibroblast cell adhesion - an in-vitro study.

Surface modification of medical grade V titanium alloy (Ti-6Al-4V) with biomolecules is an important and vital step for tailoring it for various biomedical applications. Present study investigates theinfluence of type I human collagen (T1HC) bio-conjugation through a three stage process. Polished grade V titanium alloy discs were functionalizedwith free OH group by means of controlled heat and alkali treatment followed by coating of 3-aminopropyltriethoxy (APTES) silane couplingagent. T1HC were bio-conjugated through 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride N-hydroxysuccinimide (EDCNHS)coupling reaction. At each stage, grade V titanium alloy surfaces were characterized by atomic force microscopy (AFM), scanning electronmicroscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Xrayphotoelectron spectroscopy (XPS). FTIR and XPS studies confirms thecovalent attachment of APTES with titanium alloy surface while terminalamine groups of APTES remained free for further attachment of T1HCthrough covalent bond. Aqueous stability of bio-conjugated titanium discsat various pH and time intervals (i.e. at pH of 5.5, 6.8 and 8.0 at timeinterval of 27 and 48h) confirmed the stability of T1HC bioconjugated collagen on titanium surface. Further human periodontalfibroblast cell line (HPdlF) culture revealed enhanced adhesion on theT1HC bio-conjugated surface compared to the polystyrene and polishedgrade V titanium alloy surfaces.

Applications of Nanomaterials in Dental Science: A Review.

Nanotechnology has revolutionized health care industry in a large scale and its applications are a boon to modern medicine and dental science. It is expected to pervade and further revolutionize the art and science of dentistry and may well have important applications spanning all the aspects of oral diseases, diagnosis, prevention and treatment. Materials science in dentistry has embraced the technology to produce nanomaterials that are being used in caries inhibitors, antimicrobial resins, hard tissue remineralizing agents, targeted drug delivery, scaffolds, bio-membranes, nanocrystalline hydroxyl apatite, restorative cements, adhesion promoters and boosters, bioactive glass, tissue conditioners, reinforced methacrylate resins, root canal disinfectants, friction free orthodontic arch wires and nano composites life. These upcoming technologies have potential to bring about significant benefits in the form of improvement in dental science and to society. The present review presents the latest recent developments in this interdisciplinary field bridging nanotechnology and dental science.

Folic acid and trastuzumab conjugated redox responsive random multiblock copolymeric nanocarriers for breast cancer therapy: In-vitro and in-vivo studies.

The study represents synthesis, characterization and biological evaluation of redox responsive polymeric nanoparticles based on random multiblock copolymer for doxorubicin delivery in breast cancer. The random multiblock copolymer was synthesized via ring opening polymerization of lactide with polyethylene glycol to form triblock copolymer followed by isomerization polymerization of the triblock copolymer and 2-hydroxyethyl disulfide with the help of hexamethylene diisocynate in presence of dibutyltin dilaurate as a catalyst. Folic acid was conjugated to hydroxyl group from the multiblock polymer through DCC-NHS coupling. High drug loading content of ∼22% was achieved in the polymeric nanoparticles with size range of ∼110nm and polyethylene glycol fraction of ∼18% in the multiblock copolymer. Drug release profile confirmed the redox responsive behavior of polymeric nanoparticles with ∼72% drug release at pH 5.5 in presence of 10mM GSH as compared to ∼18% drug release at pH 7.4. In vitro cellular uptake studies showed ∼22% cellular uptake with dual (folic acid and trastuzumab) conjugated polymeric nanoparticles as compared to non-targeted polymeric nanoparticles. Fluorescence activated cell sorting (FACS) studies demonstrated higher apoptosis (∼80%) as compared to non-conjugated polymeric nanoparticles (20%) in MCF-7 cell line. In vivo studies showed 91% tumor regression in Ehrlich ascites tumor (EAT) as compared to free doxorubicin treated mice without showing any significant toxicity. Thus, it is envisaged that these redox responsive polymeric nanocarriers act as Trojan horses in cancer therapeutics.

Folic Acid and Trastuzumab Functionalized Redox Responsive Polymersomes for Intracellular Doxorubicin Delivery in Breast Cancer.

Redox responsive biodegradable polymersomes comprising of poly(ethylene glycol)-polylactic acid-poly(ethylene glycol) [PEG-s-s-PLA-s-s-PLA-s-s-PEG] triblock copolymer with multiple disulfide linkages were developed to improve intracellular delivery and to enhance chemotherapeutic efficacy of doxorubicin in breast cancer with minimal cardiotoxicity. Folic acid and trastuzumab functionalized monodispersed polymersomes of size ∼150 nm were prepared by nanoprecipitation method while achieving enhanced doxorubicin loading of ∼32% in the polymersomes. Multiple redox responsive disulfide linkages were incorporated in the polymer in order to achieve complete disintegration of polymersomes in redox rich environment of cancer cells resulting in enhanced doxorubicin release as observed in in vitro release studies, where ∼90% doxorubicin release was achieved in pH 5.0 in the presence of 10 mM glutathione (GSH) as compared to ∼20% drug release in pH 7.4. Folic acid and trastuzumab mediated active targeting resulted in improved cellular uptake and enhanced apoptosis in in vitro studies in breast cancer cell lines. In vivo studies in Ehrlich ascites tumor bearing Swiss albino mice showed enhanced antitumor efficacy and minimal cardiotoxicity of polymersomes with ∼90% tumor regression as compared to ∼38% tumor regression observed with free doxorubicin. The results highlight therapeutic potential of the polymersomes as doxorubicin delivery nanocarrier in breast cancer therapy with its superior antitumor efficacy and minimal cardiotoxicity.

ROP and ATRP Fabricated Dual Targeted Redox Sensitive Polymersomes Based on pPEGMA-PCL-ss-PCL-pPEGMA Triblock Copolymers for Breast Cancer Therapeutics.

To minimize cardiotoxicity and to increase the bioavailability of doxorubicin, polymersomes based on redox sensitive amphiphilic triblock copolymer poly(polyethylene glycol methacrylate)-poly(caprolactone)-s-s-poly(caprolactone)-poly(polyethylene glycol methacrylate) (pPEGMA-PCL-ss-PCL-pPEGMA) with disulfide linkage were designed and developed. The polymers were synthesized by ring opening polymerization (ROP) of ε-caprolactone followed by atom transfer radical polymerization (ATRP) of PEGMA. The triblock copolymers demonstrated various types of nanoparticle morphologies by varying hydrophobic/hydrophilic content of polymer blocks, with PEGMA content of ∼18% in the triblock copolymer leading to the formation of polymersomes in the size range ∼150 nm. High doxorubicin loading content of ∼21% was achieved in the polymersomes. Disulfide linkages were incorporated in the polymeric backbone to facilitate degradation of the nanoparticles by the intracellular tripeptide glutathione (GSH), leading to intracellular drug release. Release studies showed ∼59% drug release in pH 5.5 in the presence of 10 mM GSH, whereas only ∼19% was released in pH 7.4. In cellular uptake studies, dual targeted polymersomes showed ∼22-fold increase in cellular uptake efficiency in breast cancer cell lines (BT474 and MCF-7) as compared to nontargeted polymersomes with higher apoptosis rates. In vivo studies on Ehrlich's ascites tumor (EAT) bearing Swiss albino mouse model showed ∼85% tumor regression as compared to free doxorubicin (∼42%) without any significant cardiotoxicity associated with doxorubicin. The results indicate enhanced antitumor efficacy of the redox sensitive biocompatible nanosystem and shows promise as a potential drug nanocarrier in cancer therapeutics.

AS1411 aptamer and folic acid functionalized pH-responsive ATRP fabricated pPEGMA-PCL-pPEGMA polymeric nanoparticles for targeted drug delivery in cancer therapy.

Nonspecificity and cardiotoxicity are the primary limitations of current doxorubicin chemotherapy. To minimize side effects and to enhance bioavailability of doxorubicin to cancer cells, a dual-targeted pH-sensitive biocompatible polymeric nanosystem was designed and developed. An ATRP-based biodegradable triblock copolymer, poly(poly(ethylene glycol) methacrylate)-poly(caprolactone)-poly(poly(ethylene glycol) methacrylate) (pPEGMA-PCL-pPEGMA), conjugated with doxorubicin via an acid-labile hydrazone bond was synthesized and characterized. Dual targeting was achieved by attaching folic acid and the AS1411 aptamer through EDC-NHS coupling. Nanoparticles of the functionalized triblock copolymer were prepared using the nanoprecipitation method, resulting in an average particle size of ∼140 nm. The biocompatibility of the nanoparticles was evaluated using MTT cytotoxicity assays, blood compatibility studies, and protein adsorption studies. In vitro drug release studies showed a higher cumulative doxorubicin release at pH 5.0 (∼70%) compared to pH 7.4 (∼25%) owing to the presence of the acid-sensitive hydrazone linkage. Dual targeting with folate and the AS1411 aptamer increased the cancer-targeting efficiency of the nanoparticles, resulting in enhanced cellular uptake (10- and 100-fold increase in uptake compared to single-targeted NPs and non-targeted NPs, respectively) and a higher payload of doxorubicin in epithelial cancer cell lines (MCF-7 and PANC-1), with subsequent higher apoptosis, whereas a normal (noncancerous) cell line (L929) was spared from the adverse effects of doxorubicin. The results indicate that the dual-targeted pH-sensitive biocompatible polymeric nanosystem can act as a potential drug delivery vehicle against various epithelial cancers such as those of the breast, ovary, pancreas, lung, and others.

Novel lipid based oral formulation of curcumin: development and optimization by design of experiments approach.

The clinical utility of curcumin (CRM) is limited due to its poor oral bioavailability. Lipid based oral formulations (LBOFs) are emerging as useful oral drug delivery systems for 'difficult to deliver' molecules like CRM. In present study, we report novel Type IV LBOF for CRM using Gelucire 44/14, Labrasol, Vit. E TPGS and PEG 400 with superior CRM loading and enhanced oral bioavailability. The optimization of LBOF for CRM loading and post dilution droplet size was carried out by design of experiments (DoE) approach with Box-Behnken design. Oral bioavailability of optimized LBOF (O-LBOF) was evaluated in male Sprague-Dawley (SD) rats at a dose of 250 mg/kg. Raw CRM (control) showed C(max) and AUC(0-∞) of 32.29 ng/ml and 38.07 ng h/ml, respectively. O-LBOF improved C(max) and AUC(0-∞) by 11.6 and 35.8 folds respectively over control.

Development of lyophilization cycle and effect of excipients on the stability of catalase during lyophilization.

INTRODUCTION: The purpose of the present study was to screen excipients such as amino acids and non-aqueous solvents for their stabilizing effect on catalase, a model protein, for lyophilization. The present study also includes optimization of lyophilization cycle for catalase formulations, which is essential from the commercial point of view, since lyophilization is an extremely costly process. MATERIALS AND METHODS: Activity of catalase was determined using catalase activity assay. Differential scanning calorimetry was used to determine eutectic melting temperature of the frozen catalase solution, which is essential for the optimization of lyophilization cycle. RESULTS: When catalase was lyophilized without excipients, it was found that about 65-78% of the initial activity of catalase was lost during the lyophilization process in a concentration dependent manner. The maximum stability of catalase during lyophilization was observed at pH 7.0. Amino acids like alanine, glycine, lysine, serine and 4-hydroxy proline showed strong stabilizing effect on catalase during lyophilization by protecting catalase activity above 95%, whereas valine and cysteine hydrochloride showed destabilizing effect on catalase. Non-aqueous solvents such as dimethyl formamide, dimethyl sulphoxide, polyethylene glycol (PEG) 200, PEG 400, PEG 600 and ethylene glycol also showed destabilizing effect on catalase during lyophilization. CONCLUSIONS: In order to prevent loss of catalase activity during lyophilization of catalase, use of amino acids like alanine, glycine, lysine, serine and 4-hydroxy proline in optimum concentration is highly advisable.