Impact of formulation parameters on self-assembled liposomes (LeciPlex® III): A detailed investigation.

The present study investigated the feasibility of fabricating self-assembled liposomes, LeciPlex®, a phospholipid-based vesicular nanocarrier using cationic, anionic, and nonionic stabilizers. The phospholipid investigated was soy phosphatidylcholine and the nano-precipitation method based on solvent diffusion was applied as the fabrication technique of liposomes in this study. The effects of various formulation variables, such as lipid and stabilizer concentration, total solid concentration, and solvent type on the self-assembly of vesicles were studied for physical characterization including particle size analysis, differential scanning calorimetry, viscosity, optical transmittance, transmission electron microscopy, and small angle neutron scattering. All three LeciPlex® systems exhibited a direct relationship between particle size and phospholipid concentration. The two categoric variables, solvent, and stabilizer used to prepare LeciPlex® demonstrated a significant effect on particle size for all three LeciPlex® systems. Small angle neutron scattering, and optical transmittance confirmed the formation of micellar systems at a phospholipid: stabilizer ratio of 1:2 and vesicular systems at a ratio of 2:1 for the systems stabilized with anionic and nonionic surfactants. In contrast to this, the LeciPlex® formed with the cationic stabilizer Dioctadecyldimethylammonium bromide (DODAB), formed vesicles at both ratios. From these investigations, it was clear that the formulation space for LeciPlex® was diversified by the addition of cationic, anionic, and non-ionic stabilizers.

Formulation, characterization and evaluation of inhalable effervescent dry powder of Rifampicin nanoparticles.

BACKGROUND: Dry powder inhaler is a popular approach to pulmonary drug delivery to treat tuberculosis. Spray dried Nanoparticles using lactose carrier is extensively used for pulmonary drug delivery. Though lactose nanoparticles show deep lung deposition, they fail to uniformly disperse nanoparticles in its original form in alveoli. Rifampicin is one of the first line drugs in tuberculosis treatment. Lung targeted drug delivery system is an approach to reduce dose related side effects of rifampicin. Inhalable nanoparticles also help to target alveolar macrophages, thus improving treatment efficiency. METHODOLOGY: This study focuses on rifampicin nanosuspension formulation and optimization using nano-precipitation method followed by characterizing effervescent DPI of rifampicin nanoparticles with effervescent pair (citric acid and sodium bicarbonate). Preliminary studies showed suitability of 4:5 solvent: antisolvent ratio and lecithin (1%) as stabilizer. The drug and stabilizer concentration in nanoparticles was successfully optimized using 3 ∗ 2 factorial design using DESIGN EXPERT software. The rifampicin nanoparticles were further converted to spray dried powder using effervescent carrier. RESULT: The effervescent pair formulation was monodisperse and had a particle size of 1.5 microns (polydispersity index 0.289), thus showing better redispersibility than lactose nanoparticles. The mass median aerodynamic diameter and fine particle diameter of both spray dried formulations were similar and suitable for deep lung deposition. CONCLUSION: These findings are suggestive that effervescent technique can be successfully employed to improve redispersibility of rifampicin nanoparticles.

Novel derivatives of arabinogalactan, pullulan & lactobionic acid for targeting asialoglycoprotein receptor: Biomolecular interaction, synthesis & evaluation.

Targeted-drug administration to liver reduces side effects by minimising drug distribution to non-target organs and increases therapeutic efficacy by boosting drug concentration in target cells. In this study, arabinogalactan-(AG), pullulan-(PL) and lactobionic acid-(LA) were selected as natural ligands to target asialoglycoprotein receptor-(ASGPR-1) present on hepatocytes. In silico docking studies were performed and binding affinities of novel ligands viz. palmitoylated AG-(PAG), lauroylated AG-(LAG), palmitoylated PL-(PPL), lauroylated PL-(LPL) and lactobionic acid-adipic acid dihydrazide conjugate-(LAD) were compared with AG, PL and LA. These novel ligands were successfully synthesized and characterized. The ligands were incorporated into drug loaded nanostructured lipid carriers-(NLCs) for surface functionalization. HepG2 cellular internalization of hepatocyte-targeted NLCs was studied using fluorescence microscopy and LAD-decorated-drug loaded NLCs giving maximum cellular uptake were studied using confocal microscopy. Toxicity potential of LAD-decorated NLCs was assessed in vivo. Molecular docking results suggested that among the ligands, order of binding affinity was found to be LAD>PAG > PPL > LPL > LAG. Acute toxicity studies revealed hemocompatibility and absence of organ toxicity for ligand LAD. Additionally, the results establish proof-of-concept of enhanced targeting efficacy of novel ASGPR targeting ligands. These ligands can be used for surface modification of nanocarriers for future targeted delivery in treating various liver disorders.

Synthetic enzyme-based nanoparticles act as smart catalyst for glucose responsive release of insulin.

BACKGROUND: Earlier studies have attempted to create electronic free insulin delivery systems using different glucose sensing mechanism, no successful clinical translation as hitherto been made. This study aimed to assess the faster responsiveness of the insulin release from this enzyme based nanoparticles which is a self-regulated insulin delivery system constructed by loading with insulin, enzyme glucose oxidase into hyaluronic acid and 2-nitroimidazole forming enzyme-based nanoparticles which works in accordance to the blood glucose level. MATERIALS AND METHOD: Enzyme-based nanoparticles were prepared by ionic gelation method. Insulin content in the nanoparticles kept for stability study was estimated by human insulin enzyme based immunosorbent assay. In in-vitro studies; different concentrations of glucose were taken and the release study of insulin was recorded. RESULTS: This enzyme-based nanoparticles were having average diameter of around 193 nm and stability studies showed that nanoparticles were stable upto 30 days at 4 °C. In-vitro studies showed the release of insulin from nanoparticle conjugates which was effectively correlated with the external glucose concentration created where different concentrations of glucose taken thus facilitating the stabilization of blood glucose levels in the hyperglycemia state which was achieved within 10 min. (400 mg/dL) wherein drug release rate remarkably increased in hyperglycemia state and no specific changes or small amount of release was observed in normoglycemia state (100 mg/dL). CONCLUSION: Overall, this preliminary study of this enzyme-based nanoparticles formulation showed excellent rapid responsiveness towards hyperglycemia which might act as a potential biomimetic system in triggering the release of insulin in sustained manner.

Metronidazole-loaded nanostructured lipid carriers to improve skin deposition and retention in the treatment of rosacea.

The objective of the present investigation was to improve the skin deposition and retention of metronidazole (MTZ) in rosacea therapy by incorporating it into nanostructured lipid carriers (NLCs). The main challenge in this endeavor was the partial hydrophilicity of MTZ, which mandated careful selection of excipients, including solid and liquid lipids, surfactants, and their ratios in combination. NLCs were produced by the phase inversion temperature method and finally converted into a gel for topical application. The prepared nanoparticles were evaluated for their particle size, zeta potential, entrapment efficiency, solid-state characteristics, surface morphology, in vitro drug release, and permeation through excised skin. The gel was additionally characterized for its pH, drug content, viscosity, and spreadability. The prepared nanoparticles were spherical in shape and of size less than 300 nm. Incorporation of judiciously chosen excipients made possible a relatively high entrapment efficiency of almost 40%. The drug release was found to be biphasic, with an initial burst release followed by sustained release up to 8 hours. In comparison to the plain drug gel, which had a tissue deposition of 11.23%, the NLC gel showed a much superior and desirable deposition of 26.41%. The lipophilic nature of the carrier, its size, and property of occlusion enabled greater amounts of drug to enter and be retained in the skin, simultaneously minimizing permeation through the skin, i.e. systemic exposure. The results of the study suggest that NLCs of anti-rosacea drugs have the potential to be used in the therapy of rosacea.

Preparation and Evaluation of N-Trimethyl Chitosan Nanoparticles of Flurbiprofen for Ocular Delivery.

PURPOSE: A major challenge in ocular therapeutics is poor bioavailability of drug, 1% or even less of the instilled dose is absorbed and frequent administration of conventional products leads to poor adherence to therapy. Hence, the present study is to synthesize N-trimethyl chitosan (TMC), a water-soluble chitosan derivative and to prepare flurbiprofen (FLU):hydroxyl propyl-ß-cyclodextrin (HP-ß-CD) complex-loaded nanoparticles for treatment of bacterial conjunctivitis which aims to increase the residence time in ocular tissue, thus enhancing patient compliance and improved efficacy. METHODS: TMC was synthesized and characterized by 1H NMR and FT-IR. TMC and chitosan (CS) nanoparticles containing inclusion complex were prepared by ionic gelation using sodium tripolyphosphate (TPP). The nanoparticles thus obtained were evaluated for particle size, zeta potential, drug entrapment, in-vitro release, in-vitro mucoadhesion, and TEM for morphology and irritation potential was evaluated by the HET-CAM technique. RESULTS: N-methyl quaternization of CS was confirmed by 1H NMR. The particle size and zeta potential of the TMC nanoparticles were found to be 201 ± 1.55 nm and +13.9 ± 1.697 mV and that of CS nanoparticles were 361.2 ± 1.55 nm and +10.9 ± 0.424 mV, respectively. The entrapment of FLU- HP-ß-CD inclusion complex in polymeric nanoparticles was found to be 10.91 ± 1.541%. The observed in-vitro release profile of TMC nanoparticles indicated characteristic burst release followed by delayed release. HET-CAM studies demonstrated the ocular safety of TMC nanoparticles. CONCLUSION: The developed TMC nanoparticles offered prolonged release potential for transmucosal ocular delivery of hydrophobic flurbiprofen.

Design and Development of Repaglinide Microemulsion Gel for Transdermal Delivery.

Microemulsion formulation of repaglinide, a BCS class II hypoglycemic agent with limited oral bioavailability, was developed considering its solubility in various oils, surfactants, and cosurfactants. The pseudo-ternary phase diagrams for microemulsion regions were constructed by water titration method at K m 1:1 and characterized for optical birefringence, percentage transmittance, pH, refractive index, globule size, zeta potential, viscosity, drug content, and thermodynamic stability. To enhance the drug permeation and residence time, the optimized microemulsions having mean globule size of 36.15 ± 9.89 nm was gelled with xanthan gum. The developed microemulsion-based gel was characterized for globule size, zeta potential, pH, and drug content. All evaluation parameters upon gelling were found to be satisfactory. Ex vivo permeability study across rat skin demonstrated higher steady-state flux (P < 0.05) for microemulsion of repaglinide in comparison to the repaglinide microemulsion gel. At the end of 24 h, the cumulative drug permeation from microemulsion and microemulsion gel was found to be 229.19 ± 24.34 and 180.84 ± 17.40 µg/cm2, respectively. The microemulsion formulation showed 12.30-fold increase in flux as compared to drug suspension with highest enhancement ratio (E r ) of 12.36. Whereas microemulsion gel exhibited 10.97-fold increase in flux (with highest E r , 11.78) as compared to repaglinide (RPG) suspension. In vivo efficacy study was performed in normal Sprague-Dawley rats by using oral glucose tolerance test. Results of RPG transdermal microemulsion gel demonstrated remarkable advantage over orally administered RPG by reducing the glucose level in controlled manner. Hence, it could be a new, alternative dosage form for effective therapy of type 2 diabetes mellitus.

Self nanoemulsifying granules (SNEGs) of meloxicam: preparation, characterization, molecular modeling and evaluation of in vivo anti-inflammatory activity.

Meloxicam, a BCS class II drug belonging to the class of NSAIDs is indicated in conditions of rheumatoid arthritis, ankylosing spondylitis and osteoarthritis in which rapid onset of drug action is desired to reduce inflammation and pain. The objective of the study was to thus develop Self Nanoemulsifying Granules (SNEGs) of Meloxicam (MLX) for enhancement of solubility; and subsequently dissolution rate, thus aiming for a faster onset of action. Preliminary studies along with molecular modeling studies were carried out for selection of appropriate lipids, surfactants and cosurfactants for the development of MLX-loaded Self Nanoemulsifying preconcentrate (SNEP). A charge inducer was incorporated into the formulation so as to increase the solubility of MLX in lipids and hence, drug loading. A three-factor D-optimal mixture design was used for optimization of MLX loaded SNEP. The role of charge inducer in increasing the drug loading of MLX in SNEDDS was studied by molecular dynamics simulation using Desmond. Optimized SNEP was adsorbed onto solid carriers to form SNEGs for improved stability and enhanced flow properties. Physical characterization studies of SNEGs, in vitro release studies, and in vivo evaluation of anti-inflammatory activity of the optimized formulation were performed. All the results indicated that MLX SNEGs can be a promising alternative to conventional oral NSAIDs therapy because of enhanced dissolution characteristics and subsequent rapid onset of action.

Serratiopeptidase Niosomal Gel with Potential in Topical Delivery.

The objective of present study was to develop nonionic surfactant vesicles of proteolytic enzyme serratiopeptidase (SRP) by adapting reverse phase evaporation (REV) technique and to evaluate the viability of SRP niosomal gel in treating the topical inflammation. The feasibility of SRP niosomes by REV method using Span 40 and cholesterol has been successfully demonstrated in this investigation. The entrapment efficiency was found to be influenced by the molar ratio of Span 40 : cholesterol and concentration of SRP in noisome. The developed niosomes were characterized for morphology, particle size, and in vitro release. Niosomal gel was prepared by dispersing xanthan gum into optimized batch of SRP niosomes. Ex vivo permeation and in vivo anti-inflammatory efficacy of gel formulation were evaluated topically. SRP niosomes obtained were round in nanosize range. At Span 40 : cholesterol molar ratio 1 : 1 entrapment efficiency was maximum, that is, 54.82% ± 2.08, and showed consistent release pattern. Furthermore ex vivo skin permeation revealed that there was fourfold increase in a steady state flux when SRP was formulated in niosomes and a significant increase in the permeation of SRP, from SRP niosomal gel containing permeation enhancer. In vivo efficacy studies indicated that SRP niosomal gel had a comparable topical anti-inflammatory activity to that of dicolfenac gel.

Design and characterization of chitosan-alginate microspheres for ocular delivery of azelastine.

The use of mucoadhesive biopolymers is one of the best approaches to prolong the drug residence inside the cul-de-sac, consequently increasing the bioavailability. Thus, the focus of this work was to develop mucoadhesive microspheres to overcome the limitations of ocular drug delivery. The chitosan-sodium alginate microspheres of azelastine hydrochloride were fabricated using modified ionotropic gelation technique. The particle size, zeta potential, entrapment efficiency and drug release kinetics were evaluated and characterized by SEM, FT-IR, DSC, in vitro mucoadhesion and in vivo study. The microspheres had average particle size in the range of 3.55 to 6.70 µm and zeta potential +24.55 to +49.56 mV. The fabricated microspheres possess maximum drug entrapment of 73.05% with 65% mucin binding efficiency and revealed a controlled release over the 8-h period following a non-Fickian diffusion. SEM showed that microspheres were distinct solid with irregular shape. FT-IR and DSC results concluded the drug entrapment into microspheres. In vivo studies on ocular rat model revealed that azelastine microspheres had better efficacy. Chitosan sodium alginate microspheres prepared were in particle size range suitable for ocular purpose. In vitro release and in vivo efficacy studies revealed that the microspheres were effective in prolonging the drug's presence in cul de sac with improved therapeutic efficacy.

Development of dorzolamide loaded 6-o-carboxymethyl chitosan nanoparticles for open angle glaucoma.

Chitosan (CS) is a biodegradable, biocompatible, and mucoadhesive natural polymer soluble in acidic pH only and can be irritating to the eye. Objective of the study was to synthesize water soluble 6-O-carboxymethyl (OCM-CS) derivative of CS, and to develop CS and OCM-CS nanoparticles (NPs) loaded with dorzolamide hydrochloride (DRZ). CS was reacted with monochloroacetic acid (MCA) for OCM-CS synthesis and was characterized by FT-IR, DSC, and (13)C NMR. CS and OCM-CS NPs were prepared by ionic gelation method. Ocular irritation potential were evaluated and therapeutic efficacy was measured by reduction in intraocular pressure (IOP) in normotensive rabbits. Maximum yield was obtained when the ratio of water/isopropyl alcohol was 1/4 at 55°C. The FT-IR, DSC and (13)C NMR confirmed the formation of an ether linkage between hydroxyl groups of CS and MCA. The particle size and zeta potential of optimised CSNPs was 250.3 ± 2.62 nm and +33.47 ± 0.723 mV, whereas those for OCM-CSNPs were 187.1 ± 2.72 nm and 30.87 ± 0.86 mV. The entrapment efficiency was significantly improved for OCM-CSNPs, compared to CSNPs. OCM-CSNPs had tailored drug release and improved bioavailability with reduction in pulse entry as compared to CSNPs. Hence, it can be concluded that DRZ loaded OCM-CSNPs would be better alternative option to available eye drops for glaucoma treatment.

Eudragit RL100 based microspheres for ocular administration of azelastine hydrochloride.

In the present study, potential of polymeric microspheres for treatment of allergic conjunctivitis was investigated. Azelastine hydrochloride loaded Eudragit RL100 microspheres were prepared by solvent evaporation technique. The change in drug-polymer ratio on the particle size, zeta potential, entrapment efficiency and in vitro drug release was investigated. As Eudragit concentration ranged from 40 to 80 mg/ml the size range obtained was 4.18-7.36 µm with positive zeta potential. With the increase in drug polymer ratio, the entrapment efficiency was increased with maximum 14.56%. In vitro release studies demonstrated prolonged release of the drug over the period of 6 hr. Scanning electron micrographs showed that microspheres were spherical with distinct solid dense structure. Fourier transform infrared and differential scanning calorimetry studies concluded slight change in peak intensities of drug in microspheres. In vivo studies in rat model indicated that reduction in eosinophil count number was more pronounced in azelastine hydrochloride microspheres than marketed formulation, Azelast®.

Design and evaluation of microemulsion gel system of nadifloxacin.

Topical microemulsion systems for the antiacne agent, nadifloxacin were designed and developed to overcome the problems associated with the cutaneous delivery due to poor water solubility. The solubility of nadifloxacin in oils, surfactants and cosurfactants was evaluated to screen the components of the microemulsion. Various surfactants and cosurfactants were screened for their ability to emulsify the selected oily phase. The pseudoternary diagrams were constructed to identify the area of microemulsion existence. The influence of k(m) (surfactant/cosurfactant) ratio on the microemulsion existence region was determined and optimum systems were designed. The systems were assessed for drug-loading efficiency and characterised for optical birefringence, pH and refractive index, robustness to dilution, globule size, drug content and thermodynamic stability. Optimised microemulsion systems were formulated into gel form and evaluated for viscosity, spreadability, drug content, ex vivo skin permeation and antibacterial activity. The maximum solubility of nadifloxacin in the microemulsion system was found to be 0.25%. The nadifloxacin microemulsions had a small and uniform globule size (67.3-121.23 nm). The stability results revealed that all formulations showed a stable globule size and the polydispersity index under stress conditions. Incorporation of nadifloxacin in microemulsion gel increased the ex vivo skin permeation and antibacterial activity when compared to marketed cream.

Microencapsulation of eugenol by gelatin-sodium alginate complex coacervation.

Present study describes microencapsulation of eugenol using gelatin-sodium alginate complex coacervation. The effects of core to coat ratio and drying method on properties of the eugenol microcapsules were investigated. The eugenol microcapsules were evaluated for surface characteristics, micromeritic properties, oil loading and encapsulation efficiency. Eugenol microcapsules possessed good flow properties, thus improved handling. The scanning electron photomicrographs showed globular surface of microcapsules prepared with core: coat ratio1:1.The treatment with dehydrating agent isopropanol lead to shrinking of microcapsule wall with cracks on it. The percent oil loading and encapsulation efficiency increased with increase in core: coat ratio whereas treatment with dehydrating agent resulted in reduction in loading and percent encapsulation efficiency of eugenol microcapsules.

Development and Evaluation of Novel Polymeric Nanoparticles of Brimonidine Tartrate.

Micro and nanoparticulate carriers have been in focus in ophthalmic drug delivery with the objective of improving bioavailability, drug targeting and reducing pulse entry of the drug in ocular cul de sac. Polymeric nanoparticles for ocular purpose have potential in reducing the pulse entry and frequency of dosing, thus improving patient compliance. In the present study, mucoadhesive sodium alginate nanoparticles were developed for Brimonidine Tartrate (BT) as a model antiglaucoma drug by controlled ionic gelation technique. These nanoparticles would not only prolong drugs residence time but also reduce pulse entry in cul de sac. Nanoparticles were evaluated for morphology, surface characteristics, drug polymer interactions, particle size, polydispersibility index, zeta potential, entrapment efficiency, in vitro release profile and in vivo efficacy. The effect of various stabilizers on stabilization of blank and drug loaded nanoparticles was investigated. Irregular shape and loss of crystallinity for BT loaded sodium alginate nanoparticles was observed by TEM and SEM images respectively. IR spectra and DSC thermograms revealed the physicochemical interaction was involved during sodium alginate nanoparticle formation and entrapment of BT. The developed nanoparticles have average particle size of 450nm with PI 0.65, the entrapment efficiency ranged from 4-18 % and zeta potential values ranged from -27.5 mV to -24.1 mV. In vitro release profile showed a gradual drug release over the period of 3 hrs. In-vivo experiments showed that it was possible to prolong the drug release over a period of 8 hr, on topical instillation of BT loaded nanoparticles to albino rabbits, hence reducing the dosage frequency.

Characterization of gelatin-sodium alginate complex coacervation system.

A gelatin and sodium alginate complex coacervation system was studied and an effect of pH and colloid mixing ratios on coacervation was investigated. A colloid mixing ratio at which optimum coacervation occurred varied with the coacervation pH. Viscometric, turbidity and coacervate dry yield investigations were used to investigate optimum conditions for complex coacervation. Optimum coacervation occurred at pH 3.5 at a gelatin sodium alginate ratio 4:1. Coacervate and equilibrium fluid was analyzed for gelatin and sodium alginate contents and yields calculated on the basis of chemical analysis showed that optimum coacervation occurred at 25% sodium alginate fraction at pH 3.5.