Enteric coating of nanostructured lipid carriers (NLCs) and enteric coating of hard gelatin capsules filled with NLCs: Feasibility studies.

Nanostructured lipid carriers (NLCs) of asenapine maleate (ASPM) were enteric coated with polymethacrylate polymers (Eudragit®) for oral delivery. The present study aimed to compare the feasibility of direct enteric coating of NLCs and enteric coating of hard gelatin capsules filled with lyophilized ASPM-NLCs. Organic solution of Eudragit® was prepared using acetone containing 3% v/v water, acetone or ethanol. Aqueous dispersion of Eudragit® was obtained by neutralization with base. Capsules were enteric coated by dip-coating method with 3:2 ratio of Eudragit® L100-55:S100 (7.5-12.5% w/v). ASPM-NLCs showed particle size of 84.91±2.14nm, polydispersity index of 0.222±0.026, entrapment efficiency of 86.9±1.8% and zeta potential of -4.83±0.29 mV. TEM images showed good sphericity of the particles with the size of ≈100nm. Non-aqueous enteric coating was not successful as NLCs were precipitated in organic solvent. Aqueous enteric coated ASPM-NLCs (lipid:coat=1:2) showed an increased size (150.8±16.7nm) and zeta potential (-23.5±2.2 mV) revealing the deposition of Eudragit®. However, aqueous enteric coated ASPM-NLCs and uncoated ASPM-NLCs showed higher drug release (18.3±3.1-22.3±3.2%) in HCl solution (pH 1.2) indicating no resistance offered by direct enteric coating of NLCs; whereas enteric coated capsules showed less drug release (4.7±0.8%) in HCl solution indicating sufficient gastric protection.

Naringin nano-ethosomal novel sunscreen creams: Development and performance evaluation.

Long term exposure of skin to UV rays produces detrimental effects such as premature skin-ageing and skin cancer. Although, zinc oxide (ZnO) and titanium dioxide (TiO2) are good sunscreen agents, they do not provide highly efficient UV radiation protection and antioxidant and anti-aging effects. The present study was aimed at developing and characterizing ethosomes loaded with naringin and then to incorporate them into sunscreen creams containing nano-ZnO and -TiO2 to achieve adequate skin penetration and skin retention so as to scavenge the free radicals by virtue of naringin's antioxidant property. Ethosomes were prepared and optimized with respect to concentrations of ethanol and cholesterol, time of sonication, drug and lipid ratio and amount of drug. The ethosomes were evaluated for size, zeta potential (ZP), polydispersity index (PDI), encapsulation efficiency and surface morphology. Ethosomal sunscreen creams were evaluated for physicochemical tests, spreadability, antioxidant, cytotoxicity and skin permeation studies. Optimized ethosomal formulation exhibited average vesicle size, PDI, ZP and drug encapsulation efficiency of 142.5 ± 5.6 nm, 0.199 ± 0.007, -72.5 ± 2.9 mV and 33.79 ± 1.35%, respectively. Naringin ethosomes showed enhanced retention in the skin (403.44 ± 15.33 µg/cm2) compared to naringin suspension (202.81 ± 9.45 µg/cm2). The optimized sunscreen cream exhibited SPF of 21.21 ± 0.62 with negligible permeation of naringin across the skin. Ethosomes showed pronounced skin permeation for naringin and optimized cream containing naringin ethosomes along with nano- ZnO and TiO2 showed good skin retention for naringin.

Targeting the intestinal lymphatic system: a versatile path for enhanced oral bioavailability of drugs.

INTRODUCTION: The major challenge of first pass metabolism in oral drug delivery can be surmounted by directing delivery toward intestinal lymphatic system (ILS). ILS circumvents the liver and transports drug directly into systemic circulation via thoracic duct. Lipid and polymeric nanoparticles are transported into ILS through lacteal and Peyer's patches. Moreover, surface modification of nanoparticles with ligand which is specific for Peyer's patches enhances the uptake of drugs into ILS. Bioavailability enhancement by lymphatic uptake is an advantageous approach adopted by scientists today. Therefore, it is important to understand clear insight of ILS in targeted drug delivery and challenges involved in it. AREAS COVERED: Current review includes an overview of ILS, factors governing lymphatic transport of nanoparticles and absorption mechanism of lipid and polymeric nanoparticles into ILS. Various ligands used to target Peyer's patch and their conjugation strategies to nanoparticles are explained in detail. In vitro and in vivo models used to assess intestinal lymphatic transport of molecules are discussed further. EXPERT OPINION: Although ILS offers a versatile pathway for nanotechnology based targeted drug delivery, extensive investigations on validation of the lymphatic transport models and on the strategies for gastric protection of targeted nanocarriers have to be perceived in for excellent performance of ILS in oral drug delivery.

Strategies for improving the specificity of siRNAs for enhanced therapeutic potential.

INTRODUCTION: RNA interference has become a tool of choice in the development of drugs in various therapeutic areas of Post Transcriptional Gene Silencing (PTGS). The critical element in developing successful RNAi therapeutics lies in designing small interfering RNA (siRNA) using an efficient algorithm satisfying the designing criteria. Further, translation of siRNA from bench-side to bedside needs an efficient delivery system and/or chemical modification. Areas covered: This review emphasizes the importance of dicer, the criteria for efficient siRNA design, the currently available algorithms and strategies to overcome off-target effects, immune stimulatory effects and endosomal trap. Expert opinion: Specificity and stability are the primary concerns for siRNA therapeutics. The design criteria and algorithms should be chosen rationally to have a siRNA sequence that binds to the corresponding mRNA as it happens in the Watson and Crick base pairing. However, it must evade a few more hurdles (Endocytosis, Serum stability etc.) to be functional in the cytosol.

Preclinical pharmacokinetics and biodistribution studies of asenapine maleate using novel and sensitive RP-HPLC method.

AIM: Asenapine maleate (ASPM) is a newer antipsychotic drug available as a sublingual tablet in the market. EXPERIMENTAL: To investigate the pharmacokinetic and tissue distribution study of ASPM following oral administration in rats, reversed-phase HPLC method was developed and validated. RESULTS: ASPM was extracted from plasma and tissue matrix by liquid-liquid extraction technique and analyzed using mobile phase consisted of phosphate buffer pH 3.0 and acetonitrile (65:35% v/v). The method showed good linearity (10-500 ng/ml) with recovery 83-102%. In pharmacokinetics study, half-life was 32.74 ± 7.51 h due to slow elimination of drug. The biodistribution study indicated preferential distribution of ASPM to highly perfused organs. CONCLUSION: The current method can be successfully applied for estimating the drug in various biological matrices.

A novel long-acting biodegradable depot formulation of anastrozole for breast cancer therapy.

The purpose of the present study was to fabricate PLGA 50:50 and PLA microspheres for controlled delivery of anastrozole. The microspheres were prepared by oil-in-water (o/w) emulsion/solvent evaporation technique and evaluated for particle size and encapsulation. The optimised formulations were studied for solid state characterization, in vitro release and pharmacokinetic studies. The maximum encapsulation efficiency for PLGA 50:50 and PLA microspheres with 40:1 polymer - drug ratio was observed to be 78.4±2.5 and 87.7±2.6%. The solid state characterization confirmed dispersion of drug at the molecular level in the polymeric matrix. Microspheres were spherical in shape with a very smooth surface texture. Drug release was found to be in a sustained fashion, releasing constantly up to 720h (30days) for PLGA and 60days for PLA microspheres. The pharmacokinetic study data revealed that the intramuscular administration of PLA microspheres showed improved pharmacokinetic profile as compared to PLGA microspheres, and therefore this formulation can be considered as the best optimised formulation with sustained exposure of the drug in vivo compared to other microspheres. From experimental results, PLA microspheres demonstrate the feasibility of employing biodegradable depot polymeric microspheres of anastrozole for long-term treatment of breast cancer.

Solid lipid nanoparticles of irbesartan: preparation, characterization, optimization and pharmacokinetic studies

ABSTRACT Irbesartan is an antihypertensive with limited bioavailability and solid lipid nanoparticles (SLN) is one of the approaches to improve bioavailability. Solid lipid nanoparticles were prepared using glyceryl monostearate by solvent emulsification method followed by probe sonication. Irbesartan loaded SLNs were characterized and optimized by parameters like particle size, zeta potential, surface morphology entrapment efficiency and in vitro release. The optimized formulation was then further evaluated for the pharmacokinetic studies in Wistar rats. Irbesartan-loaded SLN of particle size 523.7 nm and 73.8% entrapment efficiency showed good bioavailability in Wistar rats and also showed optimum stability in the studies. The SLN prepared using glyceryl monostearate by solvent emulsification method leads to improve bioavailability of the drug.

A novel nanoproliposomes of lercanidipine: Development, in vitro and preclinical studies to support its effectiveness in hypertension therapy.

AIM: The aim of the present study was to develop nanoproliposomes of lercanidipine, in order to overcome its poor biopharmaceutical properties and to improve its therapeutic efficacy in treating hypertension. MAIN METHODS: The nanoproliposomes were prepared using a modified thin-film hydration method, and the formula was optimized by varying the ratio of lipids and the types of cryoprotectants. This optimized formulation was characterized in terms of its particle size, solid-state, drug release, in-situ absorption, in-vivo pharmacokinetics, and in-vivo anti-hypertensive activity in DOCA-salt induced hypertensive rats. Finally, a PK-PD correlation was established in order to understand the clinical implications of the developed novel nanoproliposomes. KEY FINDINGS: The nanoproliposomes showed a particle size of 174.7nm and an entrapment efficiency of 85.4%. The in-vitro release displayed initial rapid release (19.33%) followed by a sustained release profile, releasing 88.37% of the encapsulated drug. The in-situ studies showed a significant increase in absorption rate across the rat intestinal membrane. The pharmacokinetics of this novel form indicated a 2.75-fold increase in the absolute bioavailability as compared to pure lercanidipine. In addition, the nanoproliposomes were found to be efficient in treating hypertension in DOCA-salt induced hypertensive rats. The PK-PD correlation demonstrated no time lag between effect and exposure, indicating that a direct PK-PD relationship can be expected in the clinic. SIGNIFICANCE: These findings suggest that nanoproliposomes are promising carriers in improving the oral bioavailability and bioactivity of lercanidipine, and can be an effective therapy in the management of hypertension.

Development and Validation of a Stability-Indicating RP-HPLC Method by a Statistical Optimization Process for the Quantification of Asenapine Maleate in Lipidic Nanoformulations.

A stability-indicating RP-HPLC method was developed for quantification of asenapine maleate (ASPM) in lipid nanoformulations. The proposed method was used to assess intrinsic stability of ASPM by conducting force degradation study. The results indicated no considerable degradation of ASPM on subjecting it to hydrolytic, oxidative, thermal and photolytic stresses. The method was validated according to ICH Q2(R1) guidelines by employing Full factorial design using Design-Expert(®) software. ASPM was precisely and accurately quantified in nanoparticles by separating it on Hyperclone BDS C18 using 80-20% v/v mixture of potassium phosphate solution containing 0.1% v/v triethylamine and acetonitrile. The effect of flow rate, pH, acetonitrile content and column temperature was assessed on method responses. The current method was linear in the range of 0.1-20 µg/mL with limit of detection (LOD) and limit of quantification (LOQ) of 29 and 89 ng/mL, respectively. The method was precise and accurate in the determination of ASPM with peak area RSD and recovery of <1.0% and 97-101% in bulk drug solution and of <1.0% and 92-104% in nanoformulations, respectively. Analysis of variance indicated the significance (P < 0.0001) of a statistical model in validating the method with respect to change in independent chromatographic factors. The developed method was successfully employed in determining ASPM content in bulk and lipid nanoformulations.

Development and evaluation of sunscreen creams containing morin-encapsulated nanoparticles for enhanced UV radiation protection and antioxidant activity.

The objective of present work was to develop novel sunscreen creams containing polymeric nanoparticles (NPs) of morin. Polymeric NPs containing morin were prepared and optimized. The creams containing morin NPs were also prepared and evaluated. Optimized NPs exhibited particle size of 90.6 nm and zeta potential of -31 mV. The entrapment efficiency of morin, within the polymeric NPs, was found to be low (12.27%). Fourier transformed infrared spectroscopy and differential scanning calorimetry studies revealed no interaction between morin and excipients. Transmission electron microscopy and atomic force microscopy revealed that the NPs were spherical in shape with approximately 100 nm diameter. Optimized NPs showed excellent in vitro free radical scavenging activity. Skin permeation and deposition of morin from its NPs was higher than its plain form. Different sunscreen creams (SC1-SC8) were formulated by incorporating morin NPs along with nano zinc oxide and nano titanium dioxide. SC5 and SC8 creams showed excellent sun protection factor values (≈40). In vitro and in vivo skin permeation studies of sunscreen creams containing morin NPs indicated excellent deposition of morin within the skin. Morin NPs and optimized cream formulations (SC5 and SC8) did not exhibit cytotoxicity in Vero and HaCaT cells. Optimized sunscreen creams showed excellent dermal safety. SC5 and SC8 creams demonstrated exceptional in vivo antioxidant effect (estimation of catalase, superoxide dismutase, and glutathione) in UV radiation-exposed rats. The optimized sunscreen creams confirmed outstanding UV radiation protection as well as antioxidant properties.

Development and validation of RP-HPLC method with ultraviolet detection for estimation of montelukast in rabbit plasma: Application to preclinical pharmacokinetics.

OBJECTIVE: To develop a liquid-liquid extraction based reverse phase liquid chromatography method for estimation of montelukast in rabbit plasma. METHODS: Chromatographic separation was carried out using Phenomenex Luna C18 column (250 mm × 4.6 mm × 5 µm) with mobile phase composed of ammonium acetate buffer (20 Mm), pH 5.5 and acetonitrile in 20:80, v/v ratio. The analyte was monitored with UV detector at 345 nm. The developed method was validated with respect to linearity, accuracy, precision, specificity and stability. RESULTS: The peak area ratio of montelukast (MKS) to that of internal standard was used for the quantification of samples. Calibration curves were linear in the concentration range of 20-2000 ng mL(-1). The LOD and LLOQ of present method were found out to be 10 ng mL(-1) and 20 ng mL(-1) respectively. The intra-day and inter-day %CV values for MKS were below 6.06% and 8.43%. Intra-day and inter-day accuracies were within 95.81% and 110.90%, respectively. Extraction recoveries of drug from rabbit plasma were >66.47%. CONCLUSION: A simple, alternative, reproducible and sensitive HPLC-UV method was developed for MKS that can be used in preclinical pharmacokinetics.

Supercritical fluid technology: concepts and pharmaceutical applications.

In light of environmental apprehension, supercritical fluid technology (SFT) exhibits excellent opportunities to accomplish key objectives in the drug delivery sector. Supercritical fluid extraction using carbon dioxide (CO(2)) has been recognized as a green technology. It is a clean and versatile solvent with gas-like diffusivity and liquid-like density in the supercritical phase, which has provided an excellent alternative to the use of chemical solvents. The present commentary provides an overview of different techniques using supercritical fluids and their future opportunity for the drug delivery industry. Some of the emerging applications of SFT in pharmaceuticals, such as particle design, drug solubilization, inclusion complex, polymer impregnation, polymorphism, drug extraction process, and analysis, are also covered in this review. The data collection methods are based on the recent literature related to drug delivery systems using SFT platforms. SFT has become a much more versatile and environmentally attractive technology that can handle a variety of complicated problems in pharmaceuticals. This cutting-edge technology is growing predominantly to surrogate conventional unit operations in relevance to the pharmaceutical production process. LAY ABSTRACT: Supercritical fluid technology has recently drawn attention in the field of pharmaceuticals. It is a distinct conception that utilizes the solvent properties of supercritical fluids above their critical temperature and pressure, where they exhibit both liquid-like and gas-like properties, which can enable many pharmaceutical applications. For example, the liquid-like properties provide benefits in extraction processes of organic solvents or impurities, drug solubilization, and polymer plasticization, and the gas-like features facilitate mass transfer processes. It has become a much more versatile and environmentally attractive technology that can handle a variety of complicated problems in pharmaceuticals. This review is focused on different techniques that use supercritical fluids and their opportunities for the pharmaceutical sector.

Glutaraldehyde cross-linked chitosan microspheres for controlled delivery of zidovudine.

Zidovudine-Chitosan microspheres were prepared by a suspension cross-linking method. The chitosan was dissolved in 2% acetic acid solution and this solution was dispersed in the light liquid paraffin. Span-80 was used as an emulsifier and glutaraldehyde as cross-linking agent. The prepared microspheres were slight yellow, free flowing and characterized by drug loading, infrared spectroscopy (IR), differential scanning colorimetry (DSC) and scanning electron microscopy (SEM). The in-vitro release studies are performed in pH 7.4 buffer solution. Microspheres produced are spherical and have smooth surfaces, with sizes ranging between 60-210 µm, as evidenced by SEM and particle size analysis. The drug loaded microspheres showed up to 60% of entrapment and release was extended up to 18-24 h. Among all the systems studied, the 35% Glutaraldehyde crosslinked, microspheres with 1 : 6 drug/chitosan ratio showed 75% release at 12 h. The infrared spectra and DSC thermograms showed stable character of zidovudine in the drug loaded microspheres and revealed the absence of drug-polymer interactions. Data obtained from in vitro release were fitted to various kinetic models and high correlation was obtained in the Higuchi model. The drug release was found to be diffusion controlled.

A study of rivastigmine liposomes for delivery into the brain through intranasal route.

The present study is mainly aimed at delivering a drug into the brain via the intranasal route using a liposomal formulation. For this purpose, rivastigmine, which is used in the management of Alzheimer's disease, was selected as a model drug. Conventional liposomes were formulated by the lipid layer hydration method using cholesterol and soya lecithin as lipid components. The concentration of rivastigmine in brain and plasma after intranasal liposomes, free drug and per oral administration was studied in rat models. A significantly higher level of drug was found in the brain with intranasal liposomes of rivastigmine compared to the intranasal free drug and the oral route. Intranasal liposomes had a longer half-life in the brain than intranasally or orally administered free drug. Delivering rivastigmine liposomes through the intranasal route for the treatment of Alzheimer's disease might be a new approach to the management of this condition.

Preparation and, in vitro, preclinical and clinical studies of aceclofenac spherical agglomerates.

Aceclofenac agglomerates were prepared by spherical crystallization technique using a three solvent system comprising acetone: dichloromethane (DCM): water (bridging liquid, good solvent and bad solvent, respectively). Hydroxypropyl methylcellulose-50cps (HPMC) in different concentrations was used as hydrophilic polymer. The effect of speed of rotation and amount of bridging liquid on spherical agglomeration were studied. The agglomerates were subjected to various physicochemical evaluations such as practical yield, drug content, particle size, loss on drying, porosity, IR spectroscopy, differential scanning calorimetry, X-ray diffraction studies, relative crystallinity, scanning electron microscopy, micromeritic properties, solubility and dissolution studies. The agglomerates showed improved micromeritic properties as well as dissolution behaviour in comparison to conventional drug crystals. The optimized agglomerates (F-9) showed good sphericity as well as high drug release, and hence they were compressed into tablets by direct compression. The tablets were found within the limits with respect to various physicochemical parameters. The dissolution rate of prepared tablets was better than that of marketed tablet and pure drug. The optimized agglomerates and tablet formulations were found to be stable for 6 months under accelerated conditions. The in vivo studies (preclinical pharmacokinetics, pharmacodynamics and toxicity studies, and clinical pharmacokinetics) of optimized agglomerates were carried out. The results of preclinical studies revealed that the agglomerates provided improved pharmacodynamic and pharmacokinetic profiles of drug besides being nontoxic. The results of pharmacokinetic studies of optimized tablet in human subjects indicated improved pharmacokinetic parameters of drug in comparison with that of marketed tablet.

Chitosan and enteric polymer based once daily sustained release tablets of aceclofenac: in vitro and in vivo studies.

The purpose of this study was to develop a once daily sustained release tablet of aceclofenac using chitosan and an enteric coating polymer (hydroxypropyl methylcellulose phthalate or cellulose acetate phthalate). Overall sustained release for 24 h was achieved by preparing a double-layer tablet in which the immediate release layer was formulated for a prompt release of the drug and the sustained release layer was designed to achieve a prolonged release of drug. The preformulation studies like IR spectroscopic and differential scanning calorimetry showed the absence of drug-excipient interactions. The tablets were found within the permissible limits for various physicochemical parameters. Scanning electron microscopy was used to visualize the surface morphology of the tablets and to confirm drug release mechanisms. Good equivalence in the drug release profile was observed when drug release pattern of the tablet containing chitosan and hydroxypropyl methylcellulose phthalate (M-7) was compared with that of marketed tablet. The optimized tablets were stable at accelerated storage conditions for 6 months with respect to drug content and physical appearance. The results of pharmacokinetic studies in human volunteers showed that the optimized tablet (M-7) exhibited no difference in the in vivo drug release in comparison with marketed tablet. No significant difference between the values of pharmacokinetic parameters of M-7 and marketed tablets was observed (p > 0.05; 95% confidence intervals). However the clinical studies in large scale and, long term and extensive stability studies at different conditions are required to confirm these results.