Injectable nimodipine-loaded nanoliposomes: Preparation, lyophilization and characteristics

Octa-Arginine-Conjugated Liposomal Nimodipine Incorporated in a Temperature-Responsive Gel for Nasoencephalic Delivery

Nimodipine is the primary clinical drug used to treat cerebral vasospasm following subarachnoid hemorrhage. Currently, tablets have low bioavailability when taken orally, and injections contain ethanol. Therefore, we investigated a new method of nimodipine administration, namely, nasoencephalic administration. Nasal administration of nimodipine was carried out by attaching the cell-penetrating peptide octa-arginine (R8) to liposomes of nimodipine and incorporating it into a temperature-sensitive in situ gel. The prepared liposomes and gels underwent separate evaluations for in vitro characterization. In vitro release exhibited a significant slow-release effect. In vitro toad maxillary cilia model, RPMI 2650 cytotoxicity, and in vivo SD rat pathological histotoxicity experiments showed that all the dosage from the groups had no significant toxicity to toad maxillary cilia, RPMI 2650 cells, and SD rat tissues and organs, and the cilia continued to oscillate up to 694 ± 10.15 min, with the survival rate of the cells being above 85%. A transwell nasal mucosa cell model and an isolated porcine nasal mucosa model were established, and the results showed that the osmolality of the R8-modified nimodipine liposomal gel to nasal mucosal cells and isolated porcine nasal mucosa was 30.41 ± 2.14 and 65.9 ± 7.34 μg/mL, respectively, which was significantly higher than that of the NM-Solution and PEGylated nimodipine liposome gel groups. Animal fluorescence imaging studies revealed that the R8-modified nimodipine liposomal gel displayed increased brain fluorescence intensity compared to the normal liposomal gel. Pharmacokinetic results showed that after transnasal administration, the AUC(0-∞) of the R8-modified nimodipine liposomal gel was 11.662 ± 1.97 μg·mL-1, which was significantly higher than that of the plain nimodipine liposomal gel (5.499 ± 2.89 μg·mL-1). Brain-targeting experiments showed that the brain-targeting efficiencies of the PEGylated nimodipine liposome gel and R8-modified PEGylated nimodipine liposome gels were 20.44 and 33.45, respectively, suggesting that R8/PEG/Lip-NM-TSG significantly increased the brain-targeting of the drug.

Study on the Nasal Drug Delivery System of NMD Liposomes In Situ Thermosensitive Gel

Nimodipine (NMD) is a 1,4-dihydropyridine calcium antagonist that is effective in the prevention and treatment of cerebral arterial vasospasm and cerebral ischemic injury caused by subarachnoid hemorrhage. Since the drug itself is highly insoluble in water and has low oral bioavailability, while injectable formulations may cause pain and inflammation, the blood-brain barrier (BBB) prevents the effective delivery of therapeutic agents to the brain tissue. Therefore, in the present study, NMD liposomes were prepared by ethanol injection and innovatively lyophilised and loaded into temperature-sensitive in situ gels for intranasal administration as sprays to deliver drugs to brain tissues bypassing the blood-brain barrier. The optimal gel formulation was obtained by screening in which liposomes were divided into lecithin, cholesterol, and NMD in the ratio of 40:10: 1; Pluronic P407, Pluronic P188, Tween 80, polyvinyl ketone and ethyl nipagin in the ratio of (180:20:3:1:1); Pluronic P407, Pluronic P188, Tween 80, polyvinyl ketone, and ethyl nipagin in the ratio of (180:20:3:1:1). The prepared flow gel can form a solidified gel after a temperature of 31.07-32.07°C and a time of 58.51-59.89 s. Meanwhile, the NMD liposome gel formulation achieved sustained release over 56 h. The pharmacokinetic results of the developed NMD liposomal temperature-sensitive in situ gel and NMD temperature-sensitive in situ gel showed that liposomal nasal mucosal in situ gel is a more effective brain-targeted drug delivery system for NMD.

Herbal Extracts Encapsulated Nanoliposomes as Potential Glucose-lowering Agents: An in Vitro and in Vivo Approach Using Three Herbal Extracts

Encapsulation of polyphenol-rich herbal extracts into nanoliposomes is a promising strategy for the development of novel therapeutic agents against type 2 diabetes mellitus. An attempt was made to encapsulate aqueous, ethanol, and aqueous ethanol (70% v/v) extracts of Senna auriculata (L.) Roxb., Murraya koenigii (L.) Spreng,. and Coccinia grandis (L.) Voigt into nanoliposomes and to screen acute bioactivities in vitro and in vivo. A wide spectrum of bioactivity was observed of which aqueous extracts encapsulated nanoliposomes of all three plants showed high bioactivity in terms of in vivo glucose-lowering activity in high-fat diet-fed streptozotocin induced Wistar rats, compared to respective free extracts. The particle size, polydispersity index, and zeta potential of the aforementioned nanoliposomes ranged from 179-494 nm, 0.362-0.483, and (-22) to (-17) mV, respectively. The atomic force microscopy (AFM) imaging reflected that the nanoparticles have desired morphological characteristics and Fourier-transform infrared (FTIR) spectroscopy analysis revealed successful encapsulation of plant extracts into nanoparticles. However, only the S. auriculata aqueous extract encapsulated nanoliposome, despite the slow release (9% by 30 hours), showed significant (p < 0.05) in vitro α-glucosidase inhibitory activity and in vivo glucose-lowering activity compared to free extract, proving worthy for future investigations.

Preclinical evaluations of Norcantharidin liposome and emulsion hybrid delivery system with improved encapsulation efficiency and enhanced antitumor activity

BACKGROUND

Norcantharidin (NCTD) has a certain degree of hydrophilicity and poor lipophilicity, and has some side-effects, including short t_1/2, vascular irritation, cardiotoxicity and nephrotoxicity, which bring difficulties for formulation research. In this study, we aim to develop a novel nanocarrier to improve encapsulation efficiency, increase sterilization stability and enhance antitumor activity.

METHODS

Phospholipid complexes methods were used for increasing the lipophilicity of norcantharidin (NCTD), then NCTD phospholipid complexes were not only loaded in the oil phase and oil-water interface surface, but also encapsulated in phospholipid bilayers to obtain NCTD liposome-emulsion hybrid (NLEH) delivery system. The in vitro cytotoxicity and apoptosis, in vivo tissue distribution, tumor penetration, heterotopic and orthotopic antitumor studies were conducted to evaluate therapeutic effect.

RESULTS

NLEH exhibited an improved encapsulation efficiency (89.3%) and a better sterilization stability, compared to NCTD liposomes and NCTD emulsions. NLEH can achieve a better antitumor activity by promoting absorption (1.93-fold), prolonging blood circulation (2.08-fold), enhancing tumor-targeting accumulation (1.19 times), improving tumor penetration, and increasing antitumor immunity.

CONCLUSIONS

The liposome-emulsion hybrid (LEH) delivery system was potential carrier for NCTD delivery, and LEH could open opportunities for delivery of poorly soluble anticancer drugs, especially drugs that are more hydrophilicity than lipophilicity.

Liposomal remdesivir inhalation solution for targeted lung delivery as a novel therapeutic approach for COVID-19

Strong infectivity enables coronavirus disease 2019 (COVID-19) to rage throughout the world. Moreover, the lack of drugs with definite therapeutic effects further aggravates the spread of the pandemic. Remdesivir is one of the most promising anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) drugs. However, the limited clinical effects make its therapeutic effect controversial, which may result from the poor accumulation and activation of remdesivir in the lung. Therefore, we developed lyophilized remdesivir liposomes (Rdv-lips) which can be reconstituted as liposomal aerosol for pulmonary delivery to improve the in vivo behavior of existing remdesivir cyclodextrin conclusion compound (Rdv-cyc) injections. Liposome encapsulation endowed remdesivir with much higher solubility and better biocompatibility. The in vitro liposomal aerosol characterization demonstrated that Rdv-lips possessed a mass median aerodynamic diameter of 4.118 µm and fine particle fraction (<5 µm) higher than 50%, indicating good pulmonary delivery properties. Compared to the Rdv-cyc intravenous injection group, the Rdv-lips inhalation group displayed a nearly 100-fold increase in the remdesivir-active metabolite nucleotide triphosphate (NTP) concentration and better NTP accumulation in the lung than the Rdv-cyc inhalation group. A faster transition from remdesivir to NTP of Rdv-lips (inhalation) could also be observed due to better cell uptake. Compared to other preparations, the superiority of Rdv-lips was further evidenced by the results of an in vivo safety study, with little possibility of inducing inflammation. In conclusion, Rdv-lips for pulmonary delivery will be a potent formulation to improve the in vivo behavior of remdesivir and exert better therapeutic effects in COVID-19 treatment.

Development and Optimization of Itraconazole-Loaded Solid Lipid Nanoparticles for Topical Administration Using High Shear Homogenization Process by Design of Experiments: In Vitro, Ex Vivo and In Vivo Evaluation

The aim of present study was to develop topical itraconazole (ITZ)-loaded solid lipid nanoparticles for treatment of superficial fungal infections. Formulations were prepared using high shear homogenization process, and optimized by employing a two-step design of experiments (DoE) approach. It comprised a Taguchi experimental design for screening of 'vital few' factors, and a central composite experimental design for optimization. Overlay of the response surface maps for percent drug entrapment (PDE), particle size, ITZ skin retention and permeation was performed to obtain the optimized ITZ-loaded SLNs (OPT-SLNs) suspension. The optimized ITZ-loaded SLNs (OPT-SLNs) showed mean particle size of (262.92 ± 8.56 nm) and zeta potential value of 22.36 mV. Excellent drug entrapment (94.21 ± 3.35%) and skin retention of ITZ (43.03 ± 1.86 μg/cm²) was achieved by OPT-SLNs. The hydrogel formulation of OPT-SLNs exhibited good gel consistency and spreadability characteristics. Pharmacodynamic and skin sensitivity studies in standardized rodent models revealed that OPT-SLNs hydrogel was more efficacious than conventional oral and topical antifungal therapies, and also safe for topical administration. Furthermore, the histoptahological evaluation depicted complete recovery of infected rats after 14-day treatment regimen of OPT-SLNs hydrogel. The developed formulation was found to have tremendous potential to enhance ITZ activity through topical administration approach.

Curcumin Exerts Antinociceptive Effects in Cancer-Induced Bone Pain via an Endogenous Opioid Mechanism

Cancer pain is one of the main complications in advanced cancer patients, and its management is still challenging. Therefore, there is an urgent need to develop novel pharmacotherapy for cancer pain. Several natural products have attracted the interest of researchers. In previous studies, curcumin has proved to exhibit antitumor, antiviral, antioxidant, anti-inflammatory, and analgesic effects. However, the analgesic mechanism of curcumin has not been elucidated. Thus, in this study, we aimed to elucidate the antinociceptive potency and analgesic mechanism of curcumin in cancer-induced bone pain. Our results showed that consecutive curcumin treatment (30, 60, 120 mg/kg, i.p., twice daily for 11 days) produced significant analgesic activity, but had no effect on the progress of the bone cancer pain. Notably, pretreatment with naloxone, a non-selective opioid receptor antagonist, markedly reversed the antinociceptive effect induced by curcumin. Moreover, in primary cultured rat dorsal root ganglion (DRG) neurons, curcumin significantly up-regulated the expression of proopiomelanocortin (Pomc) and promoted the release of β-endorphin and enkephalin. Furthermore, pretreatment with the antiserum of β-endorphin or enkephalin markedly attenuated curcumin-induced analgesia in cancer-induced bone pain. Our present study, for the first time, showed that curcumin attenuates cancer-induced bone pain. The results also suggested that stimulation of expression of DRG neurons β-endorphin and enkephalin mediates the antinociceptive effect of curcumin in pain hypersensitivity conditions.

A Novel Drug Delivery Carrier Comprised of Nimodipine Drug Solution and a Nanoemulsion: Preparation, Characterization, in vitro, and in vivo Studies

Purpose

Nimodipine (NIMO) is used clinically to treat ischemic damage resulting from subarachnoid hemorrhage. However, clinical application of NIMO is limited by poor aqueous solubility and low safety. To overcome these limitations, a novel two-vial NIMO-loaded nanoemulsion (NIMO-TNE) was designed in this study.

Methods

NIMO-TNE was prepared by mixing a nimodipine-polyethylene glycol 400 (NIMO-PEG400) solution and a commercially available 20% injectable blank nanoemulsion (BNE). Drug distribution in NIMO-TNE, physical stability, and dilution stability were evaluated in vitro, and pharmacokinetics and pharmacodynamics were evaluated in vivo. Safety was assessed using the hemolysis test and the intravenous irritation test, and acute toxicity of NIMO-TNE was compared with that of commercial Nimotop injection.

Results

Drug loading (DL) in NIMO-TNE was enhanced 5-fold compared with that in Nimotop injection. The mean particle size of NIMO-TNE was 241.53 ± 1.48 nm. NIMO-TNE and NIMO-TNE diluted in 5% glucose injection and 0.9% sodium chloride was stable for a sufficient duration to allow for clinical use. In addition, NIMO-TNE exhibited a similar pharmacokinetic profile and similar brain ischemia reduction in a rat middle cerebral artery occlusion (MCAO) model compared to Nimotop injection. Furthermore, NIMO-TNE did not induce hemolysis at 37°C, and NIMO-TNE induced less intravenous irritation than Nimotop injection. Moreover, NIMO-TNE could be injected at a 23-fold higher dose than the LD₅₀ of Nimotop injection with no obvious toxicity or side effects.

Conclusion

NIMO-TNE is a promising formulation suitable for intravenous injection, is easy to prepare, and exhibits excellent safety.

Liver Targeting Albumin-Coated Silybin-Phospholipid Particles Prepared by Nab™ Technology for Improving Treatment Effect of Acute Liver Damage in Intravenous Administration

In this study, a novel human serum albumin nanoparticle loading silybin-phospholipid complex (SLNPs) was developed for liver targeting after intravenous administration. The preparation of the drug delivery system consisted of two steps; initially, a silybin-phospholipid complex (SLC) was produced to improve the lipophilicity of SLB to then achieve enhanced encapsulation of SLB in albumin nanoparticles. FT-IR and XRD analysis confirmed the successful formation of SLC. The complex ratio of SLC in the first step was 99.6%. The encapsulation efficiency and drug loading of SLNPs in the second step were 96.2% and 5.6%, respectively. SLNPs were spherical and well-dispersed, with a zeta potential of approximately - 10 mV, and a mean particle size around 200 nm. An in vivo tissue distribution experiment and a pharmacodynamic experiment showed that, compared with SLB solution, SLNPs had an improved SLB accumulation in the liver. The hepatoprotective effect of SLNPs on CCl₄-induced acute liver damage was evaluated. CCl₄-damaged mice showed an increased enzymatic activity of ALT and AST; however, enzyme levels returned to near-normal levels in high-dose SLNP-treated mice. As SLNPs combine the enhanced oil solubility of SLC and the passive targeting of albumin nanoparticles, they possess great potential for the treatment of acute liver damage.

In Vitro Release Test of Nano-drug Delivery Systems Based on Analytical and Technological Perspectives

Background:

Nanotech products are gaining more attention depending on their advantages for improving drug solubility, maintenance of drug targeting, and attenuation of drug toxicity. In vitro release test is the critical physical parameter to determine the pharmaceutical quality of the product, to monitor formulation design and batch-to-batch variation.

Methods:

Spectrophotometric and chromatographic methods are mostly used in quantification studies from in vitro release test of nano-drug delivery systems. These techniques have advantages and disadvantages with respect to each other considering dynamic range, selectivity, automation, compatibility with in vitro release media and cost per sample.

Results:

It is very important to determine the correct kinetic profile of active pharmaceutical substances. At this point, the analytical method used for in vitro release tests has become a very critical parameter to correctly assess the profiles. In this review, we provided an overview of analytical methods applied to the in vitro release assay of various nanopharmaceuticals.

Conclusion:

This review presents practical direction on analytical method selection for in vitro release test on nanopharmaceuticals. Moreover, precautions on analytical method selection, optimization and validation were discussed.

Cisplatin-loaded polymeric complex micelles with a modulated drug/copolymer ratio for improved in vivo performance

This study aimed to evaluate the performance of cisplatin-loaded polymeric micelles (CDDP-PMs) with different drug/copolymer ratios of 1:1, 1:3 and 1:6 (w/w) prepared by coordinated complexation and self-assembly method. The mass ratio influenced the self-assembly behaviors and the complex degree, where both single- and double- complexation existed in CDDP-PMs. With the increase of CDDP/copolymer ratio, the particle size and drug loading increased, while encapsulation efficiency decreased. The PEG density of CDDP-PM_1-6, CDDP-PM_1-3 and CDDP-PM_1-1 were 0.20, 0.61 and 0.38 PEG/nm², respectively. CDDP-PM_1-3 and CDDP-PM_1-6 had similar sustained release behavior, while CDDP-PM_1-1 showed burst release. Pharmacokinetics showed the AUC of CDDP-PM_1-6, CDDP-PM_1-3 and CDDP-PM_1-1 was 27.2, 76.6 and 13.0 fold higher than CDDP solution. Tissue distribution presented the platinum concentration of CDDP-PM_1-6, CDDP-PM_1-3 and CDDP-PM_1-1 was 1.03, 0.80 and 0.48 times of CDDP solution in kidney at 10 min, and 17.61, 28.63 and 16.6 times in tumor at 48 h respectively, indicating CDDP-PMs significantly reduced nephrotoxicity and increased tumor-targeting accumulation. In vivo antitumor test showed that CDDP-PMs exhibited an improved antitumor efficacy and lower systemic toxicity compared with CDDP solution. From CDDP-PM_1-1 to CDDP-PM_1-6, the toxicity decreased with the increase of copolymer ratio, but the tumor inhibition rate also decreased. CDDP-PM_1-3 had relative high therapeutic effect and low toxicity compared with other formulations. CDDP-PM_1-3 could improve the antitumor efficacy by increasing the dose within systemic tolerability, but CDDP solution cannot. This work provides an effective strategy by modulating drug/copolymer ratio of CDDP-PMs to balance the antitumor efficacy and toxicity for better payoff. STATEMENT OF SIGNIFICANCE: Cancer chemotherapy always exists a contradiction between antitumor efficacy and toxicity. Higher efficacy against tumor often associated with larger toxicity for normal tissues. This work provides an important strategy by modulating the drug/copolymer ratios to balance the antitumor efficacy and toxicity to obtain better payoff. The cisplatin-loaded polymeric micelles (CDDP-PMs) based on the complexation between CDDP and copolymer with different mass ratios make differences in vitro and in vivo because of the single- or double-complexation degree. Most importantly, we found the balance at CDDP/copolymer ratio of 1:3, which has relative high therapeutic effect and low toxicity compared with other formulations. CDDP-PM_1-3 could improve the antitumor efficacy by increasing the dose within systemic tolerability, but CDDP solution cannot.

In Situ Generated Medical Devices

Medical devices play a major role in all areas of modern medicine, largely contributing to the success of clinical procedures and to the health of patients worldwide. They span from simple commodity products such as gauzes and catheters, to highly advanced implants, e.g., heart valves and vascular grafts. In situ generated devices are an important family of devices that are formed at their site of clinical function that have distinct advantages. Among them, since they are formed within the body, they only require minimally invasive procedures, avoiding the pain and risks associated with open surgery. These devices also display enhanced conformability to local tissues and can reach sites that otherwise are inaccessible. This review aims at shedding light on the unique features of in situ generated devices and to underscore leading trends in the field, as they are reflected by key developments recently in the field over the last several years. Since the uniqueness of these devices stems from their in situ generation, the way they are formed is crucial. It is because of this fact that in this review, the medical devices are classified depending on whether their in situ generation entails chemical or physical phenomena.

Preparation and characterization of nimodipine-loaded nanostructured lipid systems for enhanced solubility and bioavailability

Purpose

Nimodipine (NMP) is a clinical dihydropyridine calcium antagonist. However, the clinical application of NMP is limited by poor water solubility and low oral bioavailability. To overcome these drawbacks, this study designed optimal NMP-incorporated nanostructured lipid carriers (NLCs).

Methods

High-pressure homogenization was successfully applied to prepare NMP-NLC, and the nanoparticle morphology was observed by a transmission electron microscope. The existence form of NMP in NMP-NLC was investigated by powder X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopy, respectively. The in vitro release study was performed by the dialysis method, and in vivo studies including in situ intestinal perfusion and pharmacokinetics were investigated in rats with NMP detected by high-performance liquid chromatography.

Results

The obtained NMP-NLC shared a spherical shape of ~70 nm with a smooth surface and high encapsulation efficiency of 86.8%±2.1%. Spectroscopy indicated that the drug was in an amorphous state. The NMP-NLC exhibited a sustained release and diverse release profiles under different release medium, which mimicked the physiological environment. Moreover, an in situ intestinal perfusion experiment revealed that NMP-NLC could be mainly absorbed by the small intestine. Remarkable improvements in C_max and AUC_0-∞ from NMP-NLC were obtained from pharmacokinetic experiments, and the relative bioavailability of NMP-loaded nanostructured lipid systems was 160.96% relative to NMP suspensions.

Conclusion

Collectively, the NLCs significantly enhanced the oral bioavailability of NMP and might provide a promising nanoplatform for hydrophobic drug delivery.

Preservation of exosomes at room temperature using lyophilization

The application of exosomes as a therapeutic reagent or drug delivery vehicle can be expanded by developing a method to preserve exosomes. Although exosomes are generally stored at -80 °C, this temperature is not suitable for their handling or transportation and, therefore, other storage methods are desirable. Lyophilization is a promising storage method that can be used to preserve various substances at room temperature. In this study, we sought to develop a room temperature preservation method for exosomes using lyophilization and compared the properties of the lyophilized exosomes with ones stored at -80 °C. Lyophilization without cryoprotectant resulted in the aggregation of B16BL6 melanoma-derived exosomes, while the addition of trehalose, a cryoprotectant, prevented aggregation during lyophilization. PAGE analysis revealed that the proteins and RNA of exosomes were protected following lyophilization in the presence of trehalose. Lyophilization had little effect on the pharmacokinetics of Gaussia luciferase (gLuc)-labeled exosomes after an intravenous injection into mice. Moreover, it was found that lyophilized exosomes retained the activity of loaded gLuc and immunostimulatory CpG DNA for approximately 4 weeks even when stored at 25 °C. In conclusion, lyophilization with trehalose is an effective method for the storage of exosomes for various applications.

Preparation, characterization, and pharmacokinetics of liposomal docetaxel for oral administration

A docetaxel (DTX) liposomal formulation composed of egg phosphatidylcholine, sodium deoxycholate, and stearylamine was developed. Eudragit (0.5%) was coated to deliver the drug to the region between the distal small intestine and the colon. Lyophilized trehalose and mannitol were used as cryoprotectants because they preserve the particle integrity and good appearance. In vitro release studies showed that the amount of drug released from the coated liposomes was low in solution 1, which simulated the pH condition of the stomach. Especially during the average gastric emptying time, the amount of drug released decreased when Eudragit was added. The plasma DTX concentration was evaluated in pharmacokinetic studies. The plasma drug concentration after intravenous (i.v.) administration decreased rapidly within 120 min. Free DTX formulated using Tween 80 and the lyophilized Eudragit-coated liposomal formulation were compared after oral administration. The oral liposomal formulation had a longer half-life (t_1/2) and three-fold higher oral bioavailability. Thus, lyophilized Eudragit-coated liposomal DTX could be a promising therapy for various solid tumors to improve patient convenience and quality of life.

Sustained Release of Green Tea Polyphenols from Liposomal Nanoparticles; Release Kinetics and Mathematical Modelling

Background: Green tea polyphenols (GTP) are known to have several health benefits. In spite of these benefits, its application as a therapeutic agent is limited due to some of its limitations such as stability, bioavailability, and biotransformation. To overcome these limitations, liposomal nanoparticles have been used as a carrier of the GTP. Objective: Encapsulation of GTP to the liposomal nanoparticles in order to achieve a sustained release of the GTP and to determine the drug release kinetics and the mechanism of the release. Materials and Methods: GTP encapsulated liposomal nanoparticles were prepared using phosphatidyl choline and cholesterol. The synthesized particles were characterized for their particle size and morphology. In vitro release studies were carried out, followed by drug release kinetics, and determining the mechanism of release. In vitro, antioxidant assay was determined following 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Results: Atomic force microscope (AFM) and high resolution scanning electron microscope (HR SEM) images showed spherical particles of the size of 64.5 and 252 nm. An encapsulation efficiency as high as 77.7% was observed with GTP concentration of 5 mg.mL^-1. In vitro release studies showed that the loading concentrations of GTP were independent to the cumulative percentage of the drug release. GTP release by varying the pH and temperature showed a direct correlation between the release parameter and the percentage of drug release. The higher the pH and temperature, the higher was the percentage of the drug release. The release data showed a good correlation with Zero order kinetics and the mechanism of the release being anomalous mode. Radical scavenging activity of the released GTP showed a potent scavenging activity. Conclusion: GTP encapsulated liposomal nanoparticles could be used as a delivery vehicle for achieving a sustained release.

A quality by design approach for the development of lyophilized liposomes with simvastatin

Lyophilization is used to ensure an increased shelf-life of liposomes, by preserving them in dry state, more stable than the aqueous dispersions. When stored as aqueous systems, the encapsulated drugs are released and the liposomes might aggregate or fuse. The aim of this study was to develop and optimize a lyophilized formulation of simvastatin (SIM) loaded into long circulating liposomes using the Quality by Design (QbD) approach. Pharmaceutical development by QbD aims to identify characteristics that are critical for the final product quality, and to establish how the critical process parameters can be varied to consistently produce a product with the desired characteristics. In the case of lyophilized liposomes, the choice of the optimum formulation and technological parameters has to be done, in order to protect the integrity of the liposomal membrane during lyophilization. Thus, the influence of several risk factors (3 formulation factors: PEG proportion, cholesterol concentration, the cryoprotectant to phospholipids molar ratio, and 2 process parameters: the number of extrusions through 100 nm polycarbonate membranes and the freezing conditions prior lyophilization) over the critical quality attributes (CQAs) of lyophilized long circulating liposomes with simvastatin (lyo-LCL-SIM), i.e. the size, the encapsulated SIM concentration, the encapsulated SIM retention, the Tm change and the residual moisture content, was investigated within the current study using the design of experiments tool of QbD. Moreover, the design space for lyo-LCL-SIM was determined, in which the established quality requirements of the product are met, provided that the risk factors vary within the established limits.

Design and Solidification of Fast-Releasing Clofazimine Nanoparticles for Treatment of Cryptosporidiosis

Clofazimine, a lipophilic (log P = 7.66) riminophenazine antibiotic approved by the US Food and Drug Administration (FDA) with a good safety record, was recently identified as a lead hit for cryptosporidiosis through a high-throughput phenotypic screen. Cryptosporidiosis requires fast-acting treatment as it leads to severe symptoms which, if untreated, result in morbidity for infants and small children. Consequently, a fast-releasing oral formulation of clofazimine in a water-dispersible form for pediatric administration is highly desirable. In this work, clofazimine nanoparticles were prepared with three surface stabilizers, hypromellose acetate succinate (HPMCAS), lecithin, and zein, using the flash nanoprecipitation (FNP) process. Drug encapsulation efficiencies of over 92% were achieved. Lyophilization and spray-drying were applied and optimized to produce redispersible nanoparticle powders. The release kinetics of these clofazimine nanoparticle powders in biorelevant media were measured and compared with those of crystalline clofazimine and the currently marketed formulation Lamprene. Remarkably improved dissolution rates and clofazimine supersaturation levels up to 90 times equilibrium solubility were observed with all clofazimine nanoparticles tested. Differential scanning calorimetry indicated a reduction of crystallinity of clofazimine in nanoparticles. These results strongly suggest that the new clofazimine nanoparticles prepared with affordable materials in this low-cost nanoparticle formulation process can be used as viable cryptosporidiosis therapeutics.

Nanoencapsulation strategies for the delivery of novel bifunctional antioxidant/σ1 selective ligands

Nowadays sigma-1 receptors are considered as new therapeutic objectives for central nervous system neurodegenerative diseases. Among different molecules, alpha lipoic acid has been identified as a natural potent antioxidant drug, whose therapeutic efficacy is limited by its many drawbacks, such as fast metabolism, poor bioavailability and high physico-chemical instability. Alfa-lipoic acid derivatives have been recently developed demonstrating their neuroprotective activity and effectiveness in different types of oxidative stress. In this work, two derivatives containing an amide or an ester functional group with different lipophilicity, were selected for their important affinity for sigma-1 receptors. Herein, in order to improve the in vitro stability and antioxidant effectiveness of alpha-lipoic acid derivatives, we focused our efforts in the nanoencapsulation strategies. Aqueous-core nanocapsules for the delivery of the hydrophilic compound and nanostructured lipid carrier for the lipophilic derivative, were properly designed and prepared using a direct or inverse eco-friendly organic solvent-free procedure. All nanosystems were characterized in terms of mean size, polydispersity, stability, morphology, encapsulation efficiency and in vitro release profiles. In order to evaluate the nanocarriers biocompatibility and antioxidant effectiveness, in vitro biological studies (cell viability, total antioxidant capacity and total oxidative status) were developed on primary human whole blood cell cultures, on both unloaded and derivatives-loaded nanodevices.

A novel biocompatible antibacterial product: Nanoliposomes loaded with poly(hexamethylene biguanide chloride)

In this study, nanoliposome-loaded poly(hexamethylene biguanide) is introduced as a novel biocompatible antibacterial product with higher activity than microliposomes. Soy lecithin as a clean product was used to prepare various nanoliposomes through sonication, high-pressure homogenizer, and normal homogenizer and also microliposomes through two methods of lipid film hydration and incubation methods. The nanoliposomes were formed under sonication with the size of 50 nm. The prepared liposomes were then loaded with poly(hexamethylene biguanide chloride) and the inclusion percentage was measured. The release profile of liposomes in buffer showed a release of 92% for poly(hexamethylene biguanide) during 24 h. The loaded liposomes were characterized with particle size analyzer, nuclear magnetic resonance, X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. The antibacterial properties of different micro and nanoliposomes were investigated against a Gram-negative ( Escherichia coli) and a Gram-positive ( Staphylococcus aureus) bacteria. The poly(hexamethylene biguanide)–loaded nanoliposomes indicated higher antibacterial activities than microliposomes. Nanoliposomes have the potential to entrap lower poly(hexamethylene biguanide) dosages while retaining optimum therapeutic efficacy in the target site having lower cytotoxicity with lower side effects. The cytotoxicity of poly(hexamethylene biguanide) entrapped in liposomes was studied in human dermal fibroblasts and compared with free poly(hexamethylene biguanide) and blank liposomes. The maximum cytotoxicity was observed for free poly(hexamethylene biguanide) that is substantially decreased through loading within liposomes structure. Overall, the encapsulation of poly(hexamethylene biguanide) in liposomes improved the biocompatibility and safety of the product introducing a useful biocompatible antibacterial polymer for treatments of infectious diseases.

Preparation and Characterization of Novel Perfluorooctyl Bromide Nanoparticle as Ultrasound Contrast Agent via Layer-by-Layer Self-Assembly for Folate-Receptor-Mediated Tumor Imaging

A folate-polyethylene glycol-chitosan derivative was synthesized and its structure was characterized. An optimal perfluorooctyl bromide nanocore template was obtained via utilizing the ultrasonic emulsification method combining with orthogonal design. The targeted nanoparticles containing targeted shell of folate-polyethylene glycol-chitosan derivative and perfluorooctyl bromide nanocore template of ultrasound imaging were prepared successfully by exploiting layer-by-layer self-assembly as contrast agent for ultrasound. Properties of the novel perfluorooctyl bromide nanoparticle were extensively studied by Dynamic Light Scattering and Transmission Electron Microscopy. The targeted nanoparticle diameter, polydispersity, and zeta potential are around 229.5 nm, 0.205, and 44.7 ± 0.6 mV, respectively. The study revealed that spherical core-shell morphology was preserved. Excellent stability of targeted nanoparticle is evidenced by two weeks of room temperature stability tests. The results of the cell viability assay and the hemolysis test confirmed that the targeted nanoparticle has an excellent biocompatibility for using in cell studies and ultrasound imaging in vivo. Most importantly, in vitro cell experiments demonstrated that an increased amount of targeted nanoparticles was accumulated in hepatocellular carcinoma cell line Bel7402 relative to hepatoma cell line L02. And targeted nanoparticles had also shown better ultrasound imaging abilities in vitro. The data suggest that the novel targeted nanoparticle may be applicable to ultrasonic molecular imaging of folate-receptor overexpressed tumor.

Sensitization of multidrug-resistant malignant cells by liposomes co-encapsulating doxorubicin and chloroquine through autophagic inhibition

Adenosine triphosphate (ATP)-binding cassette (ABC) transporters play a key role in the development of multidrug resistance (MDR) in cancer cells. P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1) are important proteins in this superfamily which are widely expressed on the membranes of multidrug resistance (MDR) cancer cells. Besides, upregulation of cellular autophagic responses is considered a contributing factor for MDR in cancer cells. We designed a liposome system co-encapsulating a chemotherapeutic drug (doxorubicin hydrochloride, DOX) and a typical autophagy inhibitior (chloroquine phosphate, CQ) at a weight ratio of 1:2 and investigated its drug resistance reversal mechanism. MTT assay showed that the IC₅₀ of DOX/CQ co-encapsulated liposome in DOX-resistant human breast cancer cells (MCF7/ADR) was 4.7 ± 0.2 μM, 5.7-fold less than that of free DOX (26.9 ± 1.9  μM), whereas it was 19.5-fold in doxorubicin-resistant human acute myelocytic leukemia cancer cells (HL60/ADR) (DOX/CQ co-encapsulated liposome 1.2 ± 0.1 μM, free DOX 23.4 ± 2.8 μM). The cellular uptake of DOX increased upon addition of free CQ, indicating that CQ may interact with P-gp and MRP1; however, the expressions of P-gp and MRP1 remained unchanged. In contrast, the expression of the autophagy-related protein LC3-II increased remarkably. Therefore, the mechanism of MDR reversal may be closely related to autophagic inhibition. Evaluation of anti-tumor activity was achieved in an MCF-7/ADR multicellular tumor spheroid model and transgenic zebrafish model. DOX/CQ co-encapsulated liposome exerted a better anti-tumor effect in both models than that of liposomal DOX or DOX alone. These findings suggest that encapsulating CQ with DOX in liposomes significantly improves the sensitivity of DOX in DOX-resistant cancer cells.

Influence of type and proportion of lyoprotectants on lyophilized ginsenoside Rg3 liposomes

Objectives

To improve stability and shelf life, lyophilized formulations of 20(R)-Ginsenoside Rg3 liposomes (G-Rg3-Ls) were prepared.

Methods

Glucose, trehalose, sucrose, maltose, lactose, mannitol, inositol, hydroxypropyl-β-cyclodextrin and polyethylene glycol were used as single lyoprotectant and then compared in terms of their ability to protect lyophilized G-Rg3-Ls. Further, a glucose–mannitol complex was used to determine the optimal lyophilized preparation. The analysis of lyophilized liposomes or lyoprotectant was further investigated by scanning electron microscopy, thermogravimetry-differential thermal analysis, X-ray diffractometry and Fourier transform infrared spectroscopy. Cytotoxicity assay was used to assess the cyto-inhibition of freshly prepared and lyophilized liposomes.

Key findings

When the ratio of glucose–mannitol to phospholipids was 4 : 2 : 1 (w/w) the lyophilized G-Rg3-Ls exhibited good appearance, high DRR (86.52% ± 5.02%), small change in particle size (45.83 ± 0.50%) and short rehydration reconstruction time (8.3 ± 1.5 s). All indices were considerably better than those of each single protective agent. Results indicated that when the two lyoprotectants were combined, the stabilizing effect of glucose and shaping effect of mannitol were well maintained. The cyto-inhibition of freshly prepared and lyophilized G-Rg3 liposomes showed that lyophilization did not affect the bioactivity of G-Rg3.

Conclusions

The application of glucose–mannitol composite lyoprotectants can obtain a good G-Rg3 lyophilized preparation.

Liprosomes loading paclitaxel for brain-targeting delivery by intravenous administration: in vitro characterization and in vivo evaluation

In this study, a lipid-protein nanocomplex (liprosome) was evaluated for its potential use for brain-targeting drug delivery. Liprosome was fabricated with the desolvation-ultrasonication method and characterized in terms of particle size, size distribution, zeta potential, morphology, crystal state of the drug, and in vitro release. The in vivo distribution of paclitaxel loading lipid-protein nanocomplex (PTX-liprosome) and Taxol were compared after i.v. administration in mice. The prepared PTX-liprosome has a high entrapment efficiency (>90%), small particle size (approximately 110 nm), and narrow distribution (P.I.<0.2). Transmission electron microscopy (TEM) indicated that liprosome had a spherical multilayer structure. X-ray photoelectron spectroscopy (XPS) showed that the conjugate of PTX and BSA was in the interior of the PTX-liprosome. Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD) demonstrated that the drug existed in a molecular or amorphous state. Fourier transform infrared spectroscopy (FTIR) suggested that the hydrophobic interactions, electrostatic interactions and hydrogen bonds among of the PTX, lipid and protein play an important role during the formation of the PTX-liprosome. The hemolysis test showed a good safety profile for the intravenous administration of liprosome. The result of the in vivo distribution suggested that liprosome increased the drug uptake by the brain tissue and decreased drug accumulation in non-target organs. Therefore, liprosome is a potential drug delivery system for transporting PTX to the brain.

In situ forming nimodipine depot system based on microparticles for the treatment of posthemorrhagic cerebral vasospasm

The present study was conducted to examine the feasibility of nimodipine-loaded PLGA microparticles suspended in Tisseel fibrin sealant as an in situ forming depot system. This device locally placed can be used for the treatment of vasospasm after a subarachnoid hemorrhage. Microparticles were prepared via spray-drying by using the vibration mesh spray technology of Nano Spray Dryer B-90. Spherically shaped microparticles with different loadings and high encapsulation efficiencies of 93.3-97.8% were obtained. Depending on nimodipine loading (10-40%), the particle diameter ranged from 1.9 ± 1.2 μm to 2.4 ± 1.3 μm. Thermal analyses using DSC revealed that nimodipine is dissolved in the PLGA matrix. Also, fluorescent dye loaded microparticles were encapsulated in Tisseel to examine the homogeneity of particles. 3D-pictures of the in situ forming devices displayed uniform particle homogeneity in the sealant matrix. Drug release was examined by fluorescence spectrophotometry which demonstrated a drug release proportional to the square root of time. A prolonged drug release of 19.5h was demonstrated under in vitro conditions. Overall, the nimodipine in situ forming device could be a promising candidate for the local treatment of vasospasm after a subarachnoid hemorrhage.

Development and Validation of a RP-HPLC Method for Determination of Nimodipine in Sustained Release Tablets

A rapid, sensitive, and reproducible reverse phase high performance liquid chromatographic (RP-HPLC) method with UV detector for the determination of nimodipine in sustained release tablets was developed. The method involved using a SinoChoom ODS-BP C18reversed phase column (5 μm, 4.6 mm × 200 mm) and mobile phase consisting of methanol-acetonitrile-water (35 : 38 : 27, v/v). The flow rate is 1.0 mL/min, the UV detector was operated at 237 nm, and the column was maintained at 25°C. The method was validated according to official compendia guidelines. The calibration curve of nimodipine for RP-HPLC method was linear over the range of 10–100 μg/mL. The retention time was found at 7.50 min for nimodipine. The variation for interday and intraday assay was found to be less than 0.72%. The proposed RP-HPLC was proved to be suitable for the determination of nimodipine in sustained release tablets.