Long-lasting Insulin Treatment Via a Single Subcutaneous Administration of Liposomes in Thermoreversible Pluronic® F127 Based Hydrogel.

BACKGROUND: Repeated administrations of insulin injection on daily basis evoke pain and numerous complications with adverse effects on the diabetic patients' life quality. Moreover, wearing insulin pump is also associated with several problems of diabetic ketoacidosis, catheter site infection, contact dermatitis and high cost. METHOD: We have developed an in situ gel system, consisting of insulin-loaded liposomes dispersed within a thermoreversible gel (Pluronic® F127 gel), which increases the duration of insulin action for the treatment of diabetes. Vesicular phospholipid gel technique was used to encapsulate the insulin into liposomes. RESULTS: The resulting liposomal gel formulation had a longer drug-release period in vitro than a free insulin solution or liposomes and Pluronic® F127 gel individually. Furthermore, the addition of liposomes to the Pluronic® F127 gel improved the stability of the encapsulated insulin at a physiological temperature. In vivo study was performed to investigate the bioactivity and absorption of insulin released from the liposomal gel and other formulations. The liposomal gel released insulin into the bloodstream continuously for up to 7 days and significantly enhanced drug bioavailability compared to insulin released from liposomes or Pluronic® F127 gel individually. Blood glucose levels were reduced for up to 4 days. Histology data demonstrated excellent biocompatibility of the Pluronic® F127 gel-based delivery systems, with no observable inflammatory response in rat subcutaneous tissues. CONCLUSION: Obtained results show that the insulin-loaded liposomes dispersed within Pluronic® F127 gel can be used as a long-acting drug delivery system, and replacement for conventional insulin therapy.

Pulmonary delivery of triptolide-loaded liposomes decorated with anti-carbonic anhydrase IX antibody for lung cancer therapy.

Antibody-decorated liposomes can facilitate the precise delivery of chemotherapeutic drugs to the lung by targeting a recognition factor present on the surface of lung tumor cells. Carbonic anhydrase IX (CA IX) is an enzyme expressed on the surface of lung cancer cells with a restricted expression in normal lungs. Here, we explored the utility of anti-carbonic anhydrase IX (CA IX) antibody, conjugated to the surface of triptolide (TPL)-loaded liposomes (CA IX-TPL-Lips), to promote the therapeutic effects for lung cancer via pulmonary administration. It was found that the CA IX-TPL-Lips significantly improved the cellular uptake efficiency in both CA IX-positive human non-small cell lung cancer cells (A549) and A549 tumor spheroids, resulting in the efficient cell killing compared with free TPL and non-targeted TPL-Lips. In vivo, CA IX-Lips via pulmonary delivery showed specificity and a sustained release property resided up to 96 h in the lung, both of which improved the efficiency of TPL formulations in restraining tumor growth and significantly prolonged the lifespan of mice with orthotopic lung tumors. The results suggest that CA IX-decorated liposomes can potentially be used as an effective therapeutic strategy for lung cancer.

Carbonic anhydrase IX-directed immunoliposomes for targeted drug delivery to human lung cancer cells in vitro.

Targeted drug delivery to cancer cells by use of antibody-conjugated liposomes (immunoliposomes) has attracted considerable interest in recent years. Despite increasing efforts in developing immunoliposomes as drug carriers, the investigation of useful tumor-associated antigen targets is far from complete. Carbonic anhydrase IX (CA IX) is a cell surface antigen characterized by hypoxia-induced expression in many solid tumors. This study investigated the feasibility of CA IX-directed immunoliposomes for targeted delivery of docetaxel to human lung cancer cells in vitro. Docetaxel-loaded immunoliposomes targeting CA IX were developed with an encapsulation efficiency of 84.4±3.9% and an average particle size of 143.9±11.1 nm. Using fluorescence-based flow cytometry, the in vitro binding activity of the immunoliposomes was found to be significantly higher (by 1.65-fold) than that of the nontargeted liposomes in CA IX-positive lung cancer cells, whereas no such difference was observed between the two groups when CA IX was not expressed. Furthermore, immunoliposomal docetaxel exhibited the strongest growth inhibitory effect against CA IX-positive lung cancer cells when compared with nontargeted liposomal docetaxel or free docetaxel solution. These data suggested that CA IX-directed immunoliposomes could serve as a promising drug delivery system for targeted killing of lung cancer cells.

Effect of liposomes on the absorption of water-soluble active pharmaceutical ingredients via oral administration.

The objective of this study was to investigate the effect of liposomes on the absorption of water-soluble active pharmaceutical ingredients. Salbutamol sulfate (SBS) has been widely used for treatment of bronchospasm in conditions such as asthma. Using SBS as the model drug in this study, we developed SBS-loaded liposomes for oral administration and explored the relationship between their bioavailability and anti-asthmatic efficacy. SBS was entrapped in liposomes with encapsulation efficiency as high as 70%. The in vitro transport profile of SBS across a dialysis membrane for liposome suspension was compared with that for free SBS solution. Oral administration of liposomes labeled with the fluorescent dye 1,1'-dioctadecyltetramethyl indotricarbocyanine iodide (DiR) in a mouse model was assessed by a small animal imaging system. Pharmacokinetic and pharmacodynamic studies on SBS liposome suspension and free SBS solution were performed using animal models via oral administration. The results showed that liposomes could sustain the release of SBS in vitro and decrease the transport rate of SBS across the dialysis membrane. In vivo fluorescence imaging analysis demonstrated DiR liposome distribution in mouse stomach for at least 24 hr. The mean residence time of SBS from liposomes was found to be longer than that of free SBS, suggesting that the relative bioavailability of SBS was higher when liposome delivery was used. The pharmacokinetic data also showed that the drug absorption rate was relatively slower for treatment with liposomal SBS when compared to free SBS. Moreover, SBS liposome suspension was shown to give a prolonged anti-asthmatic effect after oral administration when compared to free SBS solution. Overall, this study demonstrated that use of liposomes as delivery vehicles for sustained drug release and controlled absorption could be a promising approach for improving the therapeutic potency of active pharmaceutical ingredients.

Alkylphenols from the roots of Ardisia brevicaulis induce G1 arrest and apoptosis through endoplasmic reticulum stress pathway in human non-small-cell lung cancer cells.

From the roots of Ardisia brevicaulis DIELS, two new alkylphenol derivatives, named ardisiphenol E (2) and F (3), have been isolated together with a known alkylphenol, ardisiphenol D (1). The structures of 1-3 were elucidated by chemical and spectroscopic techniques. Compounds 1 and 2 exhibited strong cytotoxicities on two human non-small-cell lung cancer cell lines (H1299 and A549). We found that compounds 1 and 2 upregulated mRNA and protein expressions of endoplasmic reticulum (ER) stress markers including C/EBP homologous protein (CHOP), binding immunoglobulin protein (Bip) and inositol-requiring enzyme 1 (IRE1) indicating 1 and 2 are novel natural ER stress inducers. Treatments with 1 and 5 µM of 1 or 2 triggered G1 arrest in H1299 and A549 cells with concomitant downregulation of ubiquitin fusion degradation protein 1 (Ufd1) and S-phase kinase-associated protein 2 (Skp2) proteins and the accumulation of p27, the key axes of ER stress-mediated G1 arrest. Compounds 1 and 2 also induced apoptosis at high concentrations (10, 20 µM) which was shown to be coupled with the upregulation of CHOP and Bim, the activation of caspase-9, caspase-3 and poly(ADP-ribose) polymerase (PARP) cleavage. These results indicate that compounds 1 and 2 induce ER stress that subsequently causes G1 arrest and apoptosis in human non-small-cell lung cancer cells and they may have potential anticancer effects.

Liposomes prolong the therapeutic effect of anti-asthmatic medication via pulmonary delivery.

PURPOSE: The main objective of this study was to develop a novel aerosolized liposome formulation for pulmonary delivery of anti-asthmatic medication and to explore the relationship between the bioavailability and anti-asthmatic efficacy of such a formulation. Asthma treatment usually requires frequent administration of medication for sustained bronchodilating response. Liposomes are known for their capability for sustained drug release and thus would be a suitable delivery system for anti-asthmatic medication for prolonged therapeutic effect. Salbutamol sulfate (SBS) was chosen as the model drug in this study because of its high water solubility and fast absorption after administration. METHODS: SBS was efficiently encapsulated into liposomes by the vesicular phospholipid gel technique. SBS permeability across the pulmonary membrane of an Asian toad was determined by in vitro study. Intratracheal administration of liposomes labeled with the fluorescent dye 1,1'-dioctadecyltetramethyl indotricarbocyanine iodide (DiR) in a rat model was assessed by a small animal imaging system and pharmacokinetic analysis. Pharmacodynamic analysis was performed in guinea pigs using the Konzett-Rössler method. RESULTS: SBS was efficiently encapsulated into liposomes with encapsulation efficiency as high as 70%. The particle size of the SBS liposome suspension was approximately 57 ± 21 nm. In the in vitro study of permeability across the pulmonary membrane of Asian toads, SBS from liposomes demonstrated a slower transport rate compared to free SBS solution. Pulmonary delivery of liposomes in a rat model showed that the liposomes were effectively distributed in the respiratory tract and lungs, and that the release of SBS from liposomes was sustained for at least 48 hours. Pharmacodynamic analysis in a guinea pig model showed that the anti-asthmatic effect of SBS liposomes persisted for up to 18 hours, whereas that of free SBS solution was less than 8 hours. CONCLUSION: The overall results demonstrated that liposomes could increase the concentration and retention time of SBS in the lungs and therefore prolong its therapeutic effect.