Current trends in PLGA based long-acting injectable products: The industry perspective.

INTRODUCTION: Poly(lactic-co-glycolic acid) (PLGA) has been used in many long-acting drug formulations, which have been approved by the US Food and Drug Administration (FDA). PLGA has unique physicochemical properties, which results in complexities in the formulation, characterization, and evaluation of generic products. To address the challenges of generic development of PLGA-based products, the FDA has established an extensive research program to investigate novel methods and tools to aid product development and regulatory review. AREAS COVERED: This review article intends to provide a comprehensive review on physicochemical properties of PLGA polymer, characterization, formulation, analytical aspects, manufacturing conditions on product performance, in-vitro release testing, and bioequivalence. Current research on formulation development was done as per QbD in vitro release testing methods, regulatory research outcomes, and bioequivalence. EXPERT OPINION: The development of PLGA-based long-acting injectables is promising and challenging when considering the numerous interrelated delivery-related factors. Achieving a successful formulation requires a thorough understanding of the critical interactions between polymer/drug properties, release profiles over time, up-to-date knowledge on regulatory guidance, and elucidation of the impact of multiple in vivo conditions to methodically evaluate the eventual clinical efficacy.

Lipid and poly (ethylene glycol)-conjugated bi-functionalized chlorine e6 micelles for NIR-light induced photodynamic therapy.

BACKGROUND: To develop a photosensitizer, chlorin e6 (Ce6)-based amphiphilic polymer, DP-Ce6, where DOPE and PEG are conjugated to Ce6, which would self-assemble to form polymeric micelles (DP-Ce6-M) in aqueous environment. METHODS: DP-Ce6-M were characterized for particle size, zeta potential, and singlet oxygen (1O2) generation. Cellular internalization, phototoxicity were investigated against monolayer and 3D spheroids of human lung adenocarcinoma cells (A549). RESULTS AND CONCLUSIONS: DP-Ce6-M formed stable micelles with particles size of 58.2 ±â€¯1.6 nm. Solubility of Ce6 was improved. Photoactivity of DP-Ce6-M was sustained in regard to 1O2 generation compared to free Ce6. The DP-Ce6-M showed enhanced internalization and growth inhibition in monolayer and spheroidal cells. Overall, DP-Ce6-M demonstrated the potential for further exploration as PDT agent for cancer treatment.

Evaluation of Anti-Tumor Efficacy of Vorinostat Encapsulated Self-Assembled Polymeric Micelles in Solid Tumors.

Vorinostat (VOR), a potent HDAC inhibitor, suffers from low solubility and poor absorption, which hinders its successful application in therapy, especially in the treatment of solid tumors. In this study, an effort to improve the physicochemical characteristics of VOR was made by encapsulating it in PEG-PLGA copolymeric micelles. VOR-loaded PEG-PLGA micelles (VOR-PEG-PLGA) were produced by thin-film hydration and physicochemically characterized. The PEG-PLGA micelles had an average size of 124.06 ± 2.6 nm, polydispersity index of 0.27 ± 0.1, and entrapment efficiency of 90 ± 2.1%. Micelles were characterized by TEM, DSC, and drug release studies. The drug release occurred in a sustained manner up to 72 h from PEG-PLGA micelles. In the in vitro cell-based studies using human breast cancer (MDA MB 231) and murine melanoma (B16F10) cell lines, VOR-PEG-PLGA micelles exhibited superior cellular internalization, enhanced cytotoxic activity, and greater apoptosis compared to free drug. Percent cell killing of 54.9% for VOR-PEG-PLGA-treated cells was observed after 24 h compared to 36% for free VOR in MDA MB 231 cell line. Further, significant tumor suppression was witnessed in B16F10 tumor-bearing mice treated with VOR-PEG-PLGA micelles with a 1.78-fold reduction in tumor volume compared to free VOR-treated animals. Overall, the VOR-PEG-PLGA micelles improved the biopharmaceutical properties of VOR, which resulted in enhanced anti-tumor efficacy. Therefore, the newly developed nano-formulation of VOR could be considered as an effective treatment option in solid tumors.

Cholesterol-grafted chitosan micelles as a nanocarrier system for drug-siRNA co-delivery to the lung cancer cells.

Combined delivery of a therapeutic small interfering RNA (siRNA) and a chemotherapeutic agent to cancer cells is promising as anticancer therapy, which could offer enhanced cell killing potential and low side effect. However, simultaneous delivery to tumor is challenging. In our study, cholesterol-modified low molecular weight chitosan (MW ~ 15 kDa) was employed as a self-assembled delivery system for both siRNA and a hydrophobic chemotherapeutic agent, curcumin to cancer cells. The siRNA/curcumin loaded nanoparticles (C-CCM/siRNA) were physico-chemically characterized for particle size (165 ±â€¯2.6 nm) and zeta potential (+24.8 ±â€¯2.2 mV). The ability of CCM to condense siRNA was determined by ethidium bromide exclusion and gel retardation assay using electrophoresis. The result demonstrated that the condensation of C-CCM with siRNA was optimum at minimum N/P ratio of 40. C-CCM/siRNA was stable at 4 °C for a period of >1 month. C-CCM/siRNA was taken up efficiently by human lung carcinoma cells, A549 in a time-dependent manner. The cellular internalization of C-CCM/siRNA was observed via clathrin-mediated endocytosis as determined by using specific endocytosis inhibitors. The study demonstrated the feasibility of the use of cholesterol conjugated chitosan as a co-delivery system for both siRNA and a hydrophobic drug for combination cancer therapy.

Transferrin-anchored poly(lactide) based micelles to improve anticancer activity of curcumin in hepatic and cervical cancer cell monolayers and 3D spheroids.

In recent years, actively targeted drug delivery systems have been utilized in pre-clinical studies for site-specific delivery of drugs, which reduces toxicities associated with chemotherapy. This study reports the preparation of the tumor homing ligand, transferrin (Tf) anchored methoxy-polyethylene glycol-poly(d,l-Lactide) polymeric micelles (Tf-PP). Curcumin which possess wide anti-cancer activity was loaded into the micelles. Tf-PPC with average particle size of 132.16 ±â€¯1.37 nm and encapsulation efficiency of 88.27 ±â€¯2.53% showed a sustained drug release. The efficacy of Tf-PPC was studied in vitro in Tf-overexpressing human cervical carcinoma (HeLa) and human hepatoma (HepG2) cells. The mouse embryo fibroblast (NIH-3T3) cells were used as control cells. Tf-PPC showed higher internalization compared to non-targeted micelles (PPC). The curcumin-mediated cytotoxicity increased significantly following Tf-PPC treatment in both the tested cell lines. In NIH-3T3 cells, Tf conjugation did not differ in comparison to the non-targeted micelles. Further, the efficiency of Tf-PPC was studied in three-dimensional (3D) HeLa tumor spheroids. The Tf-PPC was efficiently internalized by the spheroidal structures, causing higher cytotoxicity and apoptosis compared to PPC. These results reveal that the newly developed, Tf-PPC could be employed as an effective chemotherapy in the treatment of Tf- overexpressing cancers.

Transferrin-Modified Vitamin-E/Lipid Based Polymeric Micelles for Improved Tumor Targeting and Anticancer Effect of Curcumin.

PURPOSE: Transferrin receptor (TfR) is up-regulated in various malignant tumors not only to meet the iron requirement, but also to increase the cell survival via participation in various cellular signaling pathways. Here we explored transferrin as ligand for Poly(ethylene Glycol) (PEG)-ylated vitamin-E/lipid (PE) core micelles (VPM). METHODS: Transferrin modified polymer was synthesized and drug loaded micelles were evaluated in 2D Hela and HepG2 cancer cells for cellular uptake and cytotoxicity and in 3D Hela spheroids for growth inhibition, uptake and penetration studies. RESULTS: Targeted (Tf-VPM) and non-targeted (VPM) micelles showed mean hydrodynamic diameter of 114.2 ± 0.64 nm and 117.4 ± 0.72 nm and zeta potential was -22.8 ± 0.62 and -14.8 ± 1.74 mV, respectively. Cellular uptake study indicated that the Tf-CVPM were taken up by cancer cells (Hela and HepG2) with higher efficiency. Enhanced cytotoxicity was demonstrated for Tf-VPM compared to CVPM. Marked spheroid growth inhibition following treatment with Tf-CVPM was observed compared to the treatment with non-targeted CVPM. CONCLUSIONS: The developed transferrin-modified micelles have improved ability to solubilize the loaded drugs and could actively target solid tumors by its interaction with over-expressed transferrin receptors. Therefore, the nano-micelles could be further explored for its potential utilization in cancer therapy.

Cholesterol and vitamin E-conjugated PEGylated polymeric micelles for efficient delivery and enhanced anticancer activity of curcumin: evaluation in 2D monolayers and 3D spheroids.

A newly synthesized PEGylated cholesterol/α-tocopheryl succinate (α-TOS) linked polymer (CV) was self-assembled and loaded with curcumin to form a micellar system (C-CVM). The tri-functionalized amphiphilic polymer was constituted of hydrophobic cholesterol and α-TOS connected to hydrophilic PEG via a lysine linker. The synthesized polymer and the micelles were characterized by 1H NMR, DLS, zeta potentiometer, TEM, CMC determination and hemolysis studies. CVM displayed low CMC value of 15 µM with extent of hemolysis as less than 4%. The stable C-CVM with optimum % drug loading (14.2 ± 0.24) displayed Z average of 175.8 ± 0.68 nm with PDI (0.248 ± 0.075) and released curcumin in sustained manner in the in vitro drug release study. C-CVM demonstrated dose-dependent cellular uptake and cytotoxicity in murine melanoma, B16F10 and human breast cancer, MDA-MB-231 cell lines. CV exhibited marked reversal of drug resistance as indicated by significantly higher retention of P-glycoprotein substrate, rhodamine-123 in the resistant B16F10 cell line compared to standard P-glycoprotein inhibitor, verapamil. C-CVM demonstrated significantly higher spheroidal growth inhibition compared to C-PPM. The results provide strong evidence for CVM as promising drug delivery system and confirm the potential of C-CVM as chemotherapy in cancer.

Curcumin-loaded chitosan-cholesterol micelles: evaluation in monolayers and 3D cancer spheroid model.

AIM: To improve the bioavailability and anticancer potential of curcumin by using a cholesterol-conjugated chitosan micelle. Methods & methods: Cholesterol was conjugated to chitosan (15 kDa) to form self-assembled micelles, which loaded curcumin. Physicochemical characterization and formulation optimization of the drug-loaded micelles (curcumin-loaded chitosan-cholesterol micelles [C-CCM]) were performed. In vitro cellular uptake and viability of C-CCM were investigated in melanoma and breast cancer cell lines. The antitumor efficacy was evaluated in 3D lung cancer spheroid model. RESULTS & CONCLUSION: The optimized C-CCM had size of approximately 162 nm with loading efficiency of approximately 36%. C-CCM was taken up efficiently by the cells, and it reduced cancer cell viability significantly compared with free curcumin. C-CCM enhanced the antitumor efficacy in spheroids, suggesting that C-CCM could be used as an effective chemotherapy in cancer.

d-α-Tocopheryl Succinate/Phosphatidyl Ethanolamine Conjugated Amphiphilic Polymer-Based Nanomicellar System for the Efficient Delivery of Curcumin and To Overcome Multiple Drug Resistance in Cancer.

Nanomedicines have emerged as a promising treatment strategy for cancer. Multiple drug resistance due to overexpression of various drug efflux transporters and upregulation of apoptotic inhibitory pathways in cancer cells are major barriers that limit the success of chemotherapy. Here, we developed a d-α-tocopherol (α-TOS)/lipid-based copolymeric nanomicellar system (VPM) by conjugating phosphatidyl ethanolamine (PE) and α-TOS with poly(ethylene glycol) (PEG) via an amino acid linkage. The synthesized polymers were characterized by Fourier transform IR, gas-phase chromatography, and 1H and 13C NMR spectroscopy. VPM exhibited mean hydrodynamic diameter of 141.0 ± 0.94 nm with low critical micelles concentrations (CMC) of 15 µM compared to plain PEG-PE micelles (PPM) with size of 23.9 ± 0.34 nm and CMC 20 µM. The bigger hydrophobic compartment in VPM resulted in improved loading of a potent chemotherapeutic drug, curcumin (Cur), and increased encapsulation efficiency (EE) (% drug loading 98.3 ± 1.92, and 85.3 ± 3.29; EE 14.8 ± 0.16 and 12.8 ± 0.09 for VPM and PPM, respectively). Curcumin loaded Vitamin E based micelles exhibited higher cytotoxicity compared to Curcumin loaded PEG-PE micelles in tested cancer cell lines. C-VPM demonstrated ∼3.2 and ∼2.7-fold higher ability to reverse multiple drug resistance compared to PPM and verapamil (concentration used 30 µM), respectively. In the in vivo study by using B16F10 implanted C57Bl6/J mice, C-VPM reduced the tumor volume and weight more efficiently than C-PPM by inducing apoptosis as analyzed by TUNEL assay on tumor cryosections. The newly developed polymeric micelles, VPM with improved drug loadability and ability to reverse the drug resistance could successfully be utilized as a nanocarrier system for hydrophobic chemotherapeutic agents for the treatment of drug-resistant solid tumors.

Cholesterol-conjugated poly(D, L-lactide)-based micelles as a nanocarrier system for effective delivery of curcumin in cancer therapy.

Polymeric micelles have been widely explored preclinically as suitable delivery systems for poorly soluble chemotherapeutic drugs in cancer therapy. The present study reported the development of cholesterol (Ch)-conjugated poly(D,L-Lactide) (PLA)-based polymeric micelles (mPEG-PLA-Ch) for effective encapsulation and delivery of curcumin (CUR) at the tumor site. Cholesterol conjugation dramatically affected the particle size and improved drug loading (DL) and encapsulation efficiency (EE). mPEG-PLA-Ch-CUR showed bigger hydrodynamic diameter (104.6 ± 2.1 nm, and 169.3 ± 1.52 nm for mPEG-PLA and mPEG-PLA-Ch, respectively) due to increased size of the hydrophobic core. The newly developed polymer exhibited low critical micelles concentration (CMC) (25 µg/mL) which is close to lipid-based polymer, PEG-phosphatidyl ethanolamine (12.5 µg/mL) compared to mPEG-PLA (50 µg/mL). mPEG-PLA-Ch micelles exhibited relatively higher EE (93.74 ± 1.6%) and DL (11.86 ± 0.8%) compared to mPEG-PLA micelles (EE 91.89 ± 1.2% and DL 11.06 ± 0.8%). mPEG-PLA-Ch micelles were internalized by the cancer cells effectively and exhibited higher cytotoxicity compared to free CUR in both, murine melanoma (B16F10) and human breast cancer (MDA-MB-231) cells. mPEG-PLA-Ch exhibited satisfactory hemocompatibility indicating their potential for systemic application. Further, mPEG-PLA-Ch-CUR demonstrated higher rate of reduction of tumor volume in B16F10-xenografted tumor-bearing mice compared to free CUR. At the end of 22 days, the tumor reduced to 1.87-fold (627.72 ± 0.9 mm3 versus 1174.68 ± 1.64 mm3) compared to the treatment with free CUR. In conclusion, the experimental data in vitro and in vivo indicated that the newly developed CUR-mPEG-PLA-Ch micelles may have promising applications in solid tumors.

Current trends in the use of vitamin E-based micellar nanocarriers for anticancer drug delivery.

INTRODUCTION: Owing to the complexity of cancer pathogenesis, conventional chemotherapy can be an inadequate method of killing cancer cells effectively. Nanoparticle-based drug delivery systems have been widely exploited pre-clinically in recent years. Areas covered: Incorporation of vitamin-E in nanocarriers have the advantage of (1) improving the hydrophobicity of the drug delivery system, thereby improving the solubility of the loaded poorly soluble anticancer drugs, (2) enhancing the biocompatibility of the polymeric drug carriers, and (3) improving the anticancer potential of the chemotherapeutic agents by reversing the cellular drug resistance via simultaneous administration. In addition to being a powerful antioxidant, vitamin E demonstrated its anticancer potential by inducing apoptosis in various cancer cell lines. Various vitamin E analogs have proven their ability to cause marked inhibition of drug efflux transporters. Expert opinion: The review discusses the potential of incorporating vitamin E in the polymeric micelles which are designed to carry poorly water-soluble anticancer drugs. Current applications of various vitamin E-based polymeric micelles with emphasis on the use of α-tocopherol, D-α-tocopheryl succinate (α-TOS) and its conjugates such as D-α-tocopheryl polyethylene glycol-succinate (TPGS) in micellar system is delineated. Advantages of utilizing polymeric micelles for drug delivery and the challenges to treat cancer, including multiple drug resistance have been discussed.

Xanthan gum stabilized PEGylated gold nanoparticles for improved delivery of curcumin in cancer.

In recent years, gold nanoparticles (AuNPs) have received immense interest in various biomedical applications including drug delivery, photothermal ablation of cancer and imaging agent for cancer diagnosis. However, the synthesis of AuNPs poses challenges due to the poor reproducibility and stability of the colloidal system. In the present work, we developed a one step, facile procedure for the synthesis of AuNPs from hydrogen tetrachloroaurate (III) hydrate (HAuCl4. 3H2O) by using ascorbic acid and xanthan gum (XG) as reducing agent and stabilizer, respectively. The effect of concentrations of HAuCl4, 3H2O, ascorbic acid and methoxy polyethylene glycol-thiol (mPEG800-SH) were optimized and it was observed that stable AuNPs were formed at concentrations of 0.25 mM, 50 µM and 1 mM for HAuCl4.3H2O, ascorbic acid, and mPEG800-SH, respectively. The XG stabilized, deep red wine colored AuNPs (XG-AuNPs) were obtained by drop-wise addition of aqueous solution of ascorbic acid (50 mM) and XG (1.5 mg ml(-1)). Synthesized XG-AuNPs showed λmax at 540 nm and a mean hydrodynamic diameter of 80 ± 3 nm. PEGylation was performed with mPEG800-SH to obtain PEGylated XG-AuNPs (PX-AuNPs) and confirmed by Ellman's assay. No significant shift observed in λmax and hydrodynamic diameter between XG-AuNPs and PX-AuNPs. Colloidal stability of PX-AuNPs was studied in normal saline, buffers within a pH range of 1.2-7.4, DMEM complete medium and in normal storage condition at 4 ˚C. Further, water soluble curcumin was prepared using PVP-K30 as solid dispersion and loaded on to PX-AuNPs (CPX-AuNPs), and evaluated for cellular uptake and cytotoxicity in Murine melanoma (B16F10) cells. Time and concentration dependent studies using CPX-AuNPs showed efficient uptake and decreased cell viability compared to free curcumin.

Current trends in using polymer coated gold nanoparticles for cancer therapy.

The interest in using the polymer-coated gold nanoparticles (P-AuNPs) for various biomedical applications, including the delivery of chemotherapeutic in cancer has been increased in the recent years. Various biocompatible polymers, including poly(ethylene glycol), heparin, hyaluronic acid, chitosan, polystyrene sulfonate, polyethyleneimine and xanthan gum are being used for the surface decoration of AuNPs for various purposes such as to improve the stability of the NPs and the payloads, impart biocompatibility, promote long systemic circulation followed by cellular uptake to utilize the AuNPs as drug/nucleic acid delivery system for cancer therapy. This review is an attempt to elucidate various synthesis strategies explored so far, including direct synthesis, "grafting in" and "grafting from" for the preparation of the P-AuNPs. Various therapeutic applications of the P-AuNPs for cancer treatment have been illustrated.