Current Drug Delivery (v.13, #5)

Meet Our Editorial Board Member by Laszlo Otvos (631-631).

Molecularly Imprinted Polymers: Novel Discovery for Drug Delivery by Surve Dhanashree, Mohite Priyanka, Karpe Manisha, Kadam Vilasrao (632-645).
Background: Molecularly imprinted polymers (MIP) are novel carriers synthesized by imprinting of a template over a polymer. This paper presents the recent application of MIP for diagnostic and therapeutic drug delivery.
Overview: MIP owing to their 3D polymeric structures and due to bond formation with the template serves as a reservoir of active causing stimuli sensitive, enantioselective, targetted and/or controlled release. The review elaborates about key factors for optimization of MIP, controlled release by MIP for various administration routes various forms like patches, contact lenses, nanowires along with illustrations. To overcome the limitation of organic solvent usage causing increased cost, water compatible MIP and use of supercritical fluid technology for molecular imprinting were developed. Novel methods for developing water compatible MIP like pickering emulsion polymerization, co-precipitation method, cyclodextrin imprinting, surface grafting, controlled/living radical chain polymerization methods are described with illustration in this review. Various protein imprinting methods like bulk, epitope and surface imprinting are described along with illustrations. Further, application of MIP in microdevices as biomimetic sensing element for personalized therapy is elaborated.
Conclusion: Although development and application of MIP in drug delivery is still at its infancy, constant efforts of researchers will lead to a novel intelligent drug delivery with commercial value. Efforts should be directed in developing solid oral dosage forms consisting of MIP for therapeutic protein and peptide delivery and targeted release of potent drugs addressing life threatening disease like cancer. Amalgamation of bio-engineering and pharmaceutical techniques can make these future prospects into reality.

Oral administration is the most commonly used drug delivery route for the majority of conditions. Given its advantages over other routes, such as convenience and cost, its use is increasing every year despite the major advances in drug delivery. Nevertheless, oral formulations are limited and challenged by physicochemical barriers and highly variable residence times. Gastric retention is a strategy that can overcome the highly variable gastric residence time by designing formulations that remain in the stomach longer than would otherwise be expected. This is especially beneficial for drugs that have an absorption window in the stomach and proximal intestine. Various techniques are discussed and include gasgenerating tablets, floating microspheres, hydrodynamically balanced systems, bioadhesive particles, rafts and modified shape systems. Microspheres having the advantages of being multi-unit are further discussed with regard to their production methods and characterisation. Further, a summary of microsphere studies is presented that looks at methods used and key results.

Liver fibrosis is an important cause of morbidity and mortality worldwide and represent a difficult clinical challenge of global importance. The liver fibrosis progression needs to be controlled because persisted liver fibrosis can lead to liver cirrhosis or even hepatocellular carcinoma. Despite significant advances in the understanding of the liver fibrosis development, the therapeutic effect of drugs used in liver fibrosis treatment is not sufficient. Today, nanotechnology has been considered as a potential tool for developing novel drug delivery systems for the improved imaging and various diseases, including liver fibrosis. In this article, we discussed the use of nanotechnology for the treatment and imaging of liver fibrosis.

PEGylated Biodegradable Polyesters for PGSS Microparticles Formulation: Processability, Physical and Release Properties by D.R. Perinelli, M. Cespi, G. Bonacucina, A. Naylor, M. Whitaker, J.K.W. Lam, S.M. Howdle, L. Casettari, G.F. Palmieri (673-681).
Background: Particles from Gas Saturated Solution (PGSS) is an emergent method that employs supercritical carbon dioxide (scCO2) to produce microparticles. It is suitable for encapsulating biologically active compounds including therapeutic peptides and proteins. Poly(lactide acid) (PLA) and/or poly(lactic-coglycolic acid) (PLGA) are the most commonly used materials in PGSS, due to their good processability in scCO2. Previous studies demonstrated that the properties of the microparticles can be modulated by adding polyethylene glycol (PEG) or tri-block PEGylated copolymers.
Objective: In the present work, the effect of the addition of biodegradable PEGylated di-block copolymers on the physical properties and drug release performance of microparticles prepared by PGSS technique was evaluated.
Method: mPEG5kDa-P(L)LA and mPEG5kDa-P(L)LGA with similar molecular weights were synthesized and their behaviour, when exposed to supercritical CO2, was investigated. Different microparticle formulations, composed of a high (81%) or low (9%) percentage of the synthesized copolymers were prepared and compared in terms of particle size distribution, morphology, yield and protein release. Drug release studies were performed using bovine serum albumin (BSA) as a model protein.
Results: PEGylated copolymers showed good processability in PGSS without significant changes to the physical properties of the microparticles. However, the addition of PEG exerted a modulating effect on the microparticle drug dissolution behaviour, increasing the rate of BSA release as a function of its content in the formulation.
Conclusion: This study demonstrated the feasibility of producing microparticles by using PEGylated di-block copolymers through a PGSS technique at mild operating conditions (low operating pressure and temperature).

Curcumin as an antioxidative agent which has been widely used medicinally in India and China. However, rapid metabolism coupled with the instability of curcumin under physiological conditions has greatly limited its applications in vivo. In the present study, a thermosensitive hydrogel with high payload of curcumin was developed by using a co-precipitation method, and its reversion of oxidative stress in Neuro-2a cells was investigated. With an increase in drug loading capacity, the solgel transition temperature of the thermosensitive hydrogel decreased accordingly. The stability of curcumin in phosphate-buffered saline (PBS; pH=7.4) was greatly improved by encapsulation in the thermosensitive hydrogel, as indicated by an in vitro degradation test. An in vitro release study showed that the encapsulated curcumin was rapidly released from the hydrogel within 6 h. A curcumin/F-127 aqueous solution under the threshold concentration of 4?g/mL was non-toxic against Neuro-2a cells after 24-h incubation. A MitoSOX assay indicated that the developed curcumin formulation could attenuate the oxidative damage induced by H2O2 as compared to that of the H2O2 group. All these results suggested that the developed curcumin/thermosensitive hydrogel might have great potential application in the reversion of oxidative stress after traumatic brain injury.

Production of Irbesartan Nanocrystals by High Shear Homogenisation and Ultra-Probe Sonication for Improved Dissolution Rate by Karthik Sridhar, Habibur Rahman, Alejandro Sosnik, Uditta Mukherjee, Tamilselvan Natarajan, Karthik Siram, Balakumar Krishnamoorthy (688-697).
Irbesartan (IRB) is a BCS class II drug with poorly aqueous solubility and its absorption is dissolution rate limited. In the present study solubility and dissolution rate of IRB were improved by nanonization and using two poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) amphiphiles, namely Pluronic® F127 and Pluronic® F68, as nanosuspension stabilisers. In addition, the role of these surfactants in the solubilization of the drug was assessed. The nanocrystals were produced by two top-down techniques- high shear homogenisation and ultra-probe sonication. The nanocrystals were characterized for particle size, size distribution and zeta potential and compared to the unprocessed drug by FTIR, thermal analysis, scanning electron microscopy, solubility and dissolution rate. IRB nanocrystals showed greater solubility and faster dissolution rate than the original drug, solubility being higher for formulations prepared with F127 than those with F68. Presence of an endothermic peak of drug in the formulation confirmed its crystalline nature, regardless of the use of two energetic methods. SEM of the nanocrystals revealed a small rod-shaped morphology and the substantial decrease of the particles size. Overall results support these nanonization techniques as a simple, cost-effective and scalable approach to improve the aqueous solubility of drugs such as IRB that are classified into Class II of the Biopharmaceutic Classification System (BCS).

Background: Anticoagulant therapy is effective in the treatment of DVT. In this regard, LMWH demonstrated significant promise. It is widely used clinically. The goal of this study was to prepare and evaluate intravenous sustained release stealth nanoparticles encapsulating LMWH using PLGA (polylactidecoglycolide) and different grades of PEG (poly ethylene glycols).
Methods: The nanoparticles were prepared using w/o/w solvent evaporation technique. Prepared nanoparticles were evaluated for particle size, encapsulation efficiency, in-vitro drug release, anti-thrombotic activity in venous thrombosis rat model, estimation of aPTT, tissue bio-distribution studies and stability.
Results: Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) studies confirmed the formation of smooth spherical particles. FTIR study reveals successful coating of PEG on the nanoparticles. DSC and XRD results demonstrated that drug changed its physical form in the formulation. The encapsulation efficiency was 63-74%. In vitro drug release was 57-75% for 48 hrs. Macrophage uptake of LMWH with pegylated nanoparticles was less compared to conventional PLGA nanoparticles. In vivo drug release was sustained for 48hrs; Optimized formulation exhibited good enhancement in pharmacokinetic parameters when compared to free drug solution. In vivo sustained release was also demonstrated with antithrombotic activity as well aPTT activity. Optimized formulation demonstrated significant stability, excellent antithrombotic activity in venous thrombosis rat model, improved aPTT levels when compared to free drug solution.
Conclusion: An effective stealth LMWH nanoparticle formulation to treat venous thrombosis was successfully developed using w/o/w solvent evaporation technique.

Hesperetin Liposomes for Cancer Therapy by Joy Wolfram, Bronwyn Scott, Kathryn Boom, Jianliang Shen, Carlotta Borsoi, Krishna Suri, Rossella Grande, Massimo Fresta, Christian Celia, Yuliang Zhao, Haifa Shen, Mauro Ferrari (711-719).
Hesperetin is a compound from citrus fruit that has previously been found to exert anticancer activity through a variety of mechanisms. However, the application of hesperetin to cancer therapy has been hampered by its hydrophobicity, necessitating the use of toxic solubilizing agents. Here, we have developed the first liposome-based delivery system for hesperetin. Liposomes were fabricated using the thin-layer evaporation technique and physical and pharmacological parameters were measured. The liposomes remained stable for prolonged periods of time in serum and under storage conditions, and displayed anticancer efficacy in both H441 lung cancer cells and MDA-MB-231 breast cancer cells. Furthermore, the anticancer activity was not impaired in cells expressing the multidrug resistance protein 1 (MDR-1). In conclusion, the encapsulation of hesperetin in liposomes does not interfere with therapeutic efficacy and provides a biocompatible alternative to toxic solubilizing agents, thereby enabling future clinical use of this compound for cancer therapy.

Understanding microstructural evolutions of drug delivery devices during drug release process is essential for revealing the drug release mechanisms and controlling the drug release profiles. In this study, monodisperse poly (lactic-co-glycolic acid) microspheres in different diameters were fabricated by microfluidics in order to find out the relationships between the microstructural evolutions and the drug release profiles. It was found that poly (lactic-co-glycolic acid) microspheres underwent significant size expansion which took place from the periphery to the center, resulting in the formation of interfacial fast release layers. At the same time, inner pores were created and the diffusion rate was increased so that the early stage drug release was accelerated. Due to the different expansion rates, small poly (lactic-co-glycolic acid) microspheres tendered to follow homogeneous drug release while large poly (lactic-co-glycolic acid) microspheres tendered to follow heterogeneous drug release. This study suggests that the size expansion and the occurrence of interfacial fast release layer were important mechanisms for early stage drug release of poly (lactic-co-glycolic acid) microspheres.

Preparation and Evaluation of Hot-Melt Extruded Patient-Centric Ketoprofen Mini-Tablets by Abdullah S. Alshetaili, Bjad K. Almutairy, Roshan V. Tiwari, Joseph T. Morott, Sultan M. Alshehri, Xin Feng, Bader B. Alsulays, Jun-Bom Park, Feng Zhang, Michael A. Repka (730-741).
Background: Bitter tasting drugs represent a large portion of active pharmaceutical ingredients. Mini-tablets are specifically designed for patients with difficulty in swallowing particular in young children up to 10 years of age, geriatric patients and patients with esophagitis.
Objective: The present study was aimed to prepare, taste-masked mini-tablets, which are easily swallowed dosage forms, primarily to be used by pediatric and geriatric patients.
Methods: Ketoprofen (10%-50% w/w) and Eudragit® EPO were blended and extruded with a 5-mm strand die and cut into consistent mini-tablets by using an adapted downstream pelletizer.
Results: Differential scanning calorimetry and polarized light microscopy-hot stage microscopy studies confirmed that the binary mixtures were miscible under the employed extrusion temperatures. In-vitro release studies showed that drug release was less than 0.5% within the first 2 min in simulated salivary fluid (pH 6.8) and more than 90% in the first 20 min in gastric media (pH 1.0). The results of the electronic tongue analysis were well correlated with the drug release profile of the mini-tablets in the artificial saliva. Scanning electron microscopy revealed no cracks on the surface of the minitablets, confirming that the mini-tablets were compact solids. Chemical imaging confirmed the uniform distribution of ketoprofen inside the polymer matrices.
Conclusion: Eudragit® EPO containing ketoprofen at various drug loads were successfully melt extruded into tastedmasked mini-tablets. The reduced drug release at salivary pH correlated well with Astree e-Tongue studies for taste masking efficiency.

The objective of the present investigation was to develop and optimize reservoir-type of transdermal drug delivery system of Simvastatin using response surface methodology. A total of 17 experimental runs were conducted according to three-factor, three-level Box-Behnken design employing Design expert® software to determine the effect of independent variables (simvastatin concentration, percentage of poloxamer 407, and concentration of D-limonene) on cumulative amount of simvastatin permeation through human cadaver skin in 48 h (dependent variable). The experimental data was fitted to different response surface models using multiple regression analysis and observed quadratic model was the best fit model with significant p-value (p?0.0003) and coefficient of determination value of 0.9949. The second-order polynomial equation and response surface plots indicated the significant influence of concentration of simvastatin and D-limonene on the simvastatin permeation in 48 h. The highest simvastatin permeation value of 76.94 ?g/cm2 was observed in case of experimental number 10 with 1.5% (w/w) of simvastatin, 25% (w/w) of poloxamer 407, and 10% (w/w) of D-limonene. Using Derringer's desirability functional tool for optimization, the highest simvastatin permeation value of 78.7684 ?g/cm2 in 48 h was predicted under optimum condition of; simvastatin concentration of 1.4893% (w/w), poloxamer 407 percentage of 22.43% (w/w), and D-limonene concentration of 9.8541% (w/w) with optimum desirability value. The in-vivo hypolipidemic study conducted for 14 days in hyperlipidemia induced Sprague-Dawley rats revealed that the optimized patch exhibited significant lowering of blood lipid profile. Finally, histology study was performed on skin sample used in permeation study of optimized formulation and compared with untreated skin sample. The treated skin sample showed a significant distortion in stratum corneum, which supported the ex-vivo permeation result. Thus, the patch may serve as an alternative therapy to oral dosage form of simvastatin with outmost patient compliance.

The main aim of the current research is to achieve active targeting of antimicrobials in secondary urinary tract infections using the direction of renal blood flow. The objective is further extended to maintain a constant internal environment and to deliver an extended maintenance dose using Poly lactic acid (PLLA) electrospun nanofibers. The medicated nanofibers used to evaluate their physical characteristics and drug release behaviour. Therapeutic efficacy of the developed formulation was achieved by organ distribution, pharmacokinetic and challenge study. A major fraction of drug was recovered from the kidney after 32 hours results in a significant reduction in colony forming unit (CFU) count establish the therapeutic efficacy of developed formulation. Polyanionic nature of PLLA electrospun nanofibers assists as an excellent carrier for intravaginal delivery of antimicrobial in urinary tract infections.

Improved Oral Bioavailability of Lacidipine Using Nanosuspension Technology: Inferior in vitro Dissolution and Superior in vivo Drug Absorption versus Lacipil® by Juanhang Zhao, Lei Luo, Qiang Fu, Bei Guo, Yun Li, Yajie Geng, Junfeng Wang, Tianhong Zhang (764-773).
Improved dissolution is a better way of increasing the oral absorption of lacidipine (LCDP) because it is a BCS II class drug. The purpose of this study is to improve the oral bioavailability of LCDP by applying nanosuspension technology. LCDP nanosuspensions were prepared by a hybrid method of microprecipitation and high pressure homogenization. The effects of the production parameters (shearing rate and time, the stabilizers and their concentrations, homogenization pressure and number of cycles) were investigated to optimize the preparation process. In vitro characterizations (X-ray powder diffraction, differential scanning calorimetry, scanning electron microscopy and dissolution measurement) were carried out and an oral pharmacokinetic study was performed in beagle dogs. LCDP was transformed into an amorphous state during the preparation process, and the mean particle size was about 714.0 ± 12.7 nm. The dissolution rate of LCDP nanosuspensions was faster than that of physical mixtures, but slower than that of Lacipil® (the commercial tablet). Regarding the in vivo pharmacokinetics, the key pharmacokinetic parameters (Cmax and AUC0??) of the nanosuspensions were statistically significantly higher than those of both the commercial tablet and physical mixtures. So, this is an efficient drug delivery strategy to facilitate the oral administration of LCDP by using nanosuspension technology, and should be generally applicable to many poorly water-soluble drugs with dissolution rate-limited absorption.

Design of Fucoidan Functionalized - Iron Oxide Nanoparticles for Biomedical Applications by Khanh Nghia Tran, Phuong Ha-Lien Tran, Toi Van Vo, Thao Truong-Dinh Tran (774-783).
This research aims to develop an iron oxide nanoparticle drug delivery system utilizing a recent material discovered from ocean, fucoidan. The material has drawn much interest due to many biomedical functions that have been proven for human health. One interesting point herein is that fucoidan is not only a sulfated polysaccharide, a polymer for stabilization of iron oxide nanoparticles, but plays a role of an anticancer agent also. Various approaches were investigated to optimize the high loading efficiency and explain the mechanism of nanoparticle formations. Fucoidan was functionalized on iron oxide nanoparticles by a direct coating or via amine groups. Also, a hydrophobic part of oleic acid was conjugated to the amine groups for a more favorable loading of poorly water-soluble anticancer drugs. This study proposed a novel system and an efficient method to functionalize fucoidan on iron oxide nanoparticle systems which will lead to a facilitation of a double strength treatment of cancer.

Efficient Transfection of Phosphorothioate Oligodeoxyribonucleotides by lipofectamine2000 into Different Bacteria by Zhou Chen, Yue Hu, Jingru Meng, Mingkai Li, Zheng Hou, Ying Zhou, Xiaoxing Luo, Xiaoyan Xue (784-793).
Antisense technology has been a promising strategy for combating infectious diseases caused by multi-drug resistant bacterial strains, but the poor cellular uptake and transfection efficiency of these “antisense antibiotics” is strangling the development of antisense RNA therapeutics. This study was aimed at evaluating the cellular uptake characteristics and transfection efficiency of antisense phosphorothioate oligodeoxyribonucleotides (PS-ODN) in bacterial cells mediated by LipofectamineTM 2000 (LF2000). The size and surface morphology of LF2000/ODN nanoparticle were determined by dynamic light scattering and transmission electron microscope. Then the characteristics of cellular uptake were studied by flow cytometry analysis, and antibacterial efficacy of LF2000/ODN nanoparticle targeting rpoD, an RNA polymerase primary ?70, was tested by analyzing the growth inhibition of targeted bacteria and by RT-PCR analysis of the target genes. And the results indicated that the size of the spherical nanoparticle obtained was about 120 nm with a zeta potential about -5 mV, and the encapsulation efficiency of PS-ODN was about 95%. The cellular uptake efficiencies of LF2000/ODN nanoparticle by extended-spectrum ? -lactamase-producing Escherichia coli (ESBLs-E. coli) and E. coli were 40.1% and 48.5% in a time-independent manner, while 76.7% and 79.3% by meticillin-resistant Staphylococcus aureus (MRSA) and S. aureus in a time-dependent manner. Interestingly, the uptake process was not altered by the incubation temperature. After being incubated with LF2000/ODN, the growth of tested bacteria were significantly retarded and the transcription of rpoD was inhibited. Our research not only provided a basis for further studies on delivery systems for antisense antibiotics, but also highlighted a novel cellular uptake mechanism of nanoparticle.