Characterization and in vitro release of praziquantel from poly(ɛ-caprolactone) implants

Fast and sustainable production of smart nanofiber mats by solution blow spinning for food quality monitoring: Potential of polycaprolactone and agri-food residue-derived anthocyanins

The shelf life of perishable foods is estimated through expensive and imprecise analyses that do not account for improper storage. Smart packaging, obtained by agile manufacturing of nanofibers functionalized with natural pigments from agri-food residues, presents promising potential for real-time food quality monitoring. This study employed the solution blow spinning (SBS) technique for the rapid production of smart nanofiber mats based on polycaprolactone (PCL), incorporating extracts of agricultural residues rich in anthocyanins from eggplant (EE) or purple cabbage (CE) for monitoring food quality. The addition of EE or CE to the PCL matrix increased the viscosity of the solution and the diameter of the nanofibers from 156 nm to 261-370 nm. The addition of extracts also improved the mechanical and water-related properties of the nanofibers, although it reduced the thermal stability. Attenuated total reflectance Fourier-transform infrared spectroscopy confirmed the incorporation of anthocyanins into PCL nanofibers. Nanofiber mats incorporated with EE or CE exhibited visible color changes (ΔE ≥ 3) in response to buffer solutions (pH between 3 and 10), and ammonia vapor. Smart nanofibers have demonstrated the ability to monitor fish fillet spoilage through visible color changes (ΔE ≥ 3) during storage. Consequently, smart nanofibers produced by the SBS technique, using PCL and anthocyanins from agro-industrial waste, reveal potential as smart packaging materials for food.

Amorphous Solid Dispersion Formation for Enhanced Release Performance of Racemic and Enantiopure Praziquantel

Praziquantel (PZQ) is the treatment of choice for schistosomiasis, which affects more than 250 million people globally. Commercial tablets contain the crystalline racemic compound (RS-PZQ) which limits drug dissolution and oral bioavailability and can lead to unwanted side effects and poor patient compliance due to the presence of the S-enantiomer. While many approaches have been explored for improving PZQ's dissolution and oral bioavailability, studies focusing on investigating its release from amorphous solid dispersions (ASDs) have been limited. In this work, nucleation induction time experiments were performed to identify suitable polymers for preparing ASDs using RS-PZQ and R-PZQ, the therapeutically active enantiomer. Cellulose-based polymers, hydroxypropyl methylcellulose acetate succinate (HPMCAS, MF grade) and hydroxypropyl methylcellulose (HPMC, E5 LV grade), were the best crystallization inhibitors for RS-PZQ in aqueous media and were selected for ASD preparation using solvent evaporation (SE) and hot-melt extrusion (HME). ASDs prepared experimentally were subjected to X-ray powder diffraction to verify their amorphous nature and a selected number of ASDs were monitored and found to remain physically stable following several months of storage under accelerated-stability testing conditions. SE HPMCAS-MF ASDs of RS-PZQ and R-PZQ showed faster release than HPMC E5 LV ASDs and maintained good performance with an increase in drug loading (DL). HME ASDs of RS-PZQ formulated using HPMCAS-MF exhibited slightly enhanced release compared to that of SE ASDs. SE HPMCAS-MF ASDs showed a maximum release increase of the order of 6 times compared to generic and branded (Biltricide) PZQ tablets. More importantly, SE R-PZQ ASDs with HPMCAS-MF released the drug as effectively as RS-PZQ or better, depending on the DL used. These findings have significant implications for the development of commercial PZQ formulations comprised solely of the R-enantiomer, which can result in mitigation of the biopharmaceutical and compliance issues associated with current commercial tablets.

A Novel Intrauterine Device for the Spatio-Temporal Release of Norethindrone Acetate as a Counter-Estrogenic Intervention in the Genitourinary Syndrome of Menopause

The genitourinary syndrome of menopause (GSM) is a widely occurring condition affecting millions of women worldwide. The current treatment of GSM involves the use of orally or vaginally administered estrogens, often with the risk of endometrial hyperplasia. The utilization of progestogens offers a means to counteract the effects of estrogen on the endometrial tissue, decreasing unwanted side effects and improving therapeutic outcomes. In this study, a norethindrone acetate (NETA)-loaded, hollow, cylindrical, and sustained release platform has been designed, fabricated, and optimized for implantation in the uterine cavity as a counter-estrogenic intervention in the treatment of GSM. The developed system, which comprises ethyl cellulose (EC) and polycaprolactone (PCL), has been statistically optimized using a two-factor, two-level factorial design, with the mechanical properties, degradation, swelling, and in vitro drug release of NETA from the device evaluated. The morphological characteristics of the platform were further investigated through scanning electron microscopy in addition to cytocompatibility studies using NIH/3T3 cells. Results from the statistical design highlighted the platform with the highest NETA load and the EC-to-PCL ratio that exhibited favorable release and weight loss profiles. The drug release data for the optimal formulation were best fitted with the Peppas-Sahlin model, implicating both diffusion and polymer relaxation in the release mechanism, with cell viability results noting that the prepared platform demonstrated favorable cytocompatibility. The significant findings of this study firmly establish the developed platform as a promising candidate for the sustained release of NETA within the uterine cavity. This functionality serves as a counter-estrogenic intervention in the treatment of GSM, with the platform holding potential for further advanced biomedical applications.

Preformulation and Long-Term Stability Studies of an Optimized Palatable Praziquantel Ethanol-Free Solution for Pediatric Delivery

To date, the treatment for cysticercosis and neurocysticercosis consists of a single oral intake of praziquantel (5-10 mg/kg), which since it is only available as tablets, hinders its administration to pediatric patients. Praziquantel is a poorly water-soluble drug which represents a challenge for its formulation in solution, particularly for the pediatric population. Thus, this study aimed to develop a palatable solution for praziquantel using pharmaceutical-accepted co-solvent systems. A design of experiments approach was applied to identify the optimal conditions for achieving a suitable amount of praziquantel in solution using co-solvent mixtures. Thus, praziquantel solubility increased from 0.38 up to 43.50 mg/mL in the optimized system. A taste masking assay in healthy human volunteers confirmed a successful reduction of drug bitterness after the addition of selected flavors and a sweetener. Stability studies were also conducted at different temperatures (4, 25, and 40 °C) for 12 months Even though the presence of the three known impurities of praziquantel was observed, their amounts never exceeded the acceptance criteria of the USP. Thus, this novel approach should be considered a valuable alternative for further preclinical studies considering the high prevalence of this infection worldwide.

Poly-ε-Caprolactone Implants for Benznidazole Prolonged Release: An Alternative to Chagas Disease Oral Treatment

Benznidazole (BZ) tablets are the currently prescribed treatment for Chagas disease. However, BZ presents limited efficacy and a prolonged treatment regimen with dose-dependent side effects. The design and development of new BZ subcutaneous (SC) implants based on the biodegradable poly-ɛ-caprolactone (PCL) is proposed in this study for a controlled release of BZ and to improve patient compliance. The BZ–PCL implants were characterized by X-ray diffraction, differential scanning calorimetry, and scanning electron microscopy, which indicated that BZ remains in its crystalline state dispersed in the polymer matrix with no polymorphic transitions. BZ–PCL implants, even at the highest doses, induce no alteration of the levels of hepatic enzymes in treated animals. BZ release from implants to blood was monitored in plasma during and after treatment in healthy and infected animals. Implants at equivalent oral doses increase the body’s exposure to BZ in the first days compared with oral therapy, exhibiting a safe profile and allowing sustained BZ concentrations in plasma to induce a cure of all mice in the experimental model of acute infection by the Y strain of T. cruzi. BZ–PCL implants have the same efficacy as 40 daily oral doses of BZ. Biodegradable BZ implants are a promising option to reduce failures related to poor adherence to treatment, with more comfort for patients, and with sustained BZ plasma concentration in the blood. These results are relevant for optimizing human Chagas disease treatment regimens.

Development and evaluation of raloxifene hydrochloride-loaded subdermal implants using hot-melt extrusion technology

Implantable drug delivery systems are known to provide great patient compliance and allow for controlled delivery of drugs over a prolonged period of time. This study aimed to prepare novel polycaprolactone/polyethylene glycol-based raloxifene hydrochloride subdermal solid cylindrical implants using a single-step hot-melt extrusion (HME) continuous process, for the provision of a sustained and prolonged release of RX-HCl as a cornerstone and alternative treatment and prevention option of osteoporosis, most especially post-menopausal osteoporosis, and invasive breast cancer, while providing better clinical outcomes by circumventing clinical and biopharmaceutical hurdles like first-pass metabolism and patient non-adherence and incompliance associated with the oral dosage forms of raloxifene hydrochloride. The 11-mm co-rotating twin-screw extruder was used to prepare the implants. The prepared cylindrical-shaped solid implants with dimensions of 10 mm (length) by 2 mm (diameter) were characterized by DSC, PXRD, FTIR, SEM, and in vitro dissolution analysis. Based on the physicochemical characterization of the prepared implants, the HME fabrication technology and optimized process parameters were determined to be acceptable and suitable. The prepared implants showed no obvious burst release and no significant amounts of drug on the surface of the implants. F-1, F-2, and F-3 implant batches showed a maximum cumulative percent drug release of 82.9 %, 42.2 %, and 20.6 %, respectively, in a period of 30 days, and 100 % drug release would be expected in a period of about 40 days (F-1), 72 days (F-2), and up to 150 days (F-3) by simple extrapolation. Interestingly, implant batches with a low drug load exhibited a relatively faster and higher rate of release of the drug compared to implant batches with high drug loading. In the present study, a single-step HME process was successfully used to fabricate RX-HCl-loaded subdermal implants, that could potentially be used as a cornerstone regimen in the treatment and prevention of osteoporosis, most especially post-menopausal osteoporosis, by providing release of RX-HCl over a long time period, and avoiding the clinical inconveniences and possible patient incompliance caused by daily administration of the drug.

Proof of concept of a predictive model of drug release from long-acting implants obtained by fused-deposition modeling

In the pharmaceutical field, there is a growing interest in manufacturing of drug delivery dosage forms adapted to the needs of a large variety of patients. 3D printing has proven to be a powerful tool allowing the adaptation of immediate drug delivery dosage forms. However, there are still few studies focusing on the adaptation of long-acting dosage forms for patient suffering of neurological diseases. In this study, paliperidone palmitate (PP) was chosen as a model drug in combination with different polymers adapted for fused-deposition modeling (FDM). The impact of different printing parameters on the release of PP were investigated. The layer thickness and the infill percentage were studied using a quality by design approach. Indeed, by defining the critical quality attributes (CQA), a proof of concept of a prediction system, and a quality control system were studied through designs of experiments (DoE). The first part of this study was dedicated to the release of PP from a fix geometry. In the second part, the prediction system was developed to require only surface and surface to volume ratio. From that point, it was possible to get rid of a fix geometry and predict the amount of PP released from complex architectures.

Preparation, characterization and primary evaluation of trilayered biliary stent films for anti-cholangiocarcinoma and anti-biofilm formation

Excessive growth of tumor within biliary wall and formation of biofilm on inner surface of stent can cause restenosis or even obstruction after stent implantation. Therefore, it is important and valuable to develop a new biliary stent for anti-cholangiocarcinoma and anti-biofilm formation. Herein, we designed, prepared and primarily evaluated a new trilayered film for biliary stents consisting of one poly (lactic acid) (PLA) layer loaded with anti-tumor paclitaxel (PTX layer), one middle PLA isolation layer (isolation layer) and one PLA layer loaded with antimicrobial ofloxacin (OFLX layer). It is postulated that the PTX layer releases drug towards biliary wall with tumor, the OFLX layer releases drug towards lumen of bile duct and the isolation layer is used to separate from the PTX layer and the OFLX layer and facilitate drug release in unidirectional way. The prepared trilayered films were characterized in terms of morphology, microstructure, crystallinity and biodegradability. It was found that the films could effectively tune drug release by addition of different amounts of drug or PEG, release PTX and OFLX in opposite directions, effectively inhibit the proliferation of human cholangiocarcinoma RBE cells, the adherence of E. coli and S. aureus and the formation of biofilm in vitro. It is potential that the trilayered films can be used to fabricate a new biliary stent with a dual function of anti-cholangiocarcinoma and anti-biofilm formation.

Long-acting implantable dosage forms containing paliperidone palmitate obtained by 3D printing

In this work, the versatility of pressure extrusion-based printing (PEBP) was used as 3D printing process to create long-acting implantable dosage forms. Different release profiles were achieved based on the drug concentration, the way of preparation and the design of the final implants. Polycaprolactone (PCL) was used as the polymer to sustain the release of the loaded drug. Paliperidone palmitate (PP), a BCS Class II drug, used in the treatment of schizophrenia, was used as the model drug. Two PP concentrations (e.g. 5 and 10% w/w) as well as two methods of preparation before the 3D printing process, mortar and pestle and cryogenic milling, were evaluated. The amorphous state of PP was obtained by using cryogenic milling and it was maintained after printing. Two designs were printed by PEBP, a ring and a disk, to evaluate their impact on the release profile of PP. During the in vitro dissolution tests, the implant design, the amount of PP, as well as the crystalline or amorphous state of PP have shown to influence the drug release profile. During the successive steps of preparation of the long-acting implants, blends and raw materials were characterized by DSC and XRD.

Textile Materials Modified with Stimuli-Responsive Drug Carrier for Skin Topical and Transdermal Delivery

Textile materials, as a suitable matrix for different active substances facilitating their gradual release, can have an important role in skin topical or transdermal therapy. Characterized by compositional and structural variety, those materials readily meet the requirements for applications in specific therapies. Aromatherapy, antimicrobial substances and painkillers, hormone therapy, psoriasis treatment, atopic dermatitis, melanoma, etc., are some of the areas where textiles can be used as carriers. There are versatile optional methods for loading the biologically active substances onto textile materials. The oldest ones are by exhaustion, spraying, and a pad-dry-cure method. Another widespread method is the microencapsulation. The modification of textile materials with stimuli-responsive polymers is a perspective route to obtaining new textiles of improved multifunctional properties and intelligent response. In recent years, research has focused on new structures such as dendrimers, polymer micelles, liposomes, polymer nanoparticles, and hydrogels. Numerous functional groups and the ability to encapsulate different substances define dendrimer molecules as promising carriers for drug delivery. Hydrogels are also high molecular hydrophilic structures that can be used to modify textile material. They absorb a large amount of water or biological fluids and can support the delivery of medicines. These characteristics correspond to one of the current trends in the development of materials used in transdermal therapy, namely production of intelligent materials, i.e., such that allow controlled concentration and time delivery of the active substance and simultaneous visualization of the process, which can only be achieved with appropriate and purposeful modification of the textile material.

Preparation and characterization of a new solid form of praziquantel, an essential anthelmintic drug. Praziquantel racemic monohydrate

Praziquantel (PZQ) is a highly effective low-cost anthelmintic agent used as the first-choice treatment against schistosomiasis. The low solubility of the active is a major drawback for pharmaceutical formulation. A valid approach of the pharmaceutical industry for the improvement of the pharmacotechnical features of the active principles (such as solubility, processability, stability, among others), is the preparation of new solid forms, such as salts, polymorph, and pseudo-polymorph. Herein we report the preparation and characterization of a new solid form PZQ. The PZQ monohydrate (PZQ-MH) was prepared by a solventless procedure from the commercial racemate and the product was characterized at the solid-state employing optical digital microscopy, thermal methods (melting point, differential scanning calorimetry and thermogravimetric analysis), as well as and mid-infrared and near infrared spectroscopies. The chemical structure and content of water were full assessed by ¹H nuclear magnetic resonance (NMR) in solution. The amount of water in PZQ-was also determined by different approaches, including thermogravimetric analysis and the loss on drying test. Solid-state ¹³C NMR (ssNMR) and X-ray powder diffraction (XRPD) completed the structural characterization of the new monohydrate. PZQ-MH showed a crystalline behavior during XRPD experiments and showed relevant differences in spectroscopic, calorimetric, ssNMR and XRPD signals when it was compared with the known crystal (Form A) and amorphous forms of PZQ. The determination of the intrinsic dissolution rate (IDR) of PZQ-MH was carried out as a functional characterization, observing that the new form had slightly higher IDR than Form A.

Schistosomiasis: Drugs used and treatment strategies

Neglected tropical diseases (NTDs) affect millions of people in different geographic regions, especially the poorest and most vulnerable. Currently NTDs are prevalent in 149 countries, seventeen of these neglected tropical parasitic diseases are classified as endemic. One of the most important of these diseases is schistosomiasis, also known as bilharzia, a disease caused by the genus Schistosoma. It presents several species, such as Schistosoma haematobium, Schistosoma japonicum and Schistosoma mansoni, the latter being responsible for parasitosis in Brazil. Contamination occurs through exposure to contaminated water in the endemic region. This parasitosis is characterized by being initially asymptomatic, but it is able to evolve into more severe clinical forms, potentially causing death. Globally, more than 200 million people are infected with one of three Schistosome species, including an estimated 40 million women of reproductive age. In Brazil, about 12 million children require preventive chemotherapy with anthelmintic. However, according to the World Health Organization (WHO), only about 15% of the at-risk children receive regular treatment. The lack of investment by the pharmaceutical industry for the development and/or improvement of new pharmaceutical forms, mainly aimed at the pediatric public, is a great challenge. Currently, the main forms of treatment used for schistosomiasis are praziquantel (PZQ) and oxaminiquine (OXA). PZQ is the drug of choice because it presents as a high-spectrum anthelmintic, used in the treatment of all known species of schistosomiasis and some species of cestodes and trematodes. OXA, however, is not active against the three Schistosome species. This work presents a literature review regarding schistosomiasis. It addresses points such as available treatments, the role of the pharmaceutical industry against neglected diseases, and perspectives for treatment.

Three-Dimensional Printed PCL-Based Implantable Prototypes of Medical Devices for Controlled Drug Delivery

The goal of the present study was to fabricate drug-containing T-shaped prototypes of intrauterine system (IUS) with the drug incorporated within the entire backbone of the medical device using 3-dimensional (3D) printing technique, based on fused deposition modeling (FDM™). Indomethacin was used as a model drug to prepare drug-loaded poly(ε-caprolactone)-based filaments with 3 different drug contents, namely 5%, 15%, and 30%, by hot-melt extrusion. The filaments were further used to 3D print IUS. The results showed that the morphology and drug solid-state properties of the filaments and 3D prototypes were dependent on the amount of drug loading. The drug release profiles from the printed devices were faster than from the corresponding filaments due to a lower degree of the drug crystallinity in IUS in addition to the differences in the external/internal structure and geometry between the products. Diffusion of the drug from the polymer was the predominant mechanism of drug release, whereas poly(ε-caprolactone) biodegradation had a minor effect. This study shows that 3D printing is an applicable method in the production of drug-containing IUS and can open new ways in the fabrication of controlled release implantable devices.

Polymeric formulations for drug release prepared by hot melt extrusion: application and characterization

Over the past few decades hot melt extrusion (HME) has emerged as a powerful processing technology for the production of pharmaceutical solid dosage forms in which an active pharmaceutical ingredient (API) is dispersed into polymer matrices. It has been shown that formulations using HME can provide time-controlled, sustained and targeted drug delivery, and improved bioavailability of poorly soluble drugs. In this review, the basic principles of the HME process are described together with an overview of some of the most common biodegradable and nonbiodegradable polymers used for the preparation of different formulations using this method. Further, the applications of HME in drug delivery and analytical techniques employed to characterize HME products are addressed.

Development and evaluation of sustained-release etoposide-loaded poly(ε-caprolactone) implants

Poly(ε-caprolactone) implants containing etoposide, an important chemotherapeutic agent and topoisomerase II inhibitor, were fabricated by a melt method and characterized in terms of content uniformity, morphology, drug physical state, and sterility. In vitro and in vivo drug release from the implants was also evaluated. The cytotoxic activity of implants against HeLa cells was studied. The short-term tolerance of the implants was investigated after subcutaneous implantation in mice. The original chemical structure of etoposide was preserved after incorporation into the polymeric matrix, in which the drug was dispersed uniformly. Etoposide was present in crystalline form in the polymeric implant. In vitro release study showed prolonged and controlled release of etoposide, which showed cytotoxicity activity against HeLa cells. After implantation, good correlation between in vitro and in vivo drug release was found. The implants demonstrated good short-term tolerance in mice. These results tend to show that etoposide-loaded implants could be potentially applied as a local etoposide delivery system.

Preparation and evaluation of sustained-release matrix tablets based on metoprolol and an acrylic carrier using injection moulding

Sustained-release matrix tablets based on Eudragit RL and RS were manufactured by injection moulding. The influence of process temperature; matrix composition; drug load, plasticizer level; and salt form of metoprolol: tartrate (MPT), fumarate (MPF) and succinate (MPS) on ease of processing and drug release were evaluated. Formulations composed of 70/30% Eudragit RL/MPT showed the fastest drug release, substituting part of Eudragit RL by RS resulted in slower drug release, all following first-order release kinetics. Drug load only affected drug release of matrices composed of Eudragit RS: a higher MPT concentration yielded faster release rates. Adding triethyl citrate enhanced the processability, but was detrimental to long-term stability. The process temperature and plasticizer level had no effect on drug release, whereas metoprolol salt form significantly influenced release properties. The moulded tablets had a low porosity and a smooth surface morphology. A plasticizing effect of MPT, MPS and MPF on Eudragit RS and Eudragit RL was observed via DSC and DMA. Solubility parameter assessment, thermal analysis and X-ray diffraction demonstrated the formation of a solid solution immediately after production, in which H-bonds were formed between metoprolol and Eudragit as evidenced by near-infrared spectroscopy. However, high drug loadings of MPS and MPF showed a tendency to recrystallise during storage. The in vivo performance of injection-moulded tablets was strongly dependent upon drug loading.

Preparation and in vitro characterization of SN-38-loaded, self-forming polymeric depots as an injectable drug delivery system

This work describes the preparation and characterization of anticancer-loaded injectable polymeric depots that consisted of D,L-lactide (LA), ε-caprolactone (CL), and poly(ethylene glycol) (PEG) or [poly(ε-caprolactone)-random-poly(D,L-lactide)]-block-poly(ethylene glycol)-block-[poly(ε-caprolactone)-random-poly(D,L-lactide)] (PLEC) copolymers for malignant gliomas treatment. PLECs were polymerized with different percentages of LA to deliver 7-ethyl-10-hydroxycamptothecin (SN-38), a highly potent anticancer drug. SN-38-loaded depots could form directly in phosphate buffer saline with more than 98% encapsulation efficiency. The release rate of SN-38 from depots was found to depend on the amount of LA in PLECs, loading content of SN-38 in the depots, and depot weight. Encapsulation of SN-38 inside depots could enhance the stability of SN-38 where all of SN-38 released after 60 days was in an active form. Depots without SN-38 were evaluated as noncytotoxic against U-87MG, whereas SN-38-loaded depots showed cytotoxic effect as a function of concentration.

Challenges for diagnosis and control of cystic hydatid disease

This paper is based on the experience of the authors, with the aim to define the challenges for Echinococcus granulosus (E.g./CE) diagnosis and control for those countries that may now or in the future be contemplating control of hydatid disease. A variety of methods are available for diagnosis in humans but a universal gold standard is lacking. Diagnosis in definitive hosts can avoid necropsy by the use of methods such as coproantigen detection but test performance is variable between populations. A sylvatic cycle adds challenges in some countries and the epidemiology of the parasite in these hosts is poorly understood. Control by solely administering praziquantel to dogs is not effective in developing countries where the disease is endemic. Additional avenues to pursue include the instigation of participatory planning, use of an existing vaccination for intermediate hosts and development of a vaccine and long-acting anthelmitic implants for definitive hosts. Promoting public acceptance of control of the dog population by humane euthanasia and reduced reproduction is also essential.

Prevention of Schistosoma japonicum infection in mice with long-acting praziquantel implants

This work reports the prevention outcomes of a praziquantel (PZQ) implant against the infection of Schistosoma japonicum in mice. The PZQ implant produced stable plasma PZQ concentrations in a range of 100-1300 ng/mL for a period of 70 days, by releasing PZQ in subcutaneous tissues in a sustained manner. To assess the prevention effects, the mice were infected at varying times after implantation. All the mice were sacrificed at 6 weeks after infection for worm and egg recovery and counting, worm morphological examination, determination of egg-hatching rates, and analysis of hepatic histology. The infection was successfully prevented for mice with early infection times (within 2-3 weeks), as nearly no worms, paired worms, eggs, or miracidia were recovered. However, in mice with late infection times (after 3 weeks), the prevention effects were diminished due to the decreased plasma PZQ concentrations at late times. Interestingly, the implants showed robust prevention effects on repeated infection at 1 and 3 weeks. In the infection-prevented mouse livers, no granuloma formation or granulomatous inflammation was observed. The results demonstrated that by blocking the development of infecting miracidia and by deactivating the eggs, the PZQ implants encouragingly prevented the S. japonicum infection and avoided liver damage.

Poly-є-caprolactone based formulations for drug delivery and tissue engineering: A review

Biodegradable polymer based novel drug delivery systems have provided many avenues to improve therapeutic efficacy and pharmacokinetic parameters of medicinal entities. Among synthetic biodegradable polymer, poly-є-caprolactone (PCL) is a polymer with very low glass transition temperature and melting point. Owing to its amicable nature and tailorable properties it has been trialed in almost all novel drug delivery systems and tissue engineering application in use/investigated so far. This review aims to provide an up to date of drugs incorporated in different PCL based formulations, their purpose and brief outcomes. Demonstrated PCL formulations with or without drugs, intended for drug delivery and/or tissue engineering application such as microsphere, nanoparticles, scaffolds, films, fibers, micelles etc. are categorized based on method of preparation.

Study on hydrophilic 5-fluorouracil release from hydrophobic poly(ε-caprolactone) cylindrical implants

Hydrophilic 5-fluorouracil (5-FU) loaded cylindrical poly(ε-caprolactone) (PCL) implants with different implant diameters (2, 4 and 8 mm), different drug loadings (25% and 50%) and end-capping were fabricated and characterized. The implant structure, drug content and molecular weight of PCL after 120 days drug release were investigated. The in vitro release results showed that, when the drug loading was the same, drug release was fastest for the implant with a diameter of 2 mm and slowest for the implant with a diameter of 8 mm; for the implants with the same diameters, the release of drug from the implants with 50% drug loading was faster than that from the implants with 25% drug loading; however, this effect of drug loading decreased with the increase of implant diameter; in addition, 5-FU was released slightly slower from the end-capped implants than from the corresponding uncapped implants; the drug release data for all the uncapped implants were best fit with the Ritger-Peppas model. Drug release from the hydrophobic implants was found to be dominated by diffusion mechanism. Scanning electron microscopy images and drug content measurements revealed that 5-FU release took place gradually from the exterior region to the interior region of the implants.

An agent-based model for control strategies of Echinococcus granulosus

Cystic echinococcosis is a widespread zoonosis, caused by Echinococcus granulosus. The definitive hosts are carnivores and the intermediate hosts are grazing animals. Because humans are often accidentally infected with the cystic stage of the parasite, a control program is being developed for Western China. Western Sichuan Province in China is a highly endemic area. In this study, we built an agent-based model (ABM) to simulate and assess possible control strategies. These included dog dosing, control of livestock slaughter, health education, vaccination of intermediate hosts, vaccination of definitive hosts, slow-released praziquantel injections for dogs, removing unproductive old livestock, dog population reduction. These strategies were examined singly and in various combinations. The results show that vaccination based control strategies and also combined control strategies (dog dosing, slaughter control, removing old livestock, dog population reduction) can achieve a higher efficiency and be more feasible. Although monthly dog dosing achieved the highest efficiency, it required a high frequency and reliability, which were not feasible or sustainable. The model also indicated that transmission would recover soon after the chosen control strategy was stopped, indicating the need to move from a successful attack phase to a sustainable consolidation phase.

Evaluation of two polymeric blends (EVA/PLA and EVA/PEG) as coating film materials for paclitaxel-eluting stent application

The ethylene vinyl acetate copolymer (EVA)/Poly (lactic acid) (PLA) blend and EVA/Poly (ethylene glycol) (PEG) blend were applied as the drug carrier materials for a bi-layer drug-loaded stent coating film, which consisted of a paclitaxel (PTX)-loaded layer and a drug-free EVA layer. The changes of weight and appearance of the drug-free polymeric blend films with increasing time were examined by X-ray diffraction analysis (XRD), gel permeation chromatography (GPC) tests and scanning electronic microscopy (SEM), and the results showed the degradation of PLA and the leaching of PEG from the films. The effects of PLA, PEG and drug contents on in vitro drug release were investigated, and the results demonstrated that the addition of PLA promoted the drug release while the addition of PEG almost did not. Franz cells diffusion test results indicated that the bi-layer structure successfully endowed the stent coating with the release of drug in a unidirectional fashion. The release profiles of films incorporated PTX and the mechanical performance of the film could be customized by readily adjusting the contents of the blend components. Therefore, the polymeric blends could be useful drug carrier materials for drug-loaded stent coating capable of releasing drug in a highly tunable manner.

Changed crystallinity of mebendazole solid dispersion: improved anthelmintic activity

To improve the efficacy of mebendazole (MBZ), a poorly water-soluble drug, MBZ solid dispersions containing different proportions of low-substituted hydroxypropylcellulose (L-HPC) were prepared by lyophilization process. The physical characteristics of recrystallized MBZ, and solid dispersions (SD) at different MBZ:L-HPC proportions were investigated in terms of morphology (scanning electron microscopy, SEM), powder X-ray diffraction (XRD), differential scanning calorimetry (DSC) and dissolution rate. The in vivo performance was assessed by anthelmintic activity studies against enteral (pre-adult) stage of Trichinella spiralis in mice. The XRD, DSC and SEM revealed a characteristic decrease in crystallinity when increasing the L-HPC proportions in the solid dispersions. The dissolution studies demonstrated a marked increase in the dissolution rate in comparison with recrystallized drug. The considerable improvement in the dissolution rate of MBZ from solid dispersions was attributed to decreased drug crystallinity and altered surface morphology (major) and to the wetting effect of L-HPC (minor). The in vivo studies revealed that the anthelmintic effects of solid dispersions in mice were significantly increased in comparison with recrystallized MBZ (1.74-fold for SD-1:1, 3.20-fold for SD-1:2.5 and 3.80-fold for SD-1:5). These results have shown the suitability of MBZ:L-HPC solid dispersions for the treatment of enteral helmintic diseases at low doses.