Optimized zein nanospheres for improved oral bioavailability of atorvastatin

Zein-Based Nanoparticles Improve the Therapeutic Efficacy of a TrkB Agonist toward Alzheimer's Disease

The brain-derived neurotrophic factor (BDNF)/TrkB pathway plays a crucial role in neural plasticity and neuronal survival but is often deficient in neurodegenerative diseases like Alzheimer's disease (AD). CF3CN acts as a specific TrkB agonist that displays therapeutic effects in the AD mouse model, but its brain/plasma ratio (B/P ratio) distribution is not satisfactory. To increase its brain exposure, we synthesized several derivatives and employed nanoparticle (NP) formulation to optimize the most potent #2 derivative's in vivo PK profiles. We generated stable #2-loaded zein/lactoferrin composite NPs (#2/zein/LF) using the antisolvent co-precipitation method. In vivo PK studies revealed that nanoencapsulation improved #2's oral bioavailability by approximately 2-fold and significantly enhanced its plasma Cmax and t1/2, but the brain profiles were comparable. Pharmacodynamics showed that #2/zein/LF activates TrkB signaling that phosphorylates asparagine endopeptidase (AEP) T322 and decreases its enzymatic activity, resulting in reduced AEP-cleaved amyloid precursor protein and Tau fragments in the brains of AD mice, correlating with its PK profiles. After 3 months of treatment in 3xTg mice, #2/zein/LF decreased AD pathologies and alleviated cognitive dysfunction. Hence, zein/LF composite nanoencapsulation is a promising drug delivery method for improving the PK profiles of a potential preclinical candidate for treating neurodegenerative diseases.

Intensification of resveratrol cytotoxicity, pro-apoptosis, oxidant potentials in human colorectal carcinoma HCT-116 cells using zein nanoparticles

Resveratrol (RSV), a non-flavonoid stilbene polyphenol, possesses anti-carcinogenic activities against all the major stages of cancer. Zein nanoparticles (ZN NPs) have been utilized successfully in delivery of variant therapeuticals by virtue of their histocompatible nature. The goal of this work was to comparatively explore the antiproliferative, pro-apoptotic and oxidative stress potentials of RSV-ZN NPs versus RSV against human colorectal carcinoma HCT-116 cells. ZN-RSV NPs were developed and assayed for particle size analysis and RSV diffusion. The selected formula obtained 137.6 ± 8.3 nm as mean particle size, 29.4 ± 1.8 mV zeta potential, 92.3 ± 3.6% encapsulation efficiency. IC₅₀ of the selected formula was significantly lower against HCT-116 cells versus Caco-2 cells. Also, significantly enhanced cellular uptake was generated from RSV-ZN NPs versus free RSV. Enhanced apoptosis was concluded due to increased percentage cells in G2-M and pre-G1 phases. The pro-apoptotic potential was explained by caspase-3 and cleaved caspase-3 increased mRNA expression in addition to NF-κB and miRNA125b decreased expression. Biochemically, ZN-RSV NPs induced oxidative stress as demonstrated by enhanced reactive oxygen species (ROS) generation and endothelial nitric oxide synthase (eNOS) isoenzyme increased levels. Conclusively, ZN-RSV NPs obtained cell cycle inhibition supported with augmented cytotoxicity, uptake and oxidative stress markers levels in HCT-116 tumor cells in comparison with free RSV. These results indicated intensified chemopreventive profile of RSV due to effective delivery utilizing ZN nano-dispersion against colorectal carcinoma HCT-116 cells.

Zein Microparticles and Nanoparticles as Drug Delivery Systems

Zein is a natural, biocompatible, and biodegradable polymer widely used in the pharmaceutical, biomedical, and packaging fields because of its low water vapor permeability, antibacterial activity, and hydrophobicity. It is a vegetal protein extracted from renewable resources (it is the major storage protein from corn). There has been growing attention to producing zein-based drug delivery systems in the recent years. Being a hydrophobic biopolymer, it is used in the controlled and targeted delivery of active principles. This review examines the present-day landscape of zein-based microparticles and nanoparticles, focusing on the different techniques used to obtain particles, the optimization of process parameters, advantages, disadvantages, and final applications.

Formulation of Gelucire®-Based Solid Dispersions of Atorvastatin Calcium: In Vitro Dissolution and In Vivo Bioavailability Study

Atorvastatin (ATV) is a poorly water-soluble drug that exhibits poor oral bioavailability. Therefore, present research was designed to develop ATV solid dispersions (SDs) to enhance the solubility, drug release, and oral bioavailability. Various SDs of ATV were formulated by conventional and microwave-induced melting methods using Gelucire®48/16 as a carrier. The formulated SDs were characterized for different physicochemical characterizations, drug release, and oral bioavailability studies. The results obtained from the different physicochemical characterization indicate the molecular dispersion of ATV within various SDs. The drug polymer interaction results showed no interaction between ATV and used carrier. There was marked enhancement in the solubility (1.95-9.32 folds) was observed for ATV in prepared SDs as compare to pure ATV. The drug content was found to be in the range of 96.19% ± 2.14% to 98.34% ± 1.32%. The drug release results revealed significant enhancement in ATV release from prepared SDs compared to the pure drug and the marketed tablets. The formulation F8 showed high dissolution performance (% DE₃₀ value of 80.65 ± 3.05) among the other formulations. Optimized Gelucire®48/16-based SDs formulation suggested improved oral absorption of atorvastatin as evidenced with improved pharmacokinetic parameters (C_max 2864.33 ± 573.86 ng/ml; AUC_0-t 5594.95 ± 623.3 ng/h ml) as compared to ATV suspension (C_max 317.82 ± 63.56 ng/ml; AUC_0-t 573.94 ± 398.9 ng/h ml) and marketed tablets (C_max 852.72 ± 42.63 ng/ml; 4837.4 ± 174.7 ng/h ml). Conclusively, solid dispersion-based oral formulation of atorvastatin could be a promising approach for enhanced drug solubilization, dissolution, and subsequently improved absorption.

Piceatannol-Loaded Bilosome-Stabilized Zein Protein Exhibits Enhanced Cytostatic and Apoptotic Activities in Lung Cancer Cells

Piceatannol (PIC) is a naturally occurring polyphenolic stilbene, and it has pleiotropic pharmacological properties. Moreover, PIC has cytotoxic actions among various cancer cells. In this work, preparations of PIC-loaded bilosome-zein (PIC-BZ) were designed, formulated, and characterized, and the optimized PIC-BZ cytotoxic activities, measured as half maximal inhibitory concentration (IC50), against lung cancer cell line was investigated. Box-Behnken design was utilized in order to examine the effect of preparation factors on drug entrapment and particle size. PIC-BZ showed a spherical shape after optimization, and its particle size was determined as 157.45 ± 1.62 nm. Moreover, the efficiency of drug entrapment was found as 93.14 ± 2.15%. The cytotoxic activity evaluation revealed that the adjusted formulation, which is PIC-BZ formula, showed a substantially smaller IC50 versus A549 cells. Cell cycle analysis showed accumulation of cells in the G2-M phase. Moreover, it showed in the sub-G1 phase, a rise of cell fraction suggestion apoptotic improving activity. Increased early and late phases of apoptosis were demonstrated by staining of cells with annexin V. Furthermore, the cellular caspase-3 protein expression was significantly raised by PIC-BZ. In addition, the wound healing experiment confirmed the results. To conclude, compared to pure PIC, PIC-BZ demonstrated a higher cell death-inducing activity against A549 cells.

Amelioration of Pterostilbene Antiproliferative, Proapoptotic, and Oxidant Potentials in Human Breast Cancer MCF7 Cells Using Zein Nanocomposites

Purpose

This study aimed to explain the influence of zein nanosphere (ZN NS) formulation on the pharmacotherapeutic profile of PTS in MCF7 cells.

Methods

Liquid–liquid phase separation was used to formulate PTS-ZN NSs. The formulations developed were evaluated for particle-size analysis, encapsulation efficiency, and in vitro diffusion. Also, assays of cytotoxicity, uptake, cell-cycle progression, annexin V, apoptotic gene mRNA expression and biochemical assays were carried out.

Results

The PTS-ZN NS formulation selected showed 104.5±6.2 nm, 33.4±1.8 mV, 95.1%±3.6%, and 89.1%±2.65% average particle size, zeta-potential, encapsulation efficiency and in vitro diffusion, respectively. With MCF7 cells, IC₅₀ was reduced approximately 15-fold, with increased cellular uptake, accumulation in the G₂/M phase, increased percentage of cells in the pre-G₁ phase, amelioration of early and late apoptosis, raised mRNA expression of CASP3 and CASP7, lower expression of cyclin-CDK1, and enhanced oxidant potential through decreased glutathione reductase (GR) activity, and enhanced reactive oxygen–species generation and lipid-peroxidation products.

Conclusion

PTS-ZN NSs indicated enhanced antiproliferative, proapoptotic, and oxidant potential toward MCF7 cells compared to free PTS. Ameliorated results of nanosized carriers, cellular uptake, and sustained diffusion may contribute to these outcomes.

Fabrication and Characterisation of a Photo-Responsive, Injectable Nanosystem for Sustained Delivery of Macromolecules

The demand for biodegradable sustained release carriers with minimally invasive and less frequent administration properties for therapeutic proteins and peptides has increased over the years. The purpose of achieving sustained minimally invasive and site-specific delivery of macromolecules led to the investigation of a photo-responsive delivery system. This research explored a biodegradable prolamin, zein, modified with an azo dye (DHAB) to synthesize photo-responsive azoprolamin (AZP) nanospheres loaded with Immunoglobulin G (IgG). AZP nanospheres were incorporated in a hyaluronic acid (HA) hydrogel to develop a novel injectable photo-responsive nanosystem (HA-NSP) as a potential approach for the treatment of chorio-retinal diseases such as age-related macular degeneration (AMD) and diabetic retinopathy. AZP nanospheres were prepared via coacervation technique, dispersed in HA hydrogel and characterised via infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Size and morphology were studied via scanning electron microscopy (SEM) and dynamic light scattering (DLS), UV spectroscopy for photo-responsiveness. Rheological properties and injectability were investigated, as well as cytotoxicity effect on HRPE cell lines. Particle size obtained was <200 nm and photo-responsiveness to UV = 365 nm by decreasing particle diameter to 94 nm was confirmed by DLS. Encapsulation efficiency of the optimised nanospheres was 85% and IgG was released over 32 days up to 60%. Injectability of HA-NSP was confirmed with maximum force 10 N required and shear-thinning behaviour observed in rheology studies. In vitro cell cytotoxicity effect of both NSPs and HA-NSP showed non-cytotoxicity with relative cell viability of ≥80%. A biocompatible, biodegradable injectable photo-responsive nanosystem for sustained release of macromolecular IgG was successfully developed.

Co-processing of Atorvastatin and Ezetimibe for Enhanced Dissolution Rate: In Vitro and In Vivo Correlation

Development of fixed dose combinations is growing and many of these drug combinations are being legally marketed. However, the development of these requires careful investigation of possible physicochemical changes during co-processing. This requires investigation of the effect of co-processing of drug combination in absence of excipients to maximize the chance of interaction (if any). Accordingly, the aim was to investigate the effect of co-processing of ezetimibe and atorvastatin on drugs dissolution rate. The objective was extended to in vitro in vivo correlation. Drugs were subjected to wet co-processing in presence of ethanol after being mixed at different ratios. The prepared formulations were characterized using FTIR spectroscopy, X-ray powder diffraction, differential scanning calorimetry, scanning electron microscopy, and in vitro dissolution testing. These investigations proved the possibility of eutectic system formation after drugs co-processing. This was reflected on drugs dissolution rate which was significantly enhanced at dose ratio and 2:1 atorvastatin:ezetimibe molar ratio compared to the corresponding pure drugs. In vivo antihyperlipidemic effects of the co-processed drugs were monitored in albino mice which were subjected to hyperlipidemia induction using poloxamer 407. The results showed significant enhancement in pharmacological activity as revealed from pronounced reduction in cholesterol level in mice administering the co-processed form of both drugs. Besides, histopathological examinations of the liver showed marked decrease in hepatic vacuolation. In conclusion, co-processing of atorvastatin with ezetimibe resulted in beneficial eutexia which hastened the dissolution rate and pharmacological effects of both drugs.Graphical abstract.

Zein nanoparticles as nontoxic delivery system for maytansine in the treatment of non-small cell lung cancer

Purpose: Maytansine (DM1) is a potent anticancer drug and limited in clinical application due to its poor water solubility and toxic side effects. Zein is widely used in nano drug delivery systems due to its good biocompatibility. In this study, we prepared DM1-loaded zein nanoparticles (ZNPs) to achieve tumor targeting and reduce toxic side effects of DM1. Methods: ZNPs were prepared by phase separation and Box-Behnken design was used to optimize the formulation. Then, confocal fluorescence microscope and flow cytometry were used to determine cellular uptake of ZNPs. A549 cells were cultured in vitro to study cytotoxicity and used to establish tumor xenografts in nude mice. Biodistribution and antitumor activity of ZNPs were performed in vivo experiments. In addition, we also performed histological and immunohistochemical examinations on tumors and viscera. Results: The optimal prescription was obtained by using 120 μL zein added to 2 mL water under stirring in 300 rpm. The encapsulation efficiency and drug loading were 82.97 ± 0.80% and 3.32 ± 0.03%, respectively. We found that DM1-loaded ZNPs have a strong inhibitory effect on A549 cells, which stemmed from the ability of ZNPs to enhance cellular uptake. Furthermore, we demonstrated that DM1-loaded ZNPs exhibits a better antitumor efficacy than DM1, which tumor inhibition rate were 97.3% and 92.7%, respectively. The biodistribution revealed that ZNPs could targeted to tumor. Finally, we confirmed by histological that DM1-loaded ZNPs are nontoxic. Conclusion: DM1-loaded ZNPs have considerable antitumor activity. Thus, DM1-loaded ZNPs are a promising treatment of non-small cell lung cancer.

The Effect of Size, Dose, and Administration Route on Zein Nanoparticle Immunogenicity in BALB/c Mice

Background

Zein-based carriers are a promising delivery system for biomedical applications. However, few studies involve systematic investigation on their in vivo biocompatibility and immunogenicity.

Purpose

The objective of this study was to identify the immunogenicity, type of immune response, biocompatibility and systemic recall immune response of zein nanoparticles administrated via different routes in mice.

Animals and methods

Female Balb/c mice were selected as the animal model in this paper. The effect of particle size, dose and inoculation routes on immunogenicity were systematically explored. The mice were challenged at week 50 via intramuscular and subcutaneous routes to investigate the systemic recall immune responses of zein nanoparticles. Hematoxylin and eosin staining was performed to investigate the biocompatibility of zein nanoparticles at injection sites.

Results

The administration of zein particles by parenteral routes led to a long-term systemic immune response. Particle size did not affect zein-specific IgG antibody titers. IgG antibody titers and inflammatory cell infiltration at the injection sites resulting from intramuscular zein particle injection were significantly higher than those from subcutaneous injection of the same dose. For intramuscular inoculation, dose-dependent IgG antibody titers were observed after the third inoculation, while no significant difference was found via the subcutaneous route. For both routes, IgG titer showed a time-dependent decrease at all dose levels from week 5 onward, and finally plateaued at week 28. The IgG subtype assay showed a predominant Th2-type immune response for both administration routes. Challenge with zein nanoparticles at week 50 led to a significant increase in specific IgG titer at all dose levels, indicating systemic recall immune responses. Interestingly, IgG antibody levels in the subcutaneous groups showed a delayed decrease compared to those of the intramuscular injection groups at all dose levels.

Conclusion

This study indicated that immunogenicity may be one of the key challenges of using zein nanoparticles as carriers via parenteral administration. Further investigation is needed to illustrate zein immunogenicity in other forms, and the possible effect of systemic recall immune response on in vivo pharmacokinetic characteristics.

Encapsulation of Lovastatin in Zein Nanoparticles Exhibits Enhanced Apoptotic Activity in HepG2 Cells

Research on statins highlights their potent cytotoxicity against cancer cells and their potential for cancer prevention. The aim of the current study was to examine whether loading lovastatin (LVS) in zein (ZN) nanoparticles (NPs) would potentiate the anti-proliferative effects of LVS and enhance its proliferation-inhibiting activity in HepG2 cells. LVS-ZN NPs were prepared and showed excellent characteristics, with respect to their particle size, zeta potential, diffusion, and entrapment efficiency. In addition, they showed the most potent anti-proliferative activity against HepG2 cells. ZN alone showed an observable anti-proliferative that was significantly higher than that of raw LVS. Furthermore, LVS uptake by HepG2 cells was greatly enhanced by the formulation in ZN. A cell cycle analysis indicated that LVS induced a significant cell accumulation in the G2/M and pre-G phases. In this regard, the LVS-ZN NPs exhibited the highest potency. The accumulation in the pre-G phase indicated an enhanced pro-apoptotic activity of the prepared formula. The cells incubated with the LVS-ZN NPs showed the highest percentage of cells with annexin-V positive staining. In addition, the same incubations showed the highest content of caspase-3 enzyme in comparison to raw LVS or ZN. Thus, the loading of LVS in ZN nanoparticles enhances its anti-proliferative activity against HepG2 cells, which is attributed, at least partly, to the enhanced cellular uptake and the induction of apoptosis.

Zein-alpha lipoic acid-loaded nanoparticles to enhance the oral bioavailability of dapoxetine: optimization and clinical pharmacokinetic evaluation

Background

Premature ejaculation (PE) is the most common type of male sexual disorder with important psychological consequences. Dapoxetine (DPX), a recently approved drug for the treatment of PE, suffers from low bioavailability with large variability that ranges from 15–76% (mean 42%) after oral administration. The objective of this study is to optimize the parameters for the preparation of DPX-Zein-alpha lipoic acid (ALA) nanoparticles (NPs) to improve the bioavailability of DPX and consequently decrease therapeutic dose and adverse effect, leading to patient satisfaction and compliance.

Methods

We investigated the effect of ALA concentration, PVA concentration and stirring rate on nanoparticle size (Y₁), zeta potential (Y₂), initial DPX release (Y₃) and cumulative DPX release (Y₄). In addition, in vivo pharmacokinetic study was performed for the optimized DPX formulation on human healthy volunteers compared with marketed DPX tablet.

Results

The optimized DPX-loaded NPs showed Y₁, Y₂, Y₃, and Y₄ of 159.24 nm, 19.14 mV, 25.31% and 95.9 %, respectively. A single oral dose of 30 mg of optimized DPX-loaded NPs to human volunteers resulted in 2-fold improvement of AUC (1376.145±339.592 vs 709.178±146.307 in DPX), 4-fold increase in t_max (2.5±0.314 vs 0.583±0.144), prolongation of MRT (7.637±1.373 compared to 6.031±1.826 h), but with reduction in t_1/2 (5.283±1.077 vs 8.452±2.813).

Conclusion

The clinical findings suggest 194% enhancement of relative bioavailability of the optimized DPX-loaded NPs, potentially leading to a decrease in therapeutic dose and associated side effects in the treatment of PE.

Development and single dose clinical pharmacokinetics investigation of novel zein assisted- alpha lipoic acid nanoencapsulation of vardenafil

The aim of this study was to utilize the biocompatibility of the natural ingredients zein and alpha lipoic acid (ALA) as a novel nanosphere matrix formulation that encapsulates vardenafil (VRD) for improved drug delivery and bioavailability. Three formulations were prepared using zein: ALA ratio of 1:1, 2:1 and 3:1 by liquid-liquid phase separation method. Physicochemical characterization and in vitro diffusion evaluation were carried out for the prepared formulations. A single dose clinical pharmacokinetic study was carried out for the selected formulation. Results revealed VRD formulations showed particle size of 836.7 ± 191.3, 179.8 ± 18.4 and 147.3 ± 18.1 nm and encapsulation efficiency of 55.72 ± 4.36, 65.33 ± 7.82 and 69.38 ± 6.83% for F1, F2 and F3, respectively. Single dose clinical pharmacokinetic results, in healthy human volunteers, showed improved VRD bioavailability by 2.5 folds from nanosphere formula (F3) compared with the marketed tablets. The formulation of novel zein-ALA nanospheres offers the possibility for application of a biocompatible nano-carrier system in drug delivery for improved drug delivery and efficacy.

Effect of the rigid segment content on the properties of segmented polyurethanes conjugated with atorvastatin as chain extender

Segmented polyurethanes were prepared with polycaprolactone diol as soft segment and various amounts of 4,4´-Methylenebis(cyclohexyl isocyanate) and atorvastatin, a statin used for lowering cholesterol, in order to obtain SPU with different content of rigid segments. Polyurethanes with 35% or 50% of rigid segment content were physicochemically characterized and their biocompatibility assessed with L929 fibroblasts. High concentrations of atorvastatin were incorporated by increasing the content of rigid segments as shown by FTIR, Raman, NMR, XPS and EDX. Thermal and mechanical characterization showed that polyurethanes containing atorvastatin and 35% of rigid segments were low modulus (13 MPa) semicrystalline polymers as they exhibited a glass transition temperature (T_g) at -38 °C, melting temperature (T_m) at 46 °C and crystallinity close to 35.9% as determined by DSC. In agreement with this, X-ray diffraction showed reflections at 21.3° and 23.6° for PCL without reflections for atorvastatin suggesting its presence in amorphous form with higher potential bioavailability. Low content of rigid segments led to highly degradable polymer in acidic, alkaline and oxidative media with an acceptable fibroblast cytotoxicity up to 7 days possibly due to low atorvastatin content.

Self-assembled biodegradable polymeric micelles to improve dapoxetine delivery across the blood-brain barrier

Background

Dapoxetine (DPX) is the drug of choice for the specific treatment of premature ejaculation. DPX is characterized by relatively low bioavailability (42%) and short half-life (1.5 h). The aim of this study was to improve DPX bioavailability and delivery across the blood–brain barrier (BBB) using a nanostructured DPX formulation for improved DPX efficacy and patient satisfaction.

Materials and methods

DPX-loaded polymeric micelles (PMs) formulations (F1–F3) were characterized for particle sizes, entrapment efficiencies, and Fourier transform infrared spectroscopic and transmission electron microscopic evaluations. In addition, diffusion profiles of the prepared formulations were investigated. Animal model pharmacokinetic parameters in plasma and brain tissues were investigated and compared with commercial DPX tablets.

Results

Particle size analysis revealed that formulations of DPX PMs showed a narrow range of 62.7±9.3–45.45±9.1 nm for F1–F3. In addition, DPX PMs showed a sustained release pattern with 91.27%±7.64%, 79.43%±7.81%, and 63.78%±5.05% of DPX content permeated after 24 h for F1, F2, and F3, respectively. Plasma pharmacokinetic parameters for DPX PMs showed significant increase (P<0.05) for the area under drug concentration–time curves in plasma and brain tissues compared with commercial DPX tablets.

Conclusion

DPX formulations in the form of PMs improved bioavailability and efficacy across the BBB. This DPX formulation provided improved brain delivery in order to enhance the convenience and compliance of patients.

Mechanistic analysis of Zein nanoparticles/PLGA triblock in situ forming implants for glimepiride

Objectives

The study aims at applying pharmaceutical nanotechnology and D-optimal fractional factorial design to screen and optimize the high-risk variables affecting the performance of a complex drug delivery system consisting of glimepiride–Zein nanoparticles and inclusion of the optimized formula with thermoresponsive triblock copolymers in in situ gel.

Methods

Sixteen nanoparticle formulations were prepared by liquid–liquid phase separation method according to the D-optimal fractional factorial design encompassing five variables at two levels. The responses investigated were glimepiride entrapment capacity (EC), particle size and size distribution, zeta potential, and in vitro drug release from the prepared nanoparticles. Furthermore, the feasibility of embedding the optimized Zein-based glimepiride nanoparticles within thermoresponsive triblock copolymers poly(lactide-co-glycolide)-block-poly(ethylene glycol)-block-poly(lactide-co-glycolide) in in situ gel was evaluated for controlling glimepiride release rate.

Results

Through the systematic optimization phase, improvement of glimepiride EC of 33.6%, nanoparticle size of 120.9 nm with a skewness value of 0.2, zeta potential of 11.1 mV, and sustained release features of 3.3% and 17.3% drug released after 2 and 24 hours, respectively, were obtained. These desirability functions were obtained at Zein and glimepiride loadings of 50 and 75 mg, respectively, utilizing didodecyldimethylammonium bromide as a stabilizer at 0.1% and 90% ethanol as a common solvent. Moreover, incorporating this optimized formulation in triblock copolymers-based in situ gel demonstrated pseudoplastic behavior with reduction of drug release rate as the concentration of polymer increased.

Conclusion

This approach to control the release of glimepiride using Zein nanoparticles/triblock copolymers-based in situ gel forming intramuscular implants could be useful for improving diabetes treatment effectiveness.