Acyclovir Research Articles

An optimisation of critical quality attributes for acyclovir dispersible tablets: a quality by design approach

The objective of the present study is the development of dispersible tablets (DTs) of an acyclovir (ACV) by quality by design (QbD) approach using maize starch (X1), sodium starch glycolate (X2) and magnesium stearate (X3) as a critical quality attributes (CQA's). The design of experiment (DoE) comprising two levels, three factors (23) is applied to optimise the combined effect of CQA's on the dependent variables such as disintegration time (Y1), hardness (Y2) and drug release (Y3, Y4 and Y5). The centre point batch F5 has depicted the excellent properties comprising 1.20% of X1, 4.89% of X2 and 1% of X3 with better Y1 (48 ± 1.62 sec), Y2 (138 ± 1.7 N) and Y4 (101 ± 1.32%) as compared to the commercial formulation Zovirax©. The key effects of CQA's are observed on the Y1 and Y4 (p < 0.05) as compared to the Y2 of DTs.

Aqueous fullerene C60 solution suppresses herpes simplex virus and cytomegalovirus infections

Fullerene C60 is known as a promising therapeutic agent due to its antioxidant, anti-inflammatory and other properties, along with the lack of noticeable toxicity. In this article, we describe antiviral properties of aqueous fullerene C60 dispersion (ndC60) produced by biocompatible diafiltration technology and C60 amino derivatives against Herpes simplex virus type 1 (HSV-1) and Human cytomegalovirus (HCMV) infections. Their activity in vitro was evaluated by a plaque reduction assay using Vero and HF cells in pre- and post-treatment modes. Therapeutic efficacy of dnC60 and C60 derivatives was studied in DBA mice using cutaneous model of HSV-1 infection. Data obtained indicated low cytotoxicity of all used compounds for both cell lines (CC50 > 1 mg/ml). The antiviral activity of dnC60 in most tests exceeded the activity of both C60 amino adducts and acyclovir (ACV), and it demonstrated significant therapeutic effect against HSV-1 skin infection in mice.

Polymeric Electrospun Fibrous Dressings for Topical Co-delivery of Acyclovir and Omega-3 Fatty Acids.

Herpetic infections caused by Herpes simplex virus (HSV) are among the most common human infections, affecting more than two quarters of the world's population. The standard treatment for orofacial herpes is the administration of antiviral drugs, mainly acyclovir (ACV). However, current products are mostly based on semisolid formulations that have limited ability to promote drug skin penetration and tend to leak from the application site, thus showing reduced ability to sustain local drug residence. This work reports on the production of poly (ε-caprolactone) (PCL) fibrous matrices with ACV and omega-3 fatty acids (ω3) for application as dressings to the topical treatment of orofacial herpes. PCL fibrous matrices with the co-incorporated bioactive compounds were obtained by electrospinning and characterized regarding their morphology, chemical, physical, and mechanical properties. The potential use of the developed polymeric fibrous matrices for topical applications was evaluated by: (i) the release kinetics of the bioactive compounds; (ii) the occlusive factor of the fibrous mat; (iii) ACV skin permeation capacity; and (iv) the cytotoxicity in a keratinocyte cell line. PCL fibrous matrices loaded with the bioactive compounds presented a smooth morphology and a good balance between flexibility and hardness essential to be durable for handling, while having a desirable texture to be used comfortably. The fibrous mat also provided a sustained release of ACV during 96 h and improved the skin permeability of this drug (Kp = 0.00928 ± 0.000867 cm/h) presenting also high porosity (74%) and a water vapor transmission rate (WVTR) of 881 ± 91 g/m2day, essential to maintain moist and oxygen for faster healing of herpes lesions. Furthermore, cytotoxicity studies suggest that the fibrous mat are safe for topical application. Overall, the PCL based electrospun fibrous matrices with ACV and ω3 hereby described have the potential to be used as therapeutic bandage systems for the treatment of orofacial herpes.

Development of thermosensitive in situ gel nanoemulsions for ocular delivery of acyclovir

The aim of the current study was to formulate thermosensitive in situ gel nanoemulsions (NEs) containing acyclovir (ACV) for ocular drug delivery and evaluate their ex vivo corneal permeation ability and ocular irritation possibility. ACV loaded NEs were prepared by low energy method. Physicochemical properties, drug release, and stability studies of in situ gel NEs were investigated. The optimized formulation was chosen for excised bovine corneal permeation, hen's egg test-chorioallantoic membrane and modified Draize tests to evaluate its ocular permeation and irritation. The optimum in situ gel NE consisting Triacetin, Transcutol®P, Poloxamer 407, and Poloxamer188 had the mean droplet size and polydispersity index of 28 nm and 0.38 respectively. Moreover, physicochemical properties such as pH, viscosity, osmolality, and refractive index were acceptable for ocular administration. This formulation showed a sustained drug release pattern compared to the control solution. Based on the permeation study results, drug permeation of optimum formulation was about 2.8-fold higher than the control solution. Irritation tests illustrated that the optimum in situ gel NE could be well tolerated by the eye. In conclusion, these results demonstrated that this new ACV formulation could be considered as a novel ophthalmic delivery system for the treatment of ocular viral infections.

Matrix-based controlled release delivery of acyclovir from poly-(ethylene co-vinyl acetate) rings

Up to 85% of the US adult population carries herpes simplex virus type-1 (HSV-1), with a smaller percentage (22%) infected with HSV-2. Herpesviruses can survive in lytic phase, when the viruses are actively replicating, or in latency, when the virus is functionally dormant in ganglia. Among drugs to treat these infections is acyclovir (ACV). ACV exhibits poor oral bioavailability and a short in vivo half-life; only about 10–15% of ingested drug enters the bloodstream and its half-life is about 3 h. With those disadvantages and the possibility of poor patient compliance, viral replication may not always be suppressed. To abrogate these shortcomings we propose local distribution via sustained drug release. We present a matrix-based antiherpetic ring, composed of poly(ethylene co-vinyl acetate), that releases ACV directly to the vaginal epithelium. A 30-day in vitro drug release trial showed that approximately 135 ± 20 μg/day of ACV was consistently released. Rings were nontoxic in cell culture and suppressed primary HSV-1 and HSV-2 replication. We expect these data form the basis for novel interventions in human health, where new prophylactics and therapeutics against genital herpes are truly needed.

High Incidence of Herpes Zoster after Cord Blood Hematopoietic Cell Transplant Despite Longer Duration of Antiviral Prophylaxis

Introduction Herpes zoster (HZ) after hematopoietic cell transplant (HCT) is a well-known complication with a peak incidence during the first year post-HCT. Cord blood transplant (CBT) recipients are at increased risk for viral infections and historically have a cumulative incidence of HZ approaching 80% by 2.5 years in the context of short-term peri-HCT antiviral prophylaxis. In 2009, international guidelines for prevention of infections after HCT recommended maintaining HZ prophylaxis for at least 1 year after HCT. We retrospectively studied the impact of longer-term antiviral prophylaxis on the incidence of HZ after CBT. Methods Between 2006 and 2016, we performed 360 CBT at our Institution. Patients who were seronegative for varicella zoster virus (VZV) or received the live varicella vaccine (i.e. Varivax®) pre-CBT without a history of chickenpox or HZ were excluded. From 2006-2008, CBT recipients received acyclovir (ACV) 800 mg BID or valacyclovir (VACV) 500 mg BID for HSV and VZV prophylaxis. From 2008-2016, patients who were CMV seropositive received higher-dose prophylaxis with VACV 2g TID through day +100. Before 2009, institutional guidelines recommended to continue prophylaxis until the end of immunosuppression; after 2009, prophylaxis was recommended for at least 1 year and until 8 months after immunosuppression ends. For patients discharged from our center, data were collected through standardized questionnaires and medical records. We abstracted HZ events and other variables for up to 5 years post-CBT. We calculated the cumulative incidence of HZ after CBT, treating death and second HCT as competing risk events. Variables were evaluated for an association with development of HZ using Cox proportional hazards regression; those of biological interest and with a P value ≤ 0.3 in univariable analyses were considerate for multivariable model. Results The study cohort consisted of 227 CBT recipients with a median follow up of 25.4 months (interquartile range [IQR], 6.8 - 49). Follow up time was truncated at the time of death (n=113), second HCT (n=13) or last available records (n=32). Cohort characteristics are shown in Table 1. Among 1-year survivors, 91% were still receiving prophylaxis for a median duration of 20.6 months post-CBT (IQR, 14.1 - 29.4). HZ occurred in 44 patients (19%) at a median of 23.6 months (IQR, 16.1 - 30.3). Most patients (n=31/44, 70%) were not taking antiviral prophylaxis when HZ developed. The cumulative incidence of HZ by 1-year post-CBT was low (1.8%; 95% CI, 0.1%-4%) but increased starting from the second year and reached 26% (95% CI, 19%-33%) by 5 years (Figure 1). Disseminated HZ occurred in 5 cases (11%), and post-herpetic neuralgia occurred in 14 cases (31.8%). Of the 13 HZ episodes that occurred in patients reportedly taking antiviral prophylaxis, 6/13 had clear documentation of ongoing antiviral prophylaxis and 5/13 were still receiving immunosuppressive treatment for graft-versus-host disease (GvHD). All patients responded to antiviral treatment, which consisted of ACV (n=18), VACV (n=16), and famciclovir (n=1). In a multivariable analysis, patients who received myeloablative conditioning or had acute GvHD grades 2-4 had a higher risk of HZ, whereas the use of antiviral prophylaxis was associated with a lower risk of HZ (Table 2). Among 35 patients who discontinued prophylaxis before completing immunosuppressive therapy, 28.5% developed HZ. We found no association between CD4+ T cell counts at 1-year after-CBT and HZ risk. Conclusions In this cohort of 227 CBT recipients with up to 5 years of follow up, the cumulative incidence of HZ was 26% at 5 years, despite antiviral prophylaxis for &amp;gt;1 year in the majority of patients. Furthermore, these patients had high rates of post-herpetic neuralgia and disseminated VZV. Antiviral prophylaxis protected against HZ but there were breakthrough cases. Given that a high number of patients interrupted prophylaxis while still receiving immunosuppressants, adherence to antiviral prophylaxis should be emphasized by health care providers. Based on our findings, the lack of alternative prophylactic strategies at this time, and the safety of ACV/VACV, longer duration of prophylaxis should be considered, especially in patients with ongoing immunosuppression. Recent data demonstrating the safety and efficacy of the HZ subunit vaccine after autologous HCT support future study of HZ vaccination after allogeneic HCT. Disclosures Delaney: Nohla Therapeutics: Employment, Equity Ownership; Biolife Solutions: Membership on an entity's Board of Directors or advisory committees. Boeckh:Chimerix: Research Funding; GSK: Other: Personal fees; GSK: Research Funding; Merck: Research Funding; Merck: Other: Personal fees; Clinigen: Other: Personal fees. Milano:ExCellThera: Research Funding; Amgen: Research Funding. Hill:Takeda: Other: research support; Karius: Other: research support; Amplyx: Consultancy; Nohla Therapeutics: Consultancy, Other: research support.

Antiviral activity of nano-realgar against herpes simplex virus Type II in vitro

To explore the antiviral activity of nano-realgar against herpes simplex virus Type II (HSV-2) in vitro. Methods: Acyclovir (ACV) as a positive control, the cytotoxicity of nano-realgar at different concentrations (including 200.00, 150.00, 100.00, 50.00, 25.00, 12.50, 6.25, 3.13, 1.54, 0.78, 0.39 and 0 mg/L) on normal Vero cells were determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. HSV-2 virus titer was determined by plaque assay, and the Vero cells model of HSV-2 infection was established. Subsequently, the antiviral effects of nano-realgar at different concentrations (including 20.00, 10.00, 5.00, 2.50, 1.25, 0.63, 0.31, 0.15, 0.08, 0.04 and 0 mg/L) on infected cells model were evaluated by the observation of cytopathic effect (CPE) and MTT method under the 3 modes including pre-treatment, treatment and direct inactivation. Results: The 50% cytotoxic concentration (CC50) of nano-realgar on Vero cells was 37.15 mg/L. The titer of HSV-2 was 7.30 log PFUs/mL. In the 3 modes, the half-maximal effective concentration (EC50) of nano-realgar on HSV-2 infected Vero cells were 0.13, 1.80 and 0.52 mg/L, and the corresponding therapeutic index (TI) were 285.77, 20.64, 71.44, respectively. The TI value of nano-realgar on pre-treatment mode was higher than that of nano-realgar on treatment and direct inactivation modes. Conclusion: Nano-realgar can play a good anti-HSV-2 activity in the 3 modes (pre-treatment, treatment and direct inactivation), and the anti-HSV-2 efficacy of nano-realgar on pre-treatment mode is better than that of nano-realagr on other 2 modes.

Virtual screening identified compounds that bind to cyclin dependent kinase 2 and prevent herpes simplex virus type 1 replication and reactivation in neurons

HSV-1 is one of the most prevalent viruses worldwide, and due to the limited therapies mainly with acyclovir and analogues and the emergence of acyclovir (ACV) resistant strains, the search for new drugs with different modes of action is needed. This study identified compounds that bind in silico to cyclin dependent kinase 2 (CDK2), a cellular enzyme required for efficient HSV-1 replication, and have anti-HSV-1 activity. Compounds obtained from virtual screening by Pharmit were filtered in FAF-Drugs4 for good pharmacokinetic and toxicological profiles and submitted to molecular docking on CDK2 using Autodock Vina. The six most promising compounds were evaluated for inhibiting lytic replication of HSV-1 wild-type and ACV-resistant strains on human fibroblasts. The compounds were also assayed for cytotoxicity. Compounds 1, 2 and 3 showed antiviral activity with EC50 (50% of effective drug concentration) of 32, 29 and 64 μM and CC50 (50% of cytotoxic concentration) of 159, 1410 and 2044 μM, respectively. Compounds 1 and 2 were also active against ACV resistant strains and compound 3 inhibited the reactivation of HSV-1 in neurons, which is an important finding to guide drug design of new anti-HSV-1 antivirals with different modes of action. These compounds are promising candidates for optimization into more potent agents to treat HSV-1 infections and recurrences.

Formulation of acyclovir-loaded solid lipid nanoparticles: 2. Brain targeting and pharmacokinetic study

Acyclovir (ACV) is widely used in the treatment of herpes encephalitis. The present study was conducted to prepare chitosan-tween 80 coated solid lipid nanoparticles (SLNs) as a delivery system for brain targeting of ACV in rabbits. The SLNs were prepared and coated in one step by microemulsion method using a coating solution containing chitosan (0.1% w/v) and tween 80 (2% w/v) for loading sustained release ACV. In vitro characterization was performed for coated ACV-SLNs. Concerning in vivo experiments; a single intravenous bolus dose of coated ACV-SLNs was given versus free ACV solution to rabbits (62 mg/kg). Plasma pharmacokinetic parameters were calculated from the ACV concentration-time profiles in plasma using the two compartmental analysis. The values of AUC0−∞ and MRT of coated ACV-SLNs were higher than free drug by about twofold, 233.36 ± 41.56 μg.h/mL and 1.81 ± 0.36 h, respectively. The noncompartmental analysis was conducted to estimate the brain pharmacokinetic parameters. The AUC0−∞ brain/AUC0−∞ plasma ratio for coated ACV-SLNs and free ACV was 0.22 and 0.12, respectively. These results indicated the effectiveness of using coated ACV-SLNs for brain targeting.

Fabrication of Non-Enzymatic Sensor Utilizing Carbon Nanotubes- Nafion Film for Nanoscale Determination of Antiviral Drug

Rapid emergence of viral diseases has posed a consequential threat to all human and veterinary health. Over past two decades these diseases are major cause of death among all infectious diseases worldwide. Acyclovir (ACV) which is a synthetic purine based nucleoside analogue plays a pivotal role in the therapy of viral diseases and possesses the best safety profile of all antivirals licensed so far. ACV is an emerging drug for the clinical treatment against herpes simplex virus, hepatitis B virus, varicella zoster virus and epstein-barr virus. ACV is marketed in the form of ophthalmic ointments, dermal cream, injections, capsules and oral tablets which have been extensively and effectively used for the treatment of herpes virus infections. The drug provides remarkable therapeutic benefit in the therapy of viral diseases like cold sores, keratitis, corneal blindness, encephalitis and virally infected central nervous system. Several adverse outcomes like neurotoxicity, nephrotoxicity, urticaria, phlebophlogosis, diarrhoea, cephalalgia, emesis and swoon are associated with higher intake of ACV and its abuse. Various analytical techniques other than electrochemical have several inconveniences which include lengthy and tedious sample preparation procedures, long analysis time and need of trained technicians. Chromatographic methods suffer from consumption of large volumes of high purity organic solvents and requirement of expensive sophisticated instruments. These methods also suffer from lack of selectivity and sensitivity which makes them unsuitable for routine analysis. In recent years, much attention has been focused on the preparation of a variety of nanomaterials with highly controllable size, shape, surface charge and physicochemical characteristics. The alluring properties of nanomaterial exhibit signal amplification due to which they are prodigiously used for the fabrication of a wide range of electrochemical sensors. Single walled carbon nanotubes (SWNTs) displaying quantum dots and wires at very low temperatures enhances the electrode conductivity and facilitates the electron transfer between myriad electroactive species and the underlying electrode. Nafion which is a sulfonated tetrafluorethylene copolymer possessing pronounced antifouling capacity, chemical inertness, strong adsorption ability, thermal stability and biocompatibility renders it to be extensively employed as an electrode modifier. A simple and sensitive approach is proposed for the accurate monitoring of antiviral drug ACV utilizing glassy carbon electrode (GCE) fabricated with SWNTs and nafion composite film employing square wave voltammetry for the first time. The developed sensor exhibits effective and sustained electron mediating behavior displaying higher peak currents at lower potential than those obtained at bare GCE. The developed sensor engendered ∼2.5 fold larger electroactive surface area in comparison to bare GCE which substantially accelerated the rate of electron transfer via improved electrical conductivity. At optimal experimental conditions, oxidation current showed a wide linear response for ACV in the concentration range from 10 nM to 30 µM. The proposed sensor exhibited pronounced analytical performance for the determination of ACV with limit of detection corresponding to 1.8 nM and high sensitivity of 15.4 µA µM-1. The modified sensor showcased high recognition selectivity, fair reproducibility and long term stability of signal response in the physiological environment. The developed prototype was successfully implemented to quantify ACV in several commercially available pharmaceuticals. The versatile method described herein was efficaciously applied further in detecting ACV in real human urine sample of patient undergoing pharmacological treatment with ACV. The results explicitly demonstrate the applicability of the developed sensor in quality control, pharmacokinetic studies and clinical analysis.

Signal detection of oral drug-induced dementia in chronic kidney disease patients using association rule mining and Bayesian confidence propagation neural network.

Among the mechanisms responsible for cognitive dysfunction in chronic kidney disease (CKD) are albuminuria and oxidative stress. However, there may be other causes not yet identified. In fact, the full relevance of CKD patient drug use and its relationship to dementia has hardly been barely investigated. We identified drugs affecting cognitive function in CKD patients by analyzing the spontaneous reporting system in Japan using Association rule mining (ARM) and Bayesian confidence propagation neural network (BCPNN). The signal detection criterion used were as follows: case ≥ 3, lift > 1, conviction > 1 (ARM) and IC025 >0 (BCPNN). Drugs with more than 20 cases were valaciclovir (lift: 11.21, conviction: 1.28, IC025: 3.12), amantadine (lift: 19.69, conviction: 1.68, IC025: 3.05), nalfurafine (lift: 8.35, conviction: 1.19, IC025: 2.18), pregabalin (lift: 6.05, conviction: 1.12, IC025: 1.78), and acyclovir (lift: 5.89, conviction: 1.12, IC025: 1.68). This study is the first report to use a large-scale medical database to identify drugs related to oral drugs-induced dementia in CKD.

Formulation Development and Evaluation of Ethosomal Gel of Acyclovir for the Treatment of Herpes Zoster

The present study is to develop and evaluate an ethosomal gel formulation of acyclovir (ACV). It aims to provide a topical treatment for many viral infections that affect the skin. Administration of medications topically having the facility of delivering a high concentration of the drug to the skin than would be possible with systemic therapy. Topical administration of drugs is better for local action and the efficiency of the topically administered drug is increased with liposome, proliposomes and ethosomes. Recently, it was found that ethosomal carriers were phospholipid vesicular systems having relatively high concentrations of alcohol, enhances dermal and transdermal delivery of both lipophilic as well as hydrophilic molecules. ACV is the common antiviral agent that is used to treat infections caused by certain types of viruses. It treats cold sores around the mouth (caused by herpes simplex), shingles (caused by herpes zoster) and chickenpox. ACV 5% cream is used for the treatment of infection along with oral dosage forms like tablets. These formulations show poor therapeutic outcome due to the poor bioavailability (15-20%) of oral dosage forms. Ethosomes were formulated using phospholipid, ethanol, polyethylene glycol and purified water by cold method. Ethosomes were evaluated for vesicle size, shape, optical microscopy, entrapment efficiency and in-vitro release study. AEF5 have better drug entrapment efficiency than the other formulation. The best formulation (AEF5) was used to prepare gel by using carbopol 934 as a gelling agent. The ethosomes were entrapped in gel matrix of carbopol 980 in different concentration 0.5%, 1.00% and 1.5% w/w. FT-IR studies revealed no interaction between the drug and excipients. The formulated gel formulation was evaluated with parameter pH, viscosity, spreadability, in-vitro release test, washability, extrudability study and stability studies. The formulation AEG2 have better in-vitro drug release profile which contains carbopol 980 concentration 1%w/w. The present work also focuses on making the formulation more pharmaceutically acceptable. Keywords: Acyclovir, Ethosomal gel, Viral infections, Phospholipid, % Entrapment efficiency, Vesicle size

Descemet Membrane Endothelial Keratoplasty in Irreversible Corneal Edema Due to Herpes Simplex Virus Endotheliitis.

To report the clinical outcome and postoperative course of Descemet membrane endothelial keratoplasty (DMEK) in irreversible corneal edema due to herpes simplex virus (HSV) endotheliitis. This is a retrospective, noncomparative, interventional case series. Nineteen eyes of 19 patients underwent standard DMEK combined with cataract surgery (triple DMEK) between May 2016 and April 2018. All patients received perioperative oral acyclovir (ACV) and prednisolone. Patients were followed up on day 1, on day 7, at 1 month, and then at 3 monthly intervals. Preoperative and postoperative best spectacle-corrected visual acuity (BSCVA), graft clarity, pachymetry, and endothelial cell loss after 1 year were recorded. Postoperative complications and HSV recurrence were noted until the last follow-up visit. All eyes were phakic with variable grades of cataract with a preoperative BSCVA of 1.0 logarithm of the minimum angle of resolution or worse. The mean follow-up period was 19.3 ± 5.4 months. After 1 year, 14 (73.7%) eyes achieved a BSCVA of 0.3 or better. Seventeen (89.5%) patients had a clear graft at the last visit without any rejection episode. One graft failed after 16 months. After 3 months, the mean pachymetry reduced from 667.1 ± 62.1 to 512.8 ± 27.1 μm (P < 0.001). The mean endothelial cell loss after 1 year was 36.7 ± 13.4%. Three (15.8%) eyes had recurrence: one with recurrent endotheliitis and 2 with dendritic keratitis despite oral ACV, which responded to oral valacyclovir and ACV eye ointment. One patient had re-recurrence of endotheliitis after 20 months. DMEK in persistent corneal edema after HSV endotheliitis remains challenging but has encouraging outcomes. The postoperative course may be complicated by HSV recurrence. Prophylactic oral antivirals for 1 year or more and topical antivirals are useful for the prevention of recurrence.

Psoromic Acid, a Lichen-Derived Molecule, Inhibits the Replication of HSV-1 and HSV-2, and Inactivates HSV-1 DNA Polymerase: Shedding Light on Antiherpetic Properties.

Psoromic acid (PA), a bioactive lichen-derived compound, was investigated for its inhibitory properties against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), along with the inhibitory effect on HSV-1 DNA polymerase, which is a key enzyme that plays an essential role in HSV-1 replication cycle. PA was found to notably inhibit HSV-1 replication (50% inhibitory concentration (IC50): 1.9 μM; selectivity index (SI): 163.2) compared with the standard drug acyclovir (ACV) (IC50: 2.6 μM; SI: 119.2). The combination of PA with ACV has led to potent inhibitory activity against HSV-1 replication (IC50: 1.1 µM; SI: 281.8) compared with that of ACV. Moreover, PA displayed equivalent inhibitory action against HSV-2 replication (50% effective concentration (EC50): 2.7 μM; SI: 114.8) compared with that of ACV (EC50: 2.8 μM; SI: 110.7). The inhibition potency of PA in combination with ACV against HSV-2 replication was also detected (EC50: 1.8 µM; SI: 172.2). Further, PA was observed to effectively inhibit HSV-1 DNA polymerase (as a non-nucleoside inhibitor) with respect to dTTP incorporation in a competitive inhibition mode (half maximal inhibitory concentration (IC50): 0.7 μM; inhibition constant (Ki): 0.3 μM) compared with reference drugs aphidicolin (IC50: 0.8 μM; Ki: 0.4 μM) and ACV triphosphate (ACV-TP) (IC50: 0.9 μM; Ki: 0.5 μM). It is noteworthy that the mechanism by which PA-induced anti-HSV-1 activity was related to its inhibitory action against HSV-1 DNA polymerase. Furthermore, the outcomes of in vitro experiments were authenticated using molecular docking analyses, as the molecular interactions of PA with the active sites of HSV-1 DNA polymerase and HSV-2 protease (an essential enzyme required for HSV-2 replication) were revealed. Since this is a first report on the above-mentioned properties, we can conclude that PA might be a future drug for the treatment of HSV infections as well as a promising lead molecule for further anti-HSV drug design.

MON-198 EVALUATION OF CYTOMEGALO VIRUS (CMV) TREATMENT IN KIDNEY TRANSPLATATION: A MULTI-CENTRAL STUDY IN VIET NAM

Cytomegalovirus (CMV) infection is associated with significantly decreased outcomes of kidney transplantation (KTx). To evaluate the effectiveness of CMV prevention and treatment in KTx patients in Viet Nam was the aim of our multicenter study. We conducted a prospective cross-sectional study about prevention and treatment of CMV in 847 patients (pts) from 7 KTx centers in Viet Nam. The immunosuppressive drugs used depend on each center, with Basiliximab for induction, and with Calcineurin inhibitors (tacrolimus or cyclosporine), Antiproliferative agents (mycophenolate mofetil, or mycophenolate sodium or azathioprine), mTOR inhibitor, steroids for maintenance. CMV prevention was taken with either acyclovir (ACY) (dose 200mgx4) or valganciclovir (VALG) (dose 450mg) for the first 100 to 200 days after KTx. CME infection was diagnosed by CMV-DNA, and treated with intravenous ganciclovir (5mg/kg/12h). Ganciclovir, ACY or VALG dose were adjusted to the kidney function. Preemptive therapy was defined as CMV-DNA, when it was switched from negative to positive even if the number of copies was less than 500 (in the time of CMV prophylaxis, but the patient was in the high risk group (D+/R- or after acute rejection treatment progress). 847 KTx patients from 1992 to 2015, were recruited living and deceased donor transplantation. Mean age: 42.5 ± 12.7yo (11yso; 81yso). Male /female: 576/271. 581/847pts (68.60%) received CMV prevention and 266/847 (31.40%) pts didn't received CMV prevention. Of 581 CMV prevention, 28 proceed CMV infection. All of them were on ACY prevention (except 10pts of D-/R- group). 3/28pts died because of late detective of severe pneumonia (table 1). Table 1CMV risk classificationsCMV risk classificationsTotalPrevention (n=581)Infection (n=189)Pre-emptiveDeathACYValGACYValGGanciclovirACYValGD+/R+796493592802830D+/R-198500000D-/R+1710100000D-/R-154100000Total84751566280283/28 (10.71%)0n=847 (%)581/847 (68.60%)28/581 (4.82%)3/581 (0.52%) Open table in a new tab Of 266pts without CMV prevention, 42pts suffered CMV infection, and all received preemptive therapy. 11/42pts died because of severe pneumonia, too. Table 2CMV risk classifications of CMV non- prevention group treatmentCMV risk classificationsTotalCMV non- preventionCMV infectionPre-emptiveDeathD+/R+796244404011D+/R-196000D-/R+176110D-/R-1510110Total84726642/266 (15.76%)4211/42 (26.19%)n=847 (%)84731.404.96 Open table in a new tab In the non- CMV prevention group, the percentage of infection was triple (42/266, 15.76%) than the acyclovir prevention group (3/581 (0.52%)) with p<0.005, (table 1 and 2). Frequency of CMV in the dialysis community is CMV infection of 95.99%. Valganciclovir was highly efficient for CMV prevention than acyclovir. In our study, aciclovir is still effectively, so we must be to follow-up patients carefully and early convert Aciclovir to ValG or Ganciclovir when the CMV-DNA was switched from negative to positive. CMV prophylaxis should recommended for all of patients even the D-/R- group if they were receiving the high level of immunosuppressive drug. In addition, the level of immunosuppressive drugs should be adjusted to suit each individual.

Clinical study on varicella zoster virus infection in children following allogeneic hematopoietic stem cell transplantation

Objective To analyze the risk factors of varicella zoster virus(VZV) infection after allogeneic hematopoietic stem cell transplantation(allo-HSCT) in children, and to provide reference for the diagnosis, monitoring and prophylaxis of VZV infection after allo-HSCT. Methods A total of 367 patients, who underwent allo-HSCT in Pediatric Transplantation Center of Nanfang Hospital Affiliated to Southern Medical University from January 2012 to June 2015 were collected.Clinical characteristics and risk factors of the patients complicated with VZV after allo-HSCT were retrospectively analyzed. Results Thirty-four patients (9.26%) were complicated with VZV infection after allo-HSCT.The median onset time was 96.5 d(19-326 d). Two of 34 patients relapsed 3 times, 1 case of them relapsed twice, 3 cases of them relapsed once, and 4 cases of 34 patients were complicated with VZV encephalitis.All cases were treated with antivirus drugs, infusion of immunoglobulin, reduction of immunosuppressant dosages, with external use of Acyclovir ointment.The median therapy time was 13 days (7-28 days). All of their herpes subsided, and neurological symptoms such as headache, vomiting and convulsion disappeared.VZV-DNA both in blood and cerebrospinal fluid turned negative.No patient had herpetic dissemination and visceral involvement, and no one died directly of VZV infection.Results indicated that age(χ2=6.863, P=0.009), underlying disease(χ2=14.793, P=0.022), type of HSCT(χ2=14.459, P=0.001) and resource of stem cell (χ2=20.585, P=0.002) were significant risk factors for VZV infection after allo-HSCT, while sex (χ2=0.106, P=0.745) and antithymocyte globulin in conditioning regimen(χ2=0.010, P=0.921) had no relation to it. Conclusions VZV infection mainly occur within 12 months after allo-HSCT and is prone to be complicated with VZV encephalitis.The effect of Acyclovir is good.Monitoring and prophylaxis of VZV infection after allo-HSCT should be strengthened in children with high risk factors. Key words: Varicella zoster virus; Allogeneic Hematopoietic stem cell transplantation; Child; Prophylaxis

Mechanism of resistance to acyclovir in thymidine kinase mutants from Herpes simplex virus type 1: a computational approach

Herpes simplex virus type 1 (HSV-1) infections affect about two-thirds of the world population, and the standard treatment consists of acyclovir (ACV) and its analogs, which interact with thymidine kinase (TK) blocking viral replication. Lately, the emergence of ACV-resistant strains has been reported, especially associated with TK mutations. In this context, ACV therapy fails against isolates encoding Y172C and Y53H/R163H TK mutants, but the molecular mechanism of drug resistance remains unclear. Thus, we examined the effects of these mutations on ACV and the cofactor ATP binding through molecular modeling approaches. We showed that Y172C prevents the anchoring of the aromatic ring of ACV through π–π stacking interactions, leading to an inversed binding mode and different interactions. On the other hand, Y53H/R163H remarkably affected the cofactor binding mode which shifted away from its binding site and also influenced the interaction network of ACV. This is likely due to the loss of polar interactions with R163 residue. Unlike what was observed in the wild-type complex, both drug and cofactor binding poses were not well positioned to allow the phosphorylation reaction which explains the resistance observed. Moreover, energy analysis corroborated the experimental data and showed lower theoretical affinity of ACV with mutant enzymes resulted from energetic loss in polar solvation in Y172C and electrostatic terms in Y53H/R163H mutant enzyme. Therefore, our study shed light on the resistance mechanism toward ACV of two mutant TKs identified in clinical HSV-1 strains and may further support the development of new anti-herpetic drugs to treat resistant infections. Communicated by Ramaswamy H. Sarma

Amentoflavone Inhibits HSV-1 and ACV-Resistant Strain Infection by Suppressing Viral Early Infection.

Infection of Herpes simplex virus 1 (HSV-1) induces severe clinical disorders, such as herpes simplex encephalitis and keratitis. Acyclovir (ACV) is the current therapeutic drug against viral infection and ACV-resistant strains have gradually emerged, leading to the requirement for novel antiviral agents. In this study, we exhibited the antiviral activity of amentoflavone, a naturally occurring biflavonoid, toward HSV-1 and ACV-resistant strains. Amentoflavone significantly inhibited infection of HSV-1 (F strain), as well as several ACV-resistant strains including HSV-1/106, HSV-1/153 and HSV-1/Blue at high concentrations. Time-of-drug-addition assay further revealed that amentoflavone mainly impaired HSV-1 early infection. More detailed study demonstrated that amentoflavone affected cofilin-mediated F-actin reorganization and reduced the intracellular transportation of HSV-1 from the cell membrane to the nucleus. In addition, amentoflavone substantially decreased transcription of viral immediate early genes. Collectively, amentoflavone showed strong antiviral activity against HSV-1 and ACV-resistant strains, and amentoflavone could be a promising therapeutic candidate for HSV-1 pathogenesis.

Photodegradation mechanisms of acyclovir in water and the toxicity of photoproducts

Acyclovir (ACV), an anti-virus drug, was widely detected in natural water at concentrations ranging from ng L−1 to μg L−1 due to inefficient biological treatments in sewage treatment plant. Photochemical experiments involving the irradiation from a xenon lamp simulating sunlight were conducted to explore the environmental behavior and potential risks of ACV. Isopropanol was used as a radical trapping agent for mechanism research, and the toxicity of the photoproducts of ACV was evaluated by the acute toxicity test of Photobacterium phosphoreum T3 spp. The results indicated that the ACV photodegradation followed pseudo first-order reaction kinetics, and the ACV removal rate increased when the pH was elevated from 5 to 10. The photochemical reaction pathway revealed by HPLC–MS/MS suggested that the C–C bond and C–N bond of ACV could be attacked by ·OH; thus, the photoproducts were mostly composed of hydroxyl substitution products. The intermediate photoproducts in the course of photodegradation exhibited a higher toxicity than the parent ACV, and the highest toxicity effect was observed at 6 h, which implied that the photoproducts of ACV might pose a great potential risk on aquatic environments.

TAT-surface modified acyclovir-loaded albumin nanoparticles as a novel ocular drug delivery system

The aim of this study was to develop acyclovir (ACV)-loaded bovine serum albumin (BSA) nanoparticles (NPs) which were surface modified with transactivating transduction (TAT) peptide to improve the transcorneal drug delivery in treating viral related keratitis. The TAT-surface modifications were carried out by both conjugation (TAT-con) and coating (TAT-coat) techniques. Characterization of physicochemical properties and assessment of in vitro transcorneal permeation across human corneal epithelial (HCE-T) cell multilayers of prepared TAT-surface modified ACV-BSA NPs were subsequently investigated. The prepared TAT-surface modified ACV-BSA NPs appeared to be spherical in shape and uniform in size of about 200 nm with surface charges ranging between −20 and −30 mV. Increasing TAT amount in TAT-coat ACV-BSA NPs resulted in an increased size of NPs as expected, but it was not the case for TAT-con ACV-BSA NPs. The prepared TAT-coat ACV-BSA NPs were shown to have less cytotoxic effects on HCE-T cells used in permeation studies than those of TAT-con ACV-BSA NPs and ACV solution. The in vitro transcorneal permeation results indicated that TAT-coat ACV-BSA NPs could bring about the highest ACV permeability as compared to ACV-BSA NPs and ACV solution. Such TAT-surface modified ACV-BSA NPs could be developed as novel ocular drug delivery systems.