Bi-polymeric Spongy Matrices Through Cross-linking Polymerization: Synthesized and Evaluated for Solubility Enhancement of Acyclovir.

In this study, two hydrophilic polymers hydroxypropyl methyl cellulose and beta-cyclodextrin (ß-CD) are used to synthesize highly responsive and spongy polymeric matrices. Porous and stimulus-responsive polymeric network was developed to improve the solubility of acyclovir (ACV) at significant level. Grafting was successfully carried out by free radical polymerization technique. Spongy matrices were characterized by percentage entrapment efficiency, drug loading, solubility studies, FTIR, powder X-ray diffraction, TGA, DSC, XRD, SEM, swelling studies, and in vitro studies. Acute oral toxicity studies were conducted to determine the safety of oral administration of prepared HPMC-ßCD-g-poly(AMPS) formulation. Porous and spongy structures were depicted in SEM images. Complex formation and thermal stability of constituents and drug (ACV) were analyzed by FTIR, TGA, and DSC spectra. XRD analysis revealed reduction in acyclovir crystallinity in spongy matrices. Particle size of optimized formulation was found in the range of 197 ± 2.55 nm. The momentous difference with reference product committed that drug solubility and release characteristics were markedly enhanced by the developed spongy matrices. Toxicity studies endorsed that developed spongy matrices were non-toxic and compatible to biological system. The efficient method of preparation, enhanced solubility, excellent physico-chemical characteristics, high dissolution, and non-toxic HPMC-ßCD-g-poly(AMPS) spongy matrices may be a promising approach for oral delivery of poorly soluble drugs.

Carrageenan-Based Acyclovir Mucoadhesive Vaginal Tablets for Prevention of Genital Herpes.

Women are the most affected by genital herpes, which is one of the most common sexually transmitted infections, affecting more than 400 million people worldwide. The application of vaginal microbicides could provide a safe method of protection. Acyclovir is a safe and effective medication for vaginal administration, and numerous benefits have been observed in the treatment of primary or recurrent lesions due to genital herpes. Vaginal tablets based on a combination of the polymers iota-carrageenan and hydroxypropyl methylcellulose were developed for the controlled release of acyclovir. Swelling, mucoadhesion and drug release studies were carried out in simulated vaginal fluid. The tablets, containing a combination of iota-carrageenan and hydroxypropyl methylcellulose, have an adequate uptake of the medium that allows them to develop the precise consistency and volume of gel for the controlled release of acyclovir. Its high mucoadhesive capacity also allows the formulation to remain in the vaginal area long enough to ensure the complete release of acyclovir. These promising formulations for the prevention of genital herpes deserve further evaluation.

PEGylated Lipid Polymeric Nanoparticle-Encapsulated Acyclovir for In Vitro Controlled Release and Ex Vivo Gut Sac Permeation.

Currently, pharmaceutical research is directed wide range for developing new drugs for oral administration to target disease. Acyclovir formulation is having common issues of short half-life and poor permeability, causing messy treatment which results in patient incompliance. The present study formulates a lipid polymeric hybrid nanoparticles for antiviral acyclovir (ACV) agent with Phospholipon® 90G (lecithin), chitosan, and polyethylene glycol (PEG) to improve controlled release of the drugs. The study focused on the encapsulation of the ACV in lipid polymeric particle and their sustained delivery. The formulation developed for the self-assembly of chitosan and lecithin to form a shell encapsulating acyclovir, followed by PEGylation. Optimisation was performed via Box-Behnken Design (BBD), forming nanoparticles with size of 187.7 ± 3.75 nm, 83.81 ± 1.93% drug-entrapped efficiency (EE), and + 37.7 ± 1.16 mV zeta potential. Scanning electron microscopy and transmission electron microscopy images displayed spherical nanoparticles formation. Encapsulation of ACV and complexity with other physical parameters are confirmed through analysis using Fourier transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction. Nanoparticle produced was capable of achieving 24-h sustained release in vitro on gastric and intestinal environments. Ex vivo study proved the improvement of acyclovir's apparent permeability from 2 × 10-6 to 6.46 × 10-6 cm s-1. Acyclovir new formulation was achieved to be stable up to 60 days for controlled release of the drugs. Graphical abstract.

Development of a Novel Polymeric Nanocomposite Complex for Drugs with Low Bioavailability.

Semi-synthetic biopolymer complex (SSBC) nanoparticles were investigated as a potential oral drug delivery system to enhance the bioavailability of a poorly water-soluble model drug acyclovir (ACV). The SSBCs were prepared from cross-linking of hydroxyl groups on hyaluronic acid (HA) with poly(acrylic acid) (PAA) resulting in ether linkages. Thereafter, conjugation of 2-hydroxypropyl-ß-cyclodextrin (HP-ß-CD) onto HA-PAA was accomplished using a 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS)-promoted coupling reaction. Nanoparticle powders were prepared by spray drying of drug-loaded SSBC emulsions in a laboratory nano spray dryer. The prepared SSBC was characterized by Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), 1H nuclear magnetic resonance (NMR) imaging, and X-ray diffraction (XRD) spectroscopy. The average particle size was found to be 257.92 nm. An entrapment efficiency of 85% was achieved as ACV has enhanced affinity for the hydrophobic inner core of the complex. It was shown that SSBC improved the solubility of ACV by 30% and the ex vivo permeation by 10% compared to the conventional ACV formulation, consequentially enhancing its bioavailability. Overall, this study resulted in the successful preparation of a hybrid chemically conjugated SSBC which has great potential for enhanced oral absorption of ACV with possible tuneable ACV permeability and solubility, producing an "intelligent" nanoenabled drug delivery system.

Preparation and evaluation of niosome gel containing acyclovir for enhanced dermal deposition.

Niosomes suggest a versatile vesicle delivery system with possible transport of drugs via topical route for skin delivery. The aim of the present research was to optimize niosome gel formulation of acyclovir and to evaluate in both in vitro and in vivo rabbit model. Niosome formulations were formulated by coacervation phase separation technique with different ratios of nonionic surfactants, phospholipids and cholesterol using 32 factorial design. Altering the surfactant concentration has influenced the drug entrapment, but not vesicle size. At high surfactant combinations, the acyclovir release from niosomes was strongly influenced by cholesterol:lecithin ratio. Ex vivo drug permeation data indicate substantial difference in flux values and was influenced by the niosome composition. Ex vivo studies using formulation (B8) for drug deposition indicate greater amount of niosome being diffused into the skin layers and formed a depot, compared to commercial acyclovir cream (control). Two distinct dermatopharmacokinetic profiles were observed, in vivo, for niosome gel formulation (B8) and control, which were analog to the profiles observed with ex vivo deposition studies. In vivo plasma drug level suggests low systemic exposure of acyclovir (Cmax: 9.44 ± 2.27 ng/mL and 14.54 ± 3.11 ng/mL for niosome formulation and control, respectively). Comparison of kinetic data of acyclovir in the stratum corneum and plasma signifies that the niosome formulation forms a depot in the epidermis or dermis region. This study concludes that the niosome gel formulation (B8) could be a viable vesicular system for an impressive transdermal delivery of acyclovir by topical application.

Synkinesis in Bell's palsy in a randomised controlled trial.

OBJECTIVES: To study the development of synkinesis in Bell's palsy. Frequency, severity, gender aspects and predictors were analysed. DESIGN: Data from the randomised controlled Scandinavian Bell's palsy trial including 829 patients. MAIN OUTCOME MEASURES: Frequency and severity of synkinesis at 12 months were the main outcome measures. Mean Sunnybrook synkinesis scores, voluntary movement scores and composite scores between 6 and 12 months were compared. RESULTS: In 743 patients with a 12-month follow-up, synkinesis frequency was 21.3%. There was no gender difference. Synkinesis was moderate to severe in 6.6% of patients. Those with synkinesis at 6 months had a synkinesis score of 4.1 (±2.8 sd), which increased to 4.7 (±3.2) (P = 0.047) at 12 months (n = 93). Sunnybrook composite score at 1 month was the best predictor for synkinesis development with receiver operating characteristics and area under the curve (AUC) 0.87. Risk for synkinesis increased with a lower Sunnybrook composite score. Furthermore, at 1 month, symmetry of voluntary movement had higher predictive value for synkinesis than resting symmetry with AUC 0.87 and 0.77, respectively. Gentle eye closure and open-mouth smile were the only independent significant predictive items (AUC 0.86). CONCLUSIONS: Moderate-to-severe synkinesis was present in 6.6% of patients. The mean synkinesis score increased between 6 and 12 months, and outcome should therefore be evaluated after at least 12 months. Sunnybrook composite score and symmetry of voluntary movement at 1 month were good predictors for synkinesis.

Lipid Nanocarrier: an Efficient Approach Towards Ocular Delivery of Hydrophilic Drug (Valacyclovir).

This research focuses on the fabrication and evaluation of solid lipid nanoparticles (SLNs) for improved ocular delivery of valacyclovir (VAC). Stearic acid and tristearin were selected as the lipid carrier while Poloxamer 188 and sodium taurocholate were used as surfactant and co-surfactant, respectively. The physiochemical properties of the optimized batch (SLN-6) fulfil the prerequisites needed for an ideal ocular formulation like submicron size (202.5 ± 2.56 nm), narrow PDI (0.252 ± 0.06), high zeta potential (-34.4 ± 3.04 mV) and good entrapment efficiency (58.82 ± 2.45%). The in vitro release study of SLN-6 exhibited a sustained release profile (>60% in 12 h). The ex vivo studies performed on excised cornea exhibited enhanced drug permeation of SLNs (22.17 ± 1.41 µg/cm2 h) in comparison to the drug solution (3.78 ± 1.34 µg/cm2 h). Apart, the corneal hydration studies, histopathology and Hen's Egg Test Chorio Allantoic Membrane (HETCAM) assay, confirmed the non-irritancy of SLNs. The in vivo study confirmed improved ocular bioavailability of VAC from SLN-6 (AUC0-12: 856.47 ± 7.86 µg h/mL) in contrast to the drug solution (AUC0-12: 470.75 ± 8.91 µg h/mL). Hence, the overall studies suggested the potential of SLNs in efficient ocular delivery of a hydrophilic molecule like VAC.

Polish consensus guidelines on the use of acyclovir in the treatment and prevention of VZV and HSV infections.

A physician has to perform a benefit-risk assessment each time acyclovir is prescribed "off label" for children. A group of Polish infectious disease experts was created to develop evidence-based guidelines on the use of acyclovir in the treatment and prevention of varicella zoster and herpes simplex infections. In primary varicella zoster virus infections, oral acyclovir treatment is recommended in children over 12 years of age and should be considered in younger children who fall into one of the groups at risk of severe varicella. Intravenous acyclovir therapy in varicella is recommended in patients with immune deficiencies, newborns and in complicated cases. When there is a justified need for prevention of varicella, oral acyclovir prophylaxis may be considered if immunoglobulin cannot be administered, and if it is too late for vaccination. Oral acyclovir treatment of herpes zoster may be beneficial to otherwise healthy patients with a rash in places other than the trunk and in patients over 50 years of age. In immunocompetent patients with herpes simplex infections, indications for treatment with oral acyclovir include primary (genital herpes, skin herpes in children with atopic dermatitis, ocular herpes simplex, severe gingivostomatitis, paronychia and pharyngitis) and recurrent infections. Intravenous acyclovir should be administered for herpes infections in neonates, immunocompromised patients and patients who develop complications including neurological.

Mucoadhesive plasticized system of branched poly(lactic-co-glycolic acid) with aciclovir.

Commercially available antibacterial semisolid preparations intended for topical application provide only short-term drug release. A sustained kinetics is possible by exploitation of a biodegradable polymer carrier. The purpose of this work is to formulate a mucoadhesive system with aciclovir (ACV) based on a solid molecular dispersion of this drug in poly(lactic-co-glycolic acid) branched on tripenterythritol (PLGA/T). The ACV incorporation into PLGA/T was carried out either by solvent method, or melting method, or plasticization method using various plasticizers. The drug-polymer miscibility, plasticizer efficiency and content of residual solvent were found out employing DSC. Viscosity was measured at the shear rate range from 0.10 to 10.00 s(-1) at three temperatures and data were analyzed by Newtonian model. The mucoadhesive properties were ascertained in the tensile test on a mucin substrate. The amount of ACV released was carried out in a wash-off dissolution test. The DSC results indicate a transformation of crystalline form of ACV into an amorphous dissolved in branched polyester carrier, and absence of methyl formate residuals in formulation. All the tested plasticizers are efficient at Tg depression and viscosity decrease. The non-conventional ethyl pyruvate possessing supportive anti-inflammatory activity was evaluated as the most suitable plasticizer. The ACV release was strongly dependent on the ethyl pyruvate concentration and lasted from 1 to 10 days. The formulated PLGA/T system with ACV exhibits increased adhesion to mucosal hydrophilic surfaces and prolonged ACV release controllable by degradation process and viscosity parameters.

Acyclovir for herpetic gingivostomatitis in children.

QUESTION: Every year I see preschool children with gingivostomatitis. There seems to be quite a substantial burden of illness with this condition. Because it is caused by herpes simplex virus type 1, should I prescribe antiherpetic therapy with oral acyclovir? ANSWER: While most children with primary gingivostomatitis will be asymptomatic, some will experience considerable pain and discomfort and are at risk of dehydration. There are no large, well designed studies to clearly determine appropriate therapy for all children. Based on a single randomized study, treatment should be started only within the first 72 hours of symptom onset if substantial pain or dehydration are documented.

Valacyclovir Decreases Plasma HIV-1 RNA in HSV-2 Seronegative Individuals: A Randomized Placebo-Controlled Crossover Trial.

BACKGROUND: Acyclovir (ACV), a highly specific anti-herpetic drug, acts as a DNA chain terminator for several human herpesviruses (HHVs), including HHV-2 (HSV-2), a common human immunodeficiency virus (HIV)-1 co-pathogen. Several trials demonstrated that HSV-2 suppressive therapy using ACV or its prodrug valacyclovir (valACV) reduced plasma HIV-1 viral load (VL) in HIV-1/HSV-2 coinfected persons, and this was proposed to be due to a decrease in generalized immune activation. Recently, however, we found that ACV directly suppresses HIV-1 ex vivo in tissues free of HSV-2 but endogenously coinfected with other HHVs. Here, we asked whether valACV suppresses VL in HIV-1 infected HSV-2-seronegative persons. METHODS: Eighteen HIV-1 infected HSV-2-seronegative individuals were randomly assigned in a double blind placebo-controlled, crossover trial. Eligible participants had CD4 cell counts of ≥500 cells/µL and were not taking antiretroviral therapy. Subjects in group A received 12 weeks of valACV 500 mg given twice daily by mouth followed by 2 weeks of a no treatment washout and then 12 weeks of placebo; subjects in group B received 12 weeks of placebo followed by 2 weeks of no treatment washout and then 12 weeks of valACV 500 mg twice daily. RESULTS: HIV-1 VL in plasma of patients treated with valACV 500 mg twice daily for 12 weeks was reduced on average by 0.37 log10 copies/mL. CONCLUSIONS: These data indicate that the effects of valACV on HIV-1 replication are not related to the suppression of HSV-2-mediated inflammation and are consistent with a direct effect of ACV on HIV-1 replication.

Feasibility Investigation of Cellulose Polymers for Mucoadhesive Nasal Drug Delivery Applications.

The feasibility of various cellulose polymer derivatives, including methylcellulose (MC), hydroxypropyl methylcellulose (HPMC), sodium-carboxymethylcellulose (sodium-CMC), and cationic-hydroxyethylcellulose (cationic-HEC), for use as an excipient to enhance drug delivery in nasal spray formulations was investigated. Three main parameters for evaluating the polymers in nasal drug delivery applications include rheology, ciliary beat frequency (CBF), and permeation across nasal tissue. Reversible thermally induced viscosity enhancement was observed at near nasal physiological temperature when cellulose derivatives were combined with an additional excipient, poly(vinyl caprolactam)-poly(vinyl acetate)-poly(ethylene glycol) graft copolymer (PVCL-PVA-PEG). Cationic-HEC was shown to enhance acyclovir permeation across the nasal mucosa. None of the tested cellulosic polymers caused any adverse effects on porcine nasal tissues and cells, as assessed by alterations in CBF. Upon an increase in polymer concentration, a reduction in CBF was observed when ciliated cells were immersed in the polymer solution, and this decrease returned to baseline when the polymer was removed. While each cellulose derivative exhibited unique advantages for nasal drug delivery applications, none stood out on their own to improve more than one of the performance characteristics examined. Hence, these data may be useful for the development of new cellulose derivatives in nasal drug formulations.

Development and optimisation of mucoadhesive nanoparticles of acyclovir using design of experiments approach.

The aim of our study was to improve the bioavailability of acyclovir (ACV) by delivery of mucoadhesive nanoparticles (NPs) and controlled delivery of drug at its absorption window. Central composite design was used by which the effects of independent variables (gelatin and Pluronic F-68) on various responses such as particle size, polydispersity index, entrapment efficiency, loading efficiency, drug release and mucoadhesive strength were studied. The optimised formulation was evaluated for morphology, stability, pharmacokinetic and gastrointestinal tracking. The optimised NPs were found to be nearly spherical. Changes in characteristics of NPs were not significant after six months of accelerated stability studies. In vivo mucoadhesion study showed significant retention of mucoadhesive NPs in upper gastro-intestinal tract for more than 12 h. Pharmacokinetic study in rats revealed that mucoadhesive NPs could maintain relatively steady plasma concentration of ACV for more than 10 h. The AUC0-∞ and mean residence time of optimised formulation (7527.9 ng h/mL and 12.09 h) were significantly high than tablet dispersion (3841.13 ng h/mL and 7.97 h).

Prophylactic treatment with a novel bioadhesive gel formulation containing aciclovir and tenofovir protects from HSV-2 infection.

OBJECTIVES: Over-the-counter access to an inexpensive, effective topical microbicide could reduce the transmission of HIV and would increase women's control over their health and eliminate the need to obtain their partners' consent for prophylaxis. Chronic infection with herpes simplex virus 2 (HSV-2), also known as human herpes virus 2, has been shown to facilitate HIV infection and speed the progression to immunodeficiency disease. Our objective is to develop a drug formulation that protects against both HSV-2 and HIV infection and adheres to the vaginal surface with extended residence time. METHODS: We developed a formulation using two approved antiviral active pharmaceutical ingredients, aciclovir and tenofovir, in a novel bioadhesive vaginal delivery platform (designated SR-2P) composed of two polymers, poloxamer 407 NF (Pluronic(®) F-127) and polycarbophil USP (Noveon(®) AA-1). The efficacy of the formulation to protect from HSV-2 infection was tested in vitro and in vivo. In addition to its efficacy, it is essential for a successful microbicide to be non-irritating to the vaginal mucosa. We therefore tested our SR-2P platform gel in the FDA gold-standard microbicide safety model in rabbits and also in a rat vaginal irritation model. RESULTS: Our studies indicated that SR-2P containing 1% aciclovir and 5% tenofovir protects (i) Vero cells from HSV-2 infection in vitro and (ii) mice from HSV-2 infection in vivo. Our results further demonstrated that SR-2P was not irritating in either vaginal irritation model. CONCLUSIONS: We conclude that SR-2P containing aciclovir and tenofovir may be a suitable candidate microbicide to protect humans from vaginal HSV-2 infection.

Exploration of statistical experimental design to improve entrapment efficiency of acyclovir in poly (d, l) lactide nanoparticles.

OBJECTIVE: In current exploration, systematic attempts have been made to improve the entrapment efficiency of a model hydrophilic drug substance, i.e. acyclovir, in poly (d, l) lactide (PLA) nanoparticles (NPs) using a modified nanoprecipitation technique. METHODS: Formulation parameters such as drug to polymer ratio, antisolvent selection, electrolyte (NaCl) addition, pH alteration and temperature were screened to improve the entrapment efficiency of acyclovir in PLA NPs. The temperature of the system (0-5 °C), phase volume ratio (1:2), stirring speed (2000 rpm), sonication time (5 min), etc. were kept constant during the preparation of NPs. Drug to polymer ratio and electrolyte addition emerged as critical formulation parameters affecting particle size as well as entrapment efficiency. Hence, in the present investigation a 3(2) full factorial design was used to investigate the combined influence of two factors, i.e. drug to polymer ratio (X1) and the amount of electrolyte, i.e. NaCl (X2) on particle size (Y1) and entrapment efficiency (Y2). The NPs were also evaluated for drug-excipient compatibility study by employing DSC and FT-IR analysis, whereas in vitro drug release studies were performed using dialysis bag technique in phosphate buffer pH 7.4. RESULTS: Statistically significant models were evolved to predict entrapment efficiency and particle size. The effect of factors X1, X2 and [Formula: see text] was found to be statistically significant in nature. Response variables, i.e. entrapment efficiency and particle size, were simultaneously optimized using desirability function using Design Expert software. This process allowed the selection of most suitable level of factors to achieve desired level of particle size and entrapment efficiency. The results of multiple linear regression analysis revealed that for obtaining desirable particle size (less than 250 nm) and entrapment efficiency (more than 17%), the NPs should be prepared using 1:3 drug to polymer ratio and 0.04 M NaCl. Acyclovir was found to be compatible with PLA as indicated by DSC and FT-IR studies. The experimental values obtained from the optimized formulation highly agreed with the predicted values. The drug release from the optimized formulation exhibited biphasic pattern and the drug release kinetics was best explained by Weibull model. CONCLUSION: In conclusion, results of the present study demonstrated that PLA NPs with expected particle size and entrapment efficiency can be obtained by adopting the concept of quality by design.

Evaluation of microporous polycaprolactone matrices for controlled delivery of antiviral microbicides to the female genital tract.

Acyclovir (ACV) as a model antiviral microbicide, was incorporated in controlled-release polycaprolactone (PCL) matrices designed for application as intra-vaginal ring inserts (IVRs). Microporous materials incorporating acyclovir up to a level of ~10 % w/w were produced by rapidly cooling suspensions of drug powder in PCL solution followed by solvent extraction from the hardened matrices. Around 21, 50 and 78 % of the drug content was gradually released from matrices over 30 days in simulated vaginal fluid at 37 °C, corresponding to drug loadings of 5.9, 7.0 and 9.6 % w/w. The release behaviour of matrices having the lowest drug loading followed a zero order model, whereas, the release kinetics of 7.0 and 9.6 % ACV-loaded PCL matrices could be described effectively by the Higuchi model, suggesting that Fickian diffusion is controlling drug release. Corresponding values of the diffusion co-efficient for ACV in the PCL matrices of 3.16 × 10(-9) and 1.07 × 10(-8) cm(2)/s were calculated. Plaque reduction assays provided an IC50 value of 1.09 µg/mL for acyclovir against HSV-2 and confirmed the antiviral activity of released acyclovir against HSV-2 replication in primate kidney cells (Vero) at levels ~70 % that of non-formulated acyclovir at day 30. Estimated minimum in vivo acyclovir concentrations produced by a PCL IVR (19 µg/mL) exceeded by a factor of 20 the IC50 value against HSV-2 and the reported ACV vaginal concentrations in women (0.5-1.0 µg/mL) following oral administration. These findings recommend further investigations of PCL matrices for vaginal delivery of antiviral agents in the treatment and prevention of sexually transmitted infections such as AIDS.

Development of solid lipid nanoparticles and nanostructured lipid carriers for improving ocular delivery of acyclovir.

The objective of the present investigation was to improve the ocular bioavailability of acyclovir by incorporating it into solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs). This required optimization of the process parameters, such as type of lipid, drug to lipid ratios, type and concentration of surfactants, and type and amount of liquid lipids used in the formulations. SLNs and NLCs were prepared by the modified hot oil in water microemuslion method. The prepared nanoparticles were evaluated for their particle size, zeta potential, entrapment efficiency, solid state characteristics, surface morphology, in vitro drug release, and permeation through excised cornea. The prepared nanoparticles were spherical and within the size range suitable for ocular drug delivery (400-777.56 nm). Incorporation of liquid oil in the structure of SLNs resulted in the formation of NLCs with high entrapment efficiency (25-91.64%) compared to SLNs (11.14%). The drug release from SLNs and NLCs was rather a surface-based phenomenon. In comparison to free drug solution, NLCs were capable of having faster permeation through the excised cornea indicating their potential enhanced corneal penetration properties. However, SLNs have reduced the permeation rate significantly. The results of the study suggest that SLNs can be successfully converted to physically superior NLCs, which have the potential to be developed further as ocular drug delivery systems for ACV.

Galactose decorated PLGA nanoparticles for hepatic delivery of acyclovir.

The present study explores prospective of surface tailored nanoparticles for targeted delivery of acyclovir along with the interception of minimal side effects. Acyclovir loaded plain and galactosylated poly lectic co glycolic acid (PLGA) nanoparticles were efficiently prepared and characterized by Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), size, polydispersity index, zeta potential, and entrapment efficiency. The formulations were evaluated for in vitro drug release and hemolysis. Further, biodistribution study and fluorescent microscopic studies were carried out to determine the targeting potential of formulations. SEM revealed smooth morphology and spherical shape of the nanoparticles. In vitro, the galactosylated nanoparticles were found to be least hemolytic and exhibited a sustained release pattern. In vivo studies exhibited an augmented bioavailability, increased residence time and enhanced delivery of acyclovir to the liver upon galactosylation. It may therefore be concluded that galactose conjugated PLGA nanoparticles can be used suitably as vehicles for delivery of bioactives specifically to the hepatic tissues and may be thus exploited in the effective management of various liver disorders.

Design and development of multiple emulsion for enhancement of oral bioavailability of acyclovir.

The objective of this investigation was to design and develop water-in-oil-in-water type multiple emulsions (w/o/w emulsions) entrapping acyclovir for improving its oral bioavailability. Multiple emulsions (MEs) were prepared and optimized using Span-80 and Span-83 as lipophilic surfactant and Brij-35 as hydrophilic surfactant. The physio-chemical properties of the w/o/w emulsions - particle size, viscosity, phase separation (centrifugation test) and entrapment efficiency were measured and evaluated along with macroscopic and microscopic observations to confirm multiple nature, homogeneity and globule size. Stability study, in vitro and ex vivo release studies were performed followed by in vivo studies in rats. Stable w/o/w emulsions with a particle size of 33.098 ± 2.985 µm and 85.25 ± 4.865% entrapment efficiency were obtained. Stability studies showed that the concentration of lipophilic surfactant was very important for stability of MEs. Drug release from the prepared formulations showed initial rapid release followed by a much slower release. In vivo studies in rats indicated prolonged release and better oral bioavailability as compared to drug solution. The overall results of this study show the potential of the w/o/w emulsions as promising drug delivery systems for acyclovir.

Safety and pharmacokinetics of aciclovir in women following release from a silicone elastomer vaginal ring.

OBJECTIVES: Systemic aciclovir and its prodrug valaciclovir are effective in treating and reducing recurrences of genital herpes simplex virus (HSV) and reducing transmission. Local aciclovir delivery, if it can achieve and maintain comparable intracellular genital tract levels, may be equally effective in the treatment and suppression of genital HSV. Intravaginal ring (IVR) delivery of aciclovir may provide pre-exposure prophylaxis against HSV acquisition. METHODS: Tolerability and pharmacokinetics were evaluated in six HIV-negative women with recurrent genital HSV who switched their daily oral valaciclovir suppression to an aciclovir IVR for 7 days (n = 3) or 14 days (n = 3). Blood and cervicovaginal lavage (CVL) were collected after oral and IVR dosing to measure aciclovir concentrations and genital swabs were obtained to quantify HSV shedding by PCR. RESULTS: The rings were well tolerated. Median plasma aciclovir concentrations were 110.2 ng/mL (IQR, 85.9-233.5) 12-18 h after oral valaciclovir. Little or no drug was detected in plasma following IVR dosing. Median (IQR) CVL aciclovir levels were 127.3 ng/mL (21-660.8) 2 h after oral valaciclovir, 154.4 ng/mL (60.7-327.5) 12-18 h after oral valaciclovir and 438 ng/mL (178.5-618.5) after 7 days and 393 ng/mL (31.6-1615) after 14 days of aciclovir ring use. Median CVL aciclovir levels 2 h after oral dosing were similar to levels observed 7 (P = 0.99) and 14 (P = 0.75) days after ring use. HSV DNA was not detected in genital swabs and there was no significant change in inflammatory mediators. CONCLUSIONS: This first-in-human study demonstrated that an IVR could safely deliver mucosal levels of aciclovir similar to oral valaciclovir without systemic absorption. More intensive site-specific pharmacokinetic studies are needed to determine whether higher local concentrations are needed to achieve optimal drug distribution within the genital tract.