<Emphasis Type="Italic">In vitro</Emphasis> activity of telithromycin against <Emphasis Type="Italic">Haemophilus influenzae</Emphasis> at epithelial lining fluid concentrations

Background  

Haemophilus influenzae is one of the main aetiological agents of community-acquired respiratory tract infections. The primary aim of this study was to evaluate the antibacterial activity of telithromycin against H. influenzae clinical isolates showing different pattern of resistance in comparison with azithromycin and clarithromycin at 1/4 ×, 1/2 ×, 1 ×, 2 ×, 4 × minimum inhibitory concentration (MIC) and to peak concentrations in epithelial lining fluid (ELF). The secondary aim was to determine the influence of CO₂ enriched atmosphere on bacterial susceptibility.     

Macrolide resistance and <Emphasis Type="Italic">In Vitro</Emphasis> selection of resistance to antibiotics in <Emphasis Type="Italic">Lactobacillus</Emphasis> isolates

Spreading of resistance to antibiotics is of great concern due to the increasing rate of isolation of multiresistant pathogens. Since commensal bacteria may transfer determinants of resistance to pathogens, studies on development of resistance should include also lactobacilli. Resistance to macrolides, penicillins and tetracycline was determined in 40 isolates of Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus crispatus, and Lactobacillus casei isolated from faeces of apparently healthy volunteers. Frequency of mutation and changes in susceptibility after serial exposure to these antibiotics at concentrations of 4× and 8× MIC were evaluated in susceptible isolates. Acquired resistance was defined as an increment in MIC values of at least four times in respect to the pre-selection values. Resistance to macrolides and/or tetracycline was identified in 14 and 4 isolates, respectively. ermB gene and A2058G mutation in 23S rRNA were detected in macrolide resistant isolates. Frequencies of mutation of susceptible isolates (n=26) were lower for ampicillin and erythromycin than for tetracycline. Serial exposure to antibiotics led to selection of resistant mutants. However, acquired resistance was rather unstable and was lost after subcultures in antibiotic-free medium in most mutants. Resistance to erythromycin was associated to a A2058G mutation in 23S rRNA. In conclusion, results indicate that resistance to macrolides and tetracycline is present among intestinal lactobacilli. Decrease in susceptibility following serial exposure to antibiotics might occur in lactobacilli, in a strain- and antibiotic-dependent way. Since lactobacilli are often used as probiotics, their ability to acquire resistance should be evaluated for isolates candidate to be included in probiotics based products.     

Hydroxyurea-Lactose Interaction Study: <Emphasis Type="Italic">In Silico</Emphasis> and <Emphasis Type="Italic">In Vitro</Emphasis> Evaluation

The Maillard reaction between hydroxyurea (a primary amine-containing drug) and lactose (used as an excipient) was explored. The adduct of these compounds was synthesized by heating hydroxyurea with lactose monohydrate at 60 °C in borate buffer (pH 9.2) for 12 h. Synthesis of the adduct was confirmed using UV–visible spectroscopy and Fourier transform infrared, differential scanning calorimetry, high-pressure liquid chromatography, and liquid chromatography-mass spectrometry studies. An in silico investigation of how the adduct formation affected the interactions of hydroxyurea with its biological target oxyhemoglobin, to which it binds to generate nitric oxide and regulates fetal hemoglobin synthesis, was carried out. The in silico evaluations were complemented by an in vitro assay of the anti-sickling activity. Co-incubation of hydroxyurea with deoxygenated blood samples reduced the percentage of sickled cells from 38% to 12 ± 1.6%, whereas the percentage of sickled cells in samples treated with the adduct was 17 ± 1.2%. This indicated loss of anti-sickling activity in the case of the adduct. This study confirmed that hydroxyurea can participate in a Maillard reaction if lactose is used as a diluent. Although an extended study at environmentally feasible temperatures was not carried out in the present investigation, the partial loss of the anti-sickling activity of hydroxyurea was investigated along with the in silico drug–target interactions. The results indicated that the use of lactose in hydroxyurea formulations needs urgent reconsideration and that lactose must be replaced by other diluents that do not form Maillard adducts.     

Preparation and <Emphasis Type="Italic">In Vitro</Emphasis>/<Emphasis Type="Italic">In Vivo</Emphasis> Evaluation of Microparticle Formulations Containing Meloxicam

In this study, we have formulated chitosan-coated sodium alginate microparticles containing meloxicam (MLX) and aimed to investigate the correlation between in vitro release and in vivo absorbed percentages of meloxicam. The microparticle formulations were prepared by orifice ionic gelation method with two different sodium alginate concentrations, as 1% and 2% (w/v), in order to provide different release rates. Additionally, an oral solution containing 15 mg of meloxicam was administered as the reference solution for evaluation of in vitro/in vivo correlation (ivivc). Following in vitro characterization, plasma levels of MLX and pharmacokinetic parameters [elimination half-life (t _1/2), maximum plasma concentration (C _max), time for C _max (t _max)] after oral administration to New Zealand rabbits were determined. Area under plasma concentration–time curve (AUC_0–∞) was calculated by using trapezoidal method. A linear regression was investigated between released% (in vitro) and absorbed% (in vivo) with a model-independent deconvolution approach. As a result, increase in sodium alginate content lengthened in vitro release time and in vivo t _max value. In addition, for ivivc, linear regression equations with r ² values of 0.8563 and 0.9402 were obtained for microparticles containing 1% and 2% (w/v) sodium alginate, respectively. Lower prediction error for 2% sodium alginate formulations (7.419 ± 4.068) compared to 1% sodium alginate formulations (9.458 ± 5.106) indicated a more precise ivivc for 2% sodium alginate formulation.     

<Emphasis Type="Italic">In Vitro</Emphasis> Preservation of Spanish Biodiversity

Spanish territories contain many of the hot spots of plant biodiversity among European countries. Most of the Spanish territory is found in the Mediterranean basin and in the Canary Islands, a region of great floral singularity and diversity (Macaronesian bioregion). Therefore, an important effort must be made to contribute to its conservation. Several strategies can be considered, but seed conservation under standard conditions is the most resource-efficient method. However, the application of this methodology is not always possible for recalcitrant seeds or species for which vegetative propagation is necessary or convenient under some circumstances. Micropropagation is one of the measures suggested for preserving endangered species. During the 1990s, several in vitro culture protocols for Spanish endemics were established. The main purpose of this strategy was to obtain a considerable number of individuals to reduce the loss of natural populations. Likewise, diverse slow growth protocols were developed for this material. However, these efforts usually did not lead to the establishment of in vitro collections. The advantages and disadvantages of the in vitro conservation strategy will be reviewed for some cases. The establishment of the in vitro protocols together with the development of cryopreservation techniques created the ideal conditions to generate cryogenic collections. In this paper, we review the knowledge and experience accumulated during the last decades in micropropagation, slow growth, and cryopreservation for Spanish plant wild species. Their application in the development ex situ collections and their contribution toward an integrated system to conserve threatened species will be discussed.     

Improved Skin Penetration Using <Emphasis Type="Italic">In Situ</Emphasis> Nanoparticulate Diclofenac Diethylamine in Hydrogel Systems: <Emphasis Type="Italic">In Vitro</Emphasis> and <Emphasis Type="Italic">In Vivo</Emphasis> Studies

Delivering diclofenac diethylamine transdermally by means of a hydrogel is an approach to reduce or avoid systemic toxicity of the drug while providing local action for a prolonged period. In the present investigation, a process was developed to produce nanosize particles (about 10 nm) of diclofenac diethylamine in situ during the development of hydrogel, using simple mixing technique. Hydrogel was developed with polyvinyl alcohol (PVA) (5.8% w/w) and carbopol 71G (1.5% w/w). The formulations were evaluated on the basis of field emission scanning electron microscopy, texture analysis, and the assessment of various physiochemical properties. Viscosity (163–165 cps for hydrogel containing microsize drug particles and 171–173 cps for hydrogel containing nanosize drug particles, respectively) and swelling index (varied between 0.62 and 0.68) data favor the hydrogels for satisfactory topical applications. The measured hardness of the different hydrogels was uniform indicating a uniform spreadability. Data of in vitro skin (cadaver) permeation for 10 h showed that the enhancement ratios of the flux of the formulation containing nanosize drug (without the permeation enhancer) were 9.72 and 1.30 compared to the formulation containing microsized drug and the marketed formulations, respectively. In vivo plasma level of the drug increased predominantly for the hydrogel containing nanosize drug-clusters. The study depicts a simple technique for preparing hydrogel containing nanosize diclofenac diethylamine particles in situ, which can be commercially viable. The study also shows the advantage of the experimental transdermal hydrogel with nanosize drug particles over the hydrogel with microsize drug particles.     

Thidiazuron Promotes <Emphasis Type="Italic">In Vitro</Emphasis> Plant Regeneration of <Emphasis Type="Italic">Arachis correntina</Emphasis> (<Emphasis Type="Italic">Leguminosae</Emphasis>) via Organogenesis

Arachis correntina (Burkart) Krapov. & W.C. Gregory is a herbaceous perennial leguminous plant growing in the Northeast of the Province Corrientes, Argentina. It is important as forage. The development of new A. correntina cultivars with improved traits could be facilitated through the application of biotechnological strategies. The purpose of this study was to investigate the plant regeneration potential of mature leaves of A. correntina in tissue culture. Buds were induced from both petiole and laminae on 0.7% agar-solidified medium containing 3% sucrose, salts and vitamins from Murashige and Skoog (MS) supplemented with 0.5–25 M thidiazuron (TDZ). Shoot induction was achieved by transference of calli with buds to MS supplemented with 5 M TDZ. Fifty-four percent of the regenerated shoot rooted on MS + 5 M naphthaleneacetic acid. Histological studies revealed that shoots regenerated via organogenesis.     

<Emphasis Type="Italic">In Vitro</Emphasis> and <Emphasis Type="Italic">In Vivo</Emphasis> Evaluation of Hydroxyzine Hydrochloride Microsponges for Topical Delivery

Hydroxyzine HCl is used in oral formulations for the treatment of urticaria and atopic dermatitis. Dizziness, blurred vision, and anticholinergic responses, represent the most common side effects. It has been shown that controlled release of the drug from a delivery system to the skin could reduce the side effects while reducing percutaneous absorption. Therefore, the aim of the present study was to produce an effective drug-loaded dosage form that is able to control the release of hydroxyzine hydrochloride into the skin. The Microsponge Delivery System is a unique technology for the controlled release of topical agents, and it consists of porous polymeric microspheres, typically 10–50 μm in diameter, loaded with active agents. Eudragit RS-100 microsponges of the drug were prepared by the oil in an oil emulsion solvent diffusion method using acetone as dispersing solvent and liquid paraffin as the continuous medium. Magnesium stearate was added to the dispersed phase to prevent flocculation of Eudragit RS-100 microsponges. Pore inducers such as sucrose and pregelatinized starch were used to enhance the rate of drug release. Microsponges of nearly 98% encapsulation efficiency and 60–70% porosity were produced. The pharmacodynamic effect of the chosen preparation was tested on the shaved back of histamine-sensitized rabbits. Histopathological studies were driven for the detection of the healing of inflamed tissues.     

Development and <Emphasis Type="Italic">In Vitro</Emphasis>/<Emphasis Type="Italic">In Vivo</Emphasis> Evaluation of Etodolac Controlled Porosity Osmotic Pump Tablets

The aim of the current work was the design and evaluation of etodolac controlled porosity osmotic pump (CPOP) tablets exhibiting zero-order release kinetics. Variables influencing the design of (1) core tablets viz., (a) osmogent type (sodium chloride, potassium chloride, mannitol, and fructose) and (b) drug/osmogent ratio (1:0.25, 1:0.50, and 1:0.75), and (2) CPOP tablets viz., (a) coating solution composition, (b) weight gain percentage (1–5%, w/w), and (c) pore former concentration (5%, 10%, and 20%, v/v), were investigated. Statistical analysis and kinetic modeling of drug release data were estimated. Fructose-containing core tablets showed significantly (P < 0.05) more retarded drug release rates. An inverse correlation was observed between drug/fructose ratio and drug release rate. Coating of the optimum core tablets (F4) with a mixture of cellulose acetate solution (3%, w/v), diethyl phthalate, and polyethylene glycol 400 (85:10:5, v/v, respectively) till a 4% w/w weight gain enabled zero-order sustained drug delivery over 24 h. Scanning electron microscopy micrographs of coating membrane confirmed pore formation upon contact with dissolution medium. When compared to the commercial immediate-release Napilac® capsules, the optimum CPOP tablets (F4–34) provided enhanced bioavailability and extended duration of effective etodolac plasma concentration with minimum expected potential for side effects in healthy volunteers.KEY WORDS: cellulose acetate, controlled porosity osmotic pump, etodolac, osmogent, zero order     

<Emphasis Type="Italic">In Vitro</Emphasis> and <Emphasis Type="Italic">In Vivo</Emphasis> Assessment of Docetaxel Formulation Developed for Esophageal Stents

Esophageal cancer (EC) mostly affects the elderly population and is frequently diagnosed at an advanced stage. Self-expanding metal stents (SEMS) are the most popular mode of palliation, but they are associated with reocclusion caused by tumor growth. To overcome this problem, docetaxel (DTX)-loaded polyurethane formulations were prepared for stent application. The films were evaluated against the cancer cell lines, OE-19 and OE-21, and normal esophageal cell line Het-1A. The DTX and the formulations were evaluated in vitro for the cytotoxicity and in vivo in nude mice. It was found that DTX and the formulations have a weak activity against the EC cell lines and an even weaker activity against Het-1A cell line. Preliminary in vivo studies showed skin toxicity in nude mice necessitating modification of the formulation. Reevaluation in a mouse xenograft model resulted in toxicity at high dose formulations while the low dose formulation exhibited modest advantage over commercial IV formulation; however, there was no significant difference between the commercial IV and blank formulation. DTX combination with an anti-cancer agent having complementary mode of action and non-overlapping toxicity could yield better outcome in future.     

<Emphasis Type="Italic">In Vitro</Emphasis> and <Emphasis Type="Italic">In Vivo</Emphasis> Evaluation of Proniosomes Containing Celecoxib for Oral Administration

The objectives of this research were to prepare celecoxib proniosomes and evaluate the influence of proniosomal formulation on the oral bioavailability of the drug in human volunteers. A new proniosomal delivery system for a poorly water-soluble drug such as celecoxib was developed and subjected to in vitro and in vivo studies. Proniosomes were prepared by sequential spraying method, which consisted of cholesterol, span 60, and dicetyl phosphate in a molar ratio of 1:1: 0.1, respectively. The average entrapment percent of celecoxib proniosome-derived niosomes was about 95%. The prepared proniosomes showed marked enhancement in the dissolution of celecoxib as compared to pure drug powder. The bioavailability of 200 mg single dose of both celecoxib proniosomal formulation and a conventional marketed celecoxib capsule was studied in human volunteers. The obtained results show that the proniosomal formulation significantly improved the extent of celecoxib absorption than conventional capsule. The mean relative bioavailability of the proniosomal formulation to the conventional capsule was 172.06 ± 0.14%. The mean T _max for celecoxib was prolonged when given as proniosomal capsule. There was no significant difference between the values of K _el and t _1/2 for both celecoxib preparations. In conclusion, the proniosomal oral delivery system of celecoxib with improved bioavailability was established.     

<Emphasis Type="Italic">Azospirillum brasilense</Emphasis> siderophores with antifungal activity against <Emphasis Type="Italic">Colletotrichum acutatum</Emphasis>

Anthracnose, caused by the fungus Colletotrichum acutatum is one of the most important diseases in strawberry crop. Due to environmental pollution and resistance produced by chemical fungicides, nowadays biological control is considered a good alternative for crop protection. Among biocontrol agents, there are plant growth-promoting bacteria, such as members of the genus Azospirillum. In this work, we demonstrate that under iron limiting conditions different strains of A. brasilense produce siderophores, exhibiting different yields and rates of production according to their origin. Chemical assays revealed that strains REC2 and REC3 secrete catechol type siderophores, including salicylic acid, detected by thin layer chromatography coupled with fluorescence spectroscopy and gas chromatography–mass spectrometry analysis. Siderophores produced by them showed in vitro antifungal activity against C. acutatum M11. Furthermore, this latter coincided with results obtained from phytopathological tests performed in planta, where a reduction of anthracnose symptoms on strawberry plants previously inoculated with A. brasilense was observed. These outcomes suggest that some strains of A. brasilense could act as biocontrol agent preventing anthracnose disease in strawberry.     

Development of a Prolonged-Release Pramipexole Transdermal Patch: <Emphasis Type="Italic">In Vitro</Emphasis> and <Emphasis Type="Italic">In Vivo</Emphasis> Evaluation

The current study aimed to develop a prolonged-release pramipexole (PPX) transdermal patch for the treatment of Parkinson’s disease. Permeation parameters of PPX were investigated using human cadaver skin. Pramipexole patches were prepared using DURO-TAK^® pressure-sensitive-adhesive (PSA) and evaluated for drug stability, drug loading, in vitro drug release, and in vitro permeation through mouse skin. The results indicated that blends of DURO-TAK^® 87-2852 and DURO-TAK^® 87-2510 were suitable for creating a prolonged-release PPX patch due to their advantages in drug release, drug loading, and stability. The final formulation consisted of 87-2852/87-2510 (70:30), 10% PG, and 15% PPX and showed a cumulative permeation amount of 1497.19?±?102.90 μg/cm² with a continuous flux over 6.0 μg/(cm²·h) across human cadaver skin for 7 days. In vivo studies in rats indicated that PPX patch produced a significantly longer (p?<?0.001) half-life (t _1/2, 75.16?±?17.37 h) and mean residence time (MRT, 135.89?±?24.12 h) relative to oral tablets (Sifrol^®) and had a relative bioavailability of 51.64?±?21.32%. Therefore, this study demonstrated the feasibility of developing a prolonged-release PPX patch, which proposed the potential to serve as an alternate to conventional oral tablets and may therefore improve patient compliance.     

Enhancement of the Oral Bioavailability of Felodipine Employing 8-Arm-Poly(Ethylene Glycol): <Emphasis Type="Italic">In Vivo</Emphasis>, <Emphasis Type="Italic">In Vitro</Emphasis> and <Emphasis Type="Italic">In Silico</Emphasis> Evaluation

Poor oral bioavailability is the single most important challenge in drug delivery. Prominent among the factors responsible for this is metabolic activity of the intestinal and hepatic cytochrome P450 (CYP450) enzymes. In preliminary studies, it was demonstrated that 8-arm-PEG was able to inhibit the felodipine metabolism. Therefore, this report investigated the oral bioavailability-enhancing property of 8-arm-PEG employing detailed in vitro, in vivo, and in silico evaluations. The in vitro metabolism of felodipine by cytochrome P450 3A4-expressed human liver microsomes (HLM) was optimized yielding a typical Michaelis–Menten plot through the application of Enzyme Kinetic Module software from where the enzyme kinetic parameters were determined. In vitro investigation of 8-arm-poly(ethylene glycol) against CYP3A4-catalyzed felodipine metabolism employing human liver microsomes compared closely with naringenin, a typical grapefruit flavonoid, yielding IC₅₀ values of 7.22 and 121.97 μM, respectively. The investigated potential of 8-arm-poly(ethylene glycol) in oral drug delivery yielded satisfactory in vitro drug release results. The in vivo studies of the effects of 8-arm-poly(ethylene glycol) on the oral bioavailability of felodipine as performed in the Large White pig model showed a >100% increase in plasma felodipine levels compared to controls, with no apparent effect on systemic felodipine clearance. The outcome of this research presents a novel CYP3A4 inhibitor, 8-arm-poly(ethylene glycol) for oral bioavailability enhancement.     

Studies on Core-Shell Nanocapsules of Felodipine: <Emphasis Type="Italic">In Vitro</Emphasis>-<Emphasis Type="Italic">In Vivo</Emphasis> Evaluations

The present study aimed for in vitro-in vivo-in silico simulation studies of experimentally designed (3²-factorial) Capmul PG-8-cored, Eudragit RSPO-Lutrol F 127 nanocapsules to ferry felodipine using GastroPlus?. The in silico parameter sensitivity analysis for pharmacokinetic parameters was initially assessed to justify the preparation of felodipine-loaded nanocapsules (FLNs) with enhanced solubility to overcome the bioavailability issues of felodipine. The overall integrated desirability ranged between 0.8187 and 0.9488 for three optimized FLNs when analyzed for mean particle size, zeta potential, encapsulation efficiency, and in vitro dissolution parameters. The morphological evaluation (SEM, TEM, and AFM) demonstrated spherical nanoparticles (200–300 nm). Validated LC-MS/MS analysis demonstrated enhanced relative bioavailability (13.37-fold) of optimized FLN as compared to suspension. The simulated regional absorption of the FLN presented significant absorption from the cecum (26.3%) and ascending colon (20.1%) with overall absorption of 67.4% from the GIT tract. Furthermore, in vitro-in vivo correlation demonstrated the Wagner-Nelson method as the preferred model as compared to mechanistic and numerical deconvolution on the basis of least mean absolute prediction error, least standard error of prediction, least mean absolute error, and maximum correlation coefficient (r ² = 0.920). The study demonstrated enhanced oral absorption of felodipine-loaded nanocapsules, and GastroPlus? was found to be an efficient simulation tool for in vitro-in vivo-in silico simulations.     

<Emphasis Type="Italic">Ty</Emphasis>1<Emphasis Type="Italic">/copia</Emphasis>- and <Emphasis Type="Italic">Ty</Emphasis>3<Emphasis Type="Italic">/gypsy</Emphasis>-like DNA sequences in <Emphasis Type="Italic">Helianthus </Emphasis>species

Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes.     

Development of Molecularly Imprinted Olanzapine Nano-particles: <Emphasis Type="Italic">In Vitro</Emphasis> Characterization and <Emphasis Type="Italic">In Vivo</Emphasis> Evaluation

Molecularly imprinted nano-particles (MINPs) selective for olanzapine were prepared using methacrylic acid (MA) as monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker, and 2,2-azobis (2-isobutyronitrile) (AIBN) as the initiator in 36 different ratios. The reaction runs with considerable fine powder formation were selected for further binding and selectivity studies. The MINP with the best selectivity (MINP-32) was chosen for further structural characterization by Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), adsorption-desorption isotherm for specific surface area, volume and average pore diameter determination. All characterization methods confirmed the successful formation of MINP. The optimum conditions for maximum template loading on the MINP-32 were found by experimental design using response surface methodology (RSM) and choosing absorbent amount, pH, and time as the main factors. MINPs with maximum template loading also indicated significant selectivity between template and its analog (clozapine). The release profile demonstrated a maximum release of about 95% after 288 h for MINP-32 in comparison with about 94% after 120 h for non-MINP-32. The same slow release of drug from MINP-32 was also observed during animal study of the plasma level of template, 20–28 μg/ml versus 5–10 μg/ml. The MINP-32 of this study represents a desirable ability to keep the memory of the template with significant selectivity and good capability to control the release of template in vitro and in vivo and hence could be a promising drug delivery system.     

The Biodegradation of Zein <Emphasis Type="Italic">In Vitro</Emphasis> and <Emphasis Type="Italic">In Vivo</Emphasis> and its Application in Implants

A unique polymer-based sustained-release implant drug delivery system was prepared by using biocompatible and biodegradable Zein as the skeleton meterial. After preparing Zein colloids, the Zein-loaded implant rods were formulated by injection molding followed by evaporating the solvent, and being coated with poly(lactic-co-glycolic) acid (PLGA) solution. Drug release kinetics was examined by using Fluorouracil (5-FU) as model drug. Nearly zero-order release was achieved for the model drugs for a period of 0–25 days when the implants were incubated in distilled water at 37°C. And then the degradation kinetics of the rods in vivo and in vitro were evaluated, which indicated that Zein could be absorbed by body and has good degradation property. The effects of different ratios of Zein/5-FU and the rods’ diameter on drug release were studied, respectively. The plasma concentration of 5-FU in the implants were determined by HPLC after implanting a single dose of the implants in rats. All data were subsequently processed by using the computer program 3P97, and the values were showed as follows: the area under the plasma concentration–time curve (AUC) value was 321.88 (μg/ml) × day, and the mean residence time (MRT) value was 23.05 days. The sustained-release implants of Zein/5-FU were successfully formulated. The uniqueness of the article is that Zein has been used as a skeleton material in implant delivery system for the first time and zero-order release kinetics has been obtained successfully.     

In planta transformation of <Emphasis Type="Italic">Notocactus scopa</Emphasis> cv. <Emphasis Type="Italic">Soonjung</Emphasis> by <Emphasis Type="Italic">Agrobacterium </Emphasis><Emphasis Type="Italic">tumefaciens</Emphasis>

Notocactus scopa cv. Soonjung was subjected to in planta Agrobacterium tumefaciens-mediated transformation with vacuum infiltration, pin-pricking, and a combination of the two methods. The pin-pricking combined with vacuum infiltration (20-30 cmHg for 15 min) resulted in a transformation efficiency of 67-100%, and the expression of the uidA and nptII genes was detected in transformed cactus. The established in planta transformation technique generated a transgenic cactus with higher transformation efficiency, shortened selection process, and stable gene expression via asexual reproduction. All of the results showed that the in planta transformation method utilized in the current study provided an efficient and time-saving procedure for the delivery of genes into the cactus genome, and that this technique can be applied to other asexually reproducing succulent plant species.