Short communication safety, tolerability and pharmacokinetics of enfuvirtide administered by a needle-free injection system compared with subcutaneous injection

BACKGROUND

Injection site reactions (ISRs) can present a challenge to patients when using enfuvirtide (ENF). This study compared ISRs associated with use of a needle-free injection device (NFID) with those associated with a standard 27-gauge half-inch needle/syringe (NS).

METHODS

In this single-blind, crossover study, 58 ENF-naive participants were randomized to self-administer ENF with the NFID for 4 weeks (followed by 4 weeks using NS) or with the NS for 4 weeks (followed by 4 weeks using the NFID). A primary composite endpoint of painful ISR was defined as the combination of grade 1-3 ongoing pain plus either associated grade 3-4 (> or =25 mm) induration or grade 2-4 nodules/cysts (>20 mm). An ISR summary score described ISR frequency/severity. Self-reported device preference was also evaluated at baseline and at study completion.

RESULTS

Fewer participants using NFID experienced the primary composite endpoint of painful ISRs (10/28; 35.7%) compared with NS (20/28; 71.4%) (P=0.004). There was a trend towards a reduced incidence/severity of ISR signs and symptoms with NFID, with significant reductions seen in pain/discomfort and pruritus (P<0.05 and P<0.01, respectively). At the end of the study, most participants (22/25; 88%) expressed a preference for NFID. Haematoma was the sole NFID-related serious adverse event, but this did not lead to discontinuation.

CONCLUSIONS

Compared with a standard NS, use of an NFID to administer ENF was associated with a substantially lower incidence of painful ISRs, was generally safe and well-tolerated, and was preferred by most participants in the study.

Optimization of a jet-propelled particle injection system for the uniform transdermal delivery of drug/vaccine

A jet-propelled particle injection system, the biolistics, has been developed and employed to accelerate micro-particles for transdermal drug delivery. We have examined a prototype biolistic device employing a converging-diverging supersonic nozzle (CDSN), and found that the micro-particles were delivered with a wide velocity range (200-800 m/s) and spatial distribution. To provide a controllable system for transdermal drug delivery, we present a contoured shock-tube (CST) concept and its embodiment device. The CST configuration utilizes a quasi-steady, quasi-one dimensional and shock-free supersonic flow to deliver the micro-particles with an almost uniform velocity (the mean velocity and the standard deviation, 699 +/- 4.7 m/s) and spatial distribution. The transient gas and particle dynamics in both prototype devices are interrogated with the validated computational fluid dynamics (CFD) approach. The predicted results for static pressure and Mach number histories, gas flow structures, particle velocity distributions and gas-particle interactions are presented and interpreted. The implications for clinical uses are discussed.

[Needle-free injection--science fiction or comeback of an almost forgotten drug delivery system?]

The first to create a "needle-free injector" was the American anesthetist Robert A. Hingson, 65 year ago. Since that time those devices underwent a changeful history. In 1986 an outbreak of hepatitis B among patients receiving injections from a needle-free multiple-use-nozzle injector was documented and related to the use of the injector device. Due to such risk of transmission of infection with these reusable devices, their application has been restricted. In 1998 the WHO recommended that only conventional needles and syringes should be used for immunization until safe needle-free injectors are identified through independent safety testing. Since needle-free injection has shown numerous advantages in comparison to conventional injection, new systems were developed that combine the advantages of needle-free injection with sufficient safety in mass vaccination programs. As an alternative to this early injector type, the disposable-cartridge injectors were developed. The newest research field in the area of the needle-free injection systems opened with the development of powder injectors, in which the drug preparation is no longer a suspension or solution, but a powdered solid. This injector type using powder formulations shows a number of advantages in comparison with the conventional needle/syringe injection technique as well as towards the liquid jet injectors. Due to this new kind of injectors the comeback of the needle-free injection technique in large-scale vaccination programs of the WHO seems reasonable and within reach.

Intracellular targeting of CEA results in Th1-type antibody responses following intradermal genetic vaccination by a needle-free jet injection device

The route and method of immunization, as well as the cellular localization of the antigen, can influence the generation of an immune response. In general, intramuscular immunization results in Th1 responses, whereas intradermal delivery of DNA by gene gun immunization often results in more Th2 responses. Here we investigate how altering the cellular localization of the tumor antigen CEA (carcinoembryonic antigen) affects the quality and amplitude of DNA vaccine-induced antibody responses in mice following intradermal delivery of DNA by a needle-free jet injection device (Biojector). CEA was expressed either in a membrane-bound form (wild-type CEA) or in two truncated forms (CEA6 and CEA66) with cytoplasmic localization, where CEA66 was fused to a promiscuous T-helper epitope from tetanus toxin. Repeated intradermal immunization of BALB/c mice with DNA encoding wild-type CEA produced high antibody titers of a mixed IgG1/IgG2a ratio. In contrast, utilizing the DNA construct that resulted in intracellular targeting of CEA led to a reduced capacity to induce CEA-specific antibodies, but instead induced a Th1-biased immune response.

The Effects of System Parameters on In Vivo Injection Performance of a Needle-Free Injector in Human Volunteers

PURPOSE

For a novel needle-free injection (NFI) system, the relationship between frequency of wet or incomplete injections and device-related factors and subject physiological variables was examined.

MATERIALS AND METHODS

A total of 26 device configurations of a single-use pre-filled NFI system (Intraject) were used to deliver a total of 3,211 subcutaneous injections into the abdomen of 302 healthy volunteers. Two validated methods were used to determine completeness of each injection (defined as >or=90% dose delivery). Skin-fold thickness, body mass index (BMI), Fitzpatrick skin type, sex, age, and injection site were noted for each volunteer.

RESULTS

The proportion of complete injections ranged from 59-98% among the various combinations of device configurations. Two device parameters and two subject-related variables showed strong association with injection performance; Device gas mass (chamber pressure) and orifice size demonstrated statistically significant, independent effects, with increasing gas mass and larger orifice size associated with improved injection performance. BMI and site of injection on the abdomen also demonstrated statistically significant effects with increasing BMI and lateral rather than medial injection sites associated with better injections.

CONCLUSION

Both device-related factors and subject variables interact to mediate in vivo performance of a needle-free injector.

Needle-free delivery of macromolecules across the skin by nanoliter-volume pulsed microjets

Needle-free liquid jet injectors were invented >50 years ago for the delivery of proteins and vaccines. Despite their long history, needle-free liquid jet injectors are not commonly used as a result of frequent pain and bruising. We hypothesized that pain and bruising originate from the deep penetration of the jets and can potentially be addressed by minimizing the penetration depth of jets into the skin. However, current jet injectors are not designed to maintain shallow dermal penetration depths. Using a new strategy of jet injection, pulsed microjets, we report on delivery of protein drugs into the skin without deep penetration. The high velocity (v >100 m/s) of microjets allows their entry into the skin, whereas the small jet diameters (50-100 mum) and extremely small volumes (2-15 nanoliters) limit the penetration depth ( approximately 200 mum). In vitro experiments confirmed quantitative delivery of molecules into human skin and in vivo experiments with rats confirmed the ability of pulsed microjets to deliver therapeutic doses of insulin across the skin. Pulsed microjet injectors could be used to deliver drugs for local as well as systemic applications without using needles.

Selective fluid cushion in the submucosal layer by water jet: advantage for endoscopic mucosal resection

BACKGROUND/AIM

Numerous new techniques have recently been reported and described for the endoscopic mucosal resection of large superficial lesions of the gastrointestinal tract. We present here for the first time the application of a water jet dissector for mucosa elevation.

MATERIALS AND METHODS

In an ex vivo study, the effectiveness of a water jet dissector (Helix Hydro-Jet) placed directly on the stomach walls of 8 pigs was examined to create a mucosal elevation. After having determined optimal pressures, angle of application, and application times, 13 submucosal fluid cushions were produced in different areas of the stomach walls of 8 pigs in vivo, and the sizes of the resulting submucosal cushions were measured.

RESULTS

Using pressures between 30 and 70 bar, it was routinely possible to create submucosal fluid cushions in the stomach wall ex vivo as well as in vivo. Histological examination showed a selective edema in the submucosa without damage to the deeper mucosal layers of the gastric wall.

CONCLUSIONS

The capacity of a targeted high-pressure water jet to penetrate the mucosa and selectively create a fluid cushion in the submucosa facilitates endoscopic resection of the mucosa. This new method could contribute to ameliorate the endoscopic treatment of mucosal tumors which previously could not be resected endoscopically due to their size, extent, or location.

Needle-free liquid jet injections: mechanisms and applications

Liquid jet injections employ a high-speed jet to puncture the skin and deliver drugs without the use of a needle. They have been used to deliver a number of macromolecules including vaccines and insulin, as well as small molecules, such as anesthetics and antibiotics. This article reviews liquid jet injectors with respect to their historical perspective, clinical applications, mechanisms and future prospects. An overview of the use of jet injectors for delivery of vaccines, insulin and growth hormones is presented. Particular attention is paid to the mechanistic understanding of jet injections, especially the dependence of jet penetration on parameters such as nozzle diameter, velocity and jet power. Finally, gaps in the current understanding are presented and suggestions for future research and development are made.

Needle-free injection of DNA vaccines: a brief overview and methodology

The development of needle-free injection originally stemmed from a general apprehension of needle injections, disease transmission by accidental needle-sticks, and the need for effective mass immunization. Naked DNA vaccines, as attractive and universal as they appear, have not produced robust immune responses in test systems. However, proof of principle for DNA vaccines has been validated with a number of vaccine candidates in a variety of test systems, and the concept of DNA vaccines as a generic platform for vaccines still remains viable and attractive. Many avenues are being explored to enhance the immunogenicity of DNA vaccines. The easiest and most straightforward approach that can be quickly transitioned to a clinical trial setting is vaccine delivery by a needle-free jet injector. This approach has shown much potential in a number of cases and should become the lead method for enhancing DNA vaccines. This approach requires no additional development, and with an expanding market and willingness from jet injector manufacturers to produce prefilled syringes, the technique should become feasible for larger phase II/phase III trials.

Children's preferences concerning the physical appearance of dental injectors

PURPOSE

This pilot study was carried out to assess how the physical appearance of dental injectors influenced children's choice.

METHODS

The study group consisted of 34 randomly selected children (17 boys, 17 girls) between the ages of 7 and 11 (mean age=8.6 +/- 1.4), who had been registered for treatment at the School of Dentistry, Marmara University. A combination of tests-the Children's Fear Survey Schedule-Dental Subscale (CFSS-DS), Venham Picture Test (VPT), and facial image scale (FIS)-were used to assess the multi-dimensional character of children's dental anxiety. Dental injectors (Wand, Citoject, traditional metal injector [MI], and plastic injector [PI]) were displayed on a tray and introduced to the children. The children were asked to consider which injectors they would choose "if their tooth had to be put to sleep," and their preferences were noted starting with their first choice.

RESULTS

The children's first choice was: (1) the Wand (56%); (2) PI (29%); (3) Citoject (12%); and (4) MI (3%). The anxious children (n= 13) preferred the Wand with significantly higher ratings (Wand=84%; Citoject=8%; MI=8%; PI=0%).

CONCLUSION

The physical appearance of dental injectors is important to children and even more important for children who are anxious.

Novel delivery of botulinum toxin for the treatment of anal fissures

OBJECTIVE

Botulinum toxin A (Botox) has been used as a local treatment for anal fissure since 1994. It effects a reversible chemical sphincterotomy without the need for patient compliance. This study examines the feasibility of injecting the treatment using a needle-less system.

PATIENTS AND METHODS

The optimal angle for injection was determined in a preclinical study using fresh porcine specimens. Ten patients with chronic anal fissures were then injected with 20 units Botox at the site of the fissure. They underwent assessment with a visual analogue pain scale, incontinence score and anal manometry pre-injection, at 48 h postinjection and at six and 12 weeks postinjection. They were also examined at the initial and final visits.

RESULTS

The optimal angle for injection was 60 degrees . All 10 patients (5 male; median age 40.5 years (range 26-68 years)) attended the 48 h follow up visit but only seven attended the six and 12 week visits. Six of seven patients healed their fissures. The remaining three were contacted by telephone at six months post injection and two of three remained asymptomatic without further treatment. In seven patients who underwent full follow up the median pain score pre-injection was 5.5 out of 10 (range 1-10) and this dropped to a median of 1 (range 0-6) at 12 weeks. The median drop in resting pressure was 47 cm H2O or 37% at six weeks.

CONCLUSION

No needle injection of Botox is feasible with similar healing rates and reduction of resting pressure to conventional injection techniques.

Enfuvirtide plasma levels and injection site reactions using a needle-free gas-powered injection system (Biojector)

OBJECTIVES

To assess the use of the Biojector B2000 needle-free gas-powered injection system for subcutaneous administration of enfuvirtide in HIV-infected patients and to compare this system with standard needles and syringes with respect to ease of use, severity of injection site reactions (ISR), and enfuvirtide plasma levels.

DESIGN

An observational study among 32 treatment-experienced HIV clinic patients receiving enfuvirtide.

METHODS

Adult patients were assessed before and after switching from standard needles to the Biojector for enfuvirtide administration. Patients used the Biojector for up to 24 weeks and rated ease of use from 0 (easy) to 3 (difficult). ISR were graded from 0 to 31 for signs and symptoms (erythema, induration, pruritus, nodules/cysts, ecchymosis), duration of individual lesions, and number of lesions. Plasma was collected pre-dose and 1 h post-dose for enfuvirtide measurement. The high-pressure liquid chromatography with tandem mass spectrometry method used was specific for enfuvirtide over its known plasma metabolite. Wilcoxon rank sum tests were used to compare needle-based and Biojector outcomes.

RESULTS

The Biojector was rated as being significantly easier to use (P < 0.001) and reduced the occurrence of ISR compared with standard needles (P < 0.001). Enfuvirtide plasma levels were not statistically different between the two administration methods at either pre-dose trough (P = 0.41) or 1 h post-dose (P = 0.74).

CONCLUSIONS

The Biojector needle-free injection system was easy to use for enfuvirtide administration and was associated with a decreased severity of ISR. Plasma enfuvirtide levels pre-dose and 1 h post-dose were comparable when injecting with standard needles or the Biojector.

Clinical safety and efficacy of a powdered Hepatitis B nucleic acid vaccine delivered to the epidermis by a commercial prototype device

This clinical delivery system bridging study evaluated the performance of a single-use disposable, commercial prototype device (designated ND 5.5) for particle-mediated epidermal delivery (PMED) of a nucleic acid vaccine against Hepatitis B virus (HBV). Healthy adults, previously immunized with licensed HBV vaccine, received a single boost vaccination of HBV nucleic acid vaccine administered by ND 5.5 or XR-1, the clinical research device used in previous clinical trials. Similar increases in anti-HBV surface antigen serum antibody titers and cell-mediated immune responses were produced by ND 5.5 and XR-1 when delivering comparable effective doses of the vaccine. The overall intensity of the immune response was lower in those subjects vaccinated with two, rather than 4 administrations of vaccine delivered by ND 5.5. Skin reactions at sites of vaccine administration were equivalent with both devices. This is the first clinical demonstration of the safe and effective PMED of a nucleic acid vaccine with the ND 5.5 device.

A Lorentz-force actuated autoloading needle-free injector

The advantages of delivering injections via needle-free methods are numerous. However, conventional methods for needle-free injection lack sufficient control over depth of penetration and shape of injection. Thus, a needle-free injector was designed, constructed, and tested, using a controllable linear Lorentz-force actuator. This actuator allows rapid control of the injection pressure during injections. Using this device, precise control over delivery parameters can be achieved. The injector design was tested for repeatability and evaluated for depth control using acrylamide gel and dye.

[Comparison of the systems used for providing local anesthesia in dentistry--the Wand (Milestone Scientific) and Injex (Rosch)]

Local anesthesia is one of the basic and the most often executed interventions in dentistry. This procedure is very stressful for the patients because it is combined with pain. The new systems for delivering local anesthesia in dentistry have revolutionized the technique considerably by its simplify as well as reduction in pain.

THE AIM

this study presents the comparison between the local anesthesia delivery systems used in dentistry--The Wand and Injex, taking into consideration pain intensity during performing anesthesia and the intensification of fear before executed anesthesia with the given system.

MATERIAL AND METHODS

the Visual Analogue Scale (VAS), verbal scale and questionnaires were used to evaluate pain and fear.

RESULTS

On the basis of our investigations it can be concluded that there were statistically important differences between men and women in fear intensity combined with the anesthesia procedure--men were less afraid than women. The patients who were anaesthetized with system The WAND declared less fear before similar anesthesia in future. The average value of intensity of pain analyzed with both verbal and visual scales during anaesthetizing with the system Injex (independently from sex) was statistically significantly higher than for system The WAND--respectively 0.57 and 8.55 for The WAND, 2.02 and 32.18 for Injex (p = 0.001).

CONCLUSION

on the basis of the results of this study it can be concluded that the less stressful and painful local anesthesia delivery system is the WAND.

The penetration of a soft solid by a liquid jet, with application to the administration of a needle-free injection

Liquid jet injections have been performed on human skin in vivo and silicone rubber using Intraject needle-free injectors. The discharge characteristics of the liquid jet were measured using a custom-built test instrument. The experiments reveal that a high-speed liquid jet penetrates a soft solid by the formation and opening of a planar crack. The fluid stagnation pressure required for skin penetration decreases with increasing diameter of the liquid jet. These findings are consistent with the slow-speed penetration of a soft solid by a sharp-tipped punch. It is demonstrated that the Shergold-Fleck sharp-tipped punch penetration model [Shergold, O.A., Fleck, N.A., 2004. Mechanisms of deep penetration of soft solids. Proc. Roy. Soc. Lond. A 460, 3037-3058.] gives adequate predictions for the pressure required to penetrate a soft solid by a high-speed liquid jet.

No-needle jet anesthetic technique for no-scalpel vasectomy

PURPOSE

We describe a new, modified jet injection technique for local anesthesia for no-scalpel vasectomy without the use of a needle, which may minimize the fear of vasectomy in men due to the needle involved in local anesthesia.

MATERIALS AND METHODS

A MadaJet Medical Injector (MADA Medical Products, Carlstadt. New Jersey) was used in this study to deliver a high pressure spray of 0.1 cc local anesthetic solution directly through the scrotal skin down onto the tissue around the vas. Two or 3 jet injections are delivered to each vas and a total of 4 to 6 suffice for the entire vasectomy.

RESULTS

No-needle jet injection is remarkably effective for local anesthesia for no-scalpel vasectomy. The average volume of anesthetic solution per jet injection is 0.1 cc with 0.2 to 0.3 cc for each vas. Onset is almost immediate, within 10 to 20 seconds after injection. About 465 patients were anesthetized by the jet injection technique with great satisfaction. The average visual analog scale score for the pain of the jet injection itself was 1.71 of 10. The average visual analog scale score for the pain of subsequent vasectomy during the surgical procedure was 0.66 of 10 (median 0.2). No hematomas were noted. Patients experience the mild discomfort of a pinch, not unlike a rubber band, with the first injection.

CONCLUSIONS

No-needle anesthesia with jet injection is a new technique to deliver rapid onset of profound local anesthesia to the patient undergoing vasectomy. It is a simple and safe approach with high patient satisfaction, as reflected in low pain scores. The benefit of this technique without a needle is that it may decrease the fear of pain in men and enhance the popularity of vasectomy worldwide.

Jet injection into polyacrylamide gels: investigation of jet injection mechanics

Jet injectors employ high-velocity liquid jets that penetrate into human skin and deposit drugs in the dermal or subdermal region. Although jet injectors have been marketed for a number of years, relatively little is known about the interactions of high-speed jets with soft materials such as skin. Using polyacrylamide gels as a model system, the mechanics of jet penetration, including the dependence of jet penetration on mechanical properties, was studied. Jets employed in a typical commercial injector, (orifice diameter: 152 microm, velocity: 170-180 m/s) were used to inject fluid into polyacrylamide gels possessing Young's moduli in the range of 0.06-0.77 MPa and hardness values in the range of 4-70 H(OO). Motion analysis of jet entry into polyacrylamide gels revealed that jet penetration can be divided into three distinct events: erosion, stagnation, and dispersion. During the erosion phase, the jet removed the gel at the impact site and led to the formation of a distinct cylindrical hole. Cessation of erosion induced a period of jet stagnation ( approximately 600 micros) characterized by constant penetration depth. This stage was followed by dispersion of the liquid into the gel. The dispersion took place by crack propagation and was nearly symmetrical with the exception of injections into 10% acrylamide (Young's modulus of 0.06 MPa). The penetration depth of the jets as well as the rate of erosion decreased with increasing Young's modulus. The mechanics of jet penetration into polyacrylamide gels provides an important tool for understanding jet injection into skin.

Treatment of plantar hyperhidrosis with botulinum toxin type A

BACKGROUND

Hyperhidrosis (excessive, uncontrollable sweating) can be embarrassing and disabling, significantly impacting social and professional performance and quality of life. Treatments aim to reduce sweating, but few are effective, often carrying the risk of significant side-effects. The aims of this study were to evaluate the efficacy and safety of botulinum toxin type A (BTX-A) for plantar hyperhidrosis and to investigate the role of the Dermojet as a potential injection technique.

METHODS

Ten adult patients (five men, five women), aged 19-51 years, with severe, previously unresponsive, plantar hyperhidrosis, were recruited to this single-center, open-label, noncomparative study. The hyperhidrotic area of each foot was injected over 15-20 sites without analgesia with 50 U BTX-A + 5 mL sterile saline using a Dermojet. Patients were followed up for 8 months with monthly sweat reduction assessments using Minor's iodine-starch test. Patients provided a treatment self-assessment after completion of follow-up.

RESULTS

Within 7 days post-treatment, eight patients reported significantly decreased sweating, and seven patients were symptom free for up to 5 months. Patient self-assessment showed that seven of the 10 patients were satisfied with their treatment. One minor adverse event was reported comprising a temporary localized hematoma (one patient).

CONCLUSIONS

Intracutaneous BTX-A injection using the Dermojet offers a simple, safe, and effective alternative for treatment of plantar hyperhidrosis.

Needle-free jet injections: dependence of jet penetration and dispersion in the skin on jet power

Jet injection is a needle-free drug delivery method in which a high-speed stream of fluid impacts the skin and delivers drugs. Although a number of jet injectors are commercially available, especially for insulin delivery, a quantitative understanding of the energetics of jet injection is still lacking. Here, we describe the dependence of jet injections into human skin on the power of the jet. Dermal delivery of liquid jets was quantified using two measurements, penetration of a radiolabeled solute, mannitol, into skin and the shape of jet dispersion in the skin which was visualized using sulforhodamine B (SRB). The power of the jet at the nozzle was varied from 1 to 600 W by independently altering the nozzle diameter (30-560 microm) and jet velocity (100-200 m/s). The dependence of the amount of liquid delivered in the skin and the geometric measurements of jet dispersion on nozzle diameter and jet velocity was captured by a single parameter, jet power. Additional experiments were performed using a model material, polyacrylamide gel, to further understand the dependence of jet penetration on jet power. These experiments demonstrated that jet power also effectively describes gel erosion due to liquid impingement.

Assessment of the biological performance of the needle-free injector INJEX using the isolated porcine forelimb

BACKGROUND

The development and utilization of novel needle-free injection devices in order to minimize needle stick injuries make increasing demands for suitable assay systems, which reflect the physiological situation in humans as close as possible.

OBJECTIVES

It was therefore the goal of the present study to test the biological performance of a needle-free injector (INJEX) by the use of porcine skin as a model with a high predictive value for the feasibility in humans because of its close similarity to human skin.

METHODS

In order to use porcine skin in the context of the underlying tissues, the isolated porcine forelimb was chosen as an assay model for use with the INJEX injector. Ink or the fluorescent dye fluorescein-isothiocyanate was injected and the penetration depth was determined metrically and dye distribution histologically. To assess the resorption of heparin, needle injection was compared with needle-free injection in a perfused limb model.

RESULTS

Increasing amounts of ink increasingly penetrated into subcutaneous tissue layers in a cone-shaped manner mainly following lead structures. Penetration was hampered by skin thickness and by the deep muscle fascia, which served as a penetration barrier. Resorption of heparin was similar irrespective of injection by the use of a needle or the INJEX device.

CONCLUSIONS

The isolated porcine forelimb serves as a versatile tool for the assessment of the biological performance of needle-free injection devices such as INJEX. Further studies are necessary to correlate the model for drug delivery in humans.

[Clinical evaluation of the INJEX system, a local anesthesia system without needles: a comfort evaluation study]

The use of needless local anaesthesia systems in dentistry can be of a help in treating needle phobia patients. The aim of this comfort study was to compare a classical local infiltration anaesthesia with a needle-free system. INJEX (ROSCH AG Germany). A split mouth design study was performed. All patients in this study needed 2 restorations. In order to receive objective information on both systems needle-phobia patients were banned. Therefore the first restoration was performed with the classical system (with needle) and the well-acceptance was evaluated. The second restoration was done with the needle-free system. Both patient and dental practitioner performed an evaluation after each treatment. Evaluation by the patient was given by a questionnaire on the comfort of the treatment using Faces Pain Scale, Lickert Scale and a modified version of the Abbreviated Acceptability Rating Profile. By the dental practitioner the comfort of the treatment and the amount of local anaesthesia needed was evaluated. The study was approved by the ethical committee of Ghent University Hospital Belgium.

CONCLUSION

The INJEX system can be a valuable alternative to use in paediatric dentistry, although non needle phobia patients in this study did not preferred the needle free INJEX system above the classical local injection.

New Way to Deliver Fluids: Endoscopic Jet Injection Into the Beagle Prostate

PURPOSE

Local therapy of the prostate could have a role in the treatment of benign prostatic hyperplasia as well as prostate cancer. Endoscopic jet injection could simplify these treatments. We evaluated the tissue effects of endoscopic jet injection in an animal model.

MATERIALS AND METHODS

An endoscopic jet injector was developed. In 12 beagle dogs the prostate was injected with single shot and continuous mode jet injection. Macroscopic and histological analysis was performed 0, 2 and 14 days after jet injection.

RESULTS

Jet injection allowed complete penetration of the beagle prostate. The single shot technique resulted in only minimal tissue effects. However, the continuous mode led to major tissue damage, even complete aseptic necrosis, in the injected area.

CONCLUSIONS

A new method for endoscopic application of fluids is described. Depending on the jet injection technique it could be used to apply pharmaceutical agents or plasmids, and/or induce aseptic necrosis.