Psychological responses to the needle-free Medi-Jector or the multidose Disetronic injection pen in human growth hormone therapy

The aim of the study was to test the hypothesis that daily administration of growth hormone using the Medi-Jector results in fewer adverse psychological responses than needle injection with a multidose injection pen. The Medi-Jector is a needle-free injection device that can deliver growth hormone subcutaneously through jet injection. The group studied consisted of 18 children aged 10 y or over who were participating in a study of the bioequivalence and bioequipotence of the administration of growth hormone through jet injection or needle injection. Previously, all subjects had received growth hormone therapy with commercially available multidose injection pens. The study was designed as a prospective, randomized, two-period cross-over trial. A questionnaire was used to assess psychological responses such as non-compliance, opinion on ease of preparation, affective responses to administration and local side-effects, as well as overall preference. In addition, the subjects kept a diary during the study. The subjects found the Medi-Jector less offputting (p < 0.01), less painful with respect to both frequency (p < 0.04) and intensity (p < 0.01) and less unpleasant (p < 0.05) than a multidose injection pen with a 28G needle (p < 0.01). No difference in compliance was detected. Most subjects preferred the Medi-Jector for future use (p < 0.05). The mean score on a 1-10 point scale (10 is excellent) was 7.9 (SD 1.4) for the Medi-Jector and 6.8 (SD 2.3) for the multidose injection pen (p < 0.08). The prevalence of visible bruises each day was higher (p < 0.01) with the Medi-Jector (2.5, SD 2.1) than with the multidose injection pen (0.7, SD 1.1), but children showed indifferent affective responses to bruising. Thirteen out of 18 subjects decided to continue therapy with the Medi-Jector (p < 0.06). It is concluded that use of the Medi-Jector in growth hormone therapy tends to lead to fewer adverse psychological responses than a multidose injection pen with 28G needles.

Evaluation of a no-needle penile injector: a preliminary study evaluating tissue penetration and its hemodynamic consequences in the rat

OBJECTIVES

Intracavernous needle injection is an effective delivery method for pharmacotherapy of erectile dysfunction. Needle phobia, pain, and concern about local tissue injury have stimulated the search for new, less invasive means of inducing penile erection. In this preliminary communication, we evaluate a jet injector as an alternative to needle injection for intracavernous delivery of vasoactive drugs.

METHODS

Jet injection was evaluated in three groups of rats receiving either India ink, saline, or papaverine into the penis. The ability of the jet injection to penetrate through the tunica albuginea and deliver liquid to the corpora cavernosa smooth muscle was assessed by the degree of staining within the corpus cavernosum (ink group), histologic change (saline group), and rise in intracavernous pressure (papaverine group). Erectile capacity following cavernous nerve electric stimulation was compared before and 1 hour after injection of saline or papaverine.

RESULTS

Ink traversed the skin and tunica albuginea with extensive deposition noted within the cavernous spaces. Varying degree of subcutaneous hemorrhage were seen with saline jet injection; however, the corpus cavernous smooth muscles showed no evidence of injury. Jet injection of papaverine 3250 micrograms significantly increased cavernous pressure (39.4 +/- 4.6 cm H2O) compared with saline injection (2.8 +/- 1.3 cm H2O).

CONCLUSIONS

We conclude that acute jet injection is an effective method for intracavernous delivery of drugs. Long-term effects should be evaluated prior to clinical use.

An easily constructed pipette for pressure microinjections into the brain

A simple device for making pressure microinjections into the brain, its application for delivery of a tracer substance, biotin dextran amine, and an example of the resulting axonal transport are described. The device is based on the use of a Luer Up Hamilton microliter syringe mated directly to the plastic hub of an injection needle assembly in which the metal needle has been replaced by a glass pipette. In model experiments, the injection sites were measured in brain sections of rats, which were perfused with fixative immediately after administration of the tracer, and the relationship between the injected volume and the area of the injection site was evaluated. The results showed that the device provided accurate and reproducible delivery of the fluid.

A clinical, epidemiological and laboratory study on avoiding the risk of transmitting viral hepatitis during vaccinations with the Dermojet protected by an anticontaminant disposable device

Jet injectors may transmit blood-borne infections, such as hepatitis B virus (HBV) and human immunodeficiency virus (HIV). To evaluate the safety of an anticontaminant disposable device which protects the jet injector apparatus, 22,714 healthy subjects were intradermally inoculated (38,162 inoculations) with a variety of vaccines. All the subjects were systematically followed-up clinically and epidemiologically for 6-18 months after inoculation; blood samples from 1619 subjects, before and 60-75 days after inoculation, were examined by enzyme-linked immunosorbent assay (ELISA) for HBV, hepatitis C virus (HCV) and HIV. Before vaccination 212 (13.09%) subjects were positive: 204 positive for HBV markers and eight for the HCV marker. None of the subjects were positive for the anti-HIV marker. During the clinico-epidemiological surveillance and the laboratory investigations mentioned above no clinical viral hepatitis B or C case and no seroconversion to positivity for HBV or HCV markers among the susceptible persons in the group were reported. Considering that in similar situations there is a theoretical risk of transmission as high as 1 per 388 to 1 per 3367 injections and that in our case 38,162 inoculations were performed in 22,714 subjects with the same Dermojet protected by the same type of anticontaminant disposable device, no contamination risk being reported, the conclusion can be reached that jet injectors can be safely used in the medical practice if they are protected by the sterile anticontaminant disposable device.

Development of the OPgun for bombardment of animal tissues

A simple and inexpensive particle-bombardment device, the OPgun, was constructed for the delivery of DNA into animal tissues. This device is based on the particle-inflow gun first described for plant-cell transfection. The delivery of tungsten particles into the epidermis of the mouse ear, without the use of vacuum and without causing damage to the tissue, was demonstrated. The system was also shown to be capable of inducing antibodies to a foreign gene in mice.

Clinical immunogenicity and tolerance studies of liquid vaccines delivered by jet-injector and a new single-use cartridge (Imule): comparison with standard syringe injection. Imule Investigators Group

A new needleless jet-injector, Mini-Imojet, was developed that administers liquid vaccines from a single-use, pre-filled cartridge named Imule, which avoids the risk of cross-contamination. We conducted clinical trials in several settings in France and West Africa to compare the immunogenicity and tolerance of five vaccines (influenza vaccine, Vi capsular polysaccharide typhoid vaccine, tetanus toxoid vaccine, diphtheria-tetanus-whole cell pertussis vaccine, and inactivated hepatitis A vaccine) administered with the Imule system vs standard syringe technique. In each vaccine study, all subjects of either group were tested for serum antibody titres to calculate the geometrical mean titres and seroconversion rates after complete vaccination. Immediate local-reactions were noted after each injection, and local and general reactions were evaluated during a predetermined period of follow-up. When delivered by the Imule technique, all the administered vaccines were of equivalent or superior immunogenicity, compared to the syringe technique. The tolerance to vaccines injected by the Imule system was acceptable in all studies. The most frequently observed reactions were mild (e.g. minor bleeding, superficial papules, erythema and induration) and could be considered to be inherent to the injection technique. The technical and safety advantages of the Mini-Imojet/Imule system, compared to sterilizable, standard disposable or autodestruct syringes and to classical multi-dose vial jet-injectors, reinforces the interest of this new injection technique for collective immunizations.

Hepatitis B vaccine administration: comparison between jet-gun and syringe and needle

An open randomized controlled clinical trial was conducted to compare the reactogenicity of a recombinant hepatitis B vaccine (Engerix-B) when injected with the Bioject device (a pneumatically powered drug delivery system using disposable syringes) or with conventional syringe and needle, according to a 0.1 and 6 month vaccination schedule. Ninety-seven healthy young adults were enrolled in this study. Participants were asked to record local and general solicited symptoms and signs after each vaccination and to report each unsolicited symptom and sign that occurred during the study. The use of the jet-gun induced a statistically significant higher incidence of local symptoms and signs (solicited and unsolicited) than the use of syringe and needle.

Water-jet dissection in renal surgery: experimental study of a new device in the pig

The pig model was used for experiments with a new type of water-jet dissector, which produces high-pressure water by application of a gas and maintains the water fully sterile in a single-use delivery apparatus. The experiment was conducted ex vivo (14 kidneys) and in vivo to compare electric cautery section with water-jet dissection (5 vs 11 partial nephrectomies). Ex vivo study confirmed sparing of blood vessels and pelvicaliceal system. In vivo study did not show significant differences in blood loss but, the water-jet allowed precise dissection and tight closure of the excretory system. More frequent haemorrhages were noted on histological examination of the WJ group, but no coagulation necrosis. These are preliminary findings and further studies of long-term results may confirm the benefits of the absence of parenchymal necrosis and the definite advantage of precise closure of the pelvicaliceal system, as morbidity of partial nephrectomy is often related to secondary haemorrhages and urinary fistulae.

Effectiveness of a jet injection system in administering morphine and heparin to healthy adults

BACKGROUND

Jet injection eliminates the risk of contaminated needlestick injuries when giving intramuscular or subcutaneous medications. Clinical efficacy of the Biojector System was equivalent to that of needle and syringe injection in unpublished trials with vaccines, but had not been studied using other drugs.

OBJECTIVE

To compare the effectiveness of the Biojector with conventional needle and syringe injection in administering intramuscular morphine and subcutaneous heparin to healthy adults, as measured by plasma drug concentration.

METHODS

Intramuscular injections of morphine 8 mg (5 mg if weight < or = 65 kg) were given 24 hours apart with the jet injector and with a needle and syringe to 30 subjects at the deltoid site and 10 subjects at the dorsogluteal site. Blood samples for plasma concentrations of free morphine were drawn at 15, 30, 45, 60, 120, and 240 minutes and were analyzed using radioimmunoassay. Abdominal subcutaneous injections of heparin 3500 U were given every 8 hours for 5 days with both injection methods to 29 subjects, with 48 hours between the two series. Daily blood samples for plasma heparin were analyzed by colorimetric assay for antifactor Xa activity.

RESULTS

Mean free morphine concentration, peak value, and area under the curve did not differ significantly between the deltoid and dorsogluteal sites or between the jet injector and needle and syringe. Values of mean daily heparin concentrations and area under the curve were low and did not differ between the two injection methods.

CONCLUSION

Plasma drug concentrations provided by the Biojector were equivalent to those provided by conventional needle and syringe when administering intramuscular morphine and low-dose subcutaneous heparin.

[Jet injection, a new method for the induction of anesthesia in children]

In order to shorten anaesthesia induction and to avoid pain of the intramuscular injection, we evaluated the efficacy and safety of midazolam given by a jet-injector, utilized solely for mass inoculations until now. Premedication with midazolam with the jet-injector, indeed, proved to be effective, rapid and safe in children. The best results were found in two groups receiving 150-200 microgram/kg midazolam. Within 5 minutes, it was easy to cannulate a vein in children injected by the jet-injector, whereas the effect of intramuscular injection developed slowly, within 7 minutes. In the latter group, cannulation of the vein was more difficult than in the other groups. The separation from the parents and anaesthetic induction were greatly facilitated by midazolam given by the jet-injector. Amnesia was present not only for anaesthetic induction but also for the injection. Recovery was not more prolonged in those premedicated with midazolam with the jet-injector than with midazolam administered by other routes: oral, rectal or nasal. The children induced with the aid of jet-injector had no unpleasant recall based on interviews with the patients and parents.

Treatment of organophosphate poisoning in pigs: antidote administration by a new binary autoinjector

The therapeutic effectiveness of a new binary autoinjector containing 500 mg HI-6 and 2 mg atropine sulphate was tested in anesthetized pigs poisoned by a lethal dose of soman i.v. (9 micrograms/kg per 20 min). Pharmacokinetics and pharmacodynamics of HI-6 were studied concomitantly on administration of HI-6 alone, together with atropine sulphate, or together with atropine sulphate during soman intoxication. Cardiopulmonary parameters were monitored and serum concentrations of oxime and acetylcholinesterase (AChE) were measured in blood samples taken at intervals over a 6-h period postinjection. Five minutes after the start of soman infusion, mean AChE activity was decreased to 27 +/- 4.3% of baseline and signs of poisoning appeared. The antidotes, HI-6 and atropine sulphate, were then administered i.m. One minute after this injection there was a transient significant increase in AChE activity of 76 +/- 8.2% of baseline (p < 0.01). It then again decreased and remained suppressed throughout the experiment. Mean respiratory rate was significantly decreased (p < 0.01) to 20 +/- 3.2% of baseline after 20 min of soman infusion and remained low during the rest of the experiment. The poisoning signs were counteracted 15-20 min after antidote therapy and all pigs survived soman intoxication without ventilatory assistance. Administration of either atropine or atropine and soman had no significant effect on the pharmacokinetics of HI-6 in anesthetized pigs.

Pharmacokinetics of HI-6 and atropine in anaesthetized pigs after administration by a new autoinjector

A newly developed autoinjector (Astra Tech, Sweden) containing 500 mg HI-6 and 2 mg atropine sulphate was tested in anaesthetized normal pigs. The pharmacokinetics and pharmacodynamics of the drugs after administration by the autoinjector were compared with those after conventional needle and syringe delivery intramuscularly and intravenously. Cardiopulmonary parameters were monitored and serum concentrations of oxime, atropine, and acetylcholinesterase were determined in blood samples taken at intervals over a 6 h period postinjection. After injection in anaesthetized pigs, both HI-6 and atropine were absorbed rapidly and completely from the injection site. Therapeutic serum concentrations of HI-6, arbitrarily taken as 4 micrograms mL-1, were reached within 1 min of intravenous and autoinjector administration, and within 5 min of intramuscular injection. The concentrations remained above this level for 3-4 h. There were no significant changes in acetylcholinesterase activity, mean arterial blood pressure, or respiration frequency after injection of HI-6 and atropine sulphate. The heart rates increased significantly after administration of the two drugs (cardioacceleration defined as > or = 5% increase in heart rate), regardless of the technique employed. Our results show that HI-6 and atropine sulphate can be given intramuscularly by the new autoinjector with the same effectiveness and speed as when given intravenously. Irrespective of the injection technique, no overt signs of toxicity were observed at the drug concentrations used.

Preanesthetic medication of children with midazolam using the Biojector jet injector

BACKGROUND

A rapid, dependable, and economical technique to atraumatically sedate children before anesthesia that does not prolong postanesthesia care unit time remains elusive. The Biojector jet injection system uses carbon dioxide rather than a needle to deliver an intramuscular injection. The dose-response relationship when midazolam is administered was studied using this jet injector.

METHODS

Forty children (2.3 +/- 1.3 yr old) undergoing elective myringotomy and tube placement were randomly assigned to receive 0.05, 0.1, 0.15, 0.2, or 0.3 mg.kg-1 midazolam injected intramuscularly using the Biojector disposable syringe (0.006-inch orifice). Assessment of each child before, during, and 10 min after injection, on application of the anesthesia face mask, and every 15 min for 1 h after arrival to the postanesthesia care unit was made by an observer blinded to drug dosage.

RESULTS

Face mask tolerance using doses > or = 0.1 mg.kg-1 midazolam was acceptable and statistically different from 0.05 mg/kg. Crying on injection tended to increase with increasing dose. All children were awake and arousable, meeting discharge criteria, after 30 min from arrival in the postanesthesia care unit.

CONCLUSIONS

Midazolam (0.1-0.15 mg.kg-1) administered using jet injection effectively and rapidly produces sedation, in a manner acceptable to parents, without delaying postanesthesia care unit discharge.

Local anesthesia by jet-injection device in minor dermatologic surgery

BACKGROUND

Pain and needle-phobia can be a problem during the application of local anesthesia with syringe and needle.

OBJECTIVE

To evaluate a jet-injection device (without needle) to deliver local anesthesia.

METHODS

Two hundred and six minor dermatological procedures using a jet-injection device for administering local anesthesia into skin tissue were performed. We comment on the technical procedures, application, usefulness in relation to areas involved and the anatomical location of lesion, and total dosage of the anesthetic agent.

RESULTS

Total absence of pain during installation of anesthetic (N = 194; 94%). Good level of anesthesia in all patients. No local adverse effects.

CONCLUSION

The jet-injection device is easy to handle, it is harmless, it provides good levels of anesthesia, and the dosage of anesthetic agent is smaller than the dosage administered with conventional methods.

Immunization with plasmid DNA using a pneumatic gun

We characterize a method by which the Med-E-Jet pneumatic vaccination gun can be used to propel intact, supercoiled plasmid DNA through skin and into skeletal muscles of mice. Intramuscular injection of plasmids containing the firefly luciferase gene linked to the human cytomegalovirus promoter resulted in the expression of several hundred picograms of luciferase enzyme in quadriceps muscles. Intramuscular injections of a plasmid containing the influenza A nuclear protein gene regulated by the same promoter resulted in the generation of potent and specific anti-nuclear protein humoral and cellular immune responses. This convenient and rapid injection method would be well-suited for genetic immunization of humans.

[The safety of the jet (needle-free) injection]

The analysis of literature doesn't give strong confirmation that jet injection could provoke the transmission of the infection. Nevertheless such infection is possible because of retrograde flow of vaccine preparation which just has mixed with tissue liquid of a previous patient or taking into account a continuous contact of an injector head with patient's skin during injection. The design of the injector head has a certain significance on this matter. These risk factors can be eliminated by strict observation of rules for handling these instruments. It's necessary to conduct additional experimental researches to prove or refute the safety of jet injections.

[Anesthesia with jet injection. Use of Medi-Jector EZ dermojet for anesthesia in minor surgery]

The local anaesthetic procedure is often painful to the patient. During a period of 21 weeks, jet injection was used as the anaesthetic procedure in 55 cases of minor surgery in a single general practice. The application is discussed, giving a variety of examples. The method provides a simple and almost pain-free anaesthetic procedure in the majority of minor surgical operations. The amount of anaesthetic is reduced. The method is particularly suitable for anaesthetizing sensitive areas like the finger of a child or verrucas.

Simultaneous local pressure microejection of excitatory amino acids and field potential recording with a single micropipette in the hippocampal slice

The ability to use the same micropipette for simultaneous pressure microejection and field potential recording ('spot pressure electrode') is described. This approach allows the use of a single electrode to record both field responses to pressure microejection of drugs (fPR) and synaptically evoked field excitatory postsynaptic potentials (fEPSP). To demonstrate this, the glutamate receptor agonists alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA, 100-300 microM) and N-methyl-D-aspartate (NMDA, 1 mM) were used. Both AMPA- and NMDA-evoked fPRs exhibited properties of postsynaptic responses. Thus, they were not significantly altered by tetrodotoxin (TTX, 0.5-1 microM), but were completely and reversibly blocked by an antagonist of AMPA/kainate receptors, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 20 microM) and D-2-amino-5-phosphonopentanoic acid (AP5, 20 microM), respectively. The responses to micropressure-ejected AMPA were more stable and probably restricted to a smaller locus than responses to iontophoretic AMPA ejection. Additionally, the AMPA and NMDA contained in the pipette (up to 500 microM) did not influence the fEPSP recorded with this pipette. Our results suggest that this method might be a useful experimental tool for studying the local effects of excitatory amino acids and other compounds.

Influence of concentration and injection volume on the bioavailability of subcutaneous growth hormone: comparison of administration by ordinary syringe and by injection pen

In order to study whether the bioavailability of subcutaneously injected growth hormone (GH) is dependent on the concentration/volume injected, the relative GH bioavailability was evaluated in 14 GH-deficient patients. In a cross-over study the patients received, in random order two separate subcutaneous GH injections (Norditropin) 4 IU administered by means of an ordinary syringe (4 IU ml) and an injection pen with cartridge (Nordiject 24) (12 IU/ml). Blood samples were drawn over a 14 hr period and assayed for serum concentrations of GH and IGF-I. The mean value (+/- S.D.) of the relative absorption fraction (Fpen/sy) was 1.09 +/- 0.39. Mean values of Cmax were 8.6 ng/ml +/- 4.8 and 8.3 ng/ml +/- 7.5 for syringe and pen respectively. Corresponding values for Tmax were 311 min. +/- 131 for syringe and 309 min. +/- 104 for pen. Although a considerable interindividual variation was seen, the relative absorption fraction did not differ significantly from 1 (2 P = 0.78). Further there was no significant difference in neither Cmax (2 P = 0.39) nor Tmax (2 P = 0.55). IGF-I serum profiles tended to be higher following syringe compared to pen injection (2 P = 0.054). On the basis of this study we conclude that in this dosage regimen. GH bioavailability following pen injection equals that of injection by syringe (i.e. no effect of a three fold increase/decrease in GH concentration/volume respectively).

[Injections without needles in the treatment of insulin-dependent diabetes]

Jet injectors, which force a fluid under considerable pressure through a very small opening, have recently become available for subcutaneous administration of insulin. Use of the new devices introduced on the market is neither simpler nor more complicated than use of a syringe. Although jet injectors are highly attractive to both patients and parents, they can be used in only a limited range of diabetics. Main limitations to more widespread use include: 1) the small capacity of the devices which cannot inject more than 20 units of 40 unit/ml insulin; 2) modifications in the pharmacokinetic effects of insulins, especially long-acting insulins; 3) the high price of the injectors. Young children, who often find it difficult to accept injections, may be the main potential target for jet injector therapy. A trial period at home should always be scheduled before considering the purchase of a jet injector.

An outbreak of hepatitis B associated with jet injections in a weight reduction clinic

From January 1984 through November 1985, 31 clinical cases of hepatitis B occurred among attendees of a weight reduction clinic (clinic 1). Before the onset of illness, each case-patient had received a series of injections of human chorionic gonadotropin administered by jet injectors at clinic 1. Clinical history, risk factor assessment, serologic evaluation, and review of clinic injection records were obtained on 287 (84%) of 341 persons who had attended clinic 1 in the first 6 months of 1985. Of this cohort, 21% (60/287) had evidence of acute infection with hepatitis B virus (either documented clinical cases or antibody to hepatitis B core antigen, IgM positive). Of persons who had been given human chorionic gonadotropin at the clinic during the period studied, 24% (57/239) of those receiving human chorionic gonadotropin only by jet injector experienced acute hepatitis B virus infection. None of the 22 persons who had received injections only by syringe experienced hepatitis B virus infection. Stopping the use of the jet injectors on July 2, 1985, at clinic 1, was associated with the termination of this outbreak. This investigation demonstrated that jet injectors can become contaminated with hepatitis B virus and then may be vehicles for its transmission.

Evaluation of the insulin jet injector as a potential source of infection

In recent years jet injection of insulin has been widely used by patients with diabetes mellitus. Jet injectors may become contaminated by bacteria because of repeated use without cleaning; cleansing every 2 weeks is recommended. We investigated the occurrence of bacterial contamination by culturing jet injectors in everyday use by 19 patients with diabetes. Swabs from the interior chambers were cultured on blood agar plates. Only one of 20 cultures yielded bacterial growth, and the organism recovered was a presumed contaminant that could not be identified as any common pathogen. No study patient, nor any of more than 70 patients whom we instructed in jet injection, showed any clinical evidence of infection attributable to jet injector use. Jet injectors are unlikely to become colonized by bacteria or to cause infection in patients using them for insulin administration. The low rate of colonization may be due to the antibacterial preservatives added to commercial preparations of insulin. Additional data based on larger numbers of patients would be useful in further clarifying the risk of infection associated with jet injectors.