Echographic measurement of skin thickness in adults by high frequency ultrasound to assess the appropriate microneedle length for intradermal delivery of vaccines

Intradermal inactivated poliovirus vaccine: a preclinical dose-finding study

Intradermal delivery of vaccines has been shown to result in dose sparing. We tested the ability of fractional doses of inactivated poliovirus vaccine (IPV) delivered intradermally to induce levels of serum poliovirus-neutralizing antibodies similar to immunization through the intramuscular route. Immunogenicity of fractional doses of IPV was studied by comparing intramuscular and intradermal immunization of Wistar rats using NanoPass MicronJet600 microneedles. Intradermal delivery of partial vaccine doses induced antibodies at titers comparable to those after immunization with full human dose delivered intramuscularly. The results suggest that intradermal delivery of IPV may lead to dose-sparing effect and reduction of the vaccination cost.

A dose-ranging study in older adults to compare the safety and immunogenicity profiles of MF59®-adjuvanted and non-adjuvanted seasonal influenza vaccines following intradermal and intramuscular administration

Strategies to optimize responses to seasonal influenza vaccination in older adults include the use of adjuvants, higher antigen doses, and intradermal delivery. In this study adults aged ≥65 years (n = 450) received a single dose of 1 of 2 non-adjuvanted trivalent influenza vaccine (TIV) formulations administered intradermally (ID), both containing 6 µg of A/H1N1 and B, differing in A/H3N2 content (6 µg or 12 µg), or a single dose of 1 of 8 TIV formulations administered intramuscularly (IM) all containing 15 µg of A/H1N1 and B, differing in A/H3N2 hemagglutinin (HA) content (15 µg or 30 µg) and/or in MF59(®) adjuvant content (0%, 25%, 50%, or 100% of the standard dose). This paper focuses on the comparisons of low-dose non-adjuvanted ID, full-dose non-adjuvanted IM and full-dose MF59-adjuvanted IM formulations (n = 270). At day 22 post-vaccination, at least one European licensure immunogenicity criterion was met by all groups against all 3 strains; however, all three criteria were met against all 3 vaccine strains by the low-dose non-adjuvanted ID and the full-dose MF59-adjuvanted IM groups only. The full-dose MF59-adjuvanted IM group elicited significantly higher immune response vs. the low-dose non-adjuvanted ID formulations for most comparisons. The full-dose MF59 adjuvanted IM groups were associated with increased pain at the site of injection (P<0.01) compared to the ID groups, and the low-dose non-adjuvanted ID groups were associated with increased erythema, induration, and swelling at the injection site (P<0.0001) and unsolicited AEs compared with the IM groups. There were no differences between IM and ID groups in the frequencies of subjects experiencing solicited systemic reactions. Overall, while MF59 adjuvantation increased pain at the site of injection, and intradermal delivery increased unsolicited adverse events, erythema, induration, and swelling at the injection site, both strategies of vaccination strongly enhanced the immunogenicity of seasonal influenza vaccine in older adults compared with conventional non-adjuvanted intramuscular delivery.

TRIAL REGISTRATION

http://www.clinicaltrials.gov: NCT00848848.

Effects of age, gender, BMI, and anatomical site on skin thickness in children and adults with diabetes

Objective

We aimed to assess the effects of age, sex, body mass index (BMI), and anatomical site on skin thickness in children and adults with diabetes.

Methods

We studied 103 otherwise healthy children and adolescents with type 1 diabetes aged 5–19 years, and 140 adults with type 1 and type 2 diabetes aged 20–85 years. The thicknesses of both the dermis and subcutis were assessed using ultrasound with a linear array transducer, on abdominal and thigh skin.

Results

There was an age-related thickening of both dermis (p<0.0001) and subcutis (p = 0.013) in children and adolescents. Girls displayed a substantial pubertal increase in subcutis of the thigh (+54%; p = 0.048) and abdomen (+68%; p = 0.009). Adults showed an age-related decrease in dermal (p = 0.021) and subcutis (p = 0.009) thicknesses. Pubertal girls had a thicker subcutis than pubertal boys in both thigh (16.7 vs 7.5 mm; p<0.0001) and abdomen (16.7 vs 8.8 mm; p<0.0001). Men had greater thigh dermal thickness than women (1.89 vs 1.65 mm; p = 0.003), while the subcutis was thicker in women in thigh (21.3 vs 17.9 mm; p = 0.012) and abdomen (17.7 vs 9.8 mm; p<0.0001). In boys, men, and women, both dermis and subcutis were thicker on the abdomen compared to thigh; in girls this was only so for dermal thickness. In both children and adults, the skin (dermis and subcutis) became steadily thicker with increasing BMI (p<0.0001).

Conclusions

Skin thickness is affected by age, pubertal status, gender, BMI, and anatomical site. Such differences may be important when considering appropriate sites for dermal/subcutaneous injections and other transdermal delivery systems.

Assessment of acceptability and usability of new delivery prototype device for intradermal vaccination in healthy subjects

The objectives of this study were to assess the acceptability and usability of a newly developed intradermal prototype device, VAX-ID™, in healthy subjects. In April 2012 an investigational study was conducted in healthy subjects aged 18 to 65 y. To compare injection site and route of administration, subjects were allocated to 4 subgroups, either receiving subsequently 2 intradermal (ID) injections (one in the forearm and one in the deltoid) or an ID (forearm) and an intramuscular (IM) (deltoid) injection. All injections contained saline solution. Acceptability was assessed with a subjects' questionnaire and a daily electronic diary for 5 d. Usability was assessed with a vaccinators' questionnaire and an expert panel. A 10-point Visual Analog Scale was used to score several statements on usability and acceptability. A total of 102 healthy subjects were enrolled in the study (age: 19-63). No statistically significant differences were seen in demographic characteristics between the ID and IM groups. Anxiety before injection, pain during injection and duration of injection were rated significantly lower for ID compared to IM. One day after the injections, redness was reported more often after ID injection in the forearm versus ID in the deltoid; pain at injection site was reported significantly more often after IM vs. ID injection. The new VAX-ID prototype device was found easy to handle, easy to use and safe. The new VAX-ID prototype device was shown to have a high degree of acceptability as well as usability. Further studies with VAX-ID will be conducted using vaccine antigen allowing assessment of immunogenicity and safety. Additionally, these studies will help to further improve VAX-ID in terms of accuracy of delivered dose and feedback to the vaccinator. (NCT01963338).

Evaluation of skin and subcutaneous tissue thickness at insulin injection sites in Indian, insulin naïve, type-2 diabetic adult population

CONTEXT

Skin thickness of type-2 diabetic insulin naïve adult patients.

BACKGROUND

We have limited data on skin and subcutaneous tissue thickness of Indian type-2 diabetic population. Objective of this study was to assess skin and subcutaneous tissue thickness in insulin naïve type-2 diabetic patients as this information may be useful for insulin injection technique.

AIMS

To assess the skin and subcutaneous tissue thickness at insulin injection sites in insulin naïve, type-2 diabetic adult population across different body mass index (BMI).

SETTINGS AND DESIGN

Observational study carried out at our institute.

MATERIALS AND METHODS

One hundred and one insulin naïve type-2 diabetic subjects underwent skin thickness measurement using ultrasound at insulin administration sites. Skin and subcutaneous tissue thickness were measured and prints taken. Though, the sample size to be taken for the study was not calculated, the results obtained clearly show that the power of the study was 80%.

RESULTS

At arm and thigh, the mean skin thickness was more in males as compared to females in the BMI range <23 kg/m(2) (P < 0.05). At abdomen, skin thickness was more in males in the BMI range 19-23 kg/m(2) (P < 0.05). Across all the BMIs, mean skin plus subcutaneous thickness at arm was more in females (P < 0.05) except for BMI >25 kg/m(2) where thickness in males was comparable. At thigh, the skin plus subcutaneous tissue thickness was more in females (P < 0.05), across all BMI ranges. At abdomen, thickness was more in females for the BMI ranges 17-19 kg/m(2) and 23-25 kg/m(2), while it was comparable across all other BMI ranges (P > 0.05).

CONCLUSIONS

Skin and subcutaneous tissue thickness can be estimated by BMI. In general it is higher in females.

Tattoos and human identification: investigation into the use of X-ray and infrared radiation in the visualization of tattoos

Any person with a tattoo known to their family or friends could potentially be identified from the presence of such personal identifying markers. Problems in identification utilizing tattoos may arise when these markers are removed or defaced in some way. This paper uses infrared wavelengths at 760, 850, and 950 nm to improve the visualization of laser-removed or covered up tattoos and also to establish whether the ink pigments used can be observed on radiographs from any metal that may be present. The results obtained indicate that some older inks have a high enough metallic content to allow them to be viewed on a radiograph, while infrared light can demonstrate latent ink still present in the skin after laser removal and can also be utilized to distinguish an original tattoo through a secondary "cover-up" tattoo. Infrared photography and radiography have been shown to improve tattoo visualization in a forensic context.

Perforation of fragment simulating projectiles into goat skin and muscle

INTRODUCTION

Ballistic gelatin is the most common tissue simulant used to reproduce the penetration of projectiles into muscle but published data to support its use are primarily based on bullets, despite explosive fragments being the most common cause of injury to soldiers on current operational deployments. Published ballistic tests using animal and artificial skin and muscle tissue surrogates also lack standardisation in methodology such that limited comparisons with that of human tissues can currently be made.

METHOD

Three masses of cylindrical NATO standardised fragment simulating projectiles (FSPs) were fired at 20% ballistic gelatin and the hind thighs of a killed goat. Threshold (V(th)) and V(50) velocities required for skin perforation and depth of penetration (DoP) into muscle were compared with gelatin. The intercept and gradient of the linear regression lines for DoP versus velocity were compared between gelatin and goat with significance defined as p<0.05.

RESULTS

V(50) goat skin perforation velocities for the 0.16, 0.49 and 1.10 g FSPs were 121.1, 103.7 and 97.8 m/s, respectively. There was a significant difference in the V(50) required to perforate the gelatin surface compared with goat skin for the 0.16 and 0.49 g FSPs but not the 1.10 g. There was no statistical difference in the gradients for DoP versus velocity between animal and gelatin for either the 0.16 or 1.10 g FSPs.

DISCUSSION

This study has produced data for skin perforation velocities and generated algorithms describing velocity versus predicted DoP into muscle for three standardised projectiles, which will be used to improve the fidelity of future injury models. 20% gelatin was demonstrated to accurately reproduce the retardation of the 1.10 g FSPs into goat muscle but the addition of a skin simulant will be required to accurately predict DoP for FSPs less than 1.10 g.

Intanza (®) 9 µg intradermal seasonal influenza vaccine for adults 18 to 59 years of age

Seasonal influenza in healthy working-age adults accounts for a substantial part of the socioeconomic burden of this disease. Intanza® 9 µg (sanofi pasteur) is a microneedle-delivered intradermal trivalent inactivated influenza vaccine approved in 2009 for the prevention of seasonal influenza in adults 18 to 59 years of age. The microneedle system reliably and reproducibly delivers the vaccine to the dermis. Clinical studies show that Intanza 9 µg is as immunogenic and as well tolerated in working-age adults as a reference intramuscular trivalent inactivated vaccine. Local reactions to Intanza 9 µg, mainly erythema, are transient, mostly mild or moderate, and do not affect acceptability. Intanza 9 µg is considered satisfactory by at least 95% of both vaccinees and prescribers, especially because of the short needle and rapid administration. Because Intanza® 9 µg offers an alternative to intramuscular vaccines, it might help increase influenza vaccine coverage rates.

Comparison between shorter straight and thinner microtapered insulin injection needles

BACKGROUND

Many diabetes patients who require insulin perform multiple subcutaneous injections every day that often cause pain, discomfort, and anxiety. We compared efficacy (glycemic control) and patient preference for two types of needle: a shorter straight needle (32 gauge×4 mm, straight wall; Nippon Becton Dickinson Co., Ltd., Tokyo, Japan; hereafter referred to as BD32S4) and a thinner microtapered needle (33-gauge tip and 28-gauge base×5 mm, double-tapered wall; Terumo Corp., Tokyo, Japan; hereafter referred to as TR33T5) in a single-center study.

PATIENTS AND METHODS

Eighty-four patients with diabetes were enrolled in a randomized, open-label crossover trial. The patients injected their usual insulin dosage with one type of needle for 4 weeks and then switched to the other type for the next 4 weeks. The serum glycated albumin level was measured before and after each 4-week period. Each patient assessed pain during injection on a 150-mm visual analog scale (VAS). Needle preference, perceptions of handling, and acceptance were assessed by the patients, who completed a questionnaire after using each type of needle for 4 weeks.

RESULTS

In total, 79 patients completed the study. There was no difference of glycemic control between the two needles. The mean VAS score was -14.5 mm (95% confidence interval, -20.9, -8.0 mm), indicating that the patients perceived less pain with the BD32S4 needle. In the overall evaluation, a significantly higher percentage of patients selected the BD32S4 as the better needle compared with the TR33T5 (60.3% vs. 19.2%; P<0.0001).

CONCLUSIONS

The BD32S4 needle was more highly evaluated and was preferred by the patients with respect to pain during injection, usability, and visual impression, without having a negative impact on glycemic control. The overall preference of patients for the shorter needle in this study suggests that needle length may be one of the major contributing factors for patients' comfort in insulin injection, although the other relevant factors of needles still need to be considered.

Skin thickness on bony prominences measured by ultrasonography in patients with spinal cord injury

OBJECTIVE

The detailed assessment of soft tissues over bony prominences and identification of methods of predicting pressure sores would improve the quality of care for patients with spinal cord injury (SCI). Comparing skin thicknesses on bony prominences in patients with SCI to those in healthy individuals will represent, to our knowledge, the first study aimed at determining whether differences in skin thicknesses between these groups can be detected by ultrasound.

DESIGN

In both patients and controls, skin thicknesses on the sites at risk for pressure ulcers - sacrum, greater trochanter, and ischium - were evaluated using high-frequency ultrasound. The waist was also evaluated by the same method for control as it was considered to be a pressure-free region.

PARTICIPANTS

Thirty-two patients with complete thoracic SCI and 34 able-bodied individuals.

RESULTS

The skin was significantly thinner over the sacrum and ischial tuberosity in individuals with SCI compared with healthy individuals. No significant differences were observed in skin thicknesses over the greater trochanter or the waist between the two groups.

CONCLUSIONS

Protecting skin integrity in patients with paraplegia is challenging due to many contributing factors, such as prolonged pressure, frictional/shearing forces, and poor nutrition. Thinning of the skin can increase the risk of soft tissue damage, leading to pressure ulcers. The significant differences in skin thickness at the sacrum and ischium provide the basis for establishing the early signs of pressure damage. Measuring skin thickness by ultrasound is a reliable non-invasive method that could be a promising tool for predicting pressure ulcers.

Intradermally-administered influenza virus vaccine is safe and immunogenic in healthy adults 18-64 years of age

BACKGROUND

To increase vaccine acceptance, intradermal (ID) influenza vaccine (Fluzone(®) Intradermal, Sanofi Pasteur Inc.) may be an attractive alternative to intramuscular (IM) vaccination due to smaller needle and volume injected.

METHODS

A multicenter, randomized (2:1 ID vs IM vaccines) study, blinded for ID vaccine lots, was conducted among 4292 adults 18-64 years of age enrolled in October 2008. Three lots of investigational trivalent influenza vaccine containing 9μg hemagglutinin (HA) per strain in 0.1mL administered ID with a 30 gauge, 1.5mm long needle were compared to standard dose vaccine (0.5mL containing 15μg HA/strain) given IM.

RESULTS

The post-vaccination antibody geometric mean titers (GMT) for the ID vaccine were similar to the IM vaccine (H1N1: 193.2 vs. 178.3, H3N2: 246.7 vs. 230.7, and B: 102.5 vs. 126.9). Non-inferiority was met for the ID vaccine compared to IM vaccine as assessed by antibody GMT ratios (IM/ID) for all three virus strains (H1N1: 0.92, H3N2: 0.94, and B: 1.24). Seroconversion rates were non-inferior for H1N1 and H3N2, but not for B (ID vs. IM: H1N1: 61.2% vs. 60.5%, H3N2: 75.3% vs. 74.8%, and B: 46.2% vs. 54.2%). Seroprotection (HAI titer ≥1:40) rates were similar between groups (ID vs. IM, H1N1: 91.1% vs. 91.7%, H3N2: 90.7% vs. 91.4%, and B: 87.4% vs. 89.3%). Local injection site reactions overall were more common with ID than IM vaccine (ID vs. IM: 89.2% vs. 60.2%), but were usually grade 1 or 2 and transient. The frequencies of local injection site pain and systemic reactions were similar between vaccine groups, except more myalgia with IM vaccine.

CONCLUSIONS

The ID vaccine elicited immune responses comparable to IM vaccine except for the seroconversion rate to B virus. With the exception of pain, local injection site reactions were more common with the ID vaccine, but well-tolerated and of short duration.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00772109.

An anisotropic, hyperelastic model for skin: experimental measurements, finite element modelling and identification of parameters for human and murine skin

The mechanical characteristics of skin are extremely complex and have not been satisfactorily simulated by conventional engineering models. The ability to predict human skin behaviour and to evaluate changes in the mechanical properties of the tissue would inform engineering design and would prove valuable in a diversity of disciplines, for example the pharmaceutical and cosmetic industries, which currently rely upon experiments performed in animal models. The aim of this study was to develop a predictive anisotropic, hyperelastic constitutive model of human skin and to validate this model using laboratory data. As a corollary, the mechanical characteristics of human and murine skin have been compared. A novel experimental design, using tensile tests on circular skin specimens, and an optimisation procedure were adopted for laboratory experiments to identify the material parameters of the tissue. Uniaxial tensile tests were performed along three load axes on excised murine and human skin samples, using a single set of material parameters for each skin sample. A finite element model was developed using the transversely isotropic, hyperelastic constitutive model of Weiss et al. (1996) and was embedded within a Veronda-Westmann isotropic material matrix, using three fibre families to create anisotropic behaviour. The model was able to represent the nonlinear, anisotropic behaviour of the skin well. Additionally, examination of the optimal material coefficients and the experimental data permitted quantification of the mechanical differences between human and murine skin. Differences between the skin types, most notably the extension of the skin at low load, have highlighted some of the limitations of murine skin as a biomechanical model of the human tissue. The development of accurate, predictive computational models of human tissue, such as skin, to reduce, refine or replace animal models and to inform developments in the medical, engineering and cosmetic fields, is a significant challenge but is highly desirable. Concurrent advances in computer technology and our understanding of human physiology must be utilised to produce more accurate and accessible predictive models, such as the finite element model described in this study.

Skin and subcutaneous thickness at injecting sites in children with diabetes: ultrasound findings and recommendations for giving injection

BACKGROUND

Children who inject insulin need clear guidelines as to the length of needle best for them. We studied the distance from surface to muscle in children in order to make needle choices which are evidence-based.

METHODS

One hundred one children with type 1 diabetes were divided into three groups according to age: 2-6, 7-13, and 14-17 yr. The thickness of skin and subcutaneous (SC) tissue was measured by ultrasound in all injection sites.

RESULTS

Skin thickness varied from 1.58 mm in the arm of the youngest children to 2.29 mm in the buttocks of the adolescents. Values decreased progressively based on age (2-6 < 7-13 < 14-17) and on body site (arm < thigh < abdomen < buttocks). Skin + SC thickness varied in a similar fashion. The skin surface to muscle distances were <4 mm in nearly 10% of children, especially in the 2-6 yr group. In this group, the rate of intramuscular (IM) injections using the 4-mm pen needle when a pinch-up is not used would be 20.2%. This rate of IM injections doubles when using the 5-mm needle, and when injections are given under similar conditions it triples using the 6-mm needle.

CONCLUSIONS

It seems medically appropriate for all children to use short needles where possible to minimize inadvertent IM injections which may increase glycemic variability. Currently, the safest needle for all children appears to be the 4-mm pen needle. However, when used in children aged 2-6 yr, it should be used with a pinched skin fold.

Pilot study of a prototype minimally invasive intradermal continuous glucose monitor

INTRODUCTION

The purpose of this study was to assess point accuracy, rate-of-change accuracy, and safety of a prototype, minimally invasive continuous glucose monitoring (CGM) device over a 12 h in-clinic study. The CGM system consisted of a wireless electronics module with a disposable glucose sensor attached to the bottom. The electronics module was affixed to the abdomen using an adhesive pad on the bottom of the disposable sensor housing.

METHODS

Two CGM sensors were inserted into the abdominal tissue (left and right) of 15 adults aged 26-67 years, 5 with normoglycemia, 5 with type 1 diabetes, and 5 with type 2 diabetes. Over a 12 h period, each participant was fed three meals. Reference venous blood samples were drawn at periodic intervals (12.4 ± 5.3 min), and glucose was measured at the bedside using a laboratory reference method. For each participant, a single plasma equivalent glucose concentration was used for retrospective sensor calibration.

RESULTS

A total of 1082 paired data points were obtained from 15 subjects and 25 of 30 sensors. Statistical analysis yielded a mean absolute relative difference of 12.6% and a mean absolute difference of 16.0 mg/dl. Continuous glucose error grid analysis showed the combined point and rate-of-change accuracy was 97.4% in zone A and 1.5% in zone B (98.9% A+B), with 1.1% erroneous readings.

CONCLUSIONS

The prototype CGM system provided clinically accurate results 98.9% of the time and was well tolerated by participants, with little or no pain and no adverse events.

Microneedle and mucosal delivery of influenza vaccines

In recent years with the threat of pandemic influenza and other public health needs, alternative vaccination methods other than intramuscular immunization have received great attention. The skin and mucosal surfaces are attractive sites probably because of both noninvasive access to the vaccine delivery and unique immunological responses. Intradermal vaccines using a microinjection system (BD Soluvia(TM)) and intranasal vaccines (FluMist®) are licensed. As a new vaccination method, solid microneedles have been developed using a simple device that may be suitable for self-administration. Because coated microneedle influenza vaccines are administered in the solid state, developing formulations maintaining the stability of influenza vaccines is an important issue to be considered. Marketable microneedle devices and clinical trials remain to be developed. Other alternative mucosal routes such as oral and intranasal delivery systems are also attractive for inducing cross-protective mucosal immunity, but effective non-live mucosal vaccines remain to be developed.

An update on the application of physical technologies to enhance intradermal and transdermal drug delivery

A large number of biopharmaceuticals and other macromolecules are being developed for therapeutic applications. Conventional oral delivery is not always possible due to first-pass metabolism and degradation in the GI tract. Parenteral delivery is invasive and has poor patient compliance. Transdermal delivery provides one attractive route of administration. Transdermal administration can achieve the continuous and non-invasive delivery of drugs. However, passive transdermal delivery is restricted to small lipophilic molecules. Active physical-enhancement technologies are being investigated to increase the scope of transdermal delivery to hydrophilic molecules and macromolecules. Recent developments in transdermal technologies, such as microporation, iontophoresis and sonophoresis can enable therapeutic delivery of many drug molecules, biopharmaceuticals, cosmeceuticals and vaccines. This review provides an update of recent developments in transdermal delivery focusing on physical-enhancement technologies.

Current evidence on intradermal influenza vaccines administered by Soluvia™ licensed micro injection system

Among the several strategies explored for (1) the enhancement of the immune response to influenza immunization, (2) the improvement of the vaccine acceptability and (3) the overcoming of the egg-dependency for vaccine production, intradermal administration of influenza vaccine emerges as a promising alternative to conventional intramuscular route, thanks to the recent availability of new delivery devices and the perception of advantages in terms of immunogenicity, safety, reduction of antigen content and acceptability.

 

Data from clinical trials performed in children, adults <60 y and elderly people and post-marketing surveillance demonstrate that actually, licensed intradermal influenza vaccines, Intanza™ 9 and 15 µg and Fluzone™ Intradermal, administered by the microinjection system Soluvia™, show an excellent acceptability, tolerability and safety profile. Formulations containing 9 and 15 μg per strain demonstrate, respectively, comparable and superior immunogenicity than conventional intramuscular vaccines. Licensed intradermal influenza vaccines can be considered a valid alternative to standard intramuscular vaccination offering significant advantages in low-responder populations and helping to increase influenza vaccination coverage rates especially in people with fear of needles or high apprehension associated with annual vaccination.

Subcutaneous adipose tissue thickness in adults - correlation with BMI and recommendations for pen needle lengths for subcutaneous self-injection

OBJECTIVE

One of the aims of a subcutaneous (SC) injection is to avoid intradermal or intramuscular injections. Pen systems are an alternative solution to single-use syringes and have become standard for example diabetes therapy. Shorter and smaller needles minimize pain and the risk of intramuscular injections. The thickness of subcutaneous adipose tissue (SCAT) varies with position and with body mass index (BMI). The aim of this study was the creation of a map of SCAT thickness at typical spots for SC self-injection.

MATERIALS AND METHODS

MRI scans of 116 prospectively enroled volunteers (56 men and 60 women) were analysed. SCAT thickness was determined at 17 spots over the abdominal wall, left thigh, buttocks and upper arm, typical sites for subcutaneous self-injection. SCAT thicknesses were correlated with BMI and waist-to-hip ratio (WHR), and a linear curve fit was performed. The best fitting linear functions for the prediction of the SCAT thickness dependent on BMI and WHR were derived.

RESULTS

Correlations between SCAT and BMI were higher (0·67-0·21) than with WHR (-0·67 to 0·09). In women, correlation coefficients between SCAT data at the abdomen and BMI/WHR were higher than in men. On the other hand, data showed better correlations at the extremities in men.

CONCLUSIONS

The data, with correlation between BMI and fat thickness at different injection sites in relation to gender, provide guidance in selecting an adequate pen needle length for deep and safe subcutaneous self-injection. WHR was a much weaker predictor when compared to BMI.

Tissue engineering scaffolds containing embedded fluorinated-zeolite oxygen vectors

Efficient oxygen supply is a continuing challenge for the fabrication of successful tissue engineered constructs with clinical relevance. In an effort to enhance oxygen delivery we report the feasibility of using fluorinated zeolite particles embedded in three-dimensional (3-D) polyurethane scaffolds as novel oxygen vectors. First, 1H,1H,2H,2H-perfluorodecyltriethoxysilane was successfully coupled to zeolite framework particles to examine the dose-dependent dissolved oxygen concentration. Following this, the fluorinated-zeolite (FZ) particles were embedded in 3-D tissue engineering polyurethane scaffolds. Our data demonstrates an even distribution of FZ particles in the 3-D scaffolds without affecting the scaffold porosity or pore size. Human coronary artery smooth muscle cell (HCASMC) proliferation on FZ-containing polyurethane (PCU-FZ) scaffolds was significantly greater than on control scaffolds (P=0.05). Remarkably, cell infiltration depths on the PCU-FZ scaffolds was double that on PCU control scaffolds. Taken together, our data suggest the potential of PCU-FZ scaffolds for tissue engineering with enhanced oxygen delivery to cells.

Probe depth matters in dermal microdialysis sampling of benzoic acid after topical application: an ex vivo study in human skin

Microdialysis (MD) in the skin - dermal microdialysis (DMD) - is a unique technique for sampling of topically as well as systemically administered drugs at the site of action, e.g. sampling of dermatological drug concentrations in the dermis. Debate has concerned the existence of a correlation between the depth of the sampling device - the probe - in the dermis and the amount of drug sampled following topical drug administration. This study evaluates the relation between probe depth and drug sampling using dermal DMD sampling ex vivo in human skin. We used superficial (<1 mm), intermediate (1-2 mm) and deep (>2 mm) positioning of the linear MD probe in the dermis of human abdominal skin, followed by topical application of 4 mg/ml of benzoic acid (BA) in skin chambers overlying the probes. Dialysate was sampled every hour for 12 h and analysed for BA content by high-performance liquid chromatography. Probe depth was measured by 20-MHz ultrasound scanning. The area under the time-versus-concentration curve (AUC) describes the drug exposure in the tissue during the experiment and is a relevant parameter to compare for the 3 dermal probe depths investigated. The AUC(0-12) were: superficial probes: 3,335 ± 1,094 μg·h/ml (mean ± SD); intermediate probes: 2,178 ± 1,068 μg·h/ml, and deep probes: 1,159 ± 306 μg·h/ml. AUC(0-12) sampled by the superficial probes was significantly higher than that of samples from the intermediate and deeply positioned probes (p value <0.05). There was a significant inverse correlation between probe depth and AUC(0-12) sampled by the same probe (p value <0.001, r(2) value = 0.5). The mean extrapolated lag-times (±SD) for the superficial probes were 0.8 ± 0.1 h, for the intermediate probes 1.7 ± 0.5 h, and for the deep probes 2.7 ± 0.5 h, which were all significantly different from each other (p value <0.05). In conclusion, this paper demonstrates that there is an inverse relationship between the depth of the probe in the dermis and the amount of drug sampled following topical penetration ex vivo. The result is of relevance to the in vivo situation, and it can be predicted that the differences in sampling at different probe depths will have a more significant impact in the beginning of a study or in studies of short duration. Based on this study it can be recommended that studies of topical drug penetration using DMD sampling should include measurements of probe depth and that efforts should be made to minimize probe depth variability.

Echographic measurement of skin thickness in sites suitable for intradermal vaccine injection in infants and children

Whereas the knowledge of skin thickness is essential to determine microneedle length and ensure proper administration of and better responses to intradermal vaccines, very few figures are available, especially in infants and children. Using ultrasound echography, we investigated skin thickness in 384 children aged 4-7, 12-18, and 54-66 months at potential body sites for intradermal vaccine delivery: deltoid, suprascapular, upper back, and lumbar area. The mean epidermis plus dermis thickness was significantly higher at the suprascapular than at the deltoid site (1.29mm vs. 1.22mm) and remained relatively unchanged whatever the BMI, age, sex, and skin phototype. In the 43 children aged 54-66 months, the mean skin thickness was significantly higher in the upper than in the lumbar area (1.39mm vs. 1.31mm). In this study setting, the heterogeneity in skin thickness cannot be considered sufficient to indicate various microneedle lengths for various ages or injection sites.

Randomized trial on the influence of the length of two insulin pen needles on glycemic control and patient preference in obese patients with diabetes

OBJECTIVE

This study determined the influence of needle length for insulin administration on metabolic control and patient preference in obese patients with diabetes mellitus.

METHODS

In this multicenter, open-label crossover study, insulin pen needles of two different lengths (5 mm and 8 mm) were compared. A total of 130 insulin-treated type 1 and type 2 diabetes patients with a body mass index ≥30 kg/m(2) were randomized, and 126 patients completed the study. Patients started using the 5-mm needle for 3 months, after which they switched to injecting insulin with the 8-mm needle for another 3 months, or vice versa. Hemoglobin A1c (A1C), fructosamine, and 1,5-anhydroglucitol were measured, and self-reported side effects and patient preference were recorded.

RESULTS

No within-group changes were observed with respect to A1C, serum fructosamine, 1,5-anhydroglucitol, hypoglycemic events, bruising, and pain. When data of all 126 subjects were pooled, there was a small, but significant, difference between needle lengths (5-mm, A1C 7.47 ± 0.9%; 8-mm, 7.59 ± 1.0%; P = 0.02). Patients reported less bleeding with the 5-mm needle (P = 0.04) and less insulin leakage from the skin with the 8-mm needle (P = 0.01). There were no significant differences in patient preference, with 46% of the patients preferring the 5-mm needle, 41% the 8-mm needle, and 13% not preferring a particular needle length.

CONCLUSIONS

A 5-mm needle is similar to an 8-mm needle in obese patients with diabetes with respect to metabolic control, injection-related complaints, or patient preference and can be used safely.

Intradermal microneedle delivery of insulin lispro achieves faster insulin absorption and insulin action than subcutaneous injection

BACKGROUND

This study compared insulin lispro (IL) pharmacokinetics (PK) and pharmacodynamics (PD) delivered via microneedle intradermal (ID) injection with subcutaneous (SC) injection under euglycemic glucose clamp conditions.

METHODS

Ten healthy male volunteers were administered 10 international units (IU) of IL at 3 microneedle lengths (1.25, 1.50, or 1.75 mm) in a randomized, crossover fashion on Days 1-3 followed by a repetitive ID 1.5-mm microneedle dose (Day 4) and an SC dose (Day 5).

RESULTS

Microneedle ID delivery resulted in more rapid absorption of IL, with decreased time to maximum insulin concentration (ID vs. SC: 36.0-46.4 vs. 64.3 min, P < 0.05) and higher fractional availability at early postinjection times. ID produced more rapid effects on glucose uptake with shorter times to maximal and early half-maximal glucose infusion rates (GIRs) (ID vs. SC: time to maximum GIR, 106-112 vs. 130 min, P < 0.05; early half-maximal GIR, 29-35 vs. 42 min), increased early GIR area under the curve (AUC), and faster offset of insulin action (shorter time to late half-maximal GIR: 271-287 vs. 309 min). Relative total insulin bioavailability (AUC to 360 min and AUC to infinite measurement) did not significantly differ between administration routes. ID PK/PD parameters showed some variation as a function of needle length. Delivery of ID IL was generally well tolerated, although transient, localized wheal formation and redness were observed at injection sites.

CONCLUSIONS

Microneedle ID insulin lispro delivery enables more rapid onset and offset of metabolic effect than SC therapy and is safe and well tolerated; further study for insulin therapy is warranted.

[Immunosenescence and vaccinations in the elderly]

With increasing age, infection-induced morbidity and mortality rises. At the same time, the protective capacity of the immune system declines. This phenomenon is known as immunosenescence. It concerns all parts of the immune system and leads to a decline of cellular and humoral immune defense. As a consequence, the ability to resist infections and the immune response to vaccinations could be impaired. In order to protect senior citizens effectively against infections with dangerous pathogens like influenza viruses or pneumococci, new immunisation strategies, e.g. with shortened intervals between vaccinations, new vaccines or new vaccination techniques are required. Intradermal vaccines seem to be a promising approach, for instance. At the same time the acceptance of vaccination ought to be increased in the senior age group. Physicians, especially general practitioners play an important role because of their decisive effect on the willingness of the population to get vaccinated.

The Third Injection Technique Workshop in Athens (TITAN)

The first Injection Technique workshop brought together endocrinologists and injection experts from around the world in Strasbourg in 1997. From its work came groundbreaking recommendations which advanced best practices in areas such as the use of a skin fold when injecting. The second Injection Technique workshop, with an expanded format including nurses and diabetes educators, took place in Barcelona in 2000. The initial stimulus to use shorter injecting needles can be said to date from this meeting. The third Injection Technique workshop was held in Athens in September 2009 and involved 127 experts from across the globe. After a comprehensive review of all publications since 2000 as well as several unpublished studies, the attendees divided into smaller groups to debate and draft new injecting recommendations based on the new data and their collective experience. This paper summarizes all the formal presentations given at this practical consensus workshop.

New injection recommendations for patients with diabetes

AIM

Injections administered by patients are one of the mainstays of diabetes management. Proper injection technique is vital to avoiding intramuscular injections, ensuring appropriate delivery to the subcutaneous tissues and avoiding common complications such as lipohypertrophy. Yet few formal guidelines have been published summarizing all that is known about best practice. We propose new injection guidelines which are thoroughly evidence-based, written and vetted by a large group of international injection experts.

METHODS

A systematic literature study was conducted for all peer-reviewed studies and publications which bear on injections in diabetes. An international group of experts met regularly over a two-year period to review this literature and draft the recommendations. These were then presented for review and revision to 127 experts from 27 countries at the TITAN workshop in September, 2009.

RESULTS

Of 292 articles reviewed, 157 were found to meet the criteria of relevance to the recommendations. Each recommendation was graded by the weight it should have in daily practice and by its degree of support in the medical literature. The topics covered include The Role of the Professional, Psychological Challenges, Education, Site Care, Storage, Suspension and Priming, Injecting Process, Proper Use of Pens and Syringes, Insulin analogues, Human and Pre-mixed Insulins, GLP-1 analogs, Needle Length, Skin Folds, Lipohypertrophy, Rotation, Bleeding and Bruising, Pregnancy, Safety and Disposal.

CONCLUSION

These injecting recommendations provide practical guidance and fill an important gap in diabetes management. If followed, they should help ensure comfortable, effective and largely complication-free injections.

Intanza 15 microg intradermal seasonal influenza vaccine: in older adults (aged >or=60 years)

Intradermal seasonal influenza vaccine delivered by a microneedle injection system (Intanza) contains inactivated split virion antigens from influenza type A (H1N1 and H3N2) and B strains as recommended annually by the WHO and the EU for the prevention of seasonal influenza. In randomized, comparator-controlled, phase III trials in elderly volunteers, Intanza 15 microg elicited a strong immune response against influenza virus. In a pivotal trial, seroprotection rates with Intanza 15 microg were significantly greater than with the intramuscular comparator vaccine Vaxigrip (primary endpoint). A strong immune response was also observed with Intanza 15 microg following second and third annual vaccinations in consecutive seasons in terms of seroprotective antibody titres for all three strains (H1N1, H3N2 and B). In another phase III trial, Intanza 15 microg was as immunogenic as the intramuscular, adjuvanted vaccine Fluad, with noninferiority established in terms of ratios of geometric mean titres against H1N1 and B strains using the haemagglutinin inhibition method and against all three strains using the single radial haemolysis method. Intanza 15 microg was generally well tolerated in clinical trials in the elderly, with the most common adverse events observed being solicited injection-site reactions. The majority of solicited injection-site reactions were mild and spontaneously resolved within 1-3 days of onset; transient, visible injection-site reactions with the intradermal route of injection are not surprising as the vaccine is injected close to the skin surface.

Safety and efficacy of novel dermal and epidermal microneedle delivery systems for rabies vaccination in healthy adults

In the present pilot study, intradermal ID delivery systems with a BD microneedle from 1 to 3mm in length, and epidermal delivery (BD skin abrader) through abraded skin surface relative to standard intramuscular injection were evaluated. Circulating neutralizing antibodies were measured against the rabies virus after the Vero cells rabies vaccine was administered at D0, D7, D21 and D49. This clinical evaluation in 66 healthy volunteers shows that ID delivery using BD microneedle technology of 1/4 the IM antigen dose is safe, efficient and reliable, resulting in a protective seroconversion rate. In contrast, the epidermal delivery route did not produce an immune response against the rabies vaccine.

Comparative glycemic control, safety and patient ratings for a new 4 mm x 32G insulin pen needle in adults with diabetes

OBJECTIVE

Pen needles (PN) for subcutaneous insulin therapy have become smaller; 5 mm PNs are now the shortest in use. We evaluated the safety, efficacy and patient ratings of a new 4 mm x 32 gauge (G) PN.

RESEARCH DESIGN AND METHODS

Subjects with type 1 and type 2 diabetes and HbA1c 5.5% to 9.5% participated in a randomized non-inferiority cross-over trial, at four U.S. centers. Subjects used 4 mm x 32G PNs and either 5 mm x 31G PNs (4/5 mm) or 8 mm x 31G PNs (4/8 mm) in two, 3-week treatment periods; order of needle use was controlled. Subjects were either 'low dose' or 'regular dose' users (highest single insulin dose <or= 20 units and 21-40 units, respectively). Percent absolute change in serum fructosamine (% |Delta Fru|) was the primary endpoint; unexplained, severe hypo- or hyperglycemia was a secondary measure. Leakage at injection sites and pain measured by visual analog scale were tertiary measures. Equivalent glycemic control was defined á priori as % |Delta Fru| (including 95% CI) within 20%; 40 subjects per subgroup provides 90% power at alpha = 0.05.

CLINICAL TRIAL REGISTRATION

The study was registered on clinicaltrials.gov (identifier: NCT00928057).

RESULTS

Of 173 subjects randomized, 168 completed the study, and 163 were included in the fructosamine analyses--83 and 80 in the 4/5 mm and 4/8 mm groups, respectively. Subjects were 56% male, mean 52.6 yrs, 63% type 2. Baseline HbA1c = 7.5 +/- 1.0% and fructosamine 301 +/- 55.1 micromol/L. Mean % |Delta Fru| was 4.9% (95% CI 3.8, 6.0) and 5.5% (4.5, 6.4), respectively, for the 4/5 mm and 4/8 mm groups, meeting glycemic equivalence criteria; results were similar in both dose groups. The median |Delta Fru| was 11.0 micromol/L (8.0, 13.0) and 13.5 micromol/L (9.8, 18.0) for the 4/5 mm and 4/8 mm groups, respectively. Unexplained, severe hypo- and hyperglycemic episodes were infrequent and not different between PNs. The 4 mm PN was rated significantly less painful and preferred by approximately 2/3 of subjects (p < 0.01). All three PNs had similar reported injection site leakage.

LIMITATIONS

The study was of relatively short duration, in adults in the U.S. Further trials in other patients (e.g., GLP-1 users, pediatrics, obese) should be performed.

CONCLUSIONS

The 4 mm x 32G PN provided equivalent glycemic control compared to 31G, 5 mm and 8 mm PNs with reduced pain, no difference in insulin leakage and was preferred by patients.

Insulin pen use for type 2 diabetes--a clinical perspective

While insulin delivery technology continues to progress, its adoption in the clinic lags behind, particularly in people with type 2 diabetes. In this article the authors present their clinical perspective regarding insulin pen therapy in this population.

Skin and subcutaneous adipose layer thickness in adults with diabetes at sites used for insulin injections: implications for needle length recommendations

OBJECTIVE

During subcutaneous insulin therapy, inadvertent intramuscular (IM) injections may increase pain and/or adversely affect glucose control. The most appropriate needle length for patients depends on skin thickness (ST) and the distance to muscle fascia. ST and subcutaneous adipose layer thickness (SCT) were measured in adults with diabetes.

RESEARCH DESIGN AND METHODS

A total of 388 US adults with diabetes (in three BMI subgroups: <25, 25-29.9, and >or=30 kg/m(2)) with diverse demographic features were evaluated. Each subject had ultrasound measurements of ST and SCT at four injection sites.

RESULTS

Subjects had BMI 19.4-64.5 kg/m(2), age 18-85 years; 40% Caucasian, 25% Asian, 16% Black, 14% Hispanic; 28% type 1 diabetes. Mean ST (+/-95% CI) was: arm 2.2 mm (2.2, 2.3), thigh 1.9 mm (1.8, 1.9), abdomen 2.2 mm (2.1, 2.2) and buttocks 2.4 mm (2.4, 2.5). Multivariate analyses showed body site, gender, BMI, and race are statistically significant factors for ST but effects were small. Thigh ST was <0.6 mm thinner than the buttocks. Differences of 10 kg/m(2) account for 0.2 mm ST variation. Mean SCT was: arm 10.8 mm (10.2, 11.3), thigh 10.4 mm (9.8, 10.9), abdomen 13.9 mm (13.2, 17.7) and buttocks 15.4 mm (14.7, 16.2). Females had 5.1 mm greater SCT. Differences of 10 kg/m(2) account for 4 mm SCT variation.

ADVERSE EVENTS

A few mild hypo- or hyperglycemia events, unrelated to study procedure, were detected and treated before subject discharge from study visits.

LIMITATIONS

Only adults in the US were studied; some measurements could not be obtained on every subject, at every injection site.

CONCLUSIONS

Injection site ST does not differ by clinically significant degrees in demographically diverse adults with diabetes; SCT has a wider range. Needles >or=8 mm, inserted perpendicularly, may frequently enter muscle in limbs of males and those with BMI <25 kg/m(2). With 90 degrees insertion, needles 4-5 mm enter the subcutaneous tissue with minimal risk of IM injection in virtually all adults. These data will assist recommending appropriate length needles for subcutaneous insulin injections in adults.

Microneedle-based drug delivery systems: microfabrication, drug delivery, and safety

Many promising therapeutic agents are limited by their inability to reach the systemic circulation, due to the excellent barrier properties of biological membranes, such as the stratum corneum (SC) of the skin or the sclera/cornea of the eye and others. The outermost layer of the skin, the SC, is the principal barrier to topically-applied medications. The intact SC thus provides the main barrier to exogenous substances, including drugs. Only drugs with very specific physicochemical properties (molecular weight < 500 Da, adequate lipophilicity, and low melting point) can be successfully administered transdermally. Transdermal delivery of hydrophilic drugs and macromolecular agents of interest, including peptides, DNA, and small interfering RNA is problematic. Therefore, facilitation of drug penetration through the SC may involve by-pass or reversible disruption of SC molecular architecture. Microneedles (MNs), when used to puncture skin, will by-pass the SC and create transient aqueous transport pathways of micron dimensions and enhance the transdermal permeability. These micropores are orders of magnitude larger than molecular dimensions, and, therefore, should readily permit the transport of hydrophilic macromolecules. Various strategies have been employed by many research groups and pharmaceutical companies worldwide, for the fabrication of MNs. This review details various types of MNs, fabrication methods and, importantly, investigations of clinical safety of MN.

Intradermal influenza vaccine for older adults: a randomized controlled multicenter phase III study

In a 3-year, randomized, controlled, open-label phase III trial enrolling 3707 adults aged > or = 60 years we evaluated whether the immunogenicity of an intradermal trivalent inactivated seasonal influenza vaccine, containing 15 microg of haemagglutinin per strain per 0.1 ml dose, is superior to that of a conventional intramuscular vaccine. Intradermal vaccine was given using an intradermal microinjection system. After the first vaccination, both vaccines satisfied the immunogenicity criteria for influenza vaccines for older adults set out in European regulatory guidelines, and geometric mean haemagglutination inhibition antibody titers and seroprotection rates were higher (statistically superior) with intradermal vaccination. Higher immune responses with intradermal vaccine were also observed after the 2nd and 3rd annual vaccinations. Both vaccines were well tolerated with similar systemic reactogenicity profiles. This intradermal influenza vaccine for older adults is a beneficial option for influenza protection, consistently enhancing antibody responses without compromising safety.