Continuous subcutaneous administration of deferoxamine in patients with iron overload

Since deferoxamine B, when administered as a single daily intramuscular injection of 0.75 g, is unable to promote sufficient urinary iron excretion to achieve net negative iron balance in siderosis, we evaluated its administration as a constant infusion over 24 hours. We compared intravenous and subcutaneous routes in 24 siderotic patients who had excreted 420 to 630 mg (mean, 480 mg) of iron per month on intramuscular therapy. With the intravenous route urinary iron excretions increased to 570 to 3690 mg (mean, 1595 mg) per month. Constant subcutaneous delivery was 90 per cent as effective as intravenous administration on a dose-for-dose basis. Noteworthy net cumulative urinary iron excretions (urinary iron excretions minus transfused iron), often in excess of 1 g per month, have been maintained in all patients. Constant subcutaneous deferoxamine administration may prove to be an effective and practical means of eliminating large quantities of iron in siderosis.

A multicenter, randomized, open-label, comparative, two-period crossover trial of preference, efficacy, and safety profiles of a prefilled, disposable pen and conventional vial/syringe for insulin injection in patients with type 1 or 2 diabetes mellitus

BACKGROUND

The accuracy and convenience of pen devices for insulin injection have improved quality of life for patients with insulin-treated diabetes mellitus (DM). Prefilled, disposable pens have the advantage of simplicity, with minimal training and attention required and no installation of new cartridges necessary.

OBJECTIVE

The aim of this study was to assess patient preference, efficacy, and safety profiles of a prefilled, disposable pen (FlexPen) and conventional vial/syringe injection method for insulin injection therapy among patients with DM.

METHODS

In a multicenter, randomized, open-label, crossover study, patients with type 1 or 2 DM were transferred from previous QD or BID conventional insulin therapy to a mixture of 70% insulin aspart protamine suspension and 30% insulin aspart injection (NovoLog Mix 7030) for 4 weeks of dose optimization using their usual type of syringe. Patients were then randomly assigned to use either vial/syringe or a prefilled, disposable pen to inject the biphasic insulin aspart 7030 mixture for the next 4 weeks, followed by 4 weeks of use of the other injection device. Efficacy, safety profiles, and patient preference for the delivery systems were compared.

RESULTS

A total of 121 patients (mean [SD] age, 57.0 [12.4] years; age range, 28-81 years; mean [SD] body mass index, 31 [5.5] kg/m(2)) were enrolled. One hundred three patients completed the study. Seventy-four percent of patients (78105) indicated a preference for the pen over the vial/syringe method (95% CI, 71%-87%), compared with 20% (21105) who preferred the vial/syringe. Eighty-five percent (88104) considered the pen more discreet for use in public (compared with 9% [9104] for the vial/syringe), 74% (77104) considered it easier to use overall (compared with 21% [22104] for the vial/syringe), and 85% (89105) found the insulin dose scale on the pen easier to read (compared with 10% [10105] for the vial/syringe). Patients had statistically significant improvement in glycosylated hemoglobin values during the study (P < 0.05). No statistically significant differences in fasting plasma glucose, mean 4-point blood glucose profiles, or serum fructosamine values were found between groups. Overall, the safety profiles during treatment periods with the pen were comparable to those with the vial/syringe.

CONCLUSIONS

In this trial, differences in efficacy and safety profiles between the vial/syringe and prefilled, disposable pen appeared negligible. However, more patients expressed a preference to continue use of the pen.

Subcutaneous apomorphine in the treatment of Parkinson's disease

Apomorphine a dopamine receptor agonist was given subcutaneously to 57 levodopa treated parkinsonian patients with refractory off-period disabilities for a median period of 16 months. In 30 given intermittent suprathreshold injections the mean number of hours spent in a disabling off state fell from 6.9 to 2.9. Similar benefit was observed in 21 patients receiving continuous infusions with additional boluses on demand by mini-pump (mean reduction of hours off from 9.9 to 4.5). Twelve patients have been treated for over two years without tachyphylaxis or loss of response. The incidence of neuropsychiatric side-effects has been low (7%). Six patients failed to show a sustained worthwhile response; severe disabilities during "on" periods being the major problem. Subcutaneous apomorphine is proposed as an effective treatment for patients with incapacitating "off" period disabilities refractory to oral medication and should be considered before experimental implantation procedures.

Induction of puberty in men by long-term pulsatile administration of low-dose gonadotropin-releasing hormone

Puberty is heralded by the appearance of episodic gonadotropin secretion. Men with idiopathic hypogonadotropic hypogonadism have an abnormality in gonadotropin release and do not undergo normal puberty. Since idiopathic hypogonadotropic hypogonadism is thought to represent a disorder of gonadotropin-releasing-hormone (GnRH) secretion, we used long-term low-dose subcutaneous GnRH, administered in an episodic fashion by a portable infusion pump, in an effort to establish a normal adult pattern of gonadotropin secretion in six men. All subjects noted spontaneous erections, nocturnal emissions, and breast tenderness, which were associated with elevations of serum testosterone levels (77 +/- 13 ng per deciliter [mean +/- S.E.] before therapy vs. 520 +/- 182 ng after one month of treatment; P less than 0.001). Gonadotropin levels rose to normal adult ranges within one week of therapy and to supraphysiologic levels by 14 days. Testis size increased in four patients, and spermatogenesis was achieved in three patients by 43 weeks of therapy. These results suggest that long-term episodic GnRH administration can reverse idiopathic hypogonadotropic hypogonadism.

Consensus recommendations on the use of botulinum toxin type a in facial aesthetics

The use of botulinum toxin type A for facial enhancement is the most common cosmetic procedure currently undertaken in the United States. Overall clinical and study experience with botulinum toxin type A treatment for facial enhancement has confirmed that it is effective and safe in both the short and long term. Nevertheless, consistent guidelines representing the consensus of experts for aesthetic treatments of areas other than glabellar lines have not been published. Therefore, a panel of experts on the aesthetic uses of Botox Cosmetic (botulinum toxin type A; Allergan, Inc., Irvine, Calif.) was convened to develop consensus guidelines. This publication comprises the recommendations of this panel and provides guidelines on general issues, such as the importance of the aesthetic evaluation and individualization of treatment, reconstitution and handling of the botulinum toxin type A, procedural considerations, dosing and injection-site variables, and patient selection and counseling. In addition, specific considerations and recommendations are provided by treatment area, including glabellar lines, horizontal forehead lines, "crow's feet," "bunny lines" (downward radiating lines on the sides of nose), the perioral area, the dimpled chin, and platysmal bands. The review of each area encompasses the relevant anatomy, specifics on injection locations and techniques, starting doses (total and per injection point), the influence of other variables, such as gender, and assessment and retreatment issues. Factors unique to each area are presented, and the discussion of each treatment area concludes with a review of key elements that can increase the likelihood of a successful outcome. Summary tables are provided throughout.

Sugar micro needles as transdermic drug delivery system

We designed and fabricated an array of sugar micro needles of the length ranging from 150 micro m to 2 mm for transdermic delivery of drugs. Micro needles were molded out of maltose mixed with pharmaceutical material, being expected bio-degradable in the human skin. To test basic tolerance to the healthy human skin, a clinical experiment was carried out for 10 healthy adult volunteers. 500 microm-needles containing 5 wt% of ascorbate-2-glycoside were inserted into the skin of the forearm and snapped off to be left in the skin. They spontaneously dissolved by hydrolysis to release ascorbate in the epidermis and the dermis. No dermatological problems were observed in terms of the International Contact Dermatitis Research Group criteria. These observations indicate that the present system is a novel approach to achieve transdermic drug delivery.

Inadequate suspension of neutral protamine Hagendorn (NPH) insulin in pens

BACKGROUND

Neutral protamine Hagedorn (NPH) insulin is one of the most commonly used insulins in insulin pens. NPH in pen cartridges is in a two-phase solution with either a solvent or a short-acting insulin, and needs adequate mixing for complete resuspension. We assessed whether NPH insulin is accurately resuspended by patients and the association of suspension errors with diabetes control.

METHODS

109 patients (39 with type 1 diabetes) who had received conventional diabetic education had the NPH content of their cartridges measured by an optical system; a control cartridge was designated as 100%. A questionnaire was used to assess clinical details and insulin suspension habits. After the information about residual insulin error was known, all 109 patients were instructed to resuspend their insulin by rolling and tipping the pen 20 times. 52 patients were randomly selected to have cartridges re-analysed 3 months or 6 months later and to complete another questionnaire.

FINDINGS

Only 10 (9%) of 109 patients tipped and rolled their pen more than ten times. NPH insulin content ranged from 5% to 214% and varied by more than 20% in 71 (65%) of 109 cartridges. There was no relation between inadequate suspension and the frequency of hypoglycaemic episodes (r=0.2, p=0.08). For all patients, there was a correlation between the absolute error of NPH suspension and cycles of rolling and tipping the pen (r=-0.23, p<0.05). After education on resuspending the pen's contents, data were available from 44 of 52 patients; suspension errors decreased in 35 (80%), were unchanged in three (7%), and increased in six (13%). The 35 patients with improved NPH insulin suspension had fewer mean hypoglycaemic episodes per month compared with the previous period (0.4 [SD 0.1] vs 1.0 [0.3], p<0.05). Mean HbA1c values in patients with improved suspension quality did not differ from baseline (8.4% [0.3] vs 8.9% [0.4], p=0.07). Mixing of NPH insulin by a mechanical device showed that at least 20 cycles were necessary before complete resuspension was obtained.

INTERPRETATION

Inadequate NPH insulin suspension is common. We recommended that patients tip pens that contain NPH insulin at least 20 times, since inadequate mixing may impair diabetes control.

Pain following controlled cutaneous insertion of needles with different diameters

BACKGROUND AND AIM

Needle injections are used daily by millions of people around the world for the administration of various drugs (e.g., insulin), venepuncture, and some neurophysiological procedures. The aim of this paper was to study the influence of the outer needle diameter on the pain evoked by controlled needle insertion.

METHODS

An automated needle injection system was used to perform a series of insertions where velocity, angle of insertion, and depth of injection were controlled. The frequency of pain following needle insertions (23G, 27G, 30G, 32G) was recorded together with the pain intensity (measured using the visual analogue scale--VAS) and the occurrence of bleeding.

RESULTS

The outer needle diameter was positively and significantly correlated to the frequency of the insertion pain; for example, 63% of insertions with 23G needles caused pain, 53% of insertions with 27G and 31% of insertions with the thinnest (32G) needle (p < 0.0001) caused pain. The thickest needle caused most insertions associated with bleeding. Bleeding insertions were approximately 1.3 times more painful (as indicated by VAS scores) than insertions without concomitant bleedings (p = 0.004).

CONCLUSION

By decreasing the outer diameter of a needle, the frequency of insertion pain can be reduced and may encourage patients to adhere to demanding injection regimens such as recurrent insulin administration.

Releasable layer-by-layer assembly of stabilized lipid nanocapsules on microneedles for enhanced transcutaneous vaccine delivery

Here we introduce a new approach for transcutaneous drug delivery, using microneedles coated with stabilized lipid nanocapsules, for delivery of a model vaccine formulation. Poly(lactide-co-glycolide) microneedle arrays were coated with multilayer films via layer-by-layer assembly of a biodegradable cationic poly(β-amino ester) (PBAE) and negatively charged interbilayer-cross-linked multilamellar lipid vesicles (ICMVs). To test the potential of these nanocapsule-coated microneedles for vaccine delivery, we loaded ICMVs with a protein antigen and the molecular adjuvant monophosphoryl lipid A. Following application of microneedle arrays to the skin of mice for 5 min, (PBAE/ICMV) films were rapidly transferred from microneedle surfaces into the cutaneous tissue and remained in the skin following removal of the microneedle arrays. Multilayer films implanted in the skin dispersed ICMV cargos in the treated tissue over the course of 24 h in vivo, allowing for uptake of the lipid nanocapsules by antigen presenting cells in the local tissue and triggering their activation in situ. Microneedle-mediated transcutaneous vaccination with ICMV-carrying multilayers promoted robust antigen-specific humoral immune responses with a balanced generation of multiple IgG isotypes, whereas bolus delivery of soluble or vesicle-loaded antigen via intradermal injection or transcutaneous vaccination with microneedles encapsulating soluble protein elicited weak, IgG(1)-biased humoral immune responses. These results highlight the potential of lipid nanocapsules delivered by microneedles as a promising platform for noninvasive vaccine delivery applications.

Microinfusion using hollow microneedles

PURPOSE

The aim of the study is to determine the effect of experimental parameters on microinfusion through hollow microneedles into skin to optimize drug delivery protocols and identify rate-limiting barriers to flow.

METHODS

Glass microneedles were inserted to a depth of 720-1080 microm into human cadaver skin to microinfuse sulforhodamine solution at constant pressure. Flow rate was determined as a function of experimental parameters, such as microneedle insertion and retraction distance, infusion pressure, microneedle tip geometry, presence of hyaluronidase, and time.

RESULTS

Single microneedles inserted into skin without retraction were able to infuse sulforhodamine solution into the skin at flow rates of 15-96 microl/h. Partial retraction of microneedles increased flow rate up to 11.6-fold. Infusion flow rate was also increased by greater insertion depth, larger infusion pressure, use of a beveled microneedle tip, and the presence of hyaluronidase such that flow rates ranging from 21 to 1130 microl/h were achieved. These effects can be explained by removing or overcoming the large flow resistance imposed by dense dermal tissue, compressed during microneedle insertion, which blocks flow from the needle tip.

CONCLUSIONS

By partially retracting microneedles after insertion and other methods to overcome flow resistance of dense dermal tissue, protocols can be designed for hollow microneedles to microinfuse fluid at therapeutically relevant rates.

Minimally invasive insulin delivery in subjects with type 1 diabetes using hollow microneedles

BACKGROUND

Microneedles have previously been used to deliver insulin to animal models, but not in human subjects. This study tested the hypothesis that hollow microneedles can deliver insulin to modulate blood glucose levels in subjects with type 1 diabetes in a minimally invasive manner.

METHODS

This study was carried out in two adults with type 1 diabetes and evaluated bolus delivery of lispro insulin using a hollow microneedle compared to a catheter infusion set (9 mm). The study first determined the minimum insulin delivery depth by administering insulin from microneedles inserted 1, 3.5, and 5 mm into the skin of fasting subjects and then assessed the efficacy of insulin delivery from microneedles inserted 1 mm into the skin to reduce postprandial glucose levels. Blood samples were periodically assayed for plasma free insulin and plasma glucose levels for up to 3.5 h.

RESULTS

The first phase of the study indicated that microneedles inserted at the shallowest depth of 1 mm within the skin led to rapid insulin absorption and reduction in glucose levels. Bolus insulin delivery followed by consumption of a standardized meal in the second phase revealed that microneedles were effective in reducing postprandial glucose levels. Subjects reported no pain from microneedle treatments, and there were no adverse events.

CONCLUSIONS

This study provides the first proof of concept that hollow microneedles can effectively deliver bolus insulin to type 1 diabetes subjects in a minimally invasive manner.

Accuracy of pen injectors versus insulin syringes in children with type 1 diabetes

OBJECTIVE

To compare the accuracy and precision of insulin syringes and pen devices used by children with type 1 diabetes and their parents.

RESEARCH DESIGN AND METHODS

There were 48 subjects (32 patients, a parent of an additional 16 patients) instructed to measure out morning insulin doses three times from vials and/or cartridges containing saline mixed with small amounts of [14C]glucose (solution used as regular insulin) and [3H]glucose (solution used as NPH insulin) and to dispense the contents into a scintillation vial. Statistical analysis was used to determine the accuracy and precision of both methods of insulin delivery.

RESULTS

The absolute error in measuring out doses of regular insulin < 5 U was greater with insulin syringes compared with pen injection devices (9.9 +/- 2.4 vs. 4.9 +/- 1.6%, respectively). Both were comparable for regular insulin doses > 5 U (3.2 +/- 0.6 vs. 2.2 +/- 0.4% for syringes and pens, respectively). The accuracy in drawing up NPH doses was similar for low and high insulin doses (mean percent error of 7.5 +/- 1.5 vs. 5.6 +/- 1.1%).

CONCLUSIONS

Pen devices are more accurate than insulin syringes in measuring out insulin at low insulin doses. The accuracy of insulin syringes improves when higher doses of regular insulin are measured out and becomes comparable to pen devices.

Tumescent anesthesia with a lidocaine dose of 55 mg/kg is safe for liposuction

BACKGROUND

The safe upper limit of lidocaine dosage in tumescent anesthesia for liposuction has been reported to be 35 mg/kg.

OBJECTIVE

This study was undertaken to: 1) evaluate the safety of tumescent anesthesia in liposuction when lidocaine doses greater than 35 mg/kg are required, 2) determine the time interval when the peak plasma lidocaine level occurs following administration of tumescent anesthesia, and 3) assess if the safety of large volume tumescent anesthesia is due to significant lidocaine removed by liposuction.

METHODS

Sixty patients who underwent liposuction with a mean lidocaine dose of 57 mg/kg were prospectively evaluated for development of any signs or symptoms of lidocaine toxicity by multiple interviews over a 24-hour period. In addition, another 10 patients who received a mean lidocaine dose of 55 mg/kg had serial plasma lidocaine level measurements over a 24-hour period following liposuction. The lidocaine level of the aspirate was also measured to assess any significant lidocaine removed by liposuction.

RESULTS

No evidence of lidocaine toxicity was found based on subjective evaluation of 60 patients as well as determined by plasma sampling of 10 patients. The peak plasma lidocaine concentration occurred at approximately 4 or 8 hours after infusion of tumescent anesthesia. The 24-hour plasma lidocaine level suggests that residual lidocaine is present in the subcutaneous tissue allowing for postoperative analgesia beyond this time. A negligible amount of lidocaine was removed by liposuction as determined by the lidocaine level of the aspirate.

CONCLUSION

This study suggests that tumescent anesthesia with a total lidocaine dose of up to 55 mg/kg is safe for use in liposuction.

Insulin-infusion-pump treatment of diabetes: influence of improved metabolic control on plasma somatomedin levels

We examined whether changes in somatomedin accompany those seen in glucose and growth hormone during treatment with the insulin-infusion pump. somatomedin levels in eight insulin-dependent diabetics (13 to 29 years of age) were measured before and after 16 weeks of outpatient insulin-pump treatment, which lowered mean glucose from 245 +/- 21 to 100 +/- 5 mg per deciliter and total glycosylated hemoglobin from 16.2 +/- 1.2 to 9.7 +/- 0.3 per cent (mean +/- S.E.M.). During conventional insulin therapy, both total somatomedin and somatomedin C were within the normal range, despite elevations in growth hormone. Pump treatment resulted in a 70 to 75 per cent increase in both total somatomedin and somatomedin C (P less than 0.05) and a fall in growth-hormone concentrations. In the two growing adolescents, growth velocity doubled during 13 to 15 months of pump treatment. Our data suggest that the improved insulin delivery or metabolic control increases somatomedin levels despite a decrease in growth hormone. Thus, insulin-pump treatment may be useful in optimizing growth in diabetic children.

Insulin delivery using pen devices. Simple-to-use tools may help young and old alike

Results of landmark studies such as the Diabetes Control and Complications Trial and the United Kingdom Prospective Diabetes Study are encouraging patients with diabetes and health professionals alike to strive to achieve and maintain the best possible glucose control. Insulin pens have the potential to become a major asset for improving compliance among diabetic patients. These devices offer substantial improvements in convenience, freedom, and flexibility for all insulin-using patients. Furthermore, more accurate dosing associated with use of the pen may hold the key to better longterm outcomes.

Lipo layering of autologous fat: an improved technique with promising results

When using free fat autologous grafts as a filling material was first proposed in 1893 by Neuber, the idea rapidly gained enthusiasm and endorsements. Our early experience with autologous fat transplantation was disappointing, but even then it was clear that fat could be transferred with partial success. Since then, further clinical works by Guerrerosantos, Coleman, and others have shown that it is possible, by careful handling of transplanted fat, to improve the survival of this tissue. We have reviewed our recent experiences and have found several patients with whom autologous fat transplant has been successful with up to an 8-year postoperative follow-up.

Preference for insulin delivery systems among current insulin users and nonusers

BACKGROUND

It is not known whether preferences for the vial and syringe (VS) or the insulin injection pen device (IIPD) differ between current insulin users and nonusers. Additional benefits in treatment might be realized if preference were considered when discussing insulin use with patients initiating or changing insulin treatment.

OBJECTIVE

The objective of this study was to examine respondent preferences for the VS and the IIPD between current insulin users and nonusers.

METHODS

US residents with type 1 or 2 diabetes mellitus who responded to a year-2001 mail survey completed a 19-item self-administered questionnaire designed to assess respondents' expectations of attributes related to the VS and IIPD. Items were analyzed on a 5-point Likert-type scale with higher scores indicating greater agreement that attributes met expectations. Composite scores for ease of use, activity interference, and social acceptability were used to further examine differences between insulin users and nonusers regarding their preferences for the VS or IIPD. Observed differences in preferences were evaluated statistically using the chi-square test, paired Student t test, and regression analysis.

RESULTS

Questionnaires were received from 302 respondents, producing an adjusted response rate of 20.8%. Respondents ranged in age from 18 to 83 years (mean [SD], 52.4 [13.2] years), with 62% reporting annual income above 25,000 US dollars. Of the 242 usable responses, 99 respondents were insulin users and 143 were not. Statistical evaluation using analysis of variance revealed significant regression coefficients (P < or = 0.001) for both insulin users and nonusers for each of the 3 dimensions (ease of use, activity interference, and social acceptability with respect to preference).

CONCLUSIONS

Based on this survey analysis, overall preference for the IIPD appeared to be higher compared with the VS among both insulin users and nonusers. Social acceptability was the strongest predictor of preference for the IIPD. For current insulin users, social acceptability and ease of use were significant predictors of preference for the VS. For insulin nonusers, these results suggested that patient discussions about VS should emphasize activity interference and ease of use.

Lisuride infusion pump: a device for the treatment of motor fluctuations in Parkinson's disease

Intravenous levodopa or lisuride infusions can successfully reduce daily motor fluctuations in Parkinson's disease, which indicates adequate striatal dopaminergic mechanisms even in severe cases. In 3 patients who received continuous subcutaneous administration of lisuride, by means of a portable mini-infusion pump, in addition to oral levodopa plus decarboxylase inhibitor, mobility improved considerably and "off" periods were reduced or abolished. This response was maintained for 4 to 7 months without toxic side-effects, but increased dyskinetic movements were observed. All 3 patients were discharged and have been able to live independently during the months on treatment. These results suggest that continuous dopaminergic stimulation with the use of a portable delivery system can be a practical therapeutic tool in parkinsonian patients with complicated motor fluctuations.

Fifty-five patient years' experience with a totally implanted system for intravenous chemotherapy

A subcutaneously implanted injection system represents a new method of central venous access. Seventy-eight injection capsules were implanted in 75 cancer patients undergoing intermittent chemotherapy. The actuarial median functional survival of the injection capsules was 16 months, and with a cumulative function time of 55 patient years the complication rate was only one complication every 990 days. No cases of septicemia and few cases of local infection or clotting of the system were seen. Patient activities were not restricted, and maintenance of the system between treatment courses was unnecessary. However, in 9% of the implants a tendency to erosion through the skin was observed, necessitating explantation or reimplantation. Injection capsules seem to be particularly suited for intermittent chemotherapy, including short-term infusions and blood sampling.

Continuous subcutaneous insulin infusion in the treatment of diabetes mellitus

Low-volume, dual-rate, continuous subcutaneous insulin infusion (CSII) creates long periods of nearnormalization of blood glucose and major intermediary metabolites in most insulin-requiring diabetic patients. The technology and strategy of the system are discussed. We have observed encouraging clinical and fluorescein angiographic improvement in severe diabetic retinopathy after 3 mo of outpatient CSII; in the kidney, glomerular capillary permeability (microalbuminuria) is reduced or normalized in long-standing diabetic patients after a few days of CSII-induced strict control. Reduction in insulin dose during CSII treatment of newly diagnosed ketonuric diabetic patients may indicate improved B-cell function in this group. Although CSII must remain a research tool, undertaken only under close medical supervision, it is increasingly likely that the technique affords the conditions for testing the hypothesis that metabolic near-normalization of diabetes slows, arrests, or reverses the course of the microvascular disease associated with the syndrome.

In Vitro and In Vivo Characterization of MEMS Microneedles

Transdermal drug delivery TDD systems have many advantages but are conventionally limited by the low permeability of skin. The idea of using microneedles to painlessly penetrate the topmost impermeable stratum corneum has previously been put forward. In this paper, the fabrication of solid and hollow silicon microneedles with straight side-walls and with the following dimensions: 20-100 microm in diameter and 100-150 microm in length is described. In vitro tests demonstrate that with prior solid microneedle application, transdermal drug transport is significantly increased by 10-20 times, with the degree of enhancement being related to needle diameter. In vivo tests in diabetic animals, however, were unable to demonstrate any delivery of insulin through the hollow microneedles. It is proposed that two factors, microneedle length and tip sharpness, have to be improved for systemic drug delivery to be seen in vivo.

Increased Time in Range and Fewer Missed Bolus Injections After Introduction of a Smart Connected Insulin Pen

Background: This observational study investigated whether the connected NovoPen^® 6 could influence insulin regimen management and glycemic control in people with type 1 diabetes (T1D) using a basal-bolus insulin regimen and continuous glucose monitoring in a real-world setting. Methods: Participants from 12 Swedish diabetes clinics downloaded pen data at each visit (final cohort: n = 94). Outcomes included time in range (TIR; sensor glucose 3.9-10.0 mmol/L), time in hyperglycemia (>10 mmol/L), and hypoglycemia (L1: 3.0- <3.9 mmol/L; L2: <3.0 mmol/L). Missed bolus dose (MBD) injections were meals without bolus injection within -15 and +60 min from the start of a meal. Outcomes were compared between the baseline and follow-up periods (≥5 health care professional visits). Data were analyzed from the first 14 days following each visit. For the TIR and total insulin dose analyses (n = 94), a linear mixed model was used, and for the MBD analysis (n = 81), a mixed Poisson model was used. Results: TIR significantly increased (+1.9 [0.8; 3.0]_{95% CI} h/day; P < 0.001) from baseline to follow-up period, with a corresponding reduction in time in hyperglycemia (-1.8 [-3.0; -0.6]_{95% CI} h/day; P = 0.003) and L2 hypoglycemia (-0.3 [-0.6; -0.1]_{95% CI} h/day; P = 0.005), and no change in time in L1 hypoglycemia. MBD injections decreased by 43% over the study (P = 0.002). Change in MBD injections corresponded to a decrease from 25% to 14% based on the assumption that participants had three main meals per day. Conclusions: Our study highlights the potential benefit on glycemic control and dosing behavior when reliable insulin dose data from a connected pen contribute to insulin management in people with T1D.

Controlled transdermal delivery of model drug compounds by MEMS microneedle array

This article reports an in vitro study of microneedle-array-enhanced transdermal transport of model drug compounds dispersed in chitosan films. Each microneedle array has 400 out-of-plane, needle-shaped microstructures fabricated using micro-electro-mechanical systems (MEMS) technology to ensure adequate mechanical strength and high precision, and consistency. A nanometer coating on the microneedles ensured the biocompatibility that is important in the application of transdermal drug delivery. Model drugs selected to investigate skin permeation in vitro were calcein, a small molecule (molecular weight, 623 d) that has little skin penetration, and bovine serum albumin (BSA) (molecular weight, 66,000 d), a hydrophilic biological macromolecule. A Franz permeation cell was used to characterize the permeation rate of calcein and BSA through the rat skin. The transdermal transport behavior of BSA was investigated from solid films coated on the surface of microneedle arrays with various chitosan concentrations, film thicknesses, and BSA contents. The BSA permeation rate decreased with the increase of the chitosan concentration; the thicker the film, the slower the permeation rate. In addition, the permeation rate increased with the increase of BSA loading dose. A linear relationship existed between the permeation rate and the square root of the BSA loading dose. Results showed that the chitosan hydrophilic polymer film acts as a matrix that can regulate the BSA release rate. The controlled delivery of BSA can be achieved using the BSA-containing chitosan matrix film incorporated with the microneedle arrays. This will provide a possible way for the transdermal delivery of macromolecular therapeutic agents such as proteins and vaccines.

Practical aspects of insulin pen devices

Insulin pen devices have several advantages over the traditional vial-and-syringe method of insulin delivery, including improved patient satisfaction and adherence, greater ease of use, superior accuracy for delivering small doses of insulin, greater social acceptability, and less reported injection pain. In recent years, pens have become increasingly user-friendly, and some models are highly intuitive to use, requiring little or no instruction. Despite this progress, uptake of these devices in the United States has not matched that in many other areas of the world. There is a need for improved awareness of the current characteristics of insulin pen devices among United States health care professionals. Knowledge of the design improvements that have been incorporated into pens, both to address patient needs and as a result of the improved technology behind the device mechanics, is essential to promoting the use of insulin pen devices. This review highlights some of the practical aspects of pen use and discusses the factors to be considered when selecting among different insulin pens.