Stability of Morphine Sulfate-Clonidine and Sufentanil-Clonidine Mixtures.

BACKGROUND: Spinal analgesia is recommended for intractable cancer pain. Morphine-clonidine and sufentanil-clonidine are often used in association in intrathecal drug delivery systems, injected by intraabdominal pumps. To refill these pumps and to limit patient transport, it may be necessary to ship the mixtures in polypropylene syringes to peripheral establishments located near patient homes. The purpose of this study is to determine the stability of morphine-clonidine and sufentanil-clonidine mixtures in polypropylene syringes to ensure the best and safest transport conditions and in implantable pumps for intrathecal use. MATERIALS AND METHODS: The stability study method was conceived according to the International Council for Harmonization guidelines. For polypropylene syringes, four different mixtures of morphine-clonidine and sufentanil-clonidine were assessed over seven days. Two storage temperatures were tested (5 ± 3 °C and 25 ± 2 °C). For implantable pumps, two different mixtures of morphine-clonidine and sufentanil-clonidine were assessed over 28 days and stored at 37 °C. RESULTS: For the morphine-clonidine mixtures in polypropylene syringes, all mixtures remained stable for five days in both storage conditions (5 ± 3 °C and 25 ± 2 °C) because of relative concentrations systematically positioned between 90% and 110% (95% CIs of the mean of three samples). The two mixtures in implantable pumps remained stable for 28 days. For the sufentanil-clonidine mixtures in polypropylene syringes, cold conservation kept all the preparations stable for seven days, whereas a quick degradation was observed after only two days for ambient storage conditions. This result is similar to that with an implantable pump, in which the concentration is <90% on day 7 for low concentration mixtures. No visual modification, no significant pH modification, and no changes in turbidity assays were observed in either study. CONCLUSION: This study shows the stability of the morphine-clonidine mixtures in syringes stored at 5 °C for five days and in implantable pumps stored at 37 °C for 28 days. For the sufentanil-clonidine mixtures, the results show stability in syringes for seven days at 5 °C. Pump results show stability of seven days for low concentrations and 28 days for high concentrations.

Long-term experience with implantable treprostinil pumps in pulmonary arterial hypertension.

OBJECTIVES: To compare clinical parameters and quality of life in patients with pulmonary arterial hypertension (PAH) at the time of diagnosis, at the time of LenusPro pump implantation and during intravenous treptostinil treatment. METHODS: Seven patients with severe PAH treated with intravenous treptostinil via implantable LenusPro pumps were evaluated, including NYHA classification, six­minute walking test, BNP and quality of life assessment using the EQ-5D-5L questionnaire before and after pump implantation. RESULTS: No significant changes were observed in NYHA class and six­minute walking distance test. There was however a significant improvement in the quality of life and a decrease in BNP levels. The mean EQ-5D-5L index assessed during subcutaneous treptostinil treatment was significantly worse when compared to that assessed during its intravenous application (0.39 ± 0.24 vs 0.78 ± 0.28, p ˂ 0.05); the same is true about the pain/discomfort dimension. Complications occurred, namely one nonfatal pneumothorax, one nonfatal hemothorax, and one event of nonfatal treptostinil intoxication after refilling. CONCLUSIONS: In patients who do not tolerate subcutaneous treptostinil treatment, the use of the LenusPro implantable pump results in a significant improvement in quality of life with an acceptable safety profile (Tab. 2, Fig. 2, Ref. 19).

Experimental Drainage Device to Reduce Lymphoedema in a Rat Model.

OBJECTIVE: Despite recent advances in pharmacological research and microsurgery, lymphoedema remains an incurable disease that deeply affects quality of life. There is an urgent need for innovative approaches to restore continuous lymph flow in affected tissues. To this end, the efficacy of a subcutaneously implanted draining device in reducing lymphoedema volume in a rat hindlimb lymphoedema model was tested. METHODS: A rat model of chronic lymphoedema was developed by surgical removal of popliteal and inguinal lymph nodes, followed by irradiation. The model was characterised by monitoring limb volume via tape measure, skin water content via dielectric constant measurement, and lymphatic drainage via lymphofluoroscopy. After lymphoedema establishment in 16 Wistar rats, a device made of fenestrated tubing equipped with a miniaturised pumping system, was implanted subcutaneously in the affected limb to restore continuous recirculation of interstitial fluid. RESULTS: Lymphofluoroscopy imaging showed impaired lymphatic drainage following lymphadenectomy and irradiation. Affected limb volume and skin water content increased significantly compared with the untreated limb, with a median (interquartile range) of 3.85 (0.38) cm3 versus 3.03 (0.43) cm3 for volume (n = 16, p = .001) and 26.6 (9.1) versus 16.6 (3.7) cm3 for skin dielectric constant (n = 16, p = .001). Treatment of lymphoedema with the implanted drainage device showed that 5 weeks post-implant excess volume was significantly reduced by 51 ± 18% compared with the pre-implant situation (n = 9 sham group, n = 7 pump group). CONCLUSION: Lymphoedema volume in the rat model was significantly reduced by restoring continuous drainage of excess fluid using a novel subcutaneously implanted device, opening the way to the development of an artificial lymphatic vessel.

An implantable pump Lenus pro® in the treatment of pulmonary arterial hypertension with intravenous treprostinil.

BACKGROUND: Subcutaneous treprostinil is a prostacyclin analogue used to treat pulmonary arterial hypertension (PAH). Due to local pain it can cause a deterioration of heart related quality of life (HRQoL) or even abandonment of treatment. The aim of this paper was to assess the feasibility of treatment with intravenous treprostinil administered by means of the Lenus Pro® implantable pump. METHODS: This was a retrospective, multi-center study involving 12 patients (8 females) with PAH treated with a subcutaneous infusion of treprostinil with intolerable pain at the infusion site. Clinical evaluation, including HRQoL assessment with SF-36 questionnaire was performed, before pump implantation and 2-9 months after. The median time of follow-up time was 14 months (4-29 months). RESULTS: After implantation of the Lenus Pro® pump, no statistically significant changes were observed in the 6-min walking distance and NT-proBNP. After implantation 50% of patients were in II WHO functional class (33% before, p = 0,59). There was a significant improvement in HRQoL within the Physical Component Score (28 ± 7 vs 38 ± 8 pts., p < 0,001) and in specific domains of SF-36 form: physical role (31 ± 7 pts. vs. 41 ± 12 pts., p = 0,03), bodily pain (31 ± 12 vs. 50 ± 14 pts., p = 0,02), and vitality (37 ± 8 pts. vs. 50 ± 14 pts., p = 0,03). During the periprocedural period, one patient developed a recurrent haematoma at the implantation site. During follow-up in one patient, the drug delivering cannula slipped out of the subclavian vein, what required repositioning repeated twice, and in another patient an unexpected increase in the drug administration rate was observed. CONCLUSIONS: In patients with PAH who do not tolerate subcutaneous infusion of treprostinil, the use of the Lenus Pro® implantable pump results in significant subjective improvement of vitality and physical aspect of the HRQoL with acceptable safety profile.

Intravenous Treprostinil in Severe Inoperable Chronic Thromboembolic Pulmonary Hypertension Using Implantable Pumps-Single-Center Experience over More Than a Decade.

The management of chronic thromboembolic pulmonary hypertension has significantly changed over the last decade with the availability of both specific therapies and interventional treatments. In parallel, implantable pumps for intravenous administration of treprostinil have broadened the spectrum of continuous prostanoid infusion. We evaluated the course of 17 consecutive patients with inoperable chronic thromboembolic pulmonary hypertension treated with treprostinil by means of an implantable infusion pump between 2011 and 2023 at our center. Complications associated with the infusion system were rare, leading to 0.4 unplanned surgical interventions during 17,160 patient days. No additional safety signals were detected, and clinical benefits achieved with subcutaneous treprostinil before pump implantation could be maintained in all patients. No catheter-related infections or thromboembolic events were observed. Implantable infusion pumps offer an attractive alternative to subcutaneous treprostinil for patients intolerant to the subcutaneous route, including those with chronic thromboembolic pulmonary hypertension.

Intra thecal baclofen pump as an ad hoc measure for a case of severe tardive dystonia refractory to multiple lesioning.

Tardive dystonia is an infrequent ailment in patient reliant with chronic antipsychotic medication. The front-line envoy in the treatment of this illness is set into motion with oral agents including baclofen, benzodiazepines, and other antispasmodics. Regardless of an extensive therapy, the patients are not able to control of their spasticity/ dystonia. The authors reported a case of severe tardive dystonia treated with baclofen therapy in a patient frigid to medical therapy and multiple lesioning. Case Report: A 31-year-old female, diagnosed as a case of depressive illness and being managed with neuroleptic medications, who went onto develop tardive dystonia progressively worsening over a 4-year duration. After a comprehensive and meticulous evaluation of her neurological and psychological stratum, globus pallidus interna lesioning was reputed as the best course of action. As intended, staged lesioning was executed bilaterally with a trivial resolution eventually succumbing into recurrence, compelling a repeat lesioning. It was inaptly discouraging to see her crippled with the plight. Determined, not to give upon her, a way out with a baclofen therapy was proposed. A test dose with a 100 mcg of baclofen with an increment up to 150 mcg over a 3-day period demonstrated a promising prospect. On that account, the insertion of the baclofen pump was performed with an outstanding aftermath in her neurological endeavor. Clinical Discussion: Tardive dystonia is believed to be caused by striatal dopamine receptor super-sensitivity persuaded by the dopamine-antagonizing action of antipsychotic drugs. The first line of treatment being oral agents including oral baclofen, benzodiazepines, and antispasmodics. If the patient suffers from an early-onset primary generalized dystonia, then treatment with deep brain stimulation of the globus pallidus interna is the approved and preferred treatment approach. Recurrence of the symptoms despite of multiple lesioning can be overcome by intrathecal baclofen pump infusion as stated by many research. It is not uncommon to face complications in such a procedure, but the benefits outreach the risk, which makes it a choice of treatment. Conclusion: The use of a continuous intrathecal baclofen pump for cases with tardive dystonia refractory to conventional therapy, it has been approved as one of the safest and capable procedures.

Magnetically actuating implantable pump for the on-demand and needle-free administration of human growth hormone.

A bolus of human growth hormone (hGH) is often prescribed for the treatment of growth hormone deficiency, which requires frequent injections in current clinical settings. This painful needle-involved delivery often results in poor patient compliance, leading to low medication adherence and poor clinical outcomes. Therefore, we propose a magnetically actuating implantable pump (MAP) that can infuse an accurate dose of hGH only at the time of non-invasive magnet application from the skin. The MAP herein could reproducibly infuse 20.6 ±â€¯0.9 µg hGH per actuation without any leak at times without actuation. The infused amount increased proportionally with an increase in the number of actuations. When the MAP was implanted and actuated with a magnet in animals with growth hormone deficiency for 21 days, the profiles of plasma hGH concentration and insulin-like growth factor (IGF)-1, as well as changes in body weight, were similar to those observed in animals treated with conventional subcutaneous hGH injections. Therefore, we anticipate that the MAP fabricated in this study can be a non-invasive alternative to administer hGH without repeated and frequent needle injections.

Strategies for optimizing intravenous prostacyclin-analog therapy in patients with pulmonary arterial hypertension.

INTRODUCTION: Intravenous prostacyclin-analogs (PCA, e.g. epoprostenol, treprostinil, iloprost) have become an essential part in the therapy of patients with pulmonary hypertension (PH), mainly pulmonary arterial hypertension (PAH). They show considerable differences in pharmacology. A combination therapy including intravenous drugs is regarded as the 'gold standard' in most of PAH patients. AREAS COVERED: This review discusses and summarizes the studies and concepts on which this therapy is based. To date, intravenous prostacyclin-analogs are mainly administered when standard therapy fails to improve patients to low-risk status. However, preliminary data from uncontrolled studies suggest that an 'upfront triple' therapy including intravenous or subcutaneous prostacyclin-analogs could be preferable in selected patients. EXPERT OPINION: Various IV PCA have been evaluated in the treatment of patients with PAH. Today, combination therapy is the 'gold standard' for the majority of patients. Intravenous PCA is recommended from functional class III onwards. Timing of its initiation is still a point of discussion. An escalation of therapy to IV or SC PCA is always necessary if a low-risk status cannot be achieved with other targeted therapies. Preliminary data suggest that selected patients could benefit from an 'upfront triple' therapy. Controlled studies on which such recommendation could be based are lacking.

Implantable LENUS pro pump for treprostinil infusion in three pediatric patients.

BACKGROUND: Prostanoid treatment in patients with severe pulmonary arterial hypertension (PAH) has been proven safe and effective. Subcutaneous administration of treprostinil has side effects, which limits their use and acceptance. An implantable pump for continuous intravenous treprostinil infusion has been recently approved. We describe our experience with the implantable pump in three pediatric patients. DESCRIPTION OF CASES: The LENUS pro pump was implanted in three adolescents with severe PAH, who were treated with tadalafil, ambrisentan, and subcutaneous treprostinil. The indication of the Lenus pro pump implantation was the local side effects of subcutaneous treprostinil (pain, inflammation, and local infection) that were not well tolerated and that severely decreased their quality of life. The pump was surgically implanted under general anesthesia.One patient, in functional class IV, suffered postoperative hemodynamic instability and small pneumothorax, requiring an increase in treprostinil dose up to 85 ng/kg/min and a decrease 9 days after the pump implantation. The second patient who was discharged 4 days after surgery with treprostinil at 60 ng/kg/min reported improvement in his quality of life, but the dose requirement increased up to 92 ng/kg/min. After a 21-month follow-up, this patient received a lung transplant. The third patient presented a hematoma at the pump site with no other complications and had a follow-up of 9 months with an improvement in her quality of life. COMMENTS: Implantable pumps for continuous parenteral prostanoid infusion in pediatric patients are an alternative to external pumps, especially when familiar psychological or psychomotor issues hinder the use of external pumps.

Unexpected Acceleration in Treprostinil Delivery Administered by a Lenus Pro® Implantable Pump in Two Patients Treated for Pulmonary Arterial Hypertension.

Intravenous treprostinil administration by an implantable pump is an attractive option for pulmonary arterial hypertension (PAH) treatment and is the subject of recent publications. Short-term studies are promising, but there is still a lack of long-term prospective data. We analyzed the treprostinil flow rate administered by the Lenus Pro® implantable pump in 2 patients suffering from PAH during follow-up times of respectively 4.2 and 3 years. The flow rate delivered by the pumps in these 2 patients exceeded the manufacturer admitted margin of error within 2 years and continued to increase to reach, respectively, 158 and 120% of the expected flow rate at the end of the follow up. In one case, the implantable pump had to be removed for this reason. The ex-vivo flow rate of the withdrawn pump determined in the laboratory reached 173% of the predicted value. This correlated with the in-vivo measurement, which suggests a continuous flow increase even after pump removal and without treprostinil use. Spontaneous flow increase from such an implantable pump is a potentially major pitfall, which needs to be identified and actively managed by the responsible clinicians.

Magnetically-driven implantable pump for on-demand bolus infusion of short-acting glucagon-like peptide-1 receptor agonist.

For type 2 diabetic patients, short acting glucagon-like peptide-1 receptor agonist (GLP-1 RA) is often prescribed with frequent needled injections. Long-acting GLP-1 RA for less frequent injections do not mimic physiologic secretion of GLP-1. Therefore, an implantable pump is proposed in this work, which can deliver a short-acting GLP-1 RA, exenatide, without needles and batteries. The implanted pump can infuse an accurate amount of exenatide bolus only when a noninvasive magnetic force is applied from outside the body. The pump includes a safety feature of patterned magnets for actuation to prevent accidental infusion possibly caused by a general household magnet. The reservoir for exenatide is made of a flexible biomaterial and thus, a negative pressure build-up in the reservoir can be prevented even after multiple actuations and almost all drug consumption (~ 94%). This allows a reproducible drug dose for a longer period after implantation, hence less frequent replenishment procedures. The pump is also equipped with an intermediate container with two distinct check-valves and thus, the reservoir of exenatide can be further separated and better prevented from infiltration of the bodily fluid surrounding the implanted pump. When tested in Goto-Kakizaki rats, the pump demonstrates the efficacy of exenatide similar to conventional subcutaneous injections. Therefore, the pump can be promising for patient-friendly, optimal delivery of short-acting GLP-1 RA that better follows the physiologic secretion profile of GLP-1.

Route of Insulin Does Not Influence 25-Hydroxyvitamin D Concentrations in Type 1 Diabetes: A Brief Report.

The increased prevalence of vitamin D [25(OH)D] deficiency in type 1 diabetes mellitus (T1DM) may be related to low insulin levels in the hepatic portal venous system. In this prospective matched-control study, we demonstrate that long-term intraperitoneal insulin does not influence 25(OH)D concentrations in patients with T1DM as compared with subcutaneous insulin administration.

Intravenous treprostinil via an implantable pump in pediatric pulmonary arterial hypertension.

Intravenous prostacyclin-based therapy improves survival in children with pulmonary arterial hypertension (PAH), but is typically administered via an external infusion pump, which places a considerable burden on the patient. Implanted pumps may overcome some of the limitations of external pumps. We describe the first long-term use of an implanted pump for intravenous treprostinil delivery in a pediatric patient with PAH. Our patient was experiencing marked dyspnea on exertion despite triple combination therapy with bosentan, sildenafil, and inhaled iloprost. Parenteral prostacyclin-based therapy was discussed and the patient rejected options involving external pumps; she finally chose intravenous treprostinil delivery via an implanted pump (LENUS Pro®; fixed flow rate; 20 ml reservoir). The patient underwent pump implantation in July 2012 (aged 14 years) under general anesthesia with no peri- or postoperative complications. She showed marked improvements in fatigue and dyspnea over the subsequent weeks, and her inhaled iloprost regimen was slowly decreased and stopped after six months. During follow-up, the pump showed an unexpected, progressive increase in flow rate that allowed a treprostinil dose of 170 ng/kg/min to be achieved, but at the cost of shortened intervals between refills. The pump was therefore replaced in August 2017 with a newer model with an adjustable flow rate (Siromedes®). A catheter dislocation was corrected under local anesthesia one week after the replacement surgery. The patient is currently receiving treprostinil 170 ng/kg/min with percutaneous refills every 12-13 days. Thus, implantable pumps might be a valuable alternative to external pumps for treprostinil infusion in pediatric PAH.

Intravenous treprostinil infusion via a fully implantable pump for pulmonary arterial hypertension.

OBJECTIVES: Parenteral prostanoids infused via external pumps are well-established pulmonary arterial hypertension (PAH) treatments. However, local side-effects and systemic infections restrict their use. The purpose of this study was to investigate the safety of a fully implantable treprostinil infusion pump (LENUS Pro®) in patients with PAH. METHODS: Thirty patients with PAH undergoing pump implantation (with stable PAH therapy for ≥3 weeks pre-implantation) were included in this prospective, multicenter, observational study (NCT01979822). Primary endpoints were predefined adverse events (AEs) during implantation, in-hospital and/or during 6-month follow-up. Refill-related AEs were a secondary endpoint. RESULTS: Twenty-nine patients completed 6-month follow-up (one underwent lung transplantation). During implantation, one pneumothorax (not requiring drainage) occurred. Four patients had an in-hospital AE (including one catheter revision). During 6-month follow-up, AEs were most frequent at the first refill (10); the most common AE was seroma around the pump. No infections occurred. One pump required replacement because of a defective septum caused by use of a non-approved refill needle (associated with extravasation). Apart from the extravasation, no refill-related AEs were recorded. Post hoc efficacy analyses showed significant improvements in functional class [number in functional class I/II/III/IV: 0/5/21/2 (baseline) versus 3/8/17/0 (6 months); p = 0.012] and 6-min walk distance (mean ± standard deviation: 407 ± 122 m versus 445 ± 127 m; n = 17; p = 0.014). CONCLUSIONS: This study supports use of a fully implantable treprostinil infusion pump in patients with PAH requiring parenteral prostanoids. Refills should be performed by specialized healthcare professionals at patients' homes or at experienced centers using approved equipment.

Use of an implantable pump for controlled subcutaneous insulin delivery in healthy cats.

The aim of this study was to examine the safety and reliability of a research-grade implantable pump for controlled delivery of insulin glargine in cats. For this purpose, a small telemetrically controlled drug delivery pump with a refillable reservoir was implanted into the subcutaneous tissues of the dorsal neck in 10 clinically healthy cats. The reservoir was filled with insulin glargine, and the pump was programmed to deliver four boluses of 0.25 IU/kg, 2-3 weeks apart. As a control, insulin glargine (0.25 IU/kg) was injected SC. Blood glucose and plasma insulin glargine concentrations were measured before each bolus and SC injection and for 8 h afterward. Cats were monitored for signs of discomfort. Pumps were easily implanted and well tolerated by all cats. The experiment was completed in five of 10 cats. In four, the pump failed because of technical reasons; another cat developed severe hypoglycaemia attributable to insulin leakage. Overall, plasma insulin glargine increased after six of eight (75%) initial boluses and after one of 16 (6%) successive boluses. Glucose decreased after seven of eight (88%) initial boluses and after four of 16 (25%) successive boluses. Only the first bolus significantly increased plasma insulin glargine (P = 0.008) and decreased glucose (P = 0.008). Of 20 SC injections, 10 (50%) increased plasma insulin glargine (P <0.001) and 12 (60%) decreased glucose (P <0.001). The pump did not cause discomfort in cats, but life-threatening hypoglycaemia occurred in one. Frequent device problems suggest that the pump needs improvements. Because successive boluses did not increase plasma insulin glargine, this type of insulin may not be appropriate with the pump.

Procedural safety of a fully implantable intravenous prostanoid pump for pulmonary hypertension.

BACKGROUND: In patients with severe pulmonary arterial hypertension, subcutaneous or catheter-based intravenous application of prostanoids carries a risk of local side effects or systemic infections, which limits their use and acceptance. Recently, a fully implantable pump for continuous application of intravenous treprostinil was approved in Germany. However, surgery is a major risk for patients with severe pulmonary arterial hypertension. The purpose of this study was to investigate the safety of a fully implantable pump inserted under local or general anesthesia in patients with severe pulmonary hypertension. METHODS: All patients with pulmonary hypertension undergoing pump implantation for the continuous application of intravenous treprostinil were included from two German centers. Surgery was performed under local or general anesthesia according to the protocol of the recruiting center. Intra-operative safety and in-hospital complications were analyzed for the two different implantation regimens. RESULTS: In total, 51 patients were included. No major intra-operative complications were recorded. During the observation period, two patients died of progressive right heart failure, and two patients required treatment in the intensive care unit for acute right heart decompensation and respiratory failure. In total, major complications occurred in 8 out of 51 patients. CONCLUSIONS: Our observational study provides preliminary evidence supporting the procedural safety of a fully implantable pump inserted under local or general anesthesia for patients with severe pulmonary hypertension. The observation of major complications in a subset of patients requires extensive pre- and post-operative assessments. Future trials are required to provide further evidence for the long-term safety and efficacy of the pump using this approach.

Finding the right route for insulin delivery - an overview of implantable pump therapy.

INTRODUCTION: Implantable pump therapy adopting the intraperitoneal route of insulin delivery has been available for the past three decades. The key rationale for implantable pump therapy is the restoration of the portal-peripheral insulin gradient of the normal physiology. Uptake in clinical practice is limited to specialized centers and selected patient populations. Areas covered: Implantable pump therapy is discussed, including technical aspects, rationale for its use, and glycemic and non-glycemic effects. Target populations, summaries of clinical studies and issues related to implantable pump therapy are highlighted. Limitations of implantable pump therapy and its future outlook in clinical practice are presented. Expert opinion: Although intraperitoneal insulin delivery appears closer to the normal physiology, technical, pharmacological, and costs barriers prevent a wider adoption. Evidence from clinical studies remains scarce and inconclusive. As a consequence, the use of implantable pump therapy will be confined to a small population unless considerable technological progress is made and well-conducted studies can demonstrate glycemic and/or non-glycemic benefits justifying wider application.

Development of a Pivot Bearing Supported Sealless Centrifugal Pump for Ventricular Assist.

Since 1991, in our laboratory, a pivot bearing-supported, sealless, centrifugal pump has been developed as an implantable ventricular assist device (VAD). For this application, the configuration of the total pump system should be relatively small. The C1E3 pump developed for this purpose was anatomically compatible with the small-sized patient population. To evaluate an-tithrombogenicity, ex vivo 2-week screening studies were conducted instead of studies involving an intracorpore-ally implanted VADs using calves. Five paracorporeal LVAD studies were performed using calves for longer than 2 weeks. The activated clotting time (ACT) was maintained at approximately 250 s using heparin. All of the devices demonstrated trouble-free performances over 2 weeks. Among these 5 studies, 3 implantations were subjected to 1-month system validation studies. There were no device-induced thrombus formations inside the pump housing, and plasma-free hemoglobin levels in calves were within the normal range throughout the experiment (35, 34, and 31 days). There were no incidents of system malfunction. Subsequently, the mass production model was fabricated and yielded a normalized index of hemolysis of 0.0014, which was comparable to that of clinically available pumps. The wear life of the impeller bearings was estimated at longer than 8 years. In the next series of in vivo studies, an implantable model of the C1E3 pump will be fabricated for longer term implantation. The pump-actuator will be implanted inside the body; thus the design calls for substituting plastic for metallic parts.

Evolution of implantable and insertable drug delivery systems.

The paper describes the development of implantable and insertable drug delivery systems (IDDS) from their early stage in the 1960s until the current stage in the 2010s. It gives a detailed summary of non-degradable and biodegradable systems and their applications in different areas such as vascular disease treatment, birth control, cancer treatment, and eye disease treatment. It also describes the development of various implantable pump systems and some other atypical IDDS, the challenges and the future of IDDS.

Drug Delivery: Enabling Technology for Drug Discovery and Development. iPRECIO Micro Infusion Pump: Programmable, Refillable, and Implantable.

Successful drug delivery using implantable pumps may be found in over 12,500 published articles. Their versatility in delivering continuous infusion, intermittent or complex infusion protocols acutely or chronically has made them ubiquitous in drug discovery and basic research. The recent availability of iPRECIO(®), a programmable, refillable, and implantable infusion pump has made it possible to carry out quantitative pharmacology (PKPD) in single animals. When combined with specialized catheters, specific administration sites have been selected. When combined with radiotelemetry, the physiologic gold standard, more sensitive and powerful means of detecting drug induced therapeutic, and/or adverse effects has been possible. Numerous application examples are cited from iPRECIO(®) use in Japan, United States, and Europe with iPRECIO(®) as an enabling drug delivery device where the refillable and programmability functionality were key benefits. The ability to start/stop drug delivery and to have control periods prior dosing made it possible to have equivalent effects at a much lower dose than previously studied. Five different iPRECIO(®) applications are described in detail with references to the original work where the implantable, refillable, and programmable benefits are demonstrated with their different end-points.