Effect of hyaluronidase on the subcutaneous absorption of electrolytes in humans

Insulin Bolus Administration in Insulin Pump Therapy: Effect of Bolus Delivery Speed on Insulin Absorption from Subcutaneous Tissue

BACKGROUND

This study assessed subcutaneous absorption kinetics of rapid-acting insulin administered as a bolus using bolus delivery speeds commonly employed in commercially available insulin pumps (i.e., 2 and 40 s for delivering 1 insulin unit).

MATERIALS AND METHODS

Twenty C-peptide-negative type 1 diabetic subjects were studied on two occasions, separated by at least 7 days, using the euglycemic clamp procedure. After an overnight fast, subjects were given, in random order, a subcutaneous insulin bolus (15 U of insulin lispro, Eli Lilly) either for 30 s using an Animas IR2020 pump (fast bolus delivery) or for 10 min using a Medtronic Minimed Paradigm 512 pump (slow bolus delivery).

RESULTS

Fast bolus delivery resulted in an earlier onset of insulin action as compared with slow bolus delivery (21.0 ± 2.5 vs. 34.3 ± 2.7 min; P < 0.002). Furthermore, time to reach maximum insulin effect was found to be 27 min earlier with fast bolus delivery as compared with slow bolus delivery (98 ± 11 vs. 125 ± 16 min; P < 0.005). In addition, the area under the plasma insulin curve from 0 to 60 min for fast bolus delivery was greater than the one for slow bolus delivery (10,307 ± 1291 vs. 8192 ± 865 min·pmol/L; P = 0.027).

CONCLUSIONS

Results suggest that insulin bolus delivery with fast delivery speed may result in more rapid insulin absorption and, thus, may provide a better control of meal-related glucose excursions than that obtained with bolus delivery using slow delivery speeds. Our findings may have important implications for the future design of the bolus delivery unit of insulin pumps.

Subcutaneous Infusion of Fluids for Hydration or Nutrition: A Review

Subcutaneous infusion, or hypodermoclysis, is a technique whereby fluids are infused into the subcutaneous space via small-gauge needles that are typically inserted into the thighs, abdomen, back, or arms. In this review, we provide an overview of the technique, summarize findings from studies that have examined the use of subcutaneous infusion of fluids for hydration or nutrition, and describe the indications, advantages, and disadvantages of subcutaneous infusion. Taken together, the available evidence suggests that, when indicated, subcutaneous infusion can be effective for administering fluids for hydration or nutrition, with minimal complications, and has similar effectiveness and safety to the intravenous route. Of note, subcutaneous infusion offers several advantages over intravenous infusion, including ease of application, low cost, and the lack of potential serious complications, particularly infections. Subcutaneous infusion may be particularly suited for patients with mild to moderate dehydration or malnutrition when oral/enteral intake is insufficient; when placement of an intravenous catheter is not possible, tolerated, or desirable; at risk of dehydration when oral intake is not tolerated; as a bridging technique in case of difficult intravenous access or catheter-related bloodstream infection while infection control treatment is being attempted; and in multiple settings (eg, emergency department, hospital, outpatient clinic, nursing home, long-term care, hospice, and home).

Interstitial Pressure in Pancreatic Ductal Adenocarcinoma Is Dominated by a Gel-Fluid Phase

Elevated interstitial fluid pressure can present a substantial barrier to drug delivery in solid tumors. This is particularly true of pancreatic ductal adenocarcinoma, a highly lethal disease characterized by a robust fibroinflammatory response, widespread vascular collapse, and hypoperfusion that together serve as primary mechanisms of treatment resistance. Free-fluid pressures, however, are relatively low in pancreatic ductal adenocarcinoma and cannot account for the vascular collapse. Indeed, we have shown that the overexpression and deposition in the interstitium of high-molecular-weight hyaluronan (HA) is principally responsible for generating pressures that can reach 100 mmHg through the creation of a large gel-fluid phase. By interrogating a variety of tissues, tumor types, and experimental model systems, we show that an HA-dependent fluid phase contributes substantially to pressures in many solid tumors and has been largely unappreciated heretofore. We investigated the relative contributions of both freely mobile fluid and gel fluid to interstitial fluid pressure by performing simultaneous, real-time fluid-pressure measurements with both the classical wick-in-needle method (to estimate free-fluid pressure) and a piezoelectric pressure catheter transducer (which is capable of capturing pressures associated with either phase). We demonstrate further that systemic treatment with pegylated recombinant hyaluronidase (PEGPH20) depletes interstitial HA and eliminates the gel-fluid phase. This significantly reduces interstitial pressures and leaves primarily free fluid behind, relieving the barrier to drug delivery. These findings argue that quantifying the contributions of free- and gel-fluid phases to hydraulically transmitted pressures in a given cancer will be essential to designing the most appropriate and effective strategies to overcome this important and frequently underestimated resistance mechanism.

Subcutaneous trastuzumab: development of a new formulation for treatment of HER2-positive early breast cancer

Trastuzumab is a monoclonal antibody directed against the human epidermal growth factor receptor 2 (HER2). HER2 is amplified or overexpressed in about 15% of breast cancers and is associated with aggressive disease. Clinical benefits of trastuzumab have been established in the treatment of both early and metastatic HER2-positive breast cancer. Patients with HER2-positive early breast cancer have to be treated with trastuzumab for one year in combination with and sequentially after chemotherapy. This requires that trastuzumab is intravenously infused over 30-90 minutes every 3 weeks for one year which is time-consuming for both the patient and the health care provider. Consequently, a subcutaneous formulation of trastuzumab using a recombinant human hyaluronidase has been developed. Recombinant human hyaluronidase transiently increases absorption and dispersion in the subcutaneous space of large therapeutic proteins, such as monoclonal antibodies, allowing subcutaneous administration of trastuzumab in about 5 minutes. Thus, subcutaneous trastuzumab could represent a new treatment option that could have benefit to both the patient and the health care system. This review focuses on the development of the subcutaneous trastuzumab formulation and analyzes clinical trials assessing the pharmacokinetics, efficacy, and safety of this new formulation.

Reduction in intrasubject variability in the pharmacokinetic response to insulin after subcutaneous co-administration with recombinant human hyaluronidase in healthy volunteers

BACKGROUND

This study was designed to test the hypothesis that co-administration of recombinant human hyaluronidase (rHuPH20) with regular insulin or insulin lispro will reduce intrasubject variability in pharmacokinetic end points compared with lispro alone.

METHODS

Healthy adult volunteers (18-55 years old) were enrolled in this phase 1, randomized, double-blind, crossover study. Subjects were administered two injections, each on a separate occasion, of three treatments during six euglycemic clamps. Treatments were 0.15 U/kg insulin lispro, 0.15 U/kg insulin lispro with 5 μg/mL rHuPH20, and 0.15 IU/kg regular insulin with 5 μg/mL rHuPH20. Insulin formulations were administered at a concentration of 40 U/mL. Serum immunoreactive insulin levels, blood glucose concentration, and glucose infusion rate determinations were made at baseline and for approximately 8 h after study drug administration. Intrasubject variability was assessed using a general linear mixed model with a fixed effect for treatment using a compound symmetric covariance matrix.

RESULTS

Co-injection of rHuPH20 with lispro significantly reduced intrasubject root mean square differences in time to peak serum insulin, time to early 50% peak serum insulin (t(50%)), and time to late t(50%) levels compared with lispro alone. Also, the intrasubject coefficient of variation for percentage of total area under the plasma concentration-versus-time curve for early time intervals compared with lispro alone was reduced. Intrasubject variability for regular insulin with rHuPH20 for most pharmacokinetic parameters was similar to the variability of lispro alone, although variability in early exposure was significantly reduced.

CONCLUSIONS

Co-administration of rHuPH20 with lispro significantly reduced the variability of insulin pharmacokinetics relative to insulin lispro alone.

Review of the mechanism of action and clinical efficacy of recombinant human hyaluronidase coadministration with current prandial insulin formulations

For patients with type 1 or type 2 diabetes, achieving good glycemic control is critical for successful treatment outcomes. As many patients remain unable to reach glycemic goals with currently available rapid-acting analog insulins, ultrafast insulin products are being developed that provide an even faster pharmacokinetic profile compared with current rapid prandial insulin products. The overall strategy of these ultrafast insulin products is to better mimic the normal physiologic response to insulin that occurs in healthy individuals to further improve glycemic control. Recombinant human hyaluronidase (rHuPH20) is a genetically engineered soluble hyaluronidase approved by the U.S. Food and Drug Administration as an adjuvant to increase the absorption and dispersion of other injected drugs; mammalian hyaluronidases as a class have over 6 decades of clinical use supporting the safety and/or efficacy of hyaluronidase coadministration. Clinical findings have demonstrated that coadministration of rHuPH20 with insulin or an insulin analog achieved faster systemic absorption, reduced inter- and intrapatient variability of insulin absorption, and achieved faster metabolic effects compared with injection of either insulin formulation alone. The magnitude of this acceleration is similar to the incrementally faster absorption of prandial insulin analogs as compared with regular insulin. In addition, coadministration of rHuPH20 with regular insulin or insulin analog also improved the achievement of prandial glycemic targets. Thus, rHuPH20 coadministration shows promise as a method of establishing a more rapid insulin profile to prandial insulin in patients with diabetes and has the potential to yield substantial improvements in postprandial glycemic excursion.

Understanding clinical dehydration and its treatment

Dehydration in clinical practice, as opposed to a physiological definition, refers to the loss of body water, with or without salt, at a rate greater than the body can replace it. We argue that the clinical definition for dehydration, ie, loss of total body water, addresses the medical needs of the patient most effectively. There are 2 types of dehydration, namely water loss dehydration (hyperosmolar, due either to increased sodium or glucose) and salt and water loss dehydration (hyponatremia). The diagnosis requires an appraisal of the patient and laboratory testing, clinical assessment, and knowledge of the patient's history. Long-term care facilities are reluctant to have practitioners make a diagnosis, in part because dehydration is a sentinel event thought to reflect poor care. Facilities should have an interdisciplinary educational focus on the prevention of dehydration in view of the poor outcomes associated with its development. We also argue that dehydration is rarely due to neglect from formal or informal caregivers, but rather results from a combination of physiological and disease processes. With the availability of recombinant hyaluronidase, subcutaneous infusion of fluids (hypodermoclysis) provides a better opportunity to treat mild to moderate dehydration in the nursing home and at home.

L'hypodermoclyse : intérêts et indications en gériatrie

PURPOSE

Older people are at high risk of dehydration. Oral intakes are often inadequate routinely. Intravenous infusion may be difficult in these patients and harmful. Subcutaneous infusion or hypodermoclysis is a useful technique for the cure of a moderate dehydration in elderly patients and especially for its prevention. Moreover, this technique is of great interest in end-life patients.

CURRENT KNOWLEDGE AND KEY POINTS

When it is used correctly and when its contraindications are respected (emergency situations), hypodermoclysis is a simple, safe, sure, effective and comfortable technique. It does not need trained supervision and can be used both in an institution and at home, thus avoiding hospitalization of older subjects and reducing health costs. This technique has considerable benefits both psychologically and financially.

FUTURE PROSPECTS AND PROJECTS

The numerous advantages of hypodermoclysis should encourage its wider use in older patients at home as well as in institutions. Moreover, new indications need to be evaluated. In this way, subcutaneous infusion of therapeutics or prevention of protein-energy malnutrition by hypodermoclysis of amino acids need further investigations.

[Hypodermoclysis: a forgotten technique...]

Hypodermoclysis consists of infusing solutions in the subcutaneous tissues. It is a convenient means of correcting a moderate dehydration, notably in elderly people, when oral feeding is impossible or insufficient. The only potential problem with this technique is the occurrence of hypovolaemia due to infusion of hypo- or hypertonic solutions in subjects with previous severe salt and water disorders. For this reason, hypodermoclysis should not be used in emergencies.

Assessment of the viability of skin grafts

A number of tests are available to monitor the blood flow in free and distant pedicle skin grafts. The information from these tests aids in the development of measures to enhance vascularization and is occasionally needed to make clinical decisions in patients with distant pedicle grafts. Measurements of the disappearance of an intradermally injected small amount of 133Xe allows determination of a clearance rate and blood flow before and after clamping the original blood supply through the base. With 99mTc, which is generally more readily available, a flow index and block index can be determined. Clinically both procedures give equally good results in determining a safe time for pedicle base separation. The fluorescein test allows assessment of regional blood flow distribution within the pedicle.

Nutrition by hypodermoclysis

It is possible to administer fluid subcutaneously at a rate so slow that the forces of diffusion and perfusion are able to transfer that fluid to the circulation at a rate equal to the rate of its delivery. In clinical practice, fluid can be delivered subcutaneously in the presence of hyaluronidase at about 1 ml per minute without the accumulation of edema. Thus, 1500 ml can be delivered in 24 hours at a single site, and 3000 ml of fluid can be delivered at two sites in 24 hours. This procedure, called hypodermoclysis, is used for hydration. It is particularly useful for the aged patient in the long-term care institution when it will save the patient from the dangers of hospitalization and save society from its costs.

Value of hyaluronidase in ocular surgical akinesia

In a study of 27 cases of surgery for cataract extraction, mepivacaine 2% with hyaluronidase was found to shorten the induction times of facial nerve and retrobulbar blocks when compared to injections of mepivacaine 2% alone. The mean induction time of facial nerve blocks with hyaluronidase was 1.3 +/- 0.4 minutes. This was significantly (P less than .01) shorter than the mean induction time without hyaluronidase, 2.9 +/- 1.8 minutes. The use of hyaluronidase significantly (P less than .02) shortened the induction time of retrobulbar blocks. The median induction time with hyaluronidase was three minutes, whereas that without hyaluronidase was ten minutes. However, the use of hyaluronidase did not significantly (.25 less than P less than .50) alter the success rate of retrobulbar blocks.