Venous injection

Transcoronary venous injection is performed with a catheter system threaded percutaneously into the coronary sinus. Initial studies in swine have confirmed the feasibility and safety of this approach [121]. This delivery method has also been used to deliver skeletal myoblasts to scarred myocardium in cardiomyopathy patients [120]. With intravascular ultrasound guidance, this approach allows the operator to extend a catheter and needle away from the pericardial space and coronary artery into the adjacent myocardium. To date, human feasibility studies have had a good safety profile. This technique is limited, however, by coronary venous tortuosity, lack of site specific targeting, and its own technically challenging nature. Unlike the transendocardial approach, in which cells are... 

Bleeding at superficial sites, such as venous injection sites, catheter insertion sites, venous cutdowns, arterial punctures, and sites of recent surgical procedures, gingival... 

Rapid venous injection of potassium into the blood stream or intramminal infusion with some form of potassium is extremely toxic because of the rapid absorption. Pigs can tolerate up to 10-fold the potassium requirement, if plenty of drinking water is provided (Faries 1958). 

The compound is also toxic by injection thus for intra-venous injection into rabbits the l.d. 50 in normal saline was about 0-5 mg./kg. Pupil constriction began 2 min. after injec-tion, followed by loss of muscular co-ordination and then by lespiratory collapse. 

Schulte-Altedorneburg G, Demharter J, Linn R et al (2003) Does ultrasound contrast agent improve the diagnostic value of colour and power Doppler sonography in superficial lymph node enlargement Eur J Radiol 48 252-257 Smith MD, Elion JL, McClure RR et al (1984) Left heart opacification with peripheral venous injection of a new saccharide echo contrast agent in dogs. J Am Coll Cardiol 13 1622-1628... 

Fig. 18J7 Still-frame from a cineangiogram foUowing coronary venous injection. A catheter is positioned in the coronary sinus. The faint blush that can be appreciated distal to the catheter tip represents a small amount of contrast material that has extravasated into the myocardial tissue.

Stafford RG, Hines HB (1995) Urinary elimination of saxitoxin after intra-venous injection. Toxicon 33 1501-1510... 

Figure 9 (A) MR images from longitudinal assessment of degeneration of the posterior tibio-tarsal joint of a rat, rendered arthritic by intra-venous injection of a Mycobacterium butyricum suspension at Day 1 (200 MHz, TE/TR = 9/2500 ms, 100 x 100 pm in plane resolution, 1 mm trans-plane resolution). (B) 400 MHz images of excised tibio-tarsal joints from control and adjuvant-arthritic rats, acquired using autosampler technology (TE/TR = 8/1000 ms, 70 x 70 x 250 pm resolution). Reproduced by permission of Dr. Rasesh Kapadia, SB Pharmaceuticals, Upper Merion, PA.

Coulter et al. (2008) Gene therapy Tf-PEG-PEI-CMViNOS plasmid in liposome Mouse hbrosarcoma (RIE-1) Single intra-venous injection of Tf-PEG-PEI-CMViNOS (30 p,g) slowed tumour growth by 50%. 

The direct injection of potent vasodilatory agents such as papaverine or isosor-bide dinitrate, into the ventricles of the heart reverses the action of palytoxin in approximately one-half of the animals. These extreme measures are required because palytoxin kills quickly. Antidotes injected into the venous circulation were not able to reach the heart because the stagnation of venous blood occurs so rapidly that antidotes are simply pooled on the venous side of the circulation and never reach the heart. In these studies isosorbide dinitrate appeared to be approximately twice as effective as papaverine in reversing the toxic effects of palytoxin. 

Fosphenytoin Fosphenytoin is a water-soluble, phospho-ester prodrug of phenytoin that is rapidly converted to phenytoin in the body. It is compatible with most IV solutions and is well tolerated as an IM injection, even with the large volumes associated with loading doses (20 to 30 mL).19 It is dosed in phenytoin equivalents (PE), and it can be infused three times as fast as phenytoin, up to 150 mg PE/minute. The loading dose for patients not taking phenytoin is 15 to 20 mg PE/kg. It can be an advantage to use IM fosphenytoin when IV access cannot be obtained immediately and in patients with poor venous access. Although it has fewer cardiovascular side... 

An important difference between epidural anesthesia and spinal anesthesia is that agents injected into the epidural space may readily enter the blood due to the presence of a rich venous plexus... 

The severity of magnesium depletion and presence of symptoms dictate the route of magnesium supplementation (Table 78-7). Intramuscular magnesium is painful and should be reserved for patients with severe hypomagnesemia and limited venous access. IV bolus injection is associated with flushing, sweating, and a sensation of warmth. 

Almost 30 routes exist for administration of drugs to patients, but only a handfbl of these are commonly used in preclinical safety studies (Gad, 1994). The most common deviation from what is to be done in clinical trials is the use of parenteral (injected) routes such as IV (intravenous) and SC (subcutaneous) deliveries. Such injections are loosely characterized as bolus (all at once or over a very short period, such as five minutes) and infusion (over a protracted period of hours, days, or even months). The term continuous infusion implies a steady rate over a protracted period, requiring some form of setup such as an implanted venous catheter or infusion port. 

The rate of absorption from an SC injection site may be retarded by immobilization of the limb, local cooling to cause vasoconstriction, or application of a tourniquet proximal to the injection site to block the superficial venous drainage and lymphatic flow. In small amounts, adrenergic stimulants, such as epinephrine, will constrict the local blood vessels and, therefore, slow systemic absorption. Conversely, cholinergic stimulants (such as methacholine) will induce very rapid systemic absorption subcutaneously. Other agents may also alter their own rate of absorption by affecting local blood supply or capillary permeability. 

In the case of local administration, lipoplexes are generally retained at the site of injection, with poor dispersion (22). In contrast to small emulsions or neutral liposomes, which immediately appear in the venous outflow perfusate following intratumoral injection, the appearance of cationic liposomes is highly restricted to the injection zone (22). The authors deduced that the determining factor altering the pharmacokinetic properties is not the rate of transfer from the interstitial space to the vascular site but rather the rate of transfer from the injection site to the well-vascularized region (23). 

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