The formation and high stability of the supersaturated solution were attributable to the specifically formed intermolecular interactions between MFA and EPO.

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Pentazocine (PTZ), a narcotic-antagonist analgesic, is widely used in the management of patients with postoperative pain or initial carcinogenic pain.1) PTZ is a cationic drug having physicochemical properties of high lipophilicity, 2) and immediately reaches the brain in rats when the drug is administered parenterally. 3,4) In rats, brain-plasma concentration ratio is relatively constant, and PTZ concentration in the brain is much higher than that in the corresponding plasma. 5,6) The blood-brain barrier (BBB) appears to have little restricting effect on the uptake of this drug by the brain after parenteral administration in rats.We recently demonstrated that the major factor governing the uptake of PTZ into the brain was not only nonsaturable process but also carrier-mediated transport with a low-affinity saturable process, using the in situ rat brain perfusion technique.7) The advantage of this in situ technique is the high sensitive ability to estimate the kinetic parameters representing the individual rate process. 8,9) Moreover, this technique has greater advantages to the use of perfusate because the composition and flow rate can be adjusted according to the needs of the individual experiments. 8,9) However, this technique is too complex technically, because at least 3 arteries and veins must be ligated before perfusion. 8,9) On the other hand, the carotid injection technique can maintain the cerebral endothelial cells and vasculature of a brain in their normal physiological states and anatomical positions in the animal. Furthermore, the carotid injection technique is technically simpler than the brain perfusion technique. 8,9) Therefore, we investigated the influx transport mechanism of PTZ at the BBB in rats using the carotid injection technique, and compared the results with those from the in situ perfusion technique. The composition of Sosegon ® injection was PTZ (30 mg), lactic acid (12 ml) and sodium chloride (2.8 mg) in 1 ml of distilled water for injection. The PTZ powder used as a free base was from Kobayashi Kako Co., Ltd. (Fukui, Japan), which was used to adjust the drug concentration of the injection solution after dissolving in 0.1 M hydrochloric acid. Xylazine hydrochloride (Sigma Chemical Co., St. Louis, MO, U.S.A.) and ketamine hydrochloride (Ketaral ® 50; Sankyo Co., Ltd., Tokyo, Japan) were used as anesthetics. Amantadine hydrochloride, choline chloride, cimetidine, desipramine hydrochloride, ketotifen fumarate salt, hemicholinium-3, imipramine hydrochloride, lidocaine hydrochloride, mepyramine maleate, naloxone hydrochloride, propranolol hydrochloride and tetraethylammonium chloride (TEA) were purchased from Sigma Chemical Co. (St. Louis, MO, U.S.A.). Diphenhydramine hydrochloride, phenylalanine and HEPES were obtained from Wako Pure Chemical Industries, Ltd. (Osaka, Japan). Procainamide hydrochloride was purchased from Aldrich Chemical Co., Inc. (Milwaukee, WI, U.S.A.). Buprenorphine hydrochloride (Lepetan injection) was purchased from Otsuka Pharmaceutical Co., Ltd. (Tokyo, Japan), bu...

Naloxone, a potent and specific opioid antagonist, has been shown in previous studies to have an influx clearance across the rat blood-brain barrier (BBB) two times greater than the efflux clearance. The purpose of the present study was to characterize the influx transport of naloxone across the rat BBB using the brain uptake index (BUI) method. The initial uptake rate of [(3)H]naloxone exhibited saturability in a concentration-dependent manner (concentration range 0.5 microM to 15 mM) in the presence of unlabeled naloxone. These results indicate that both passive diffusion and a carrier-mediated transport mechanism are operating. The in vivo kinetic parameters were estimated as follows: the Michaelis constant, K(t), was 2.99+/-0.71 mM; the maximum uptake rate, J(max), was 0.477+/-0.083 micromol/min/g brain; and the nonsaturable first-order rate constant, K(d), was 0.160+/-0.044 ml/min/g brain. The uptake of [(3)H]naloxone by the rat brain increased as the pH of the injected solution was increased from 5.5 to 8.5 and was strongly inhibited by cationic H(1)-antagonists such as pyrilamine and diphenhydramine and cationic drugs such as lidocaine and propranolol. In contrast, the BBB transport of [(3)H]naloxone was not affected by any typical substrates for organic cation transport systems such as tetraethylammonium, ergothioneine or L-carnitine or substrates for organic anion transport systems such as p-aminohippuric acid, benzylpenicillin or pravastatin. The present results suggest that a pH-dependent and saturable influx transport system that is a selective transporter for cationic H(1)-antagonists is involved in the BBB transport of naloxone in the rat.

Summary:There is considerable interest in developing banks of frozen umbilical cord blood cells for transplants but it is uncertain how long frozen cells survive. Our objective was to determine the recovery of frozen umbilical cord blood cells. We quantitated recovery of hematopoietic progenitor cells (CFU-GM, BFU-E, and CFU-GEMM) from frozen umbilical cord blood cells stored for up to 12 years. Decay rates of CFU-GM, BFU-E and CFU-GEMM Umbilical cord blood cells are increasingly used for transplant, especially when no HLA-identical sibling donor is available. Consequently, there is growing interest in developing frozen HLA-typed cord blood banks.Umbilical cord blood cells in these banks may be stored for several years before use. However, there are few data on long-term survival of frozen cord blood cells; most reports focus on relatively short storage intervals. 1 We studied viability of hematopoietic progenitor cells in 12 umbilical cord blood samples frozen for up to 12 years. Materials and methodsBetween July 1985 and September 1985, cord blood samples were obtained from the placenta of 12 healthy volunteer mothers at delivery (38 to 41 weeks of gestation). Informed consent was obtained from all. Immediately after delivery of the baby, while the placenta was still in utero, the umbilical cord was double-clamped 6 to 8 cm from the baby and cord blood collected. Before collection, the venepuncture site was cleaned with alcohol and betadine. An 18 gauge needle was inserted into the umbilical vein and cord blood was aspirated into a 50 ml syringe containing 5 ml of ACD. The volume of cord blood collected ranged from 28 ml to 45 ml. The umbilical cord blood was processed using standard techniques. 2 Ficoll-Hypaque (Pharmacia, Uppsala, Sweden) gradient centrifugation was used to isolate the mononuclear cell fraction, which was resuspended at concentration of 2 ϫ 10 7 /ml. Mean (s.d.) mononuclear cell recovery was 48 Ϯ 11%. Umbilical cord blood mononuclear cells were cryopreserved using a programmable freezer (model 801 CryoMed, Mt Clemens, Ml, USA), using standard cryopreservation programs, in RPMI-1640 media, 10% DMSO and 20% fetal calf serum 3 and stored in the liquid phase of liquid nitrogen.Cells were thawed after 1 and 6 months and 1, 2 and 12 years and a small aliquot removed to assess viable cell recovery (trypan-blue exclusion test) and to assay hematopoietic progenitor cells (CFU-GM, BFU-E and CFU-GEMM) by standard techniques. 3 Recovery was calculated by comparing numbers of cells to 1 month values. StatisticsA linear model was applied to the logarithm of cell viability results. Logarithmic transformation was used to stabilize variance in observed recoveries. For a given progenitor cell assay, the model is:Log (viability) ϭ a ϩ b interval cryopreserved when the estimate of slope (b) ϭ 0, there is no trend for cell loss over time. Results were expressed as a decay factor (d) with 95% confidence intervals.Decay over time (k) was calculated as d k .

The involvement of P-glycoprotein (P-gp) in buprenorphine (BNP) transport at the blood-brain barrier (BBB) in rats was investigated in vivo by means of both the brain uptake index technique and the brain efflux index technique. P-gp inhibitors, such as cyclosporin A, quinidine and verapamil, enhanced the apparent brain uptake of [3H]BNP by 1.5-fold. The increment of the BNP uptake by the brain suggests the involvement of a P-gp efflux mechanism of BNP transport at the BBB. [3H]BNP was eliminated with an apparent elimination half-life of 27.5 min after microinjection into the parietal cortex area 2 regions of the rat brain. The apparent efflux clearance of [3H]BNP across the BBB was 0.154 ml/min/g brain, which was calculated from the elimination rate constant (2.52 x 10- 2 min- 1) and the distribution volume in the brain (6.11 ml/g brain). The efflux transport of [3H]BNP was inhibited by range from 32 to 64% in the presence of P-gp inhibitors. The present results suggest that BNP is transported from the brain across the BBB via a P-gp-mediated efflux transport system, at least in part.

A low absorption in the gastrointestinal tract of hydrophobic pharmaceutical compounds in use today considerably limits their bioavailability and therefore they are taken in large doses in order to reach the therapeutic plasma concentration, which inevitably results in undesired side effects. In this study, we demonstrate a new nanoparticle approach to overcome this problem and our experimental results show that this approach has a high efficiency of drug loading and is easily adaptable to industrial scale. Characterization of nanoparticles containing a cholesterol-lowering hydrophobic drug, probucol, using a variety of biophysical techniques revealed higher homogeneity of these particles compared to those prepared using other approaches. Intermolecular interactions of these nanoparticles are probed at a high-resolution by magic angle spinning solid-state NMR experiments.