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At least 217 records · Page 12Linked to original sources
PubMed1996

In vitro permeation study of a mucoadhesive drug delivery system for controlled delivery of nonoxynol-9.

A carbopol 934P-based drug delivery system (AmDDS) was developed to achieve the dual-controlled delivery of Nonoxynol-9 (N-9), a spermicidal agent, and EDTA, a potentiator of spermicidal activity. This gel-type system made intimate contact with vaginal mucosa and maintained an effective drug concentration within the vagina for a prolonged period of time. An existing mathematical model, based on a unilayer diffusion membrane, was applied for describing permeation of N-9 through vaginal mucosa. Vaginal permeation of N-9 from AmDDS was negligible over the initial 5 hr, then increased in a Q versus t pattern, but remained low. A relationship was observed between the permeation rate (Js) of drug through vaginal mucosa and the release flux (Q/t1/2) from AmDDS, which showed that the permeation rate (Js) increased with increased square of the release flux [(Q/t1/2)2] in a hyperbolic manner. This result indicated that release of N-9 from AmDDS is still the rate-limiting step at doses within the tested range. EDTA, at concentration of up to 0.32%, did not change the permeation rate of N-9 through vaginal mucosa. It is thus concluded that the developed AmDDS can control the intravaginal delivery of N-9 as well as its permeation through vaginal mucosa.

Adhesives↗
PubMed2005

[Effects of delivery nursing care using essential oils on delivery stress response, anxiety during labor, and postpartum status anxiety].

OBJECTIVES: This study was designed to investigate the effect of delivery nursing care using essential oils on labor stress response, labor anxiety and postpartum status anxiety for primipara. METHODS: This study used nonequivalent control group pretest-posttest design. The subjects of this experiment consisted of forty eight primipara with single gestation, full term, & uncomplicated pregnancies. Twenty four primipra were in the experimental and control group each. Their mean age was 27.9 years old, their mean gestation period 279.9 days. As a treatment, delivery nursing care using essential oils was applied by nurses. Data collected epinephrine, norepinephrine, anxiety during labor. In the 24 hours after birth, the data for the postpartum mother's status anxiety was collected. Data was analyzed by t-test, repeated measures ANOVA, Mann-Whitney U test, & Wilcoxon signed ranks test with SPSS Program. RESULTS: Plasma epinephrine, norepinephrine were significantly low in the experimental group (P=0.001, P=0.033, respectively). There was no significant difference between the two groups in anxiety during labor and postpartum mother's status anxiety. CONCLUSION: These findings indicate that delivery nursing care using essential oils could be effective in decreasing plasma epinephrine, norepinephrine. But, that could not be verified in decreasing mother's anxiety.

Adult↗
PubMed2002

Targeted drug delivery to the central nervous system via phosphonate derivatives (anionic delivery system for testosterone).

An anionic chemical delivery system (aCDS) has been developed and applied to deliver testosterone (T) to the central nervous system (CNS). The delivery of a target compound is achieved through the use of a specific targetor moiety which is an (acyloxy)alkyl-phosphonate-type functional group. The T-aCDS readily penetrates biological membranes by passive transport due to its increased lipophilicity and enters the target organ. Hydrolytic cleavage by esterases provides a negatively charged, hydrophilic intermediate phosphonate compound (TP-), which is "locked in" the CNS and should provide sustained, site-specific release of the drug. In vitro and in vivo investigations in rats showed that methyl-pivaloyloxymethyl-17-testosterylphosphonate (T-aCDS) might function as an anionic chemical delivery system of testosterone. The concentration of T-aCDS decreased fairly rapidly in vitro. The half-lives (t1/2) in different organs are as follows: blood 4.48 min (r = 0.9388), lung 5.53 min (r = 0.9661), liver 2.82 min (r = 0.9498), and brain 7.37 min (r = 0.9972). Simultaneously with the disappearance of T-aCDS, testosterone-phosphonate (TP-) appeared as a main metabolite in increasing concentration. In vivo evaluations (tail vein 11.3 mg/kg in DMSO) found maximum T-aCDS brain levels 5-10 min after administration; they fell under the borderline of detectability (< 0.1 microgram/g) after 60 min. Maximum concentration of the decomposition product (TP-) was obtained at 30 min after administration; it did not decrease significantly during the study. Even if the phosphonate derivative of the secondary, hindered hydroxyl group in this product was fairly resistant to phosphorolytic attack, the design principle can work for other compounds.

Animals↗
PubMed2005

Integrated delivery systems focus on service delivery after capitation efforts stall.

Integrated delivery systems focus on service delivery after capitation efforts stall. Integrated delivery systems are going through changes that are focusing the provider organizations more on delivering care than managing risk, says Dean C. Coddington, one of the leading researchers into capitated organizations and a senior consultant with McManis Consulting in Denver.

Advertising↗
PubMed1990

[Delivery in the scarred uterus. Apropos of 606 cases in 62,193 deliveries].

Scarred uterus represent 1 p. cent of the deliveries in our department (n = 606). Delivery is performed vaginally in 61 p. cent of the cases and by caesarean section in 39 p. cent of the cases. During two 4-year periods (1981-1984 and 1985-1988), the rate of repeated caesarean sections increases from 36 to 41 p. cent with decrease of the number of uterine ruptures which however, persists (almost 5 p. cent of scarred uteruses). The type of scarring is the major risk factor with: segmental scarring (1.5 p. cent of ruptures), gynecological (5 p. cent), segmento-corporeal (26 p. cent) and corporeal (33 p. cent). Strict obstetrical monitoring permits to control this risk (25 p. cent of ruptures occur at home). It is the uterine rupture that determines the maternal risk (3 death scarred uteruses represent almost 40 p. cent of uterine ruptures 11) and result in 3 p. cent of the maternal mortality in the department. The perinatal mortality is 63.6 for 1,000. A dynamic test of the uterus requires an obstetrical decision taking into consideration the scar, essentially segmental transverse, the head delivery with favorable cephalo-pelvic comparison and a well-trained team. This choice is dictated by the maternal risk of caesarean section, 2 for 1,000 in Europe (14) and for 1,000 in the department and a persistent high mortality in children (97 for 1,000 in Gabon).

Cesarean Section↗
PubMed1987

Emergency delivery: prehospital care, emergency department delivery, perimortem salvage.

The incidence of high-risk conditions complicating pregnancy is greater than one would suspect. Many times a pregnancy does not become high risk until labor starts. Prehospital and Emergency Department protocol should be directed at getting the mother to the labor and delivery suite as soon as possible. Most complications resulting in maternal-fetal morbidity and mortality are handled best in that setting. Prehospital and Emergency Department personnel should, however, be prepared to handle imminent delivery because it cannot be avoided when it occurs. Emergency Department personnel also should be familiar with the technique of perimortem cesarean delivery and use this technique when indicated for fetal-maternal salvage.

Cesarean Section↗
PubMed1996

Mechanisms of delivery and local drug delivery technologies.

Therapy of atherosclerotic vascular disease and neointimal hyperplasia after percutaneous interventions remain enigmatic. Despite new interventional devices, we have not altered the underlying pathological process. New devices are under development that offer the opportunity to deliver high concentrations of therapeutic agents directly to the diseased segment. The devices fall into three major mechanisms of delivery (1) diffusion, (2) infusion under pressure and (3) mechanical delivery. Diffusion catheters are atraumatic but require prolonged exposures in excess of 20 min while the pressurized infusion and mechanical catheters are more traumatic. Additionally, each system will need to be characterized with respect to efficiency of delivery with each agent used. The clinical opportunity for site-specific treatment of vascular disease is rapidly approaching. In the near future we will be able to open a narrowed vessel and also apply some agent into the lesion to facilitate healing.

Animals↗
PubMed2000

Transdermal drug delivery using electroporation. I. Factors influencing in vitro delivery of terazosin hydrochloride in hairless rats.

The use of electroporation pulses as a physical means of enhancing the permeability of skin to deliver drugs is in the early stages of development. In this article, a systematic study examining the parameters influencing electroporative transdermal delivery of terazosin hydrochloride to hairless rat skin are reported. It was found that voltage, pulse length (tau), and number of pulses were the three most important parameters, in that order. For creating a significant enhancement in drug delivery to the skin, without causing any apparent change in its external appearance, it was necessary to deliver five or more exponentially decaying electroporation pulses, at 88 +/- 2.5 V (voltage across the skin), with a decay time constant of 20 ms. Electrodes with larger area could attain the same voltages across the skin with a much lower applied voltage and possessed other advantages with regard to performance of the drug delivery system.

Administration, Cutaneous↗
PubMed1985

Bioadhesive polymers as platforms for oral controlled drug delivery III: oral delivery of chlorothiazide using a bioadhesive polymer.

Bioadhesive polymers that bind to the gastric mucin or epithelial cell surface are useful in drug delivery for the purposes of (a) retaining a dosage from in the GI tract and (b) increasing the intimacy and duration of contact of drug with the absorbing membrane. Polycarbophil has previously been shown to have bioadhesive properties in the rat stomach and small intestine and was employed in the present study with a sustained-release delivery system to demonstrate improved drug delivery. Using chlorothiazide as the model drug, drug containing albumin beads were prepared and used as the sustained-release system. The beads were physically mixed with equally sized particles of polycarbophil and placed in a capsule to produce a bioadhesive dosage form. When the dosage form contacts the stomach, the gelatin capsule dissolves, exposing the polycarbophil to the bathing fluid. The bioadhesive polymer rapidly hydrates, retaining the albumin beads and attaching to the mucin coating of the stomach. Plasma drug levels in rats showed a longer duration of action and greater bioavailability for the bioadhesive dosage form than for either albumin beads or drug powder alone. The results suggest that the principle of bioadhesion can significantly improve therapy, due to a reduced rate of gastric emptying, an increase in contact time, and the intimacy of contact of the drug with the absorbing membrane.

Acrylic Resins↗
PubMed1991

A kinetic method for measuring functional delivery of amphotericin B by drug delivery systems.

The human toxicity of amphotericin B can be considerably reduced by associating the drug with liposomes of varying lipid compositions. Some lipid compositions are much more effective than others. We show that a simple kinetic fluorescence assay using pyranine as an indirect probe of amphotericin-induced K+ currents may be used to study different liposomal drug delivery systems in vitro. We find that lipid mixtures composed of DMPC/DMPG/amphotericin at a 7:3:1 mole ratio show very slow functional delivery with a preference for ergosterol over cholesterol-containing membrane vesicles. On the other hand, amphotericin delivered from egg phosphatidylcholine liposomes lead to 100-fold increases in K+ leakage at one-fifth the amphotericin concentration of the 7:3:1 system. The egg phosphatidylcholine system as well as micellar amphotericin also show a slight selectivity towards cholesterol-containing vesicles over ergosterol. These results are consistent with previous clinical and in vitro cellular studies and this technique may prove valuable in screening of other delivery systems.

Amphotericin B↗
PubMed1987

Intraperitoneal delivery of monoclonal antibodies: enhanced regional delivery advantage using intravenous unlabeled anti-mouse antibody.

Radiolabeled monoclonal antibodies (MAb) delivered intraperitoneally expose cells in contact with peritoneal fluid to considerably higher levels of MAb than if the MAb dose were given intravenously. This regional delivery advantage for intact MAb is present mainly due to the relatively slow exit of MAb from the peritoneal fluid to the blood. Eventually, following i.p. injection, blood levels of MAb rise resulting in exposure of the animal to high systemic MAb levels and potential toxicity. In this series of experiments, systemic exposure was minimized by the administration of unlabeled goat polyclonal anti-mouse antibody intravenously from 1 1/2 to 6 h following i.p. MAb injection. This maneuver results in the formation of immune complexes with their subsequent clearance and dehalogenation by the reticuloendothelial system, thus minimizing systemic MAb exposure. This approach, of increasing systemic clearance of MAb, did not alter intraperitoneal MAb levels and thus significantly increased the regional delivery advantage to the peritoneal cavity by 70-100%. This approach provides an immunologic rationale for the further enhancement of MAb delivery to i.p. foci of malignant disease and may have diagnostic and therapeutic utility.

Animals↗
PubMed2005

Plasma CRH measurement at 16 to 20 weeks' gestation does not predict preterm delivery in women at high-risk for preterm delivery.

OBJECTIVE: The purpose of this study was to examine the utility of a single second-trimester plasma corticotropin-releasing hormone measurement as a marker for preterm delivery in women at high risk for preterm delivery. STUDY DESIGN: This is an analysis of data from a multicenter placebo-controlled trial designed to evaluate the role of 17 alpha hydroxyprogesterone caproate (17P) in the prevention of recurrent preterm birth. Women with a documented history of a previous spontaneous preterm birth at <37 weeks were enrolled (16-20 wks) and randomly assigned in a 2 to 1 ratio to weekly injections of 17P or matching placebo. Blood was collected before treatment in 170 patients (113 assigned 17P and 57 placebo) who were enrolled at 11 of the 19 centers. Plasma levels of corticotropin-releasing hormone were compared between those who delivered preterm and those delivering at term. Data were analyzed using the Wilcoxon rank-sum test. RESULTS: The overall rates of preterm birth in this cohort of 170 patients were 35.9% at <37 weeks (31.9% progesterone, 43.9% placebo), and 19.4% at <35 weeks (18.6% vs 21.1%). The median levels of corticotropin-releasing hormone were similar between those delivering at <37 weeks and those delivering > or = 37 weeks (0.39 ng/mL vs 0.37 ng/mL, P = .08). In addition, there were no differences in corticotropin-releasing hormone levels among those who delivered at <35 weeks or > or = 35 weeks (0.36 vs 0.38, P = .90). Moreover, there were no differences in corticotropin-releasing hormone levels among those in the placebo group who delivered at <37 or > or = 37 weeks (0.40 vs 0.41, P = .72) and at <35 or > or = 35 weeks (P = .64). CONCLUSION: A single measurement of corticotropin-releasing hormone at 16 to 20 weeks' gestation is not a good biomarker for recurrent preterm delivery in patients at high risk for this complication.

Adult↗
PubMed2005

Sustained delivery of bioactive cytokine using a dense collagen gel vehicle collagen gel delivery of bioactive cytokine.

OBJECTIVE: The use of cytokines as localized therapeutic agents is limited by the lack of a satisfactory delivery system. The aim of the current investigation was to determine the release kinetics and bioactivity of a simplified cytokine/collagen gel system designed to achieve extended, local delivery of bioactive cytokines at sites of premature cranial suture fusion (craniosynostosis). DESIGN: Cytokine release was determined by ELISA measurements of Tgf-beta3 collected in media. Cytokine bioactivity was determined by measuring the effect of conditioned media, containing released Tgf-beta3, on mink lung epithelial cell proliferation and osteoblast alkaline phosphatase activity. Osteoblast response was evaluated by measuring proliferation of cells cultured on collagen gel containing Tgf-beta3 using an AlamarBlue assay. RESULTS: Gels loaded with 100 and 500 ng of Tgf-beta3 produced a sustained release over 14 days with a pattern of initial large release followed by a gradual reduction in the amount released over the time. The reduced release over time was correlated to the amount initially loaded. Mink lung epithelial cell assay results indicated that Tgf-beta3 released from the collagen gel retained its bioactivity following incorporation into the collagen gel and release into the media. This bioactivity was further illustrated by a decreased alkaline phosphatase activity measured in osteoblasts cultured on the gels loaded with Tgf-beta3. Osteoblast proliferation assays demonstrated that the collagen gel has an inherent inhibitory effect on osteoblast cell number. CONCLUSIONS: This collagen gel/cytokine delivery system can retain and release bioactive cytokine over a prolonged period. These results will allow for better optimization of future in vitro and in vivo studies directed at improving the treatment of craniosynostosis.

Alkaline Phosphatase↗
PubMed2005

AAV2-mediated gene delivery to monkey putamen: evaluation of an infusion device and delivery parameters.

In this study, a modified infusion procedure and a novel infusion device designed for use in humans (Clinical Device B) were evaluated for delivery of recombinant adeno-associated virus (AAV2) to brain. The device is composed of 1.2 m of fused silica inserted through a 24.6-cm surgical steel cannula designed to fit a standard Leksell clinical stereotaxic frame and micro-infusion syringe pump. AAV2 encoding the human aromatic l-amino acid decarboxylase gene (AAV-hAADC-2) was infused into the putamen of 4 normal rhesus monkeys as a supportive study for a clinical trial in Parkinson's disease (PD) patients. Two infusion protocols were tested: a ramped procedure (slow stepwise increases in rate from 0.2 muL/min to 1 muL/min), thought to be essential for convection-enhanced delivery (CED), and a non-ramped infusion at a constant rate of 1 muL/min. The primary endpoints were safety evaluation of the infusion procedures and assessment of transgene expression at 5.5 weeks post-infusion. Clinical observations after vector infusions revealed no behavioral abnormalities during the study period. No differences in gross pathology with either the ramped or non-ramped infusion procedure were observed. Histopathology of the putamen was comparable with both procedures, and revealed only minimal localized inflammatory tissue reaction along the needle track in response to cannula placement and vector infusion. AADC immunohistochemistry demonstrated that vector was distributed throughout the putamen, with no significant difference in volume of immunostaining with either infusion procedure. Serum antibody levels against AAV2 vector exhibited a minor increase after infusion. These results validate the clinical utility of this new infusion device and non-ramped infusion conditions for intraputamenal gene therapy, and have the potential to impact a number of human diseases in which delivery of therapeutics to brain is indicated.

Animals↗
PubMed1997

Vaginal delivery of new formulations of nonoxynol-9 coprecipitated with polyvinylpyrrolidone in rabbits. Comparisons between two formulation delivery systems.

The objective of this study was to assess the efficacy of two formulation delivery systems (FDS) in preventing the onset of pregnancy in rabbits. Nonoxynol-9 (N-9) was coprecipitated with polyvinylpyrrolidone (PVP), which yields PVP/ N-9, and prepared as capsules or tablets. Semen specimens were collected (from eight male rabbits), pooled, and used for in vitro spermicidal assessment or artificial insemination (AI). In vitro spermicidal assessment was performed by introducing and mixing the FDS containing PVP or PVP/N-9 with 1.0 mL of semen, followed by incubation at 37 degrees C for 6 h. Semen samples were taken at various time intervals to determine killing of spermatozoa and dissolution of the FDS. The efficacy of the FDS in preventing the onset of pregnancy was assessed by inserting the FDS vaginally. The does were artificially inseminated at 0, 0.5, and 6 h after insertion of the FDS vaginally. The number of pregnant does and newborn rabbits was recorded. In the in vitro spermicidal trial, semen specimens exposed to both FDS containing PVP/N-9 were killed within 10 to 15 min of incubation. Tablets containing PVP only or PVP/N-9 dissolved completely after 3 h of incubation. However, capsules did not dissolve completely by 6 h of incubation. The results obtained in the in vivo trial showed that both FDS exhibited some variations in preventing the onset of pregnancy over the various time intervals following the insertion of tablets or capsules and AI. The tablet seemed to be a more efficient delivery system than the capsule, yielding significantly lower pregnancy rates at all three time intervals assessed. The tablet FDS, as applied in this study, was found to be the most efficient mode of delivery of the tested spermicidal formulations.

Administration, Intravaginal↗
PubMed1988

Improved delivery through biological membranes. 32. Synthesis and biological activity of brain-targeted delivery systems for various estradiol derivatives.

Brain-targeted delivery systems based on the dihydropyridine in equilibrium pyridinium salt redox interconversion were synthesized for estradiol, estradiol 3-benzoate, and ethynylestradiol. Initial biological evaluation indicated that while all four compounds synthesized exerted central estrogenic activity as measured by serum LH suppression, only the delivery systems based on the 17-substituted estradiol and ethynylestradiol demonstrated prolonged action (greater than 12 days). The 17-(1-methyl-1,4-dihydronicotinic acid ester) of ethynylestradiol behaved in a similar manner to the previously described estradiol analogue in various assays. Tissue distribution studies in rats showed that administration of the ethynylestradiol derivative resulted in high sustained levels of the corresponding pyridinium salt in the central nervous system (CNS) while blood levels of the oxidized metabolite rapidly fell. The sustained brain levels were associated with a prolonged release of ethynylestradiol. By 24 h, posttreatment, no ethynylestradiol was found by HPLC in the blood while levels of over 20 ng/g of tissue were detected in the CNS. This enhanced central delivery gave a dose- and time-dependent LH suppression, which indicated a three- to fivefold increased potency compared with the corresponding estradiol derivative.

Animals↗
PubMed2000

Assessing the impact of heat on the systemic delivery of fentanyl through the transdermal fentanyl delivery system.

OBJECTIVES: To examine the effects of locally applied heat on the systemic delivery of fentanyl through the Transdermal Fentanyl Delivery System. DESIGN: Open, 2-period crossover randomized study conducted in the anesthesia department of a university teaching hospital. METHOD: Six healthy adult volunteers received a fentanyl 25-microg/h patch with and without local heat for 240 minutes followed by administration without heat for an additional 20 hours. Participants then crossed over. Venous blood was drawn at baseline and hourly for 24 hours. Peak plasma concentration (CMax) of fentanyl was measured and the area under the curve (AUC) of the plasma fentanyl concentration versus time post administration graph was evaluated. RESULTS: Difference in CMax and AUC were not statistically significant over the entire 24-hour study period. However, for the 4-hour period of heat application statistically significant differences were seen in both mean CMax (heat, 0.4 ng/mL versus no heat, 0.1 ng/mL (P =.030)) and mean AUC (heat, 40 ng/mL x min versus no heat, 10 ng/mL x min (P =.010)). CONCLUSION: Local heat can speed the onset of steady state fentanyl concentration in the Fentanyl Transdermal Drug Delivery System thus limiting the delay in onset of analgesia and allowing earlier identification and treatment of side effects.

Clinical Trial↗
PubMed2002

Delivery of the macrosomic infant: cesarean section versus vaginal delivery.

The macrosomic fetus of a diabetic woman faces increased risk for injury at the time of birth. Cesarean section offers the potential for avoiding trauma to the fetus, but can result in increased morbidity in the mother as compared to vaginal delivery. In this article, the advantages and disadvantages of the 2 routes of delivery for the overgrown fetus of a diabetic mother are discussed. In addition, methods for diagnosing macrosomia by ultrasound are examined, along with the benefits and pitfalls of ultrasonic fetal weight estimation in the setting of diabetes. Finally, management approaches for selecting route of delivery for the macrosomic fetus are described and analyzed.

Cesarean Section↗