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PubMed2006

Novel delivery system based on complexation hydrogels as delivery vehicles for insulin-transferrin conjugates.

A variety of approaches have been investigated to address the problems associated with oral insulin delivery, but the bioavailability of oral insulin is still low. Insulin is rapidly degraded by the enzymes in the GI tract and is not transported across the epithelial barrier easily. The oral insulin formulation developed in this work makes use of complexation hydrogels for oral delivery of insulin bioconjugates. The insulin bioconjugates synthesized in this work consist of insulin bound to transferrin molecule which can be uptaken by the epithelial cells. The conjugates can increase the permeability of insulin across the epithelial barrier by receptor-mediated transcytosis. The transferrin in the conjugate is also shown to stabilize insulin in the presence of intestinal enzymes. Use of complexation hydrogels for delivery of insulin-transferrin conjugate may greatly increase the bioavailability of oral insulin. This is because, the complexation hydrogels are known to exhibit characteristics that make them ideal candidates for oral protein delivery. They can also inhibit the degradation of insulin in the GI tract. Thus, combination of these two approaches may provide an innovative platform for oral insulin delivery.

Administration, Oral↗

PubMed1984

Comparison of changes in ovine plasma chorionic somatomammotropin concentrations in the fetus and mother before spontaneous vaginal delivery at term and adrenocorticotropin-induced premature delivery.

Fetal and maternal plasma ovine chorionic somatomammotropin concentrations have been measured in eight pregnant ewes immediately prior to spontaneous vaginal delivery at 146 +/- 2 gestational days. In seven additional ewes, fetal and maternal plasma ovine chorionic somatomammotropin concentrations were measured immediately before and during induction of premature delivery by infusion of 1 microgram X hr-1 synthetic adrenocorticotropin (ACTH1-24) to the fetus commencing at either 120 to 122 gestational days (n = 3) or 130 to 132 gestational days (n = 4). Both fetal and maternal plasma ovine chorionic somatomammotropin concentrations fell significantly (p less than 0.05) in the 5 days before spontaneous term delivery; no change in the fetal to maternal ratio for plasma ovine chorionic somatomammotropin concentrations was observed. In contrast, the maternal plasma ovine chorionic somatomammotropin concentration rose (p less than 0.05) during infusion of ACTH1-24 to the fetus while the fetal concentration declined. During infusion of ACTH1-24 to the fetus the fetal to maternal ratio for plasma ovine chorionic somatomammotropin concentrations also fell. The finding that the parallel fall in ovine plasma ovine chorionic somatomammotropin concentrations in the fetus and mother in spontaneous term deliveries is not seen following ACTH-induced premature delivery suggests that mechanisms other than activation of the fetal adrenal axis induce the prepartum fall in ovine chorionic somatomammotropin secretion. These findings militate against a role for the fall in ovine chorionic somatomammotropin in the initiation of parturition.

Adrenocorticotropic Hormone↗

PubMed1998

A comparison of the incidence of breast feeding two and four months after delivery in mothers discharged within 72 hours and after 72 hours post delivery.

OBJECTIVE: To compare breast feeding at two and four months after delivery in mothers discharged early (ED = before 72 hours post delivery) and late (LD = after 72 hours post delivery), and to explore the factors of greatest importance to the successful practice of breast feeding. DESIGN: Ex-post facto design. SETTING: In the country of Härryda, Sweden. PARTICIPANTS: All Swedish speaking women in the country of Härryda whose babies were born between 01.01.94 and 31.05.94 and who were registered at the Child Health Station (CHS) by the age of three months. One hundred and ninety women were invited to participate and 157 (83%) accepted. MEASUREMENTS AND FINDINGS: No significant difference was found in the breast feeding rates between the ED and LD group. However, ED mothers breast fed exclusively to a higher extent at two and at four months (exclusive breast feeding: at two months 89% and 86% respectively, and at four months 84% and 74% respectively, partial breast feeding: at two months 6% and 10% respectively, and at four months 5% and 12% respectively). If the woman considered that she had received encouragement and support while breast feeding for the first time, the probability of her breast feeding at two and at four months were about six times as great (Exp(B) 5.7594, df = 1, p = 0.0270; (Exp(B) 5.9781 df = 1, p = 0.0005 respectively). KEY CONCLUSIONS: The length of the hospital stay had no significant effect on the incidence of breast feeding at two and four months post delivery. The most predominant factors influencing breast feeding were seen to be the mother's first experience of breast feeding and the degree of support, help and encouragement she received. Less than half of the women received a visit from the CHS nurse after their return home from hospital. IMPLICATIONS FOR PRACTICE: The findings suggest that it is important that the midwife or nurse should prepare, support and encourage the mother when breast feeding for the first time. The midwife's or nurse's interventions are important for the incidence of breast feeding, at least during the first four months, and indirectly affect public health. This must also be taken into consideration when caring for mothers in the delivery ward and before discharge, i.e. that the breast feeding is working well, that the mother experiences it as working well, and also for planning follow-up after discharge.

Adolescent↗

PubMed2001

Delivery of endothelial cells to balloon-dilated rabbit arteries with use of a local delivery catheter.

PURPOSE: Experiments were performed to determine if a local delivery catheter could deliver endothelial cells that would be retained on the luminal surface of balloon-dilated arteries. MATERIALS AND METHODS: Six New Zealand White rabbits underwent carotid catheterization, arteriography, and balloon angioplasty of an external iliac artery. A local delivery catheter (Dispatch) was then positioned at the site of angioplasty and the 3-mm balloon was inflated. Cultured rabbit endothelial cells (1.26 +/- 0.3 x 10(6) ), previously stained with fluorescent dye PKH26, were delivered to the artery in three infusions separated by 10 minutes. The delivery balloon was deflated and removed 25 minutes after the last delivery. The arteries were then perfusion-fixed in situ at physiologic pressure, removed, and divided into four segments, and the segments were rapidly frozen and cryosectioned. Eight sections from each arterial segment were examined by means of epifluorescence microscopy. The luminal surface of each artery was visually divided into eight sectors of equal length and each sector was assigned a score based on the degree of endothelial coverage (0 = no coverage, 1 = <50% coverage, 2 = >50% coverage). RESULTS: The endothelial coverage score for the six arteries averaged 0.40 +/- 0.46 (SD; range, 0.04-1.24). Areas of each artery receiving scores of 0, 1, and 2 averaged 68%, 25%, and 7%, respectively. Average coverage scores were 0.42, 0.38, 0.51, and 0.28 for individual segments along the length of the artery. CONCLUSIONS: The Dispatch local delivery catheter is able to deliver endothelial cells that adhere to balloon-dilated arteries. Although the magnitude of cellular retention was modest and varied among arteries, the retention along the length of each artery was constant.

Angiography↗

PubMed1998

Gastric mucosal oxygen delivery decreases during cardiopulmonary bypass despite constant systemic oxygen delivery.

UNLABELLED: Previous studies report a decrease in gastric mucosal oxygen delivery during cardiopulmonary bypass (CPB). However, in these studies, CPB was associated with a reduction in systemic oxygen delivery (DO2). Conceivably, this decrease in DO2 could have contributed to the observed decrease in gastric mucosal oxygen delivery. Thus, in the present study, we assessed the effects of the maintenance of DO2 (at pre-CPB values) during hypothermic (30-32 degrees C) CPB on the gastric mucosal red blood cell flux (GMRBC flux) using laser Doppler flowmetry. In 11 patients requiring cardiac surgery, the pump flow rate during CPB was initially set at 2.4 L x min(-1) x m(-2) and was adjusted to maintain DO2 at pre-CPB values (flow 2.5-2.7 L x min[-1] x m[-2]). Despite a constant DO2, the GMRBC flux was decreased during CPB. These decreases averaged 50% +/- 16% after 10 min, 50% +/- 18% after 20 min, 49% +/- 21% after 30 min, and 49% +/- 19% after 40 min of CPB. The rewarming period was associated with an increase in GMRBC flux. Thus, maintaining systemic DO2 during CPB seems to be an ineffective strategy to improve gastric mucosal oxygen delivery. IMPLICATIONS: In the present study, we tested the hypothesis that gastric mucosal red blood cell flux assessed by laser Doppler flowmetry could be improved by maintaining baseline systemic flow and oxygen delivery during hypothermic cardiopulmonary bypass. Despite this strategy, gastric mucosal red blood cell flux decreased by 50% during hypothermic cardiopulmonary bypass.

Animals↗

PubMed2005

Maternal and perinatal morbidity of caesarean delivery at full cervical dilatation compared with caesarean delivery in the first stage of labour.

To estimate maternal and perinatal morbidity associated with caesarean delivery at full cervical dilatation, a population-based cohort study from 1997 to 2002 was used, which included 1623 nullipara with singleton pregnancies at 37-42 weeks of gestation requiring caesarean delivery in labour. Compared to caesarean delivery at less than full dilatation, women undergoing caesarean delivery at full dilatation were more likely to have complications of intraoperative trauma (RR 2.6, P < 0.001) and infants with perinatal asphyxia (RR 1.5, P < 0.05). There was no difference in maternal or perinatal morbidity when duration of the second stage of labour or when failed assisted vaginal delivery was considered.

Adult↗

PubMed2006

Clinical spectrum of the osmotic-controlled release oral delivery system (OROS), an advanced oral delivery form.

BACKGROUND: The osmotic-controlled release oral delivery system, OROS, is an advanced drug delivery technology that uses osmotic pressure as the driving force to deliver pharmacotherapy, usually once-daily, in several therapeutic areas. OBJECTIVE: The purpose of this review is to discuss the evolution of OROS technology and examine the many therapeutic areas where OROS products are being used. METHODS: A search of Medline and EMBASE were performed using the keywords 'OROS' and 'osmotic delivery' for the period January 1990 to June 2005. Data were also obtained from the manufacturers' websites and associated publications. RESULTS: OROS technology has evolved over the last 30 years, resulting in four systems: the elementary osmotic pump; the two-layer osmotic push-pull tablet; the advanced longitudinally compressed tablet multilayer formulation; and, the L-OROS system. OROS technology is employed for drug delivery in many therapeutic areas including: cardiovascular medicine, endocrinology, urology, and central nervous system (CNS) therapeutics. Two calcium channel blockers utilizing OROS technology for the treatment of hypertension are nifedipine and verapamil. Glipizide extended-release is used for the treatment of type 2 diabetes. Doxazosin is used for the treatment of benign prostatic hyperplasia, and oxybutynin for overactive bladder. Most recent developments are with drugs that affect the CNS, including the use of methylphenidate for treatment of attention deficit hyperactivity disorder, paliperidone extended-release and OROS hydromorphone, which are under clinical development for schizophrenia and chronic pain, respectively. CONCLUSIONS: Drug delivery using the various OROS products can result in an improved safety profile, stable drug concentrations, uniform drug effects, and reduced dosing frequency. OROS technology has also enabled the use of an effective starting dose, without the need for dose titration, which allows the achievement of symptom control much earlier than that observed with immediate-release preparations. Such attributes can enhance patient compliance and convenience, thereby ensuring efficacy and improving patient outcomes.

Administration, Oral↗

PubMed1998

Delivery of inhaled nitric oxide using the Ohmeda INOvent Delivery System.

OBJECTIVES: We evaluated the Ohmeda INOvent Nitric Oxide Delivery System, which uses an inspiratory flow sensor to inject a synchronized and proportional nitric oxide (NO) flow into the mechanical ventilator circuit. This system should deliver a constant NO concentration independent of ventilator mode, minute ventilation, fraction of inspired oxygen, or ventilator brand. It should also minimize nitrogen dioxide (NO2) formation. METHODS: NO delivery by the INOvent and a premixing NO delivery system were compared using two ventilators (Puritan-Bennett 7200 and Servo 900C). NO concentration was measured within the trachea of an attached lung model using a fast-response chemiluminescence NO analyzer. NO concentration was also measured in the inspiratory limb using the electrochemical analyzer of the INOvent. For three NO concentrations (2, 5, and 20 ppm), the ventilators were set for constant flow volume control ventilation, pressure control ventilation, and spontaneous breathing with pressure support ventilation or synchronized intermittent mandatory ventilation. Different tidal volumes (300, 500, 750, and 1,000 mL) and inspiratory times (1 and 2 s) were evaluated. NO2 formation for both ventilators and delivery systems were evaluated at 20 ppm and 95% O2-. RESULTS: Regardless of ventilatory pattern, both systems delivered a constant NO concentration. The error between the target and the delivered NO dose for the INOvent was -1.3+/-3.6% with the Puritan-Bennett 7200 and -3.9+/-4.3% with the Servo 900C. For the premixing system, the error was -5.5+/-4.8% with the Puritan-Bennett 7200 and -6.7+/-6.2% with the Servo 900C. NO2 concentrations were 0.5+/-0.1 ppm during NO delivery by the INOvent, 5.8+/-1.6 ppm when NO was premixed with air, 0.3+/-0.1 ppm when NO was premixed with N2. CONCLUSION: The INOvent provides a constant NO concentration independent of the ventilatory pattern, and NO2 formation is minimal.

Administration, Inhalation↗

PubMed1999

Recent trends in drug delivery systems: intranasal drug delivery.

Nasal route of drug delivery is commonly known for treatment of local ailments like-cold, cough, rhinitis etc. Recently, efforts have been made to deliver various drugs, specially peptides and proteins, through nasal route for systemic use; utilizing the principles and concepts of rate controlled drug delivery and various polymers and absorption promoters. Considering the large number of problems associated with oral, parenteral, rectal and other routes of drug administration and gradual increase in interest of pharmaceutical scientists towards exploring the possibilities of intranasal delivery of various drugs, this article aims at giving an insight into nasal cavity, consideration of factors affecting and strategies to improve drug absorption through nasal route, pharmaceutical dosage forms and delivery systems with examples of some peptides for intra nasal delivery, its advantages and limitations.

Administration, Intranasal↗

PubMedDate not supplied

Instrumental (operative) vaginal deliveries: vacuum extraction compared with forceps delivery at Ilorin University Teaching Hospital, Nigeria.

In a four-year period (1984 to 1987) a total of 141 Nigerian women who had instrumental vaginal deliveries at term in the Obstetric unit of University of Ilorin Teaching Hospital, Ilorin, were studied. Out of this number 79 had forceps delivery while 62 had vacuum extraction. The forceps delivery rate had fluctuated between 0.11% and 0.46% while the vacuum extraction rate had steadily increased from 0.08% to 0.39% (Table 1) in our unit over the 4-year period. With the exception of fetal distress, there were no significant differences found in the indications for forceps delivery and vacuum extraction. The preapplication station, position and cervical dilatation differ in both groups (Table 4). There was less maternal trauma in vacuum extraction than forceps (Table 5). The vacuum extraction was more associated with cephalhaematoma and neonatal jaundice but less with neonatal mortality compared with forceps (Table 7). Vacuum extraction had gradually assumed more prominence as an alternative to midforceps delivery in our unit in the study period. There was no maternal mortality in the two groups.

Adolescent↗

PubMed1997

Non-viral gene delivery: vehicle and delivery characterization.

The development of non-viral gene therapy has been hampered by an inability to reproducibly manufacture and characterize delivery system components and final formulations. Formation of interpolyelectrolyte complexes as the basis of various gene delivery methods has been approached as the first step towards development of synthetic viruses. We have found that preparation of interpolyelectrolyte complexes from disperse reagents gives a more homogeneous gene delivery vehicle than other methods. Methods which increase homogeneity also result in higher transfection efficiency in vivo. Expression levels of human growth hormone and other reporter proteins in mice confirm the potential of parenteral non-viral gene delivery for some therapeutic applications. Serum is demonstrated to inhibit transfection efficiency in vivo. Our results suggest that further development of methods to manufacture homogeneous disperse non-viral delivery vehicles with stealth characteristics may enhance both the potency and reproducibility of gene transfer in vivo.

Animals↗

PubMed1995

Localized drug delivery in atherosclerotic arteries via a new balloon angioplasty catheter with intramural channels for simultaneous local drug delivery.

A dual-purpose angioplasty catheter with intramural channels and exterior pores for local drug delivery ("channeled balloon") was studied in eight atherosclerotic human necropsy arteries and in 22 rabbits with atherosclerotic peripheral arteries, in which markers (0.005 microns to 15 microns) were infused locally at 2 atmospheres during simultaneous angioplasty at 6 atmospheres. Thirteen of the rabbits were sacrificed at 4 or 24 h after procedure to determine the intramural retention over time. Histology confirmed effective angioplasty and revealed presence of markers in the arterial wall in 29 of 43 treated arteries (67%), whereas all control segments without local delivery had no marker staining. majority of the ineffective local delivery (12/14) occurred when 15 micron particles were infused (12/13 arteries without intramural markers), especially when examined 4 or 24 h later. Thus, in atherosclerotic arteries, the channeled balloon enabled simultaneous local drug delivery at low pressure during effective angioplasty, although particle size may play a role in successful intramural impregnation and retention.

Angioplasty, Balloon↗

PubMed1989

Association of episiotomy and delivery position with deep perineal laceration during spontaneous delivery in nulliparous women.

Spontaneous deliveries of 241 nulliparous women were analyzed to test the hypothesis that both episiotomy and use of stirrups for delivery of infants were related to the occurrence of third- and fourth-degree perineal lacerations. These deep perineal tears occurred in 0.9% of the women delivered of infants without the use of either episiotomy or stirrups and in 27.9% of the women delivered of infants with both episiotomy and stirrups. Women exposed to episiotomy alone or to stirrups alone had intermediate rates of laceration. There was no independent correlation of laceration with maternal age, 1- and 5-minute Apgar scores, or midwife or physician as delivery attendant. The results suggest that selective use of episiotomy and stirrups can minimize perineal trauma during spontaneous delivery in nulliparous women.

Adult↗

PubMed1995

Head entrapment and neonatal outcome by mode of delivery in breech deliveries from twenty-four to twenty-seven weeks of gestation.

OBJECTIVES: Our purpose was to determine whether there are differences in the incidence of head entrapment and adverse neonatal outcome by mode of delivery in breech deliveries from 24 to 27 weeks of gestation. STUDY DESIGN: Charts of 132 viable consecutive singleton breech deliveries from 24 to 27 weeks' gestation were reviewed. Statistical methods used included chi 2, logistic regression, and analysis of variance. RESULTS: Head entrapment occurred in four of 43 (9.3%) vaginally delivered neonates and five of 89 (5.6%) neonates delivered by cesarean section (p = 0.17). The only identifiable risk factor for head entrapment was the birth weight category 1000 to 1249 gm (odds ratio 6.4, 95% confidence interval 1.6 to 26.1). There were no statistically significant associations between head entrapment and adverse neonatal outcomes. CONCLUSIONS: There did not appear to be a difference in the incidence of head entrapment by mode of delivery for breech infants at 24 to 27 weeks' gestation, nor did there appear to be a difference in adverse neonatal outcomes after entrapment. However, this latter conclusion has limited power because of the small number of head entrapment cases.

Analysis of Variance↗

PubMed1988

Breech delivery: a critical evaluation of the mode of delivery and outcome of labor.

This is a retrospective study of 213 term, singleton, uncomplicated pregnancies presenting as breech. Thirty-two percent had elective cesarean section and 61% of those selected for vaginal delivery actually did so. Events in labor and fetal outcome suggest that vaginal delivery of a breech infant, after careful feto-maternal assessment, continuous fetal monitoring, adequate progress in labor and delivery by an experienced "midwife", provides comparable fetal outcome to delivery by elective cesarean section.

Adolescent↗

PubMed1994

Umbilical cord venous progesterone at term delivery in relation to mode of delivery.

OBJECTIVE: To determine whether the umbilical cord venous progesterone at term delivery is related to the mode of delivery. METHODS: Thirty-nine pregnant patients at term were divided into three groups: elective cesarean section (control), spontaneous vaginal delivery, and emergency cesarean section. Umbilical cord venous and maternal serum progesterone were measured by radioimmunoassay. Statistical analysis was carried out using Student's t-test, with the level of significance set at P < 0.05. RESULTS: Umbilical cord venous progesterone was significantly higher in babies delivered by emergency cesarean section (P < 0.001) and in those who had spontaneous vaginal delivery (P < 0.02), compared with the control group. Maternal serum progesterone concentrations showed no significant differences between the three groups. The Apgar scores of the stressed group of babies were significantly lower (P < 0.001). CONCLUSION: The findings demonstrate that the fetuses exposed to stress during labor produce higher progesterone secretion. This could be one possible way the fetus protects itself against the sequelae of hypoxia.

Apgar Score↗

PubMed1992

The need for pain relief in uncomplicated deliveries in an alternative birth center compared to an obstetric delivery ward.

The need for pain relief during uncomplicated labour and delivery was studied in 125 women attending an Alternative Birth Center (ABC) and 170 women attending an obstetrical ward. The ABC was staffed only with midwives and assistant nurses who took care of all deliveries. In case of complications the doctor on duty at the obstetrical ward could come in a few minutes and the patient was transferred to the obstetrical ward. At the ABC the delivery room was next to the sleeping rooms and the living room and the woman in labour could have a chat with the women, who had given birth. At the obstetrical ward this was not possible. The delivery rooms were on one floor, and after giving birth the woman was moved to another floor. Women at the ABC were older and had a higher social status than women at the obstetrical ward. Twenty four of the 170 women had initially planned to give birth at the ABC but gave birth at the obstetrical ward due to accommodation restrictions at the ABC. Women refused by the ABC resembled women giving birth at the ABC but their need for pain relief was identical with the other women giving birth at the obstetrical ward. Pain relief with pethidine was 4 times more frequent among women giving birth at the obstetrical ward (18%) than at the ABC (4.8%). Pethidine was predominantly administered to young women and primiparas at the obstetrical ward and to women with prolonged labour at both birthplaces.

Adult↗

PubMed2006

Tissue affinity of the infusate affects the distribution volume during convection-enhanced delivery into rodent brains: implications for local drug delivery.

Convection-enhanced delivery (CED) is a recently developed technique for local delivery of agents to a large volume of tissue in the central nervous system (CNS). We have previously reported that this technique can be applied to CNS delivery of nanoparticles including viruses and liposomes. In this paper, we describe the impact of key physical and chemical properties of infused molecules on the extent of CED-mediated delivery. For simple infusates, CED distribution was significantly increased if the infusate was more hydrophilic or had less tissue affinity. Encapsulation of tissue-affinitive molecules by neutral liposomes significantly increased their tissue distribution. The poorer brain distribution observed with cationic liposomes, due to their greater tissue affinity, was completely overcome by PEGylation, which provides steric stabilization and reduced surface charge. Finally, liposomal encapsulation of doxorubicin reduced its tissue affinity and substantially increased its distribution within brain tumor tissue. Taken together, the physical and chemical properties of drugs, small molecules and macromolecular carriers determine the tissue affinity of the infusate and strongly affect the distribution of locally applied agents. Thus, an increased and more predictable tissue distribution can be achieved by reducing the tissue affinity of the infusate using appropriately engineered liposomes or other nanoparticles.

Animals↗