A.N. Fisher

Stimulation of mucosal and systemic antibody responses against Bordetella pertussis filamentous haemagglutinin and recombinant pertussis toxin after nasal administration with chitosan in mice

Mice were intranasally immunised with a mixture of Bordetella pertussis filamentous haemagglutinin (FHA) and recombinant pertussis toxin, PT-9K/129G (rPT) in combination with chitosan. For both antigens, this formulation induced systemic responses as measured by serum IgG and also mucosal responses as measured by secretory IgA in lung lavage and nasal washes. Immunosorbant assays were used to measure these responses. Both the systemic and mucosal responses were considerably higher than those produced when a mixture of rPT and FHA was administered nasally without chitosan. In comparison, intraperitoneally administered rPT/FHA adsorbed to Alhydrogel elicited only a systemic response, and nasal chitosan solution produced neither systemic nor mucosal response. This study clearly demonstrated that chitosan potentiated the serum and mucosal immune responses to nasally administered FHA and rPT in mice. Hence, this nasal chitosan delivery system has potential as a new non-injectable vaccine for the prophylaxis of whooping cough.

Hyaluronic acid ester microspheres as a nasal delivery system for insulin

Abstract The use of hyaluronic acid ester microspheres for the intranasal delivery of insulin was investigated in sheep. The formulations were based on two types of microspheres produced from the same polymer but using different stabilising agents. Furthermore, the effect of varying the dose of microspheres was also assessed. For comparison, insulin was also administered nasally as a simple solution and subcutaneously as an injectable preparation. Overall, the microsphere system produced large and significant increases in the nasal absorption of insulin similar to what has been obtained for bioadhesive starch microspheres. Generally, the increase in nasal absorption of insulin (AUC and Cmax) achieved by the microsphere system was found to be independent of the dose of microspheres in the range 0.5–2.0 mg/kg. The mean relative bioavailability of the developed system was found to be 11% when compared with insulin administered by the subcutaneous route.

Nasal Absorption Enhancers for Biosynthetic Human Growth Hormone in Rats

The effects of several prospective absorption enhancers were assessed on the nasal absorption of biosynthetic human growth hormone (hGH) in the rat. These enhancers function by alternative mechanisms that include enzyme inhibition, reduction in mucus viscosity, and enhancement of membrane fluidity. The levels of plasma hGH achieved were determined by an enzyme-linked immunosorbent assay. The increase in peak height was calculated relative to nasal administration of hGH alone without any enhancers and the relative bioavailability was calculated with reference to subcutaneous injection data. A lysophospholipid, lysophosphatidylcholine, gave the highest peak concentration, with an increase in peak height of 450% and a relative bioavailability of 25.8%. However, the greatest increase in AUC (291%) was achieved with the aminopeptidase inhibitor, amastatin, which gave a relative bioavailability of 28.9%. A mucolytic agent, N-acetyl-L-cysteine, and a transmembrane fatty acid transporter, palmitoyl-DL-carnitine, were also found to promote the nasal absorption of hGH in this model, with relative bioavailabilities of 12.2 and 22.1%, respectively. Bestatin, an enzyme inhibitor, was not an effective absorption enhancer for hGH in this model.

Gamma-scintigraphy as a novel method to study the distribution and retention of a bioadhesive vaginal delivery system in sheep

Abstract The distribution and the retention time of a novel bioadhesive intravaginal delivery system based on HYAFF microspheres were studied in a sheep model. In a preliminary experiment, the vagina of the ewe was outlined by gamma scintigraphy following vaginal administration of a radiolabelled gel and this data was used as a reference for subsequent evaluation of the distribution of bioadhesive vaginal formulations. Technetium-labelled HYAFF microspheres were administered intravaginally, either as a dry powder or suspended in a vaginal pessary, and the intensity and distribution of radioactivity in the genital tract was determined for a period of 12 h. With both HYAFF formulations, the radiolabelled microspheres were dispersed along the length of the vagina and were retained at this site for the duration of the study. Twelve hours after administration, between 60 and 80% of the radioactivity remained within the vagina with retention of the microspheres being slightly higher for the dry powder formulation than for the vaginal pessary. Importantly, there was no indication of movement of the microspheres from the vagina to the upper levels of the genital tract. These studies further demonstrated the potential of HYAFF microspheres as a long-acting intravaginal delivery system and illustrated the utility of the sheep model and the gamma-scintigraphy methodology for a direct assessment of the distribution, spreading and retention time of bioadhesive formulations.

Cyclodextrins as protection agents against enhancer damage in nasal delivery systems II. Effect on in vivo absorption of insulin and histopathology of nasal membrane

Abstract An in vivo rat model was used to study the nasal absorption of insulin in the presence of selected enhancers (Laureth 9, glycodeoxycholate and L-α-lysophosphatidylcholine) either alone or in combination with 2-hydroxypropyl-β-cyclodextrin or γ-cyclodextrin. All the enhancers when administered alone with insulin produced about 50% decrease in the blood glucose concentrations, an indirect measure of the absorption of insulin across the rat nasal mucosa. In the presence of cyclodextrins the enhancing effect of L9 was maintained, whereas that of GDC and LPC was considerably reduced, but the duration of action of insulin was prolonged. Concomitantly, the histological effect of these agents on the rat nasal epithelium was studied using a perfusion fixation technique. The absorption of insulin did not consistently correlate with the histological observations and the results obtained in previous haemolysis studies. However, the histological and haemolysis observations complemented each other in that the formulations [L9:HPβC (1:4), GDC:γ-CD (1:2) and LPC:HPβC (1:12)] which caused the least damage to the spithelial membrane had been shown to completely prevent haemolysis. In conclusion, the combination of L9 and possibly LPC with cyclodextrins may provide formulations which have almost the required balance between activity and safety, for nasal delivery of insulin and could possibly be used as an adjunct to subcutaneous therapy.

Effect of L-α-lysophosphatidylcholine on the nasal absorption of human growth hormone in three animal species

Abstract The effect of L-α-lysophosphatidylcholine (LPC) on the nasal absorption of human growth hormone (hGH) in anaesthetised rats. conscious rabbits and sheep, has been examined. LPC was shown to be an effective enhancer of nasal hGH absorption in three different animal models. In the rat. concentrations of LPC in the range 0–1.0% co-administered with hGH gave absorption values, relative to subcutaneous administration (S/C), from 2.3 to 16.3%. In the rabbit, concentrations of LPC of 0 and 0.2% co-administered with hGH gave absorption values, relative to S/C. of 1.4 and 72.8% respectively. In the sheep, concentrations of LPC in the range 0–0.59% co-administered with hGH gave absorption values, relative to S/C, from 0.2 to 16.0%. The amount of hGH absorbed was directly proportional to the concentration of LPC co-administered, and in sheep this relationship was linear, with a correlation coefficient of 0.99. The shapes of the plasma concentration vs time curves were similar in all three species.

Nasal administration of morphine-6-glucuronide in sheep--a pharmacokinetic study.

The pharmacokinetics of morphine-6-glucuronide (M6G) after both intravenous dosing and nasal administration were studied in sheep. The nasal formulation consisted of M6G in combination with an absorption promoting delivery system in the form of chitosan. The mean half-life of M6G after intravenous administration was 51.0 +/- 8.2 min and that after intranasal dosing was 45.0 +/- 5.5 min. M6G clearance and volume of distribution were 5.4 +/- 1.5 mL min-1 kg-1 and 0.4 +/- 0.1 L kg-1 respectively. The plasma profile after nasal administration demonstrated rapid absorption of M6G. The bioavailability of M6G in the chitosan formulation was found to be 31.4%. These results suggest that M6G administered in combination with the chitosan delivery system may be considered as a suitable non-parenteral means of administering this analgesic.

Intranasal absorption of granulocyte-colony stimulating factor (G-CSF) from powder formulations, in sheep

Granulocyte-colony stimulating factor (G-CSF) was administered to sheep in three different nasal formulations and as a subcutaneous injection. The nasal formulations were: a solution containing L-alpha-lysophosphatidylglycerol (LPG), a powder formulation comprising small starch microspheres (SSMS) and a powder formulation comprising SSMS and LPG. Absorption of G-CSF was assessed directly by quantitation in plasma and indirectly by measurement of the pharmacodynamic response in terms of leucocyte and neutrophil counts. After the nasal delivery of the G-CSF powder formulation containing SSMS and LPG the absorption of G-CSF was significantly higher (P<0.01) than that from the simple nasal solution or the powder without the enhancer, but the resulting pharmacological response was not significantly different. The bioavailability of G-CSF from the powder formulation containing SSMS and LPG relative to the subcutaneous injection was 8.4% (+/-3.4). We also found that at the respective G-CSF doses investigated, the pharmacodynamic response of this nasal formulation, was similar to that obtained after the subcutaneous administration. The study indicates that the powder formulation containing enhancers could offer an alternative delivery route for G-CSF in the form of intranasal administration.

Intramuscular rate of disappearance of oily vehicles in rabbits investigated by gamma-scintigraphy

The fate of oily vehicles administered intramuscularly was followed with whole body gamma-scintigraphy. Groups of six rabbits received injections administered into the upper hind leg. No differences were observed in disappearance rates of various volumes (50–400 μl) of either fractionated coconut oil or sesame oil. Addition of two different concentrations of a drug substance, zuclopenthixol decanoate, to fractionated coconut oil did not influence the disappearance rate of the vehicle. Half-lives of the two oils at the injection site were in the order of 1 week for fractionated coconut oil and 1 month for sesame oil. Both oils spread approximately 25% along the muscle fibres during the first 24 h after administration. Radioactivity was mainly excreted with the urine. Insignificant amounts of radioactivity were found in blood, liver and carcass after 10 days.

Linguistic Analysis of the Preschool Five Minute Speech Sample: What the Parents of Preschool Children with Early Signs of ADHD Say and How They Say It?

A linguistic analysis was performed on the Preschool Five Minute Speech Sample (PFMSS) of 42 parents. PFMSS is a validated measure for Expressed Emotion (EE) to assess parent-child relationship. Half of these parents (n = 21, clinical group) had preschool children with early symptoms of attention deficit hyperactivity disorder (ADHD), the rest had typically developing children. Early symptoms of ADHD were identified with the Werry-Weiss Peters Rating Scale. The linguistic component of the PFMSS was analysed with keyword and linguistic pattern identification. The results of these two complementary analyses (i.e., EE and linguistic analysis) provided relevant recommendations that may improve the efficacy of psychological treatment for ADHD such as parenting interventions. We discuss the practical implications of these findings.