| 1. |
- Söderberg, Lars, et al.
(författare)
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In-vitro release of bupivacaine from injectable lipid formulations investigated by a single drop technique--relation to duration of action in-vivo.
- 2002
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Ingår i: Journal of Pharmacy and Pharmacology. - 0022-3573. ; 54:6, s. 747-755
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to develop an in-vitro release method suitable for injectable slow-release lipid formulations of local anaesthetics (or other drugs). We also aimed that the results of the in-vitro measurements should have a clear relationship to duration of action in-vivo. Six formulations of bupivacaine base in medium-chain triglyceride-glyceryl dilaurate mixtures were developed. A new apparatus was constructed for determination of their in-vitro release profiles. A bulbous glass tube was fixed inside a standard glass bottle, which was then filled with release medium. A stirring magnet was enclosed in the perforated polypropylene cylinder holding the glass tube. The stirring created a continuous, rotating downward flow of medium inside the tube, which kept the lipid phase, introduced by means of a syringe, suspended as a single, free drop. Release profiles were obtained by sampling of the release medium for up to 72 h and analysis by gas-liquid chromatography. The duration of action in-vivo of the respective formulations was tested by the hot-plate method in rats. The release profiles of bupivacaine in-vitro were mono-exponential for four formulations and bi-exponential for the other two. There was a positive correlation between the proportion of glyceryl dilaurate in the formulation and the slow half-life of release of bupivacaine. All formulations showed prolonged duration of action in-vivo, median values within the range 4.5-12 h, as compared with a 2-h effect of bupivacaine hydrochloride solution. A comparison of in-vitro release curves and durations of action in-vivo suggested that to maintain nerve blockade in-vivo the formulations must release bupivacaine at a rate of approximately 350 mug h-1 under the in-vitro conditions. To conclude, we designed and tested a novel apparatus for measuring release of a local anaesthetic (or other drug) from a fluid or semi-solid formulation in-vitro. Release rates obtained in-vitro by means of this technique may be used to guide the development of formulations with suitable durations of action in-vivo. The apparatus is, however, as yet a prototype. Rigorous evaluation of performance should be carried out on devices built to specific standards according to their intended application.
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| 2. |
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| 3. |
- Callréus, Torbjörn, et al.
(författare)
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The influence of lithium on the antidiuretic effect of desmopressin.
- 2002
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Ingår i: Journal of Pharmacy and Pharmacology. - 0022-3573. ; 54:9, s. 1279-1285
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to investigate the graded influence from lithium on the antidiuretic effects of desmopressin. Eight healthy male subjects participated in this open, randomised cross-over study with two periods comprising 6 days each. For each subject, one of the study days (6th day) was preceded by a period of lithium treatment. On the study days the subjects were orally water loaded to achieve a state of overhydration with a high urine flow rate. When a steady-state diuresis was achieved after approximately 2 h, 0.396 microg of desmopressin was administered intravenously as a bolus injection. An indirect-response model, where desmopressin was assumed to inhibit the elimination of response, was fitted to the urine osmolarity data. The effects of the independent variables, Uflow(baseline) (baseline urine flow rate), R0 (baseline osmolarity) and serum lithium concentration, on IC50 (concentration producing 50% of the maximum inhibition) could be expressed by multiple linear regression. In conclusion, we found that an indirect-response model can be a useful tool in investigating and describing the pharmacodynamic interaction between drugs, in this particular case, between lithium and desmopressin.
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| 4. |
- Karlsson, Britt M., et al.
(författare)
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The effect of the calcium antagonist nimodipine on the detoxification of soman in anaesthetized rabbits.
- 1997
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Ingår i: Journal of Pharmacy and Pharmacology (JPP). - : Oxford University Press (OUP). - 0022-3573 .- 2042-7158. ; 49:3, s. 296-300
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Tidskriftsartikel (refereegranskat)abstract
- The effect of nimodipine, a vasoactive calcium antagonist, on the disappearance of soman from blood was studied in anaesthetized rabbits intoxicated with soman (10.8 micrograms kg-1 i.v.). Blood samples from the left heart ventricle and femoral artery were used to investigate soman detoxification. The concentrations of the soman isomers C+P- and C-P- in blood samples were determined by gas chromatography coupled with high-resolution mass spectrometry. During the sampling, 15-300 s after soman injection, the soman concentration in control animals decreased from 50 to 0.029 ng mL-1; in animals pre-treated with nimodipine (10 mg kg-1) it decreased from 15 to 0.033 ng mL-1. In animals pre-treated with nimodipine the soman concentration was significantly reduced during the first minute of sampling. No differences were detected between soman concentrations in samples from the heart and femoral artery. Acetylcholinesterase inhibition was also used as an indicator of soman activity; there was no difference between the activity of this enzyme in different peripheral organs of control and nimodipine-treated animals. Nimodipine reduces the initial concentration of soman in the blood, which might be of significance in the treatment of soman intoxication.
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| 5. |
- Mercke Odeberg, Johanna, et al.
(författare)
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A pharmacokinetic and pharmacodynamic study of desmopressin: evaluating sex differences and the effect of pre-treatment with piroxicam, and further validation of an indirect response model.
- 2004
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Ingår i: The Journal of pharmacy and pharmacology. - : Oxford University Press (OUP). - 0022-3573 .- 2042-7158. ; 56:11, s. 1389-98
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Tidskriftsartikel (refereegranskat)abstract
- Desmopressin is a synthetic vasopressin analogue mainly used in treatment of diabetes insipidus and nocturia. Studies in rats have revealed a sex difference in the response to a vasopressin infusion, which was diminished after treatment with an NSAID. This study was performed in man to investigate the influence of sex and concomitant treatment of piroxicam on the pharmacokinetics and dynamics of desmopressin, and to validate a previously described indirect response model. Eight healthy males and eight healthy females participated in the trial, which was conducted in a pharmacokinetic (PK) part followed by a pharmacodynamic (PD) part. Desmopressin was administered intravenously as a single dose (PK = dose 2 microg, PD = dose 0.2 microg). Piroxicam was administered to achieve steady state. The pharmacokinetic parameters of desmopressin were estimated and calculated by means of two-compartmental analysis. In the dynamic part a study design based on an oral hydration model was used. Parameters for urine flow and urine osmolality were estimated. Individual estimates of the pharmacokinetic parameters served as input to the indirect response model that subsequently was fitted to urine osmolality data. The pharmacokinetics of desmopressin after a fixed bolus injection was neither influenced by piroxicam nor sex of the subject. The pharmacodynamics of desmopressin showed a sex difference where females exhibited a more pronounced antidiuretic effect than males, which was statistically significant when the effects were submaximal (>4.5 h after dose). The sex differences were diminished after pre-treatment with piroxicam, indicating a prostaglandin PGE(2)-mediated mechanism. The indirect response model was confirmed, although the modelling could not distinguish a sex difference, indicating a limitation of this model compared with traditional descriptive statistics.
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| 6. |
- Morales, Javier O., et al.
(författare)
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Protein-coated nanoparticles embedded in films as delivery platforms
- 2013
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Ingår i: Journal of Pharmacy and Pharmacology (JPP). - : Oxford University Press (OUP). - 0022-3573 .- 2042-7158. ; 65:6, s. 827-838
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: This work aimed to evaluate the performance of nanoparticle-loaded films based on matrices of polymethacrylates and hydroxypropylmethylcellulose (HPMC) intended for delivery of macromolecules.METHODS: Lysozyme (Lys)-loaded nanoparticles were manufactured by antisolvent co-precipitation. After size, loading efficiency and stability characterization, the selected batch of particles was further formulated into films. Films were characterized for mechanical properties, mucoadhesion, Lys release and activity after manufacture.KEY FINDINGS: We found that protein-coated nanoparticles could be obtained in USP phosphate buffer pH 6.8. Particles obtained at pH 6.8 had a z-average of 347.2 nm, a zeta-potential of 21.9 mV and 99.2% remaining activity after manufacture. This formulation was further studied for its application in films for buccal delivery. Films loaded with nanoparticles that contained Eudragit RLPO (ERL) exhibited excellent mechanical and mucoadhesive properties. Due to its higher water-swelling and solubility compared with ERL, the use of HPMC allowed us to tailor the release of Lys from films. The formulation composed of equal amounts of ERL and HPMC revealed a sustained release over 4 h, with Lys remaining fully active at the end of the study.CONCLUSIONS: Mucoadhesive films containing protein-coated nanoparticles are promising carriers for the buccal delivery of proteins and peptides in a stable form.
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| 7. |
- Alhalaweh, Amjad, et al.
(författare)
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Formation of cocrystals by spray drying
- 2010
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Ingår i: Journal of Pharmacy and Pharmacology (JPP). - : Oxford University Press (OUP). - 0022-3573 .- 2042-7158. ; 62:10 - Special issue, s. 1332-1333
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Spray drying is a widely used technique for material processing and scale-up. The cocrystals formation by spray drying is studied. In contrast to solvent evaporation method, spray drying of stiochiometric solutions of incongruently saturating cocrystals had generated pure cocrystals. The formation phenomena in spray drying could be kinetically controlled or mediated by glassy state.
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| 8. |
- Berggren, S, et al.
(författare)
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Regional transport and metabolism of roivacaine and its CYP3A4 metabolite PPX in human intestine
- 2003
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Ingår i: Journal of Pharmacy and Pharmacology. - : Oxford University Press (OUP). - 0022-3573 .- 2042-7158. ; 55:7, s. 963-972
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Tidskriftsartikel (refereegranskat)abstract
- The major aim of this study was to investigate the CYP3A4 metabolism and polarized transport of ropivacaine and its metabolite 2',6'-pipecoloxylidide (PPX) in tissue specimens from the human small and large intestine. Ropivacaine has been shown to be effective in the treatment of ulcerative colitis in human colon. This study was conducted using a modified Ussing-chamber technique with specimens from jejunum, ileum and colon collected from 11 patients. The local kinetics of ropivacaine and PPX were assessed from their concentration-time profiles in mucosal and serosal compartments. The permeability (P-app) in the absorptive direction for both ropivacaine and PPX increased regionally in the order jejunum
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| 9. |
- Björkman, Sven, et al.
(författare)
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Thermic and tremorogenic effects of thyroliberin (TRH) in reserpine-treated mice--the non-involvement of GABA-ergic mechanisms.
- 1981
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Ingår i: Journal of Pharmacy and Pharmacology (JPP). - : Oxford University Press (OUP). - 0022-3573 .- 2042-7158. ; 33:9, s. 580-585
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Tidskriftsartikel (refereegranskat)abstract
- Administration of thyroliberin (TRH) to reserpinized mice causes tremor and counteracts the hypothermia in a dose-dependent fashion. The thyroliberin response is inhibited by gamma-hydroxybutyric acid (GHB) and baclofen, but not by other, more specific GABA-ergic agents, such as THIP, gamma-acetylenic GABA, and sodium valproate. Picrotoxin neither potentiates nor inhibits the thyroliberin actions. Nor are the thyroliberin effects dependent on cholinergic, monoaminergic or histaminergic mechanisms. The results repudiate a current hypothesis, that the peptide actions may be mediated by GABA-ergic pathways in the brain.
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| 10. |
- Bramer, Tobias, et al.
(författare)
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Pharmaceutical applications for catanionic mixtures
- 2007
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Ingår i: Journal of Pharmacy and Pharmacology (JPP). - : Oxford University Press (OUP). - 0022-3573 .- 2042-7158. ; 59:10, s. 1319-1334
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Forskningsöversikt (refereegranskat)abstract
- Mixtures of oppositely charged surfactants, so called catanionic mixtures, are a growing area of research. These mixtures have been shown to form several different types of surfactant aggregates, such as micelles of various forms and sizes, and lamellar structures, such as vesicles. In this review, a short introduction to the field of catanionic mixtures is presented and the pharmaceutical possibilities offered by such mixtures are reviewed. There are several interesting ideas on how to apply catanionic mixtures to improve the delivery of, for example, drug compounds and DNA, or for HIV treatment.
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