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P Beck

Publications and source records attributed to P Beck.

167 records · Page 10Linked to original sources
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Separation of drug-loaded nanoparticles from free drug by gel filtration.

A suitable method for separating free drug and other residual compounds from drug-loaded, colloidal polymeric particles was developed. The objective of this separation procedure was to purify particle suspensions on a preparative scale by a rapid, simple, and exact method without changing the properties of the particles. The gel filtration method described in this paper using a middle-pressure chromatographic system is able to meet all these requirements. The separation process could be optimized by using only water as an eluent in combination with Sephadex G 50 medium. The purified particles appeared after 12-13 min in the eluate. Neither dispersity nor particle size or loading rate were influenced to a considerable extent.

Capsules↗
PubMedDate not supplied

Influence of polybutylcyanoacrylate nanoparticles and liposomes on the efficacy and toxicity of the anticancer drug mitoxantrone in murine tumour models.

Polybutylcyanoacrylate (PBCA) nanoparticles were prepared and loaded with mitoxantrone, a highly effective anticancer drug. The proportion of mitoxantrone bound to the particles was analysed to be about 15 per cent of the initial drug concentration with the incorporation method and about 8 per cent with the adsorption method. Selected nanoparticle formulations were tested in leukaemia- or melanoma-bearing mice after intravenous injection. Efficacy and toxicity of mitoxantrone nanoparticles were compared with a drug solution and with a mitoxantrone-liposome formulation (small unilamellar vesicles with a negative surface charge). Furthermore, influence of an additional coating surfactant, poloxamine 1508, which has been shown to change body distribution of other polymeric nanoparticles, was investigated. It was shown that PBCA nanoparticles and liposomes influenced the efficacy of mitoxantrone in cancer therapy differently: liposomes prolonged survival time in P388 leukaemia, whereas nanoparticles led to a significant tumour volume reduction at the B16 melanoma. Neither nanoparticles nor liposomes were able to reduce the toxic side-effects caused by mitoxantrone, namely leucocytopenia. A slight additional influence of the coating surfactant was observed with only one preparation.

Animals↗
PubMedDate not supplied

Supervised endurance exercise training compared to home training after first lumbar diskectomy: a clinical trial.

OBJECTIVE: We performed a randomised trial to evaluate if intensive supervised training of the back should be offered to all patients after a first lumbar diskectomy. METHODS: Forty consecutive patients were, after a first lumbar diskectomy, randomly allocated to 2 groups undergoing "supervised training" twice a week for 3 months in an outpatient clinic or "home training" after 2 hours of instruction. RESULTS: The two rehabilitation models both showed a significant effect on spinal mobility, isokinetic trunk flexion strength, isokinetic trunk extension strength and daily function. These improvements were unchanged at follow up 3 months later. The pain score remained unchanged, however, throughout the trial in both groups. No differences in effect between the two rehabilitation models could be found for any of the assessed parameters. Thirteen patients did not complete the trial, including 9 from the supervised endurance trained group, mainly because of increased pain and reprolaps (n = 4). Four patients dropped out of the home trained group, only one because of increased pain. The differences in drop-out rate and training side effects were, however, not statistically significant. CONCLUSION: We conclude that it is not worthwhile to implement 3 months of supervised intensive endurance training as opposed to home training in all cases of first lumbar diskectomy, although a beneficial effect and better compliance might be found for a selected group of such patients.

Adult↗