Polystyrene microspheres in the size range 50 nm to 3 microns were fed by gavage to female Sprague Dawley rats daily for 10 days at a dose of 1.25 mg/kg-1. Previous histological evidence of the uptake of these particles and their absorption across the gastrointestinal tract and passage via the mesentery lymph supply and lymph nodes to the liver and spleen was confirmed by analysis of tissues for the presence of polystyrene by gel permeation chromatography. Measurement of radioactivity of tissues following administration of 100 nm and 1 micron I125-labelled polystyrene latex particles for 8 days was corroborative although less secure because of the potential lability of the labelled particles. The extent of absorption of 50 nm particles under the conditions of these experiments was 34% and of the 100 nm particles 26% (as measured by determination of polystyrene content), of which total, about 7% (50 nm) and 4% (100 nm), was in the liver, spleen, blood and bone marrow. Particles larger than 100 nm did not reach the bone marrow, and those larger than 300 nm were absent from blood. No particles were detected in heart or lung tissue.

A series of three dose escalating studies were conducted to investigate the ability of the 17a-hydroxylase/C 17,20 -lyase inhibitor abiraterone acetate, to cause maximum suppression of testosterone synthesis when delivered to castrate and noncastrate males with prostate cancer. Study A was a single dose study in castrate males. Study B was a single dose study in noncastrate males and study C was a multiple dose study in noncastrate males. The drug was given orally in a once-daily dose and blood samples taken to assess pharmacokinetic (PK) parameters and hormone levels in all patients. The study drug was well tolerated with some variability in PKs. Suppression of testosterone levels to o0.14 nmol l À1 was seen in four out of six castrate males treated with a single dose of 500 mg. At 800 mg given days 1 -12 in noncastrate males, target suppression was achieved in three out of three patients, but a two-to threefold increase of Luteinising Hormone (LH) levels in two out of three patients overcame suppression within 3 days. All patients in the multiple dose study developed an abnormal response to a short Synacthen test by day 11, although baseline cortisol levels remained normal. This is the first report of the use of a specific 17a-hydroxylase/ 17,20 -lyase inhibitor in humans. Repeated treatment of men with intact gonadal function with abiraterone acetate at a dose of 800 mg can successfully suppress testosterone levels to the castrate range. However, this level of suppression may not be sustained in all patients due to compensatory hypersecretion of LH. The enhanced testosterone suppression achieved in castrate men merits further clinical study as a second-line hormonal treatment for prostate cancer. Adrenocortical suppression may necessitate concomitant administration of replacement glucocorticoid.

No abstract

SP1049C is a novel anticancer agent containing doxorubicin and two nonionic pluronic block copolymers. In preclinical studies, SP1049C demonstrated increased efficacy compared to doxorubicin. The objectives of this first phase I study were to determine the toxicity profile, dose-limiting toxicity, maximum tolerated dose and pharmacokinetic profile of SP1049C, and to document any antitumour activity. The starting dose was 5 mg m À2 (doxorubicin content) as an intravenous infusion once every 3 weeks for up to six cycles. A total of 26 patients received 78 courses at seven dose levels. The dose-limiting toxicity was myelosuppression and DLT was reached at 90 mg m À2 . The maximum tolerated dose was 70 mg m À2 and is recommended for future trials. The pharmacokinetic profile of SP1049C showed a slower clearance than has been reported for conventional doxorubicin. Evidence of antitumour activity was seen in some patients with advanced resistant solid tumours. Phase II trials with this agent are now warranted to further define its antitumour activity and safety profile.

A drug's solubility and dissolution behaviour within the gastrointestinal tract is a key property for successful administration by the oral route and one of the key factors in the biopharmaceutics classification system. This property can be determined by investigating drug solubility in human intestinal fluid (HIF) but this is difficult to obtain and highly variable, which has led to the development of multiple simulated intestinal fluid (SIF) recipes. Using a statistical design of experiment (DoE) technique this paper has investigated the effects and interactions on equilibrium drug solubility of seven typical SIF components (sodium taurocholate, lecithin, sodium phosphate, sodium chloride, pH, pancreatin and sodium oleate) within concentration ranges relevant to human intestinal fluid values. A range of poorly soluble drugs with acidic (naproxen, indomethacin, phenytoin, and piroxicam), basic (aprepitant, carvedilol, zafirlukast, tadalafil) or neutral (fenofibrate, griseofulvin, felodipine and probucol) properties have been investigated. The equilibrium solubility results determined are comparable with literature studies of the drugs in either HIF or SIF indicating that the DoE is operating in the correct space. With the exception of pancreatin, all of the factors individually had a statistically significant influence on equilibrium solubility with variations in magnitude of effect between the acidic and basic or neutral compounds and drug specific interactions were evident. Interestingly for the neutral compounds pH was the factor with the second largest solubility effect. Around one third of all the possible factor combinations showed a significant influence on equilibrium solubility with variations in interaction significance and magnitude of effect between the acidic and basic or neutral compounds. The least number of significant media component interactions were noted for the acidic compounds with three and the greatest for the neutral compounds at seven, with again drug specific effects evident. This indicates that a drug's equilibrium solubility in SIF is influenced depending upon drug type by between eight to fourteen individual or combinations of media components with some of these drug specific. This illustrates the complex nature of these fluids and provides for individual drugs a visualisation of the possible solubility envelope within the gastrointestinal tract, which may be of importance for modelling in vivo behaviour. In addition the results indicate that the design of experiment approach can be employed to provide greater detail of drug solubility behaviour, possible drug specific interactions and influence of variations in gastrointestinal media components due to disease. The approach is also feasible and amenable to adaptation for high throughput screening of drug candidates.

Non-ionic and carboxylated fluorescent polystyrene microspheres (100, 500 nm, 1 and 3 microns in diameter), were fed by gavage (2.5% w/v; 1.25 mg kg-1) daily for 10 days to female Sprague Dawley rats. Peyer's patches, villi, liver, lymph nodes and spleen of animals fed the non-ionic microspheres from 100 nm to 1 micron showed unequivocal evidence of uptake and translocation of the particles. Heart, kidney and lung showed no evidence of the presence of microspheres. Carboxylated microspheres were taken up to a lesser degree than the non-ionised particles. Experiments with 125I radiolabelled 100 nm and 1 micron particles showed a higher uptake of the smaller particles, which were concentrated in GI tissue and liver. Particles were not distributed randomly in the tissues, but were concentrated at the serosal side of the Peyer's patches and could be seen traversing the mesentery lymph vessels towards the lymph nodes. The results demonstrate a need to re-examine the possibilities of particulate oral delivery, as well as the potential toxicity of ingested particulates.

D-Limonene is well tolerated in cancer patients at doses which may have clinical activity. The favorable toxicity profile supports further clinical evaluation.

In the recent of years, the use of lipid nanoparticles (LNPs) for RNA delivery has gained considerable attention, with a large number in the clinical pipeline as vaccine candidates or to treat a wide range of diseases. Microfluidics offers considerable advantages for their manufacture due to its scalability, reproducibility and fast preparation. Thus, in this study, we have evaluated operating and formulation parameters to be considered when developing LNPs. Among them, the flow rate ratio (FRR) and the total flow rate (TFR) have been shown to significantly influence the physicochemical characteristics of the produced particles. In particular, increasing the TFR or increasing the FRR decreased the particle size. The amino lipid choice (cationic—DOTAP and DDAB; ionisable—MC3), buffer choice (citrate buffer pH 6 or TRIS pH 7.4) and type of nucleic acid payload (PolyA, ssDNA or mRNA) have also been shown to have an impact on the characteristics of these LNPs. LNPs were shown to have a high (>90%) loading in all cases and were below 100 nm with a low polydispersity index (≤0.25). The results within this paper could be used as a guide for the development and scalable manufacture of LNP systems using microfluidics.