Bioequivalence of Sandoz methylphenidate osmotic-controlled release tablet with Concerta® (Janssen-Cilag).

The aim was to assess the bioequivalence of Sandoz methylphenidate osmotic-controlled release (OCR) tablets (Sandoz [Methylphenidate[ MPH OCR) with Concerta®, a methylphenidate formulation indicated for the treatment of attention deficit/hyperactivity disorder (ADHD). Four open-label, randomized, single-dose, two-way crossover bioequivalence studies were conducted in healthy subjects: three fasting studies with 54-, 36- and 18-mg doses of methylphenidate, and one fed study with the 54-mg dose. The d- and l-threo-methylphenidate plasma levels were quantified using liquid chromatographic methods with tandem mass spectrometry (LC MS/MS). Bioequivalence of the formulations was accepted if the 90% geometric confidence intervals of the ratio of least-squares means of Sandoz MPH OCR to Concerta® of ln-transformed area under the curve (AUC0-t ) and C max were within the acceptance range of 80-125%. All studies met the bioequivalence criteria, and 90% geometric confidence intervals for AUC0-t and C max were within the predefined range. All plasma concentration time curves for Sandoz MPH OCR under fasting conditions showed a biphasic profile comparable with Concerta®, confirmed by bioequivalence of the partial metrics AUC0-2h, AUC2-24 h, C max(0-2 h) and C max(2-24 h). Both products were well tolerated and no relevant differences in the safety profiles were observed. It was concluded that Sandoz MPH OCR is bioequivalent to Concerta® in terms of rate and extent of absorption when administered as a single dose of one extended-release tablet of 54, 36, or 18 mg under fasting conditions and at a dose of 54 mg under fed conditions.

Histone-deacetylase inhibition and butyrate formation: Fecal slurry incubations with apple pectin and apple juice extracts.

OBJECTIVE: Butyrate plays a major role among the short-chained fatty acids formed by the microbial flora of the colon. It is considered to be an important nutrient of the colon mucosa and has been shown to trigger differentiation and apoptosis of colon-derived cells in culture. Inhibition of histone deacetylase (HDAC) seems to play a central role in these effects. Butyrate was thus suggested to act as a chemopreventive metabolite that can prevent the occurrence of colorectal cancer, one of the most abundant types of cancer in Western industrialized countries. Some polymeric carbohydrates such as pectin, resistant to digestion in the small intestine, have been shown to serve as substrates for butyrate formation by the microflora of the colon. METHODS: In this study we investigated fermentation supernatants (FSs) from incubations of human fecal slurry with apple pectin and with polyphenol-rich apple juice extracts (AJEs). RESULTS: We found that FSs from fermentations with pectin were rich in butyrate and very active in HDAC inhibition in nuclear extracts prepared from the colon tumor cell lines HT-29 and Caco-2 and in intact HeLa Mad 38 cells bearing a reporter gene driven by HDAC inhibition. The butyrate levels explained most of the HDAC-inhibitory potency in FSs from pectin-rich fermentations. FSs from fermentations with AJEs showed lower butyrate yields but comparable HDAC inhibition. Combined incubations of pectin with AJEs led to effects similar to those with FSs from incubations with pectin as the only substrate added. These effects could not be explained by a direct HDAC-inhibitory potency of AJEs. Furthermore, the FSs were not cytotoxic at the HDAC-inhibitory concentrations. CONCLUSION: These findings suggest that butyrate is the most relevant HDAC inhibitor formed in fermentations of human fecal slurry with apple pectin, whereas addition of AJEs leads to the formation of butyrate and other, yet unknown, HDAC inhibitors.

Inhibition of histone-deacetylase activity by short-chain fatty acids and some polyphenol metabolites formed in the colon.

Colorectal cancer is the most abundant cause of cancer mortality in the Western world. Nutrition and the microbial flora are considered to have a marked influence on the risk of colorectal cancer, the formation of butyrate and other short-chain fatty acids (SCFAs) possibly playing a major role as chemopreventive products of microbial fermentation in the colon. In this study, we investigated the effects of butyrate, other SCFAs, and of a number of phenolic SCFA and trans-cinnamic acid derivatives formed during the intestinal degradation of polyphenolic constituents of fruits and vegetables on global histone deacetylase (HDAC) activity in nuclear extracts from colon carcinoma cell cultures using tert-butoxycarbonyl-lysine (acetylated)-4-amino-7-methylcoumarin (Boc-Lys(Ac)-AMC) as substrate. Inhibition of HDAC activity, e.g., by butyrate, is related to a suppression of malignant transformation and a stimulation of apoptosis of precancerous colonic cells. In nuclear extracts from HT-29 human colon carcinoma cells, butyrate was found to be the most potent HDAC inhibitor (IC50=0.09 mM), while other SCFAs such as propionate were less potent. In the same assay, p-coumaric acid (IC50=0.19 mM), 3-(4-OH-phenyl)-propionate (IC50=0.62 mM) and caffeic acid (IC50=0.85 mM) were the most potent HDAC inhibitors among the polyphenol metabolites tested. Interestingly, butyrate was also the most potent HDAC inhibitor in a whole-cell HeLa Mad 38-based reporter gene assay, while all polyphenol metabolites and all other SCFAs tested were much less potent; some were completely inactive. The findings suggest that butyrate plays an outstanding role as endogenous HDAC inhibitor in the colon, and that other SCFAs and HDAC-inhibitory polyphenol metabolites present in the colon seem to play a much smaller role, probably because of their limited levels, their marked cytotoxicity and/or their limited intracellular availability.