Permeability and toxicity characteristics of L-cysteine and 2-methyl-thiazolidine-4-carboxylic acid in Caco-2 cells.

Acetaldehyde is a known mutagenic substance and has been classified as a group-one carcinogen by the WHO. It is possible to bind acetaldehyde locally in the gastrointestinal (GI) tract with the semi-essential amino acid l-cysteine, which reacts covalently with acetaldehyde and forms compound 2-methyl-thiozolidine-4-carboxylic acid (MTCA). The Caco-2 cell line was used to determine the permeation of l-cysteine and MTCA, as well as the possible cell toxicity of both substances. Neither of the substances permeated through the Caco-2 cells at the concentrations used in this study, and only the highest concentration of MTCA affected the viability of the cells in the MTT (3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazolium bromide) test. These results showed that when l-cysteine is administered in formulations releasing it locally in the lower parts of GI tract, it is not absorbed but can react with acetaldehyde, and that neither l-cysteine nor MTCA is harmful to the cells when present locally in the upper parts of GI tract. This study also shows that MTCA is sensitive at a lower pH of 5.5. Since stable MTCA is desired in different parts of the GI tract, this observation raises concern over the influence of lower pH on l-cysteine-containing product ability to bind and eliminate carcinogenic acetaldehyde.

Computational prediction of local drug effect on carcinogenic acetaldehyde in the mouth based on in vitro/in vivo results of freely soluble L-cysteine.

BACKGROUND: The computational models for predicting oral drug absorption in humans using in vitro and in vivo data have been published. However, only a limited number of studies are available on the prediction of local drug efficacy in the mouth using computational models. AIM: The goal of this study was to develop a simulation model for prediction of drug amount and effect on carcinogenic acetaldehyde in the mouth. METHODS: The model was based partly on our previous studies in which we showed in vivo that l-cysteine-containing tablets can eliminate carcinogenic salivary acetaldehyde in the mouth during smoking. To develop as informative a model as possible, we also investigated whether a lower saliva pH (4.7) can affect the freely soluble l-cysteine dissolution rate and cysteine stability profile in the mouth, compared to the normal saliva pH of 7.4. RESULTS: Stability of the active drug is not pH dependent and thus users with normal, healthy saliva pH and those with lower pH can benefit from cysteine-containing products. The simulated saliva profiles of l-cysteine and acetaldehyde corresponded to the in vivo results. CONCLUSIONS: The model developed can be used as an alternative tool to obtain faster and cheaper answers on how freely soluble drugs affect local conditions in the mouth. Because tobacco smoke contains more than 60 carcinogenic compounds, the model developed can offer a new view in eliminating or reducing not only one toxic compound from smoke but also many others compounds using only one formulation containing various active compounds.

Comparison of melibiose and trehalose as stabilising excipients for spray-dried ß-galactosidase formulations.

Spray-dried protein formulations commonly require stabilising excipients to prevent protein degradation during processing and storage, and trehalose has been commonly used. The purpose of this work was to evaluate melibiose in spray-dried protein formulations in comparison to trehalose. The protein-activity-preserving efficacy, process behaviour and storage stability were studied. Spray drying of ß-galactosidase was carried out using different process temperature, drying air flow and feed liquid atomisation settings. Both melibiose and trehalose reduced protein activity loss during drying. A decrease in activities was observed when the process temperature exceeded a threshold temperature. During storage (30 days at 18% RH and 20 or 40 °C), the formulations dried below this threshold temperature showed no further activity loss, and the stabilising efficacy of the two disaccharides was equal. With higher process temperatures, the remaining protein activities after storage trended higher with melibiose formulations. All formulations remained amorphous. The powder yields of melibiose formulations were similar to trehalose. There was a difference in residual moisture contents, with melibiose formulations giving drier products. In conclusion, protein formulations with melibiose could be spray dried into amorphous powders that were physically stable, contained lower moisture contents and protected protein activity at least as well as trehalose formulations.

The role of active transport in the transcellular movement of the peripheral α2-adrenoceptor antagonist, MK-467: An in vitro pilot study.

MK-467 is a peripherally acting α2-adrenoceptor antagonist due to its low lipid solubility and poor penetration of the blood-brain barrier (BBB). The aim of this study was to assess whether MK-467 could be a substrate of an active efflux transport mechanism. Using Madin-Darby Canine Kidney cells (MDCKII) and MDCKII cells transfected with the human multidrug resistance gene 1, drug transport was assessed in apical-basolateral and basolateral-apical directions. MK-467 was studied at 2 concentrations: 200 and 1000 ng/mL. Samples for analysis were taken at 15, 30, 45, 60, and 90 min after drug application. Drug concentrations were measured using liquid chromatography and mass spectrometry. MK-467 showed no apparent permeability in the apical-basolateral direction, transport in the basolateral-apical direction occurred in both cell lines. Efflux ratios were not calculated. However, MK-467 appeared to undergo active cellular transport. The identity of the transporter requires further investigation.

L'objectif de la présente étude était d'évaluer si le MK-467 pourrait être un substrat pour un mécanisme de transport par efflux actif. En utilisant des cellules rénales canines (Madin-Darby Canine Kidney cells, MDCKII) et des cellules MDCKII transfectées par le gène humain 1 multi-résistant aux médicaments, le transport des médicaments a été évalué dans les 2 directions : apicale-basolatérale et basolatéraleapicale. Deux concentrations de MK-467 ont été évaluées : 200 et 1000 ng/mL. Les échantillons pour l'analyse ont été prélevés 15, 30, 45, 60 et 90 min après l'application du médicament. Les concentrations du MK-467 ont étés mesurées par la chromatographie en phase liquide et la spectrométrie de masse. MK-467 n'a pas démontré une perméabilité visible dans la direction apicale-basolatérale; le transport dans la direction basolatérale-apicale a été vérifié dans les 2 lignes cellulaires. Les ratios d'efflux n'ont pas été calculés. Cependant, le MK-467 semble subir un transport cellulaire actif. Pour clarifier le véhicule de la substance, des recherches plus approfondies (ultérieures) sont nécessaires.(Traduit par Docteur Serge Messier).

Spray-dried amorphous isomalt and melibiose, two potential protein-stabilizing excipients.

The possibility of producing amorphous isomalt and melibiose by spray drying was studied. The impact of process parameters on yield and solid-state stability was compared to sucrose and trehalose. All powders remained amorphous during 2-3 weeks. Processing was challenging due to powder stickiness. Low-temperature and low-humidity drying processes generally performed best. Most isomalt and sucrose powder was retrieved when using 60°C inlet temperature, 800L/h atomizing rate, 1.4ml/min feed rate, 15% concentration and 100% aspirator rate, giving 42-43°C outlet temperature. Isomalt was the most problematic, because it had the lowest Tg and became sticky very easily, therefore process parameters needed to be precisely balanced. There was more freedom in designing processes for melibiose but best yields were obtained with low-temperature (50°C inlet temperature, 800L/h atomizing rate, 4.9ml/min feed rate, 10% concentration and 100% aspirator, 39°C outlet temperature). Trehalose was different in that higher temperatures resulted in better yields. Yet, trehalose generally contained the highest moisture contents. The possibility to produce amorphous isomalt and melibiose at low-temperature process conditions makes them promising considering spray drying applications for heat-sensitive proteins. Melibiose is a better candidate than isomalt because of easier processability and superior solid-state stability.

Patient-reported adverse drug reactions and their influence on adherence and quality of life of chronic myeloid leukemia patients on per oral tyrosine kinase inhibitor treatment.

PURPOSE: To evaluate adverse drug reactions (ADRs) experienced by chronic myeloid leukemia (CML) patients during per oral tyrosine kinase inhibitor (TKI) treatment and correlation of ADR symptoms with medication adherence and perceived quality of life (QoL). PATIENTS AND METHODS: Eighty-six adult, chronic-phase CML patients who had been on TKI treatment (79% on imatinib, 10.5% dasatinib, and 10.5% nilotinib) for at least 6 months participated in the study (mean age: 57.8 years, 52% males). The mean time from diagnosis was 5.1 years. All patients were interviewed, and patient-reported ADRs were obtained using a structured list. Adherence was assessed using Morisky's 8-item Medication Adherence Scale (MMAS). The symptoms' interference with patient's daily QoL was measured by asking patients about the influence of symptom(s) on their mood, general condition, enjoyment of life, walking, relationships, and work. RESULTS: Ninety-seven percent of the patients were suffering from at least one ADR. The mean number of different symptoms was seven (range: 0-15, median 6). The most commonly perceived ADRs were muscle soreness or cramp (69/86, 80%); swelling of hands, legs, feet, or around the eyes (59/86, 69%); and fatigue (43/86, 50%). No correlation was found between adherence and ADRs, because symptoms were equally common in each MMAS adherence class. Half of the patients felt that the ADRs had a negative influence on their daily QoL. A quarter of the patients reported that ADRs affected either their mood, general condition, or enjoyment of life. The incidence of almost all ADRs was much higher among patients reporting negative influence of ADRs on their daily life compared to total study population (P=0.016). CONCLUSION: TKI-related ADRs were common among CML patients irrespective of patient's adherence level. Patients who reported that ADRs had a negative influence on their daily QoL perceived more ADRs than those who did not experience a negative influence.

Formulation and stability of cytokine therapeutics.

Cytokines are messenger proteins that regulate the proliferation and differentiation of cells and control immune responses. Interferons, interleukins, and growth factors have applications in cancer, autoimmune, and viral disease treatment. The cytokines are susceptible to chemical and physical instability. This article reviews the structure and stability issues of clinically used cytokines, as well as formulation strategies for improved stability. Some general aspects for identifying most probable stability concerns, selecting excipients, and developing stable cytokine formulations are presented. The vast group of cytokines offers possibilities for new biopharmaceuticals. The formulation approaches of the current cytokine products could facilitate development of new biopharmaceuticals.

Enantiospecific ketoprofen concentrations in plasma after oral and intramuscular administration in growing pigs.

BACKGROUND: Ketoprofen is a non-steroidal anti-inflammatory drug which has been widely used for domestic animals. Orally administered racemic ketoprofen has been reported to be absorbed well in pigs, and bioavailability was almost complete. The objectives of this study were to analyze R- and S-ketoprofen concentrations in plasma after oral (PO) and intra muscular (IM) routes of administration, and to assess the relative bioavailability of racemic ketoprofen for both enantiomers between those routes of administration in growing pigs. METHODS: Eleven pigs received racemic ketoprofen at dose rates of 4 mg/kg PO and 3 mg/kg IM in a randomized, crossover design with a 6-day washout period. Enantiomers were separated on a chiral column and their concentrations were determined by liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were calculated and relative bioavailability (Frel) was determined for S and R -ketoprofen. RESULTS: S-ketoprofen was the predominant enantiomer in pig plasma after administration of the racemic mixture via both routes. The mean (± SD) maximum S-ketoprofen concentration in plasma (7.42 mg/L ± 2.35 in PO and 7.32 mg/L ± 0.75 in IM) was more than twice as high as that of R-ketoprofen (2.55 mg/L ± 0.99 in PO and 3.23 mg/L ± 0.70 in IM), and the terminal half-life was three times longer for S-ketoprofen (3.40 h ± 0.91 in PO and 2.89 h ± 0.85 in IM) than R-ketoprofen (1.1 h ± 0.90 in PO and 0.75 h ± 0.48 in IM). The mean (± SD) relative bioavailability (PO compared to IM) was 83 ± 20% and 63 ± 23% for S-ketoprofen and R-ketoprofen, respectively. CONCLUSIONS: Although some minor differences were detected in the ketoprofen enantiomer concentrations in plasma after PO and IM administration, they are probably not relevant in clinical use. Thus, the pharmacological effects of racemic ketoprofen should be comparable after intramuscular and oral routes of administration in growing pigs.