Radka Opatřilová

Investigation of new acyloxy derivatives of cholic acid and their esters as drug absorption modifiers

Skin penetration enhancers are used in the formulation of transdermal delivery systems for drugs that are otherwise not sufficiently skin-permeable. Intestinal absorption promoters/enhancers are used as excipients in oral formulations of poorly oral-bioavailable drugs. Series of fourteen acyloxy derivatives of 5β-cholic acid as potential drug absorption modifiers was generated by multistep synthesis. The synthesis of all newly prepared compounds is presented here. Structure confirmation of all generated compounds was accomplished by (1)H NMR, (13)C NMR, IR and MS spectroscopy methods. All the prepared compounds were analyzed using RP-TLC, and their lipophilicity (R(M)) was determined. The hydrophobicity (logP) and solubility (logS) of the studied compounds were also calculated using two commercially available programs. All the target compounds were tested for their in vitro transdermal penetration activity and as potential intestinal absorption enhancers. The anti-proliferative activity of all the final compounds was also assessed against the human cancer cell lines: T-lymphoblastic leukemia cell line and the breast adenocarcinoma cell line. Their cytotoxicity was also evaluated against the normal human skin fibroblast cells. Two compounds showed anti-proliferative effect on cancer cells without affecting the growth of normal cells, which should be promising in potential development of new drugs. Most of the target compounds showed minimal anti-proliferative activity (IC(50)>37 μM), indicating they would have low cytotoxicity when administered as chemical absorption modifiers. The relationships between the lipophilicity and the chemical structure of the studied compounds as well as the relationships between their chemical structure and enhancement effects are discussed in this article.

New propanoyloxy derivatives of 5β-cholan-24-oic acid as drug absorption modifiers.

A series of final twelve propanoyloxy derivatives of 5β-cholan-24-oic acid (O-propanoyl derivatives of cholic acid) as potential drug absorption modifiers (skin penetration enhancers, intestinal absorption promoters) was generated by multistep synthesis. Structure confirmation of all generated compounds was accomplished by 1H NMR, 13C NMR, IR and MS spectroscopy methods. All the prepared compounds were analyzed using RP-TLC, and their lipophilicity (RM) was determined. The hydrophobicity (log P), solubility (log S), polar surface area (PSA) and molar volume (MV) of the studied compounds were also calculated. All the target compounds were tested for their in vitro transdermal penetration effect and as potential intestinal absorption enhancers. The cytotoxicity of all the evaluated compounds was evaluated against normal human skin fibroblast cells. Their anti-proliferative activity was also assessed against human cancer cell lines: T-lymphoblastic leukemia cell line and breast adenocarcinoma cell line. One compound showed selective cytotoxicity against human skin fibroblast cells and another compound possessed the highest cytotoxicity against all the tested cell lines. Only one compound expressed anti-proliferative effect on leukemia cancer cells without affecting the growth of normal cells, which should be promising in potential development of new drugs. Most of the target compounds showed minimal anti-proliferative activity (IC50>37 μM), indicating they would have moderate cytotoxicity when administered as chemical absorption modifiers. The relationships between the lipophilicity/polarity and the chemical structure of the studied compounds as well as the relationships between their chemical structure and enhancement effect are discussed in this article.

New polyfluorothiopropanoyloxy derivatives of 5β-cholan-24-oic acid designed as drug absorption modifiers

A series of final six propanoyloxy derivatives of 5β-cholan-24-oic acid (tridecafluoroctylsulfanyl- and tridecafluoroctylsulfinylethoxycarbonylpropanoyloxy derivatives) as potential drug absorption promoters (skin penetration enhancers, intestinal absorption promoters) was generated by multistep synthesis. Structure confirmation of all generated compounds was accomplished by (1)H NMR, (13)C NMR, IR and MS spectroscopy methods. All the prepared compounds were analyzed using RP-TLC, and their lipophilicity (RM) was determined. The hydrophobicity (log P), solubility (logS), polar surface area (PSA) and molar volume (MV) of the studied compounds were also calculated. All the target compounds were tested for their in vitro transdermal penetration effect and as potential intestinal absorption enhancers. The cytotoxicity of all the evaluated compounds was evaluated against normal human skin fibroblast cells. Their anti-proliferative activity was also assessed against human cancer cell lines: T-lymphoblastic leukaemia cell line and breast adenocarcinoma cell line. One compound showed high selective cytotoxicity against human skin fibroblast cells and another compound possessed high cytotoxicity against breast adenocarcinoma cell line and skin fibroblast cells. Only one compound expressed anti-proliferative effect on leukaemia and breast adenocarcinoma cells without affecting the growth of normal cells, which should be promising in potential development of new drugs. Most of the target compounds showed minimal anti-proliferative activity (IC50>37μM), indicating they would have moderate cytotoxicity when administered as chemical absorption modifiers. The relationships between the lipophilicity/polarity and the chemical structure of the studied compounds as well as the relationships between their chemical structure and penetration enhancement effect are discussed in this article.

Quantitative analysis of drug losses administered via nasogastric tube - In vitro study

PURPOSE Drug administration through nasogastric tube (NGT) is a standard practice but the real amount of the delivered drug is unknown. Therefore, we designed a study to determine the losses of various dosage forms administered by different methods through NGT. METHODS In vitro model was used. Five different administration methods (A-E) and six dosage forms (simple compressed tablets - T/S; film coated tablets - T/FC; enteric coated tablets - T/EC; capsules with powder filling - C/P; capsules containing extended release pellets - C/ER; capsules containing gastro-resistant pellets - C/GR) were investigated. Measurement was repeated six times for each drug-method combination. The overall losses were determined by gravimetry. In method A partial losses associated with each step of drug administration were also determined. RESULTS Significant drug losses were measured (4-38%). Only methods A (crushing-beaker-syringe-water-NGT) and B (crushing-water-syringe-NGT) were suitable for administration of all tested dosage forms. Method B proved the most effective for all kinds of tablets and C/GR (p<0.05) and tended to be more effective also for C/ER (p=0.052) compared to method A. C/P showed minimal losses for both tested methods (B and E). Flushing of the drug through NGT causes major losses during drug administration compared to crushing and transfer (p<0.05). All methods for intact pellets (C-E) were found inappropriate for clinical practice due to NGT clogging. CONCLUSIONS Choosing a suitable administration method can significantly affect the amount of drugs delivered through NGT.

Diazepam filled hard capsules intended for detoxification of patients addicted to benzodiazepines and Z-drugs

Objectives The abuse of benzodiazepines and Z-drugs reduces the quality of life of millions of addicted people worldwide. They cannot be discontinued abruptly due to harmful withdrawal symptoms. Detoxification is usually based on replacement of short/middle acting benzodiazepines or Z-drugs by diazepam and tapering the dose over time. In order to enhance patient adherence to an individual withdrawal plan, suitable diazepam dosage forms have to be available. Hard capsules containing an exact and uniform dose could be used for the relief of symptoms caused by altering the plasma level and overcoming psychogenic stress from the dose reduction. Methods This work demonstrates that capsules with a content of diazepam ranging from 2.125mg to 0.492 mg (dose decreasing always by 15%) cannot be easily prepared by standard mortar technology in a pharmacy. To meet mass and content uniformity European Pharmacopoeia criteria, capsules were prepared by improved technology based on the preparation of binary blends of calcium phosphate anhydrous and diazepam in descending concentrations in a high-speed mixer (time 30 s) and densification of about 10% during filling of the capsules. Results All batches (n=20) prepared by improved technology met the requirement for content uniformity compared with only nine batches prepared by standard mortar blender technology. Based on the process capability index, none of the samples prepared by standard technology fitted pharmacopeia limits at the statistically acceptable level. On the other hand, all batches prepared by improved technology exhibited acceptable process capability index. Conclusions We have shown that at least 99.73% of batches prepared by our improved technology would meet the pharmacopoeia limits for content uniformity and are suitable for treatment of this type of addiction.