Influence Of Drug Concentration Research Articles

Abstract 6561: Mathematical analysis for the combinatorial cytotoxic properties of the standardized extract of Annona cherimola or Solanum nigrum with 5-FU against head and neck cancer cells

Abstract The use of total standardized plant extracts is frequently used in low-income countries for several diseases. Solanum sp. and Annona sp. are edible folk herbs with reported uses for the treatment of several malignancies. Natural herb products and folk medicine might not be a potent anticancer and might be recommended for combination therapy. 5- FU is a commonly used antimetabolite chemotherapeutic agent used for the treatment of several neoplastic disorders. In the current work, we mathematically evaluated the influence of adding total standardized extract of A. cherimola and S. nigrum to the cytotoxic profile of 5-FU in head and neck cancer cells. Cytotoxicity assessment and combination analysis were calculated after MTT assays followed by fitting to the Emax model and calculating the combination index (CI-value). After 24 h exposure, both A. cherimola and S. nigrum extracts were more potent than 5-FU with IC50‘s of 29.4±4.4, 7.3±1.3 and 3.4±4.4 µg/ml, respectively. Both A. cherimola and S. nigrum extracts significantly decreased the IC50‘s of 5-FU to 5.2±0.55 and 7.6±0.85 µg/ml, respectively; however, the CI-values were indicative of additive and antagonistic interactions, respectively (0.91 and 2.49, respectively). After 48 h of exposure, the IC50‘s of 5-FU, A. cherimola and S. nigrum extracts were 3.1±0.45, 0.87±0.22 and 7.2±0.65 µg/ml, respectively. Similarly, a combination of A. cherimola or S. nigrum extracts with 5-FU showed additive and antagonistic interaction with CI-values of 1.05 and 3.37, respectively. After 72 h of exposure, the IC50‘s of 5-FU, A. cherimola and S. nigrum extracts were 1.9±0.1, 2.1±0.24 and 2.1±0.1 µg/ml, respectively. Similarly, a combination of A. cherimola and S. nigrum extracts with 5-FU showed additive and antagonistic interaction with CI-values of 1.2 and 2.21, respectively. Then, the CnT model was used to assess the relative influence of drug concentration and exposure time on the cytotoxic profile of treatments under investigation. For S. nigrum and its combination with 5-FU, n-values were 0.9 and 0.63 which is indicative of the relatively high influence of drug concentration. On the other hand, the n-value for 5-FU treatment was 0.37; this indicates a higher influence of drug exposure time compared to other treatments. The n-values of A. cherimola and its combination with 5-FU were 0.51 and 0.54, respectively; this indicates a comparable influence of both drug concentration and exposure time. Further PCR analysis showed over-expression of the apoptotic gene, BAX, after 5-FU combination with A. cherimola and decreased after combination with S. nigrum. In conclusion, some natural herbal remedies such as A. cherimola might influence the cytotoxic profile of 5-FU and particularly after short exposure time; while on the other hand, some herbal remedies such as S. nigrum significantly antagonize its cytotoxic activity against head and neck cancer cells and should be avoided during the treatment with 5-FU Citation Format: Serag Eldin I. Elbehairi, Fahad A. Alabbasi, Aly F. Mohamed, Nahla G. Mohamed, Mohammad I. Basuony, Mahmoud M. Salem, Metwaly M. Montaser, Mohammad Y. Alfaifi, Safaa Y. Eid, Ahmed M. Al-Abd. Mathematical analysis for the combinatorial cytotoxic properties of the standardized extract of Annona cherimola or Solanum nigrum with 5-FU against head and neck cancer cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6561.

Synthesis and characterization of a molecularly imprinted polymer (MIP) for solid-phase extraction of the antidiabetic gliclazide from human plasma.

Gliclazide is a sulfonylurea frequently prescribed for the management of type 2 diabetes mellitus in elderly patients and for patients with chronic renal or hepatic diseases. Even though it is considered a safer alternative, the drug can provoke side effects in some patients, especially hypoglycemia, due to the high interindividual variability. Therefore, the quantification of gliclazide in biological samples is usually recommended in order to assure efficacy and safety of the pharmacotherapy. However, due to the complexity of biological matrices, therapeutic monitoring can be very challenging, especially in the sample preparation step. For that reason, the synthesis and characterization of a novel and selective molecularly imprinted polymer (MIP) was proposed to be employed as sorbent for the extraction of gliclazide from human plasma samples by a molecularly imprinted solid-phase extraction (MISPE) procedure. Synthesis conditions were optimized (monomer, crosslinker and porogen) and the polymer was characterized for its morphological, physicochemical and stability properties. The influence of drug concentration, solvent composition and pH on the coefficient of distribution (Kd) and imprinting factor (IF) were studied, as well as repeatability between batches and selectivity. A bioanalytical method was developed applying the developed MIP as sorbent in solid phase extraction and liquid chromatography using a Poroshell 120 C18 (100×4.6mm, 4μm) column, acetonitrile and 10mM potassium phosphate buffer pH3.0 (50:50) at a flow-rate of 1.2mL/min as mobile phase, temperature of 30°C, injection volume of 40μL and detection at 230nm. The best reaction yield, extraction capacity, and selectivity was obtained using 2-hydroxyethyl methacrylate (2-HEMA), ethyleneglycol dimethacrylate (EGDMA) and acetonitrile. The optimized MIP showed coefficient of distribution (Kd) of 59.85μg/g, imprinting factor (IF) of 1.60, and selectivity for gliclazide and other sulfonylureas compared to possible concurrent drugs. The developed method by MISPE-HPLC-UV showed to be appropriate to determine gliclazide in human plasma samples.

Percutaneous delivery of levetiracetam as an alternative to topical nonsteroidal anti-inflammatory drugs: formulation development, in vitro and in vivo characterization.

The study focused on formulation of carmellose sodium hydrogels and nonionic microemulsions with 5% and 10% of levetiracetam and investigation of drug concentration influence on their physicochemical characteristics and in-use stability as well as influence of drug concentration and carrier type on in vitro drug release and in vivo antihyperalgesic/antiedematous activity in a rat model of localized (intraplantar) carrageenan-induced inflammation. Hydrogels were pseudoplastic semisolids with thixotropy and pH 7.37-7.58. Microemulsions were low viscous Newtonian nanodispersions of oil droplets (13.11-15.11nm) in water, with pH 4.01-4.64. Physical stability of the investigated systems was preserved over the 3-month storage under ambient conditions. Levetiracetam release followed zero order and Korsmeyer-Peppas models (R2 ≥ 0.99) reflecting the combined effects of drug concentration and carrier viscosity. All levetiracetam-loaded formulations produced significant reduction of hyperalgesia and paw swelling induced by carrageenan (p < 0.001). Their efficacy in exerting antihyperalgesic activity was significantly higher than that observed with the reference 5% ibuprofen hydrogel preparation (up to 6h) (p < 0.001), while antiedematous activity was comparable with the reference product. No erythema and visible blood vessels were observed in a rat ear test. The study demonstrated percutaneous delivery of levetiracetam as useful and safe therapeutic option for localized inflammatory pain with potential to overcome the insufficient efficacy of topically applied nonsteroidal anti-inflammatory drugs in the form of a hydrogel. Graphical abstract.

Layered gelatin/PLLA scaffolds fabricated by electrospinning and 3D printing- for nasal cartilages and subchondral bone reconstruction

In the present work the advantages of two kinds of different, well known and applicable, biomaterials (PLLA and gelatin) and two kinds of scaffold fabrication techniques (3D printing - FDM and electrospinning) were combined in order to create a novel multifunctional layered scaffold for nasal cartilages and subchondral bone reconstruction. The pore size of scaffolds produced by 3D printing technology was designed to solve the problem that otolaryngologists currently have with fixing the nasal cartilage implant with needle and threads. The effect of the solution concentration for the electrospinning process on the microstructure and mechanical properties of gelatin nanofibers produced as well as the influence of drug concentration on the mechanical properties of membranes were investigated. The commercially available FDM – 3D printing system was used. 3D scaffolds varying in structure and geometry were designed and printed. The influence of the internal architecture of 3D printed scaffolds on their mechanical properties was tested. Hybrid layered scaffolds consisting of a top gelatin nanofibrous layer and a bottom 3D printed porous PLLA material were developed. The mineralization ability of a scaffold was determined in simulated body fluid. The cytotoxicity, proliferation and morphology of Murine fibroblasts L929 cultured on obtained biomaterials were evaluated.

Abstract 1085: Time dependent analysis for the combination of standardized Annona cherimola and Solanum nigrum extracts with 5-FU against head and neck cancer cells

Abstract Phytochemicals of natural origin constitutes very initiative field of anticancer drug discovery. Annona sp. and Solanum nigrum are folk herbs with reported use for the treatment of several neoplasias. Natural herb products and folk medicine might not be potent anticancer remedies and are recommended for combination therapy. In the current work, we mathematically evaluated the influence of combining standardized extracts of A. cherimola and S. nigrum to the cytotoxic profile of 5-FU against head and neck cancer cells (HEP-2). Cytotoxicity assessment and combination analysis were calculated after MTT assays followed by fitting to Emax model and calculating the combination index (CI-value). After 24 h exposure, both A. cherimola and S. nigrum extracts were more potent than 5-FU with IC50 of 29.4±4.4, 7.3±1.3 and 3.4±4.4 µg/ml, respectively. Both A. cherimola and S. nigrum extracts significantly decreased the IC50 of 5-FU to 5.2±0.55 and 7.6±0.85 µg/ml, respectively; however the CI-values were indicative of additive and antagonistic interactions, respectively (0.91 and 2.49, respectively). After 48 h of exposure, the IC50 of 5-FU, A. cherimola and S. nigrum extracts were 3.1±0.45, 0.87±0.22 and 7.2±0.65 µg/ml, respectively. Similarly, combination of A. cherimola and S. nigrum extracts with 5-FU showed additive and antagonistic interaction with CI-values of 1.05 and 3.37, respectively. After 72 h of exposure, the IC50 of 5-FU, A. cherimola and S. nigrum extracts were 1.9±0.1, 2.1±0.24 and 2.1±0.1 µg/ml, respectively. Similarly, combination of A. cherimola and S. nigrum extracts with 5-FU showed additive and antagonistic interaction with CI-values of 1.2 and 2.21, respectively. Then, CnT model was used to assess the relative influence of drug concentration and exposure time on the cytotoxic profile of treatments under investigation. For S. nigrum and its combination with 5-FU, n-values were 0.9 and 0.63 which is indicative of relatively high influence of drug concentration. On the other hand, n-value for 5-FU treatment was 0.37; this indicates higher influence of drug exposure time compared to other treatment. The n-values of A. cherimola and its combination with 5-FU were 0.51 and 0.54, respectively; this indicate comparable influence of both drug concentration and exposure time. As a confirmatory measure, expression of the apoptotic gene, BAX, was increased after 5-FU combination with A. cherimola and decreased after combination with S. nigrum. In conclusion, some natural herb remedies such as A. cherimola might influence the cytotoxic profile of 5-FU and particularly after short exposure time; while on the other hand, some herb remedies such as S. nigrum significantly antagonizes its cytotoxic activity against head and neck cancer cells. Citation Format: Serag Eldin I. Elbehairi, Aly F. Mohamed, Nahla G. Mohamed, Mohammad I. Basuony, Mahmoud M. Salem, Metwally M. Montaser, Mohammad Y. Alfaifi, Ayman M. Noreddin, Ahmed M. Al-Abd. Time dependent analysis for the combination of standardized Annona cherimola and Solanum nigrum extracts with 5-FU against head and neck cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1085. doi:10.1158/1538-7445.AM2017-1085

Antimicrobial activity of biopolymer–antibiotic thin films fabricated by advanced pulsed laser methods

We report on thin film deposition by matrix assisted pulsed laser evaporation (MAPLE) of two polymer–drug composite thin film systems. A pulsed KrF* excimer laser source (λ=248nm, τ=25ns, ν=10Hz) was used to deposit composite thin films of poly(d,l-lactide) (PDLLA) containing several gentamicin concentrations. FTIR spectroscopy was used to demonstrate that MAPLE-transferred materials exhibited chemical structures similar to those of drop cast materials. Scanning electron microscopy data indicated that MAPLE may be used to fabricate thin films of good morphological quality. The activity of PDLLA–gentamicin composite thin films against Staphylococcus aureus bacteria was demonstrated using drop testing. The influence of drug concentration on microbial viability was also assessed. Our studies indicate that polymer–drug composite thin films prepared by MAPLE may be used to impart antimicrobial activity to implants, medical devices, and other contact surfaces.

Impact of acoustic airflow nebulization on intrasinus drug deposition of a human plastinated nasal cast: New insights into the mechanisms involved

PurposeThe impact of 100Hz (Hertz) acoustic frequency airflow on sinus drug deposition of aerosols was investigated using a human plastinated nasal cast. The influence of drug concentration and endonasal anatomical features on the sinus deposition enhanced by the 100Hz acoustic airflow was also examined. MethodsPlastinated models were anatomically, geometrically and aerodynamically validated (endoscopy, CT scans, acoustic rhinometry and rhinomanometry). Using the gentamicin as a marker, 286 experiments of aerosol deposition were performed. Changes of airborne particles metrology produced under different nebulization conditions (100Hz acoustic airflow and gentamicin concentration) were also examined. ResultsAerodynamic and geometric investigations highlighted a global behaviour of plastinated models in perfect accordance with a nasal decongested healthy subject. The results of intrasinus drug deposition clearly demonstrated that the aerosols can penetrate into the maxillary sinuses. The 100Hz acoustic airflow led to increase the deposition of drug into the maxillary sinuses by a factor 2–3 depending on the nebulization conditions. A differential intrasinus deposition of active substance depending on maxillary ostium anatomical features and drug concentration was emphasized. ConclusionThe existence of a specific transport mechanism of penetration of nebulized particles delivered with acoustic airflow was proposed.

Influence of drug concentration on the diffusion parameters of caffeine

Background and Objectives:In the fields of the pharmaceutical and cosmetic industries and in toxicology, the study of the skin penetration of molecules is very interesting. Various studies have considered the impact of different physicochemical drug characteristics, skin thickness, and formulations, on the transition from the surface of the skin to the underlying tissues or to the systemic circulation; however, the influence of drug concentration on the permeation flux of molecules has rarely been raised. Our study aims to discover the influence of caffeine concentration in a formulation on the percutaneous penetration from gels, as a result of different dose applications to polysulfate membrane and human skin.Materials and Methods:For this purpose, three identical base gels were used at 1, 3, and 5% of caffeine, to evaluate the effect of the concentration of caffeine on in vitro release through the synthetic membrane and ex vivo permeation through the human skin, using diffusion FranzTM cells.Results:The diffusion through the epidermal tissue was significantly slower than through the synthetic membrane, which recorded an increase of flux with an increase in the concentration of caffeine. The skin permeation study showed that diffusion depended not only on the concentration, but also on the deposited amount of gel. Nevertheless, for the same amount of caffeine applied, the flux was more significant from the less concentrated gel.Conclusion:Among all the different concentrations of caffeine examined, 1% gel of caffeine applied at 5 mg / cm2 showed the highest absorption characteristics across human skin.

Liposomes for (trans)dermal delivery of tretinoin: influence of drug concentration and vesicle composition

The influence of drug concentration and vesicle composition on the (trans)dermal delivery of tretinoin (TRA) was studied. To this purpose tretinoin was incorporated at different concentrations in unilamellar liposomes (UVs) prepared by sonication using phospholipids with different transition temperature (Tc): hydrogenated soy phosphatidylcholine (Tc = 51°C) or dipalmitoylphosphatidylcholine (Tc = 41°C). Vesicle dispersions were characterized in terms of morphology, size distribution and incorporation efficiency by using respectively optical and polarized light microscopy, transmission electron microscopy, dynamic laser light scattering, and HPLC. The effect of the vesicular incorporation of tretinoin at different molar ratios was investigated by zeta potential measurements and differential scanning calorimetry analysis. These analyses indicated that tretinoin principally interacts with the lipid groups until bilayer saturation. At higher concentration the ionized drug interacts with the polar head. Interactions between new-born pig skin and vesicle containing different amount of tretinoin were evaluated in vitro using Franz cells. The results obtained confirmed that liposomes saturated with TRA (molar fraction = 0.3) are capable of significantly promoting drug accumulation in the pig skin and that (trans)cutaneous delivery is strongly dependent on vesicular stability on the skin.

Development and physicochemical characterization of dexamethasone-loaded polymeric nanocapsule suspensions

The influence of drug concentration, oil phase, and surfactants on the characteristics of dexamethasone-loaded nanocapsules was investigated. The best formulations were obtained at dexamethasone concentrations of 0.25 and 0.50 mg.mL-1 (encapsulation efficiency: 80-90%; mean size: 189-253 nm). The type of oil phase influenced only the stability of dexamethasone-loaded nanocapsules. The association of polysorbate 80 and sorbitan monooleate provided a more stable formulation. Sunflower oil and sorbitan sesquioleate used for the first time as oil phase and surfactant for nanocapsules, respectively, have allowed obtaining suspensions with low mean size and narrow size distribution.

Effect of pH on In Vitro Permeation of Ondansetron Hydrochloride Across Porcine Buccal Mucosa

The influence of drug concentration, pH in donor chamber, and 1-octanol/buffer partition coefficient on transbuccal permeation of ondansetron hydrochloride (pKa, 7.4) across porcine buccal mucosa was studied by using an in-line Franz type diffusion cell at 37°C. The pH was adjusted to several values and the solubility of the drug in different pH was measured. Solubility of ondansetron hydrochloride decreases with increasing pH. The permeability of the drug was evaluated at different donor pH and drug concentrations. Permeability of un-ionized (Pu) and ionized (Pi) species of drug was calculated by fitting the data to a mathematical model. The steady state flux increased linearly with the donor concentration (r2 = 0.9843) at pH 7.4. The permeability coefficient and the partition coefficient of the drug increased with increasing pH. The values of Pu and Pi were 4.86 × 10− 6 cm/sec and 7.18 × 10− 7 cm/sec, respectively. The observed permeability coefficients and the permeability coefficients calculated from the mathematical model at various pH showed good linearity (r2 = 0.9799). The total permeability coefficient increased with increasing the fraction of un-ionized form of the drug. The drug permeated through buccal mucosa by a passive diffusion process. The non-ionized species of drug penetrated well through buccal mucosa and the permeation was a function of pH. Transbuccal delivery is a potential route for the administration of ondansetron hydrochloride.

Enhanced photodynamic activity of meso-tetra(4-hydroxyphenyl)porphyrin by incorporation into sub-200 nm nanoparticles

A photosensitizer, meso-tetra(hydroxyphenyl)porphyrin (p-THPP) was incorporated into sterile submicronic nanoparticles of poly( d, l-lactide-co-glycolide) (50:50 and 75:25 PLGA) and poly( d, l-lactide) (PLA). With all polymers used, sub-130 nm p-THPP-loaded nanoparticles with similar drug loadings and entrapment efficiencies were produced using the emulsification–diffusion technique. The photodynamic activity (photocytotoxicity) of these nanoparticles was evaluated on EMT-6 mammary tumour cells in comparison with the free drug. The influence of drug concentration (3–10 μg/ml), incubation time (5–60 min) and light dose (6–9 J/cm 2) on p-THPP photocytotoxic efficiency was investigated. With all p-THPP formulations tested, cell viability decreased with increasing values of these parameters. The beneficial effect of nanoencapsulation compared to free drug was highlighted at drug concentrations up to 6 μg/ml and short incubation times (15–30 min). The most important photocytotoxicity was observed with 50:50 PLGA nanoparticles allowing low drug doses and short drug administration–irradiation intervals for local photodynamic therapy.

Intravesical Instillation of Terodiline—An in Vivo Study of Drug Absorption in Rabbit and Man

The absorption of intravesically administered terodiline was investigated in 8 healthy volunteers (10−4) and in 33 rabbits (10−4M., 4 × 10−4M. and 1.6 × 10−3M.). In the humans, the amount of drug retained and the serum concentration were registered. In the rabbits, the influence of drug concentration, pH (5 and 9.2) and volume (5 and 20ml.) were evaluated. Liquid scintigraphy of the bladder wall and of serum and tissue samples from striated muscle, kidney and liver was performed. Further, autoradiography of the bladder wall and calculation of drug retention were done.In the humans, 20 ± 5% of the administered terodiline dose was retained in the body. Clinically significant serum concentrations were not detected.In the rabbits, 21 ± 4% of the drug was retained with the pH = 5 terodiline solution as compared with 64 ± 3% with the pH = 9.2 solution. With increasing terodiline concentrations, drug retention increased, as did the tissue and serum activities. At a given concentration, the total amount of drug retained increased with a larger volume. The drug gradient between the bladder muscle layer and serum was of a magnitude of about 100, independent of the drug concentration within the muscle layer.It is concluded that the pH and concentration of the solution are factors of major importance for the amount of terodiline absorbed from the bladder. Compared with the one obtainable by systemic drug administration, the large gradient between the bladder muscle and the serum is conspicuous, and may be of clinical interest.

The in Vitro Pfnetration of Hydrophilic and Lipophilic Drugs from Transparent Oil-Water Gels Through Excised Human Epidermis: A Comparative Study with Other Dermatological Vehicles

AbstractWithin the scope OF evaluating transparent oil-water gels as dermatological vehicles, the percutaneous absorption of both a hydrophilic drug, tetracaine hydrochloride, and a lipophilic drug, benzyl nicotinate, is studied using excised human epidermis. From a comparison of the results with those of release experiments, it appears that in most cases the penetration of both drugs through the epidermis occurs at a much lower rate than their release from the vehicles. This indicates that the penetration process constitutes the rate limiting step.For both drugs the penetration rate from the transparent oil-water gel through human epidermis is comparable to those from other commonly used vehicles. Due to the higher lipophilicity of benzyl nicotinate, however, its penetration occurs faster than for tetracaine hydrochloride. As to the influence OF drug concentration in the vehicle on penetration rate, the results do not provide a decisive answer.

Influence of Drug Concentration on In Vitro Release of Salicylic Acid from Ointment Bases

The effect of drug concentration on in vitro release of salicylic acid from a series of ointment bases was investigated. The bases were commercially available vehicles containing lanolin and/ or lanolin derivatives and formed stable water-in-oil or oil-in-water emulsions. Release tests were performed both with the anhydrous and with the emulsion forms of the bases, at varying salicylic acid concentrations (0.5–5.0% w/v), and involved the use of silicone rubber membranes. The release of salicylic acid from the bases was in agreement with a reported diffusional model. A linear relationship between release rate, q/√t, and drug concentration in ointments existed when the drug was completely dissolved in the vehicles. The method reported is of potential utility for the determination of drug solubility in ointments and for the evaluation of the optimal drug concentration in topical vehicles. The relationships among type of vehicle, drug concentration, drug solubility, and release rate are discussed.