Design and dermatokinetic appraisal of lornoxicam-loaded ultrafine self-nanoemulsion hydrogel for the management of inflammation: In vitro and in vivo studies.

The present study aimed to evaluate the impact of ultrafine nanoemulsions on the transdermal delivery of lornoxicam (LOR) for management of the inflammation. The transdermal administration of LORNE could increase the efficacy of LOR with a reduction in side effects. Merging the beneficial properties of ultrafine nanoemulsions and their components (penetration enhancers) can lead to good solubilization, a small droplet size, and more effective LOR carriers. Therefore, this study aims to develop and evaluate the potential use of ultrafine nanoemulsions of LOR (LORNE) to elucidate their skin targeting for the treatment of inflammation. Based on solubility and pseudo ternary phase diagram tests, ultrafine LORNE composed of Labrafil M 2125 CS, Cremophor RH40, and Transcutol HP to deliver LOR was developed and characterized for its physicochemical properties, emulsification, and in vitro release. The selected LORNE was incorporated into carbopol gel (LORNE-Gel) and examined for ex vivo skin permeation, retention, dermatokinetics, anti-inflammatory efficacy, and skin irritation. The selected LORNE12-Gel could improve skin permeation, retention, and dermatokinetic results significantly (p < 0.05) with enhanced CSkin max and AUC0-48h compared to LOR-Gel. Moreover, LORNE12-Gel showed a remarkable anti-inflammatory effect compared to LOR-Gel after topical application. No signs of skin irritation were observed following treatment, indicating the safety of LORNE12-Gel. Thus, this study demonstrated that LOR-loaded LORNE12-Gel could be promising as an efficient transdermal nanocarrier for an anti-inflammatory alternative.

Formulation and in vitro and in vivo evaluation of surfactant-stabilized mucoadhesive nanogels for vaginal delivery of fluconazole.

Surfactant-stabilized mucoadhesive nanogels (NGs) for vaginal delivery of fluconazole (FLZ) were studied and evaluated in this work. FLZ-NG formulations were prepared using two different types of mucoadhesive polymers, Carbopol 934 (Ca934) and Pluronic F-127 (PF127). A rheology study revealed a non-Newtonian pseudoplastic flow behavior (shear thinning) in the prepared NGs. The viscosity of Ca934 NG (0.47 Pa s) was much lower compared to the PF127 NG (6.10 Pa s). The rheology study results correlated well with the in vitro FLZ release profile from the NG formulations. A pH study (pH = 3.90-4.90) revealed that the formulations were physiologically suitable for vaginal application, to avoid the irritation of the vaginal mucosa. Finally, in vitro and in vivo antimicrobial tests were performed. FLZ incorporated into the Ca934 gel had the strongest antimicrobial effect, with a mean inhibition zone of 24 ± 1.6 mm. Based on these results, it was concluded that the mucoadhesive NG incorporating FLZ resulted in a sustained release and enhanced antimicrobial effect, which would enhance and prolong the therapeutic effects of vaginally delivered FLZ.

Effects of Nigella sativa, Lepidium sativum and Trigonella foenum-graecum on sildenafil disposition in beagle dogs.

The present study was conducted to investigate the effects of some commonly used herbs namely Nigella sativa, Lepidium sativum and Trigonella foenum-graecum on the pharmacokinetics of sildenafil in beagle dogs. The study design involved four treatments in a non-balanced crossover design. Sildenafil was given one tablet 100 mg orally to each dog and blood samples were obtained. After a suitable washout period, animals were commenced on a specific herb treatment for 1 week. Blood samples were withdrawn at different time intervals and sildenafil was analyzed by HPLC method. Oral administration of Nigella sativa resulted in reduction of AUC0-∞, C max and t 1/2 as compared to the control. Treatment of Lepidium sativum resulted in a significant reduction in the C max and AUC. There were no significant differences between the rests of the pharmacokinetic parameters relative to those of the control. For Trigonella foenum-graecum, the effects were similar to those obtained in case of Lepidium sativum. It was concluded that concurrent use of investigated herbs alters the pharmacokinetics of sildenafil. Co-administration of investigated herbs should be cautious since their concomitant use might result in decrease in sildenafil bioavailability.

Effect of Curcuma longa on CYP2D6- and CYP3A4-mediated metabolism of dextromethorphan in human liver microsomes and healthy human subjects.

Effect of Curcuma longa rhizome powder and its ethanolic extract on CYP2D6 and CYP3A4 metabolic activity was investigated in vitro using human liver microsomes and clinically in healthy human subjects. Dextromethorphan (DEX) was used as common probe for CYP2D6 and CYP3A4 enzymes. Metabolic activity of CYP2D6 and CYP3A4 was evaluated through in vitro study; where microsomes were incubated with NADPH in presence and absence of Curcuma extract. In clinical study phase-I, six healthy human subjects received a single dose (30 mg) of DEX syrup, and in phase-II DEX syrup was administered with Curcuma powder. The enzyme CYP2D6 and CYP3A4 mediated O- and N-demethylation of dextromethorphan into dextrorphan (DOR) and 3-methoxymorphinan (3-MM), respectively. Curcuma extract significantly inhibited the formation of DOR and 3-MM, in a dose-dependent and linear fashion. The 100 µg/ml dose of curcuma extract produced highest inhibition, which was about 70 % for DOR and 80 % for 3-MM. Curcuma significantly increases the urine metabolic ratio of DEX/DOR but the change in DEX/3-MM ratio was statistically insignificant. Present findings suggested that curcuma significantly inhibits the activity of CYP2D6 in in vitro as well as in vivo; which indicates that curcuma has potential to interact with CYP2D6 substrates.

Effects of fenugreek, garden cress, and black seed on theophylline pharmacokinetics in beagle dogs.

CONTEXT: Herb-drug interactions are a serious problem especially for drugs with a narrow therapeutic index, taking into consideration that herbal medicines are commonly used in various parts of the world. OBJECTIVE: The present study investigates the effect of fenugreek, garden cress, and black seed on the pharmacokinetics of theophylline in beagle dogs. MATERIALS AND METHODS: Beagle dogs received theophylline (200 mg) orally and blood samples were withdrawn at different time intervals (0.33, 0.66, 1.0, 1.5, 2, 3, 4, 6, 8, 12, 24, and 30 h). After a suitable washout period, each herb was given orally at doses of 25, 7.5, and 2.5 g, twice daily for 7 d. On the eighth day, theophylline was re-administrated orally and blood samples were collected. Plasma concentrations of theophylline were determined using HPLC and pharmacokinetic parameters were calculated using a non-compartmental analysis. RESULTS: Treatment with fenugreek (25 g, orally) lead to a decrease in Cmax and AUC0-t of theophylline of about 28% (p < 0.05) and 22% (p < 0.05), respectively, with no significant changes in T1/2λ compared with the baseline values. Garden cress caused a decrease in Cmax to a lesser extent and delayed Tmax of theophylline (2.10 ± 0.24 h versus 3.40 ± 0.74 h), while AUC0-∞ increased by 37.44%. No significant effect was observed for the black seed treatment on theophylline disposition as measured by Cmax, Tmax, AUC0-∞, and CL/F. DISCUSSION AND CONCLUSION: The concurrent use of fenugreek or garden cress alters theophylline pharmacokinetic behavior in an animal model. This could represent a modulation in cytochrome P450 activity, which is responsible for theophylline metabolism in beagle dogs. Further confirmation of these results in humans will warrant changes in theophylline dosing before the co-administration of such herbs.

Evaluation of skin permeation and analgesic activity effects of carbopol lornoxicam topical gels containing penetration enhancer.

The current study was designed to develop a topical gel formulation for improved skin penetration of lornoxicam (LOR) for enhancement of its analgesic activity. Moreover, the effect of different penetration enhancers on LOR was studied. The LOR gel formulations were prepared by using hydroxylpropyl methylcellulose (HPMC) and carbopol. The carbopol gels in presence of propylene glycol (PG) and ethanol were developed. The formulated gels were characterized for pH, viscosity, and LOR release using Franz diffusion cells. Also, in vitro skin permeation of LOR was conducted. The effect of hydroxypropyl ß-cyclodextrin (HP ß-CD), beta-cyclodextrin (ß-CD), Tween 80, and oleic acid on LOR permeation was evaluated. The optimized LOR gel formulation (LORF8) showed the highest flux (14.31 µg/cm(2)/h) with ER of 18.34 when compared to LORF3. Incorporation of PG and HP ß-CD in gel formulation (LORF8) enhanced the permeation of LOR significantly. It was observed that LORF3 and LORF8 show similar analgesic activity compared to marketed LOR injection (Xefo). This work shows that LOR can be formulated into carbopol gel in presence of PG and HP ß-CD and may be promising in enhancing permeation.

Pharmacokinetic interaction studies of fenugreek with CYP3A substrates cyclosporine and carbamazepine.

The present study investigated the effect of fenugreek seed powder on disposition of CYP3A substrates, cyclosporine and carbamazepine. Rabbits were treated with fenugreek seed powder (300 mg/kg p.o.) for 8 days and on 8th day the single dose of cyclosporine (30 mg/kg, p.o.) and carbamazepine (40 mg/kg, p.o.) were administered to the corresponding group after 1 h of fenugreek administration. Blood samples were drawn at several time points and analyzed by using UPLC-MS (cyclosporine) and HPLC (carbamazepine). Pharmacokinetic parameters were calculated by using PK Solver. The present investigation reveals that there was no statistically significant difference between pre- and post-treated pharmacokinetic parameters such as AUC(o-t), AUC(o-∞), C(max), T(max), T(1/2), K(el), MRT(o-∞) , V(z/F), and Cl/F for cyclosporine and carbamazepine. Two tailed "P" values for all these pharmacokinetic parameters were more than 0.05, indicating insignificant impact of fenugreek treatment on the disposition of cyclosporine and carbamazepine. Further, fenugreek may also not have any significant effect on the functionality of P-glycoprotein as cyclosporine is a substrate to P-glycoprotein. The outcomes of present study suggested that fenugreek may not likely to interfere cyclosporine and carbamazepine pharmacokinetics, when co-administered with these drugs.

Modulation of CYP2D6 and CYP3A4 metabolic activities by Ferula asafetida resin.

Present study investigated the potential effects of Ferula asafetida resin on metabolic activities of human drug metabolizing enzymes: CYP2D6 and CYP3A4. Dextromethorphan (DEX) was used as a marker to assess metabolic activities of these enzymes, based on its CYP2D6 and CYP3A4 mediated metabolism to dextrorphan (DOR) and 3-methoxymorphinan (3-MM), respectively. In vitro study was conducted by incubating DEX with human liver microsomes and NADPH in the presence or absence of Asafetida alcoholic extract. For clinical study, healthy human volunteers received a single dose of DEX alone (phase-I) and repeated the same dose after a washout period and four-day Asafetida treatment (phase-II). Asafetida showed a concentration dependent inhibition on DOR formation (in vitro) and a 33% increase in DEX/DOR urinary metabolic ratio in clinical study. For CYP3A4, formation of 3-MM in microsomes was increased at low Asafetida concentrations (10, 25 and 50 µg/ml) but slightly inhibited at the concentration of 100 µg/ml. On the other hand, in vivo observations revealed that Asafetida significantly increased DEX/3-MM urinary metabolic ratio. The findings of this study suggest that Asafetida may have a significant effect on CYP3A4 metabolic activity. Therefore, using Ferula asafetida with CYP3A4 drug substrates should be cautioned especially those with narrow therapeutic index such as cyclosporine, tacrolimus and carbamazepine.

Squalene-containing nanostructured lipid carriers promote percutaneous absorption and hair follicle targeting of diphencyprone for treating alopecia areata.

PURPOSE: Diphencyprone (DPCP) is a therapeutic agent for treating alopecia areata. To improve skin absorption and follicular targeting nanostructured lipid carriers (NLCs) were developed. METHODS: Nanoparticles were characterized by size, zeta potential, molecular environment, differential scanning calorimetry (DSC), and nuclear magnetic resonance (NMR). In vitro and in vivo skin absorption experiments were performed. Fluorescence and confocal microscopes for imaging skin distribution were used. RESULTS: NLCs with different designs were 208 ~ 265 nm with > 77% DPCP encapsulation. NLCs incorporating a cationic surfactant or more soybean phosphatidylcholine (SPC) showed higher lipophilicity compared to typical NLCs by Nile red emission. All NLCs tested revealed controlled DPCP release; burst release was observed for control. The formulation with more SPC provided 275 µg/g DPCP skin retention, which was greater than control and other NLCs. Intersubject deviation was reduced after DPCP loading into NLCs. Cyanoacrylate skin biopsy demonstrated greater follicular deposition for NLCs with more SPC compared to control. Cationic NLCs but not typical or SPC-containing carriers were largely internalized into keratinocytes. In vivo skin retention of NLCs with more SPC was higher than free control. Confocal imaging confirmed localization of NLCs in follicles and intercellular lipids of stratum corneum. CONCLUSIONS: This work encourages further investigation of DPCP absorption using NLCs with a specific formulation design.

Skin permeation of small-molecule drugs, macromolecules, and nanoparticles mediated by a fractional carbon dioxide laser: the role of hair follicles.

PURPOSE: To evaluate skin permeation enhancement mediated by fractional laser for different permeants, including hydroquinone, imiquimod, fluorescein isothiocyanate-labeled dextran (FD), and quantum dots. METHODS: Skin received a single irradiation of a fractional CO(2) laser, using fluence of 2 or 4 mJ with densities of 100 ∼ 400 spots/cm(2). In vitro and in vivo skin penetration experiments were performed. Fluorescence and confocal microscopies for imaging delivery pathways were used. RESULTS: The laser enhanced flux of small-molecule drugs 2 ∼ 5-fold compared to intact skin. A laser fluence of 4 mJ with a 400-spot/cm(2) density promoted FD flux at 20 and 40 kDa from 0 (passive transport) to 0.72 and 0.43 nmol/cm(2)/h, respectively. Microscopic images demonstrated a significant increase in fluorescence accumulation and penetration depth of macromolecules and nanoparticles after laser exposure. Predominant routes for laser-assisted delivery may be intercellular and follicular transport. CO(2) laser irradiation produced 13-fold enhancement in follicular deposition of imiquimod. Laser-mediated follicular transport could deliver permeants to deeper strata. Skin barrier function as determined by transepidermal water loss completely recovered by 12 h after irradiation, much faster than conventional laser treatment (4 days). CONCLUSIONS: Fractional laser could selectively enhance permeant targeting to follicles such as imiquimod and FD but not hydroquinone, indicating the importance of selecting feasible drugs for laser-assisted follicle delivery.

Effects of Lepidium sativum, Nigella sativa and Trigonella foenum-graceum on phenytoin pharmacokinetics in beagle dogs.

The present work was designed to evaluate the effect of some commonly used herbs viz. garden cress (Lepidium sativum), black seed (Nigella sativa) and fenugreek (Trigonella foenum-graceum) on the disposition of phenytoin after oral administration in a dog model. Phenytoin was given orally at a dose of 50 mg, and blood samples were obtained for the determination of drug's pharmacokinetic parameters. After a suitable washout period, animals were commenced on a specific herb treatment for one week. Garden cress treatment caused a modest increase in maximum observed concentration (Cmax ) and terminal half-life (T1/2λ ) of phenytoin with a reduction in clearance by 33%. The effect of black seed therapy was more drastic on drug elimination and to a lesser extent on its volume of distribution at steady state (Vss ) with a consequent reduction in systemic exposure measured by area under the curve (AUC0-∞ ) by about 87%. The effect of fenugreek therapy resembled, albeit to a lesser extent, that of black seed with a significant reduction in AUC0-∞ by ~72%. In addition, there was a 73% increase in Vss . Our findings suggest that the phenytoin disposition can be significantly altered by the concurrent consumption of tested herbal products.

Risk assessment of excess drug and sunscreen absorption via skin with ablative fractional laser resurfacing : optimization of the applied dose for postoperative care.

The ablative fractional laser is a new modality used for surgical resurfacing. It is expected that laser treatment can generally deliver drugs into and across the skin, which is toxicologically relevant. The aim of this study was to establish skin absorption characteristics of antibiotics, sunscreens, and macromolecules via laser-treated skin and during postoperative periods. Nude mice were employed as the animal model. The skin received a single irradiation of a fractional CO2 laser, using fluences of 4-10 mJ with spot densities of 100-400 spots/cm(2). In vitro skin permeation using Franz cells was performed. Levels of skin water loss and erythema were evaluated, and histological examinations with staining by hematoxylin and eosin, cyclooxygenase-2, and claudin-1 were carried out. Significant signs of erythema, edema, and scaling of the skin treated with the fractional laser were evident. Inflammatory infiltration and a reduction in tight junctions were also observed. Laser treatment at 6 mJ increased tetracycline and tretinoin fluxes by 70- and 9-fold, respectively. A higher fluence resulted in a greater tetracycline flux, but lower skin deposition. On the other hand, tretinoin skin deposition increased following an increase in the laser fluence. The fractional laser exhibited a negligible effect on modulating oxybenzone absorption. Dextrans with molecular weights of 4 and 10 kDa showed increased fluxes from 0.05 to 11.05 and 38.54 µg/cm(2)/h, respectively. The optimized drug dose for skin treated with the fractional laser was 1/70-1/60 of the regular dose. The skin histology and drug absorption had recovered to a normal status within 2-3 days. Our findings provide the first report on risk assessment of excessive skin absorption after fractional laser resurfacing.

Box-Behnken Design for Assessing the Efficiency of Aflatoxin M1 Detoxification in Milk Using Lactobacillus rhamnosus and Saccharomyces cerevisiae.

Milk contaminated with aflatoxin can lead to liver cancer. Aflatoxin B1 (AFB1), a serious animal feed contaminant, is transformed into Aflatoxin M1 (AFM1) and secreted in milk. In this study, a biological method using probiotic bacteria, Lactobacillus rhamnosus (L. rhamnosus) in combination with Saccharomyces cerevisiae (S. cerevisiae), was used to assess their antiaflatoxigenic effect in animal milk. A Box-Behnken design was used to establish the optimal ratio of L. rhamnosus and S. cerevisiae, incubation time, and temperature for efficient AFM1 detoxification from milk. To achieve this, the primary, interaction, and quadratic effects of the chosen factors were investigated. To investigate the quadratic response surfaces, a second-order polynomial model was built using a three-factor, three-level Box-Behnken design. The quantity of AFM1 was detected by the ELISA technique. The results of these experiments obtained an optimum condition in AFM1 detoxification of the three tested factors in order to maximize their effect on AFM1 detoxification in milk. The model was tested in three highly contaminated milk samples to assure the efficacy of the model. AFM1 detoxification was up to 98.4% in contaminated milk samples. These promising results provide a safe, low-cost, and low-time-consuming solution to get rid of the problem of milk contamination with AFM1.

In vitro and in vivo percutaneous absorption of seleno-L-methionine, an antioxidant agent, and other selenium species.

AIM: To investigate the in vitro and in vivo percutaneous absorption of seleno-L-methionine (Se-L-M), an ultraviolet (UV)-protecting agent, from aqueous solutions. METHODS: Aqueous solutions of Se-L-M were prepared in pH 4, 8, and 10.8 buffers. The pH 8 buffer contained 30% glycerol, propylene glycol (PG) and polyethylene glycol (PEG) 400. The in vitro skin permeation of Se-L-M via porcine skin and nude mouse skin was measured and compared using Franz diffusion cells. The in vivo skin tolerance study was performed, which examined transepidermal water loss (TEWL), skin pH and erythema. RESULTS: In the excised porcine skin, the flux was 0.1, 11.4 and 8.2 µg·cm(-2)·h(-1) for the pH 4, 8, and 10.8 buffers, respectively. A linear correlation between the flux and skin deposition was determined. According to permeation across skin with different treatments (stripping, delipidation, and ethanol treatments), it was determined that the intracellular route comprised the predominant pathway for Se-L-M permeation from pH 8 buffer. Aqueous solutions of seleno-DL-methionine (Se-DL-M), selenium sulfide and selenium-containing quantum dot nanoparticles were also used as donor systems. The DL form showed a lower flux (7.0 vs 11.4 µg·cm(-2)·h(-1)) and skin uptake (23.4 vs 47.3 µg/g) as compared to the L form, indicating stereoselective permeation of this compound. There was no or only negligible permeation of selenium sulfide and quantum dots into and across the skin. With in vivo topical application for 4 and 8 h, the skin deposition of Se-L-M was about 7 µg/g, and values were comparable to each other. The topical application of Se-L-M for up to 5 d did not caused apparent skin irritation. However, slight inflammation of the dermis was noted according to the histopathological examination. CONCLUSION: Se-L-M was readily absorbed by the skin in both the in vitro and in vivo experiments. The established profiles of Se-L-M skin absorption will be helpful in developing topical products of this compound.

Brand and generic medications: are they interchangeable?

BACKGROUND AND OBJECTIVES: Generic substitution has become a common practice since the late 1970s in the United States. At that time, many of these generics caused bioavailability problems, which fueled suspicions about their efficacy and safety, and the Food and Drug Administration (FDA) standards for bioequivalence. In Saudi Arabia, the increasing number of local products raised several concerns with regard to switching from brands to generics. Our objective was to review and examine the basis of the controversy surrounding brand and generic interchangeability and to explore a practical approach in pursuing a switch. DATA SOURCES: Articles indexed initially under terms such as generic medications, generic substitution, bioequivalence and bioinequivalence were identified. These terms were used to search the indexing service, MEDLINE (1966-2006). References from the extracted articles, and additional data sources, including the Code of Federal Regulations and Regulatory Guidance from the FDA Center for Drug Evaluation and Research were also reviewed. DATA SYNTHESIS: For most drugs, bioequivalence testing generally should enable clinicians to routinely substitute generic for innovator products. However, for narrow therapeutic, critical dose drugs, or for highly variable drugs, safe switching between products cannot be assured. These drugs need special precautions and blood level monitoring upon switching. FDA firmly believes that approved generic and brand drugs can be dispensed with the full expectation that the consumer will receive the same clinical benefit. CONCLUSION: Performing the switch process is an advisable practice to reduce health care costs in countries with strong post-marketing surveillance program, but caution is to be exercised when narrow therapeutic index drugs or highly variable drugs are prescribed.

Effect of Trigonella foenum-graecum L. on Metabolic Activity of CYP2D6 and CYP3A4.

BACKGROUND: The present study investigated the effect of fenugreek seeds powder and its alcoholic extract on metabolic activity of drug-metabolizing enzymes CYP2D6 and CYP3A4. MATERIALS AND METHODS: Dextromethorphan (DEX) was used as a probe for measuring metabolic activity, based on its CYP2D6- and CYP3A4-mediated metabolism to dextrorphan (DOR) and 3-methoxymorphinan (3-MM), respectively. For the in vitro investigations, DEX (25µM) was incubated with human liver microsomes and NADPH and tested with and without the fenugreek extract. For the in vivo study, phase I, 6 subjects received a single dose of DEX (30 mg); in phase II, after washout period, the fenugreek seeds powder was administered for 1 week and DEX was administered with its last dose. RESULTS: In vitro, fenugreek extract inhibits CYP2D6-mediated O-demethylation of DEX. Higher concentrations (50 and 100µg/ml) of extract inhibit CYP2D6 and CYP3A4 activity. In vivo results indicated that fenugreek does not significantly inhibit CYP2D6 and CYP3A4 metabolic activity. There was no significant change in the levels of DEX metabolites (DOR 12% and 3-MM 9%) excreted in urine and their urine metabolic ratios (P values: 0.257 and 0.333 DEX/DOR and DEX/3-MM, respectively). CONCLUSION: In vitro and in vivo observations suggested that fenugreek may not have substantial effect on the metabolic activity of CYP2D6 and CYP3A4.

In vitro--in vivo evaluation of tableted caseinchitosan microspheres containing diltiazem hydrochloride.

Casein-chitosan microspheres containing diltiazem hydrochloride (DTZ.HCL) were prepared using aqueous coacervation technique. The formed microspheres were not suitable for tableting by direct compression due to their poor binding properties. The effect of hydroxypropylmethylcellulose (HPMC), ethylcellulose (EC), carbopol 940 and egg albumin as dry binders at different concentrations on the properties of the tablets was studied. Each blend of microspheres with dry binder and 2% w/w magnesium stearate as glidant was hand-filled into the die cavity of a single punch tablet machine to ensure constant amount of drug (90 mg) in each tablet. The compression force was adjusted to produce tablets with hardness value about 7.73 +/- 0.79 Kp. The prepared tablets showed good appearance and low friability. The tested binders HPMC (10 and 30% w/w) and EC (20 and 30% w/w) gave fast tablet disintegration with high initial drug release (burst effect) while, carbopol 940 (5 and 10% w/w) and egg albumin (30% w/w) gave non-disintegrating tablets with low initial drug release. Tableted microspheres prepared with 30% egg albumin showed drug release profile similar to one of the commercial tablets (Dilzem retard, 90 mg) and was chosen for in-vivo study. Tableted microspheres and commercial tablets were administered orally in different occasions to six beagle dogs and diltiazem was assayed in dog plasma. The pharmacokinetic parameters including maximum drug concentration (Cmax) and time to reach that maximum (Tmax) were 106.24 +/- 17.96 ng.ml-1 and 5.8 +/- 2.04 hours, respectively, for the commercial sustained release DTZ tablets while, those were 107.9 +/- 12.89 ng.ml-1 and 3.6 +/- 1.36 hours, respectively for tableted microspheres. The elimination half-lives were nearly the same for the commercial and the formulated tablets (8.22 +/- 4.19 and 7.95 +/- 4.28 hours, respectively). No statistical differences (P > 0.05) were found between the two treatments for area under the plasma concentration curve (AUC0 infinity), mean residence time (MRT) and rate of drug absorption (Cmax/AUC0 infinity) indicating comparable extent and rate of drug absorption for both formulations. It was concluded that the formulated tableted microspheres provide an acceptable delivery for DTZ over an extended period of time.

Effect of Garden Cress Seeds Powder and Its Alcoholic Extract on the Metabolic Activity of CYP2D6 and CYP3A4.

The powder and alcoholic extract of dried seeds of garden cress were investigated for their effect on metabolic activity of CYP2D6 and CYP3A4 enzymes. In vitro and clinical studies were conducted on human liver microsomes and healthy human subjects, respectively. Dextromethorphan was used as a common marker for measuring metabolic activity of CYP2D6 and CYP3A4 enzymes. In in vitro studies, microsomes were incubated with NADPH in presence and absence of different concentrations of seeds extract. Clinical investigations were performed in two phases. In phase I, six healthy female volunteers were administered a single dose of dextromethorphan and in phase II volunteers were treated with seeds powder for seven days and dextromethorphan was administered with last dose. The O-demethylated and N-demethylated metabolites of dextromethorphan were measured as dextrorphan (DOR) and 3-methoxymorphinan (3-MM), respectively. Observations suggested that garden cress inhibits the formation of DOR and 3-MM metabolites. This inhibition of metabolite level was attributed to the inhibition of CYP2D6 and CYP3A4 activity. Garden cress decreases the level of DOR and 3-MM in urine and significantly increases the urinary metabolic ratio of DEX/DOR and DEX/3-MM. The findings suggested that garden cress seeds powder and ethanolic extract have the potential to interact with CYP2D6 and CYP3A4 substrates.

Nanostructured lipid carriers (NLCs) for drug delivery and targeting.

Nanostructured lipid carriers (NLCs) are drug-delivery systems composed of both solid and liquid lipids as a core matrix. It was shown that NLCs reveal some advantages for drug therapy over conventional carriers, including increased solubility, the ability to enhance storage stability, improved permeability and bioavailability, reduced adverse effect, prolonged half-life, and tissue-targeted delivery. NLCs have attracted increasing attention in recent years. This review describes recent developments in drug delivery using NLCs strategies. The structures, preparation techniques, and physicochemical characterization of NLCs are systematically elucidated in this review. The potential of NLCs to be used for different administration routes is highlighted. Special attention is paid to parenteral injection and topical delivery since these are the most common routes for investigating NLCs. Relevant issues for the introduction of NLCs to market, including pharmaceutical and cosmetic applications, are discussed. The related patents of NLCs for drug delivery are also reviewed. Finally, the future development and current obstacles needing to be resolved are elucidated.

Camptothecin-Loaded Liposomes with α-Melanocyte-Stimulating Hormone Enhance Cytotoxicity Toward and Cellular Uptake by Melanomas: An Application of Nanomedicine on Natural Product.

In this study, we attempted to develop functional liposomes loaded with camptothecin and attached to α-melanocyte-stimulating hormone (α-MSH) to target melanoma cells. The liposomes were mainly composed of phosphatidylcholine, cholesterol, and stearylamine, and were characterized by the vesicle size, zeta potential, camptothecin encapsulation efficiency, and release behavior. Results revealed that α-MSH liposomes possessed an average size of approximately 250 nm with a surface charge of 60 mV. Camptothecin was successfully entrapped by the targeted liposomes with an encapsulation percentage of nearly 95%. The liposomes provided sustained and controlled camptothecin release. Non-targeted liposomes with the drug exerted superior cytotoxicity against melanomas compared to the free control. Cell viability was reduced from 48% to 32% compared to conventional liposomes. Peptide ligand conjugation further promoted cytotoxicity to 18% viability, which was a 2.7-fold decrease versus the free control. According to the images of fluorescence microscopy, α-MSH liposomes exhibited greater cell endocytosis than did non-targeted liposomes and the free control. α-MSH liposomes were predominantly internalized in the cytoplasm. These findings demonstrate that α-MSH liposomes could enhance the anti-melanoma activity of camptothecin owing to their targeting ability and controlled drug delivery.