Microwave-Assisted Formation of Ternary Inclusion Complex of Pterostilbene

Pterostilbene (PTS) is a naturally occurring phytoalexin. PTS displays limited water solubility, which consequently results in its diminished oral bioavailability. Therefore, a ternary inclusion complex (TIC) of PTS with β-cyclodextrin (βCD) in the presence of ternary substance Pluronic® F-127 (PLF) was prepared using microwave technology. The PTS-TIC was characterized by dissolution performance. Further, the prepared TIC was characterized by DSC, FTIR, NMR, XRD, and SEM analysis. Additionally, the antioxidant activity of PTS and PTS-TIC was also evaluated. Phase-solubility studies revealed that PTS's solubility in water was increased by 6.72 times when βCD/PLF was present. In comparison with PTS, prepared PTS-TIC produced a considerable improvement in PTS release. After 1 h, 74.03 ± 4.47% of PTS was released from PTS-TIC. Outcomes of DSC, FTIR, NMR, XRD, and SEM analysis revealed that the PTS was enclosed in the βCD cavity. In terms of antioxidant properties, the PTS-TIC formulation demonstrated superior activity compared to PTS, possibly attributed to the improved solubility of PTS resulting from the formation of TIC using microwave technology. It was concluded that microwave technology proved to be an extremely beneficial means of interacting PTS with βCD. In addition to increasing the solubility of PTS, the findings are also expected to improve its bioavailability by increasing its solubility. As a result, this study could provide insight into potential methods for enhancing the solubility of polyphenolic substances like PTS.

Formulation and characterization of eprosartan mesylate and β-cyclodextrin inclusion complex prepared by microwave technology

The goal of this work was to improve the aqueous solubility and dissolution rate of eprosartan mesylate by preparing inclusion complex of drug with β-cyclodextrin (β-CD) by microwave technique. In order to determine the solubility of eprosartan, phase solubility was determined and dissolution study was also conducted. Further, analytical techniques for instance, particle size distribution, differential scanning calorimetry, powder X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy were used for the characterization of inclusion complex. In addition, the binding pattern of eprosartan with the β-CD was investigated by molecular modeling study. Phase solubility study revealed that approximately 4.48 folds improvement in the solubility of drug was noted with β-CD (10 mM). The estimated stability constant (K_c) values for eprosartan:β-CD binary mixture was found to be 280.78 M^–1. The prepared inclusion complex of drug with β-CD presented better drug release profile (62.96 ± 2.01% in 1 h) as compared to their physical mixture (41.41 ± 1.77% in 1 h) or drug per se (29.97 ± 3.13%). The inclusion complex demonstrated different features and properties from pure drug, and we inferred that this could be due to the inclusion of drug into cyclodextrin cavity that confirmed by different analytical method. Molecular modeling study demonstrated a good affinity of eprosartan to entangle to β-CD. The outcomes have shown that guest molecule has many significant interactions with the host molecule. These observations are very interesting and may be a valuable approach to improve the solubility and in turn the bioavailability of eprosartan.

Herb-drug interaction: Pharmacokinetics and pharmacodynamics of anti-hypertensive drug amlodipine besylate in presence of lepidium sativum and curcuma longa

1. Effects of Lepidium sativum and Curcuma longa were investigated on pharmacokinetics and pharmacodynamics of antihypertensive drug (amlodipine).2. Hypertensive rats were treated with amlodipine, Lepidium sativum, Lepidium sativum + amlodipine, Curcuma longa, and Curcuma longa + amlodipine; and their blood pressures were measured. Amlodipine in plasma samples was analysed using UPLC-TQD. Product ions of amlodipine were monitored at m/z 409.18 > 238 and 409.18 > 294; and of nitrendipine at m/z 361.16 > 315.1 and 361.16 > 329.10.3. Lepidium sativum + amlodipine treatment showed highest reduction in systolic blood pressure (SBP). Mean anti-hypertensive effect of Lepidium sativum and Curcuma longa was similar to amlodipine. Mean SBPs (1-24 h) of amlodipine, Lepidium sativum, Lepidium sativum + amlodipine, Curcuma longa, and Curcuma longa + amlodipine treated animals were found as 149.5 ± 2.4 mmHg, 151.6 ± 1.09 mmHg, and 141.8 ± 2.5 mmHg, 154.9 ± 2.2 mmHg and 144.4 ± 2.6 mmHg (p-values ≪0.05); respectively. Lepidium sativum and Curcuma longa significantly increased amlodipine C_max by 83% (p-value 0.018) and 53% (p-value 0.035); and AUC_0-t by 48% (p-value >0.05) and 56% (p-value 0.033); respectively.4. Results of pharmacokinetic and pharmacodynamic studies are in agreement. Lepidium sativum and Curcuma longa augment antihypertensive effect of amlodipine, which is also supported by pharmacokinetic observations.

Effects of garden cress, fenugreek and black seed on the pharmacodynamics of metoprolol: an herb-drug interaction study in rats with hypertension

CONTEXT

Garden cress (GC), fenugreek (FG), and black seed (BS) are traditional herbal medicine for managing hypertension.

OBJECTIVE

The effects of the three herbs on the pharmacodynamics of metoprolol tartrate (MT) in hypertensive rats were investigated.

MATERIALS AND METHODS

Wistar rats were divided in five groups (n = 6). Group I served as normal control group and Group II (hypertensive control group) had rats treated orally with N-nitro L-arginine methyl ester (L-NAME, 40 mg/kg/day) only. Groups III, IV, and V rats were orally treated with L-NAME (40 mg/kg/day) + GC (300 mg/kg, once daily), L-NAME (40 mg/kg/day) + FG (300 mg/kg, once daily) and L-NAME (40 mg/kg/day) + BS (300 mg/kg, once daily), respectively, for 2 weeks, and on the 14th day, blood pressure and heart rate were recorded using a tail-cuff blood pressure-measuring system. On the 16th day, a single dose of MT (10 mg/kg) was orally administered, and the rats' blood pressure and heart rate were recorded.

RESULTS

GC, FG, and BS decreased systolic blood pressure (SBP) by 8.7%, 8.5%, and 8.7%, respectively, in hypertensive rats. A greater decrease in SBP by 14.5%, 14.8%, and 16.1% was observed when hypertensive rats were treated with L-NAME + GC + MT, L-NAME + FG + MT, and L-NAME + BS + MT, respectively. Similarly, hypertensive rats treated with the combination of herbs and MT had significantly lower diastolic blood pressure (DBP) than those treated with herbs alone and those treated with L-NAME alone.

CONCLUSIONS

The combination of investigated herbs and MT had a beneficial effect on hypertension. However, the concurrent administration of drugs, particularly those predominantly cleared through CYP450 2D6-catalyzed metabolism, with the three investigated herbs should be considered with caution.

Assessment of glibenclamide pharmacokinetics in poloxamer 407-induced hyperlipidemic rats

The aim of the present research was to describe the consequences of hyperlipidemia (HL) on the pharmacokinetics of glibenclamide (Gb) in poloxamer 407-induced hyperlipidemic rats. Rats were given intraperitoneal dose of poloxamer 407 to cause hyperlipidemia. A single oral dose of Gb (10 mg/Kg) was given to normal and HL rats. The C_max and t_max after oral dose of Gb in normal rats were 340.10 µg/ml and 3.67 h, respectively. Whereas, the C_max and t_max after oral dose of Gb in HL rats were noted as 773.39 µg/ml and 2.50 h respectively. The AUC value of Gb was found considerably higher in the HL rats. While the plasma clearance (CL) after oral dose of Gb was 2.53 ml/h and 1.39 ml/h in normal and HL rats respectively. The improved plasma concentration of Gb following oral dosing in rats with HL seems to be due to a direct influence on hepatic clearance or metabolizing enzymes. In conclusion, the Gb pharmacokinetics was considerably affected by the HL in rats. Such findings play an important role for predicting the alterations in the pharmacokinetics of drugs including GB, in cases having hyperlipidemia.

Effect of Hibiscus sabdariffa and Zingiber officinale on pharmacokinetics and pharmacodynamics of amlodipine

OBJECTIVES

To study the effect of Zingiber officinale and Hibiscus sabdariffa on pharmacokinetics and pharmacodynamics of amlodipine.

METHODS

Hypertension was induced in rats (SBP 173.2 ± 1.7 mmHg, mean, 1-24 h). Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP) and heart rate (HR) of group-I (amlodipine treated), group-II (Z. officinale, and Z. officinale + amlodipine) and group-III (H. sabdariffa, and H. sabdariffa + amlodipine) animals were measured by "tail-cuff system". Pharmacokinetics of amlodipine with and without herbs (Z. officinale or H. sabdariffa) was also investigated.

RESULTS

Z. officinale as well as H. sabdariffa decreased the SBP, DBP and MBP. Concurrent treatment with Z. officinale + amlodipine (SBP 129.4 ± 4.5) or H. sabdariffa + amlodipine (SBP 130.4 ± 3.9) showed higher decrease in BP (mean, 1-24h), than individually administered amlodipine (SBP 149.5 ± 2.4) or Z. officinale (SBP 150.2 ± 3.1) or H. sabdariffa (SBP 139.1 ± 1.2). These herbs also influenced the Cmax, AUC0-t, and Tmax of amlodipine. H. sabdariffa increased AUC0-t of amlodipine from 81.8 ± 14.7 to 125.0 ± 10.6 (ng h/mL).

CONCLUSION

Simultaneous administration of Z. officinale or H. sabdariffa with amlodipine, improves its pharmacodynamic response.

Delivery of Insulin via Skin Route for the Management of Diabetes Mellitus: Approaches for Breaching the Obstacles

Insulin is used for the treatment of diabetes mellitus, which is characterized by hyperglycemia. Subcutaneous injections are the standard mode of delivery for insulin therapy; however, this procedure is very often invasive, which hinders patient compliance, particularly for individuals requiring insulin doses four times a day. Furthermore, cases have been reported of sudden hypoglycemia occurrences following multidose insulin injections. Such an invasive and intensive approach motivates the quest for alternative, more user-friendly insulin administration approaches. For example, transdermal delivery has numerous advantages, such as prolonged drug release, low variability in the drug plasma level, and improved patient compliance. In this paper, the authors summarize different approaches used in transdermal insulin delivery, including microneedles, chemical permeation enhancers, sonophoresis, patches, electroporation, iontophoresis, vesicular formulations, microemulsions, nanoparticles, and microdermabrasion. Transdermal systems for insulin delivery are still being widely researched. The conclusions presented in this paper are extracted from the literature, notably, that the transdermal route could effectively and reliably deliver insulin into the circulatory system. Consistent progress in this area will ensure that some of the aforementioned transdermal insulin delivery systems will be introduced in clinical practice and commercially available in the near future.

Investigating Non-Therapeutic Pharmaceutical Substances for Improving In-Vitro Efficacy of Clindamycin Phosphate Against MRSA and Staphylococcus Epidermidis

The aim of present study was to investigate the effect of pharmaceutical excipients and other active substances on antimicrobial efficacy of standard antibiotic against resistant and susceptible microorganisms. Pharmaceutical excipients (sodium lauryl sulfate [SLS], Tween-80, citric acid, NaOH, NaCl) and active substances (fusidic acid, sorbic acid) were investigated to check in-vitro efficacy and their effect on the efficacy of standard antibiotic. Clindamycin was selected as standard antibiotic. Clindamycin was found to be ineffective against methicillin-resistant Staphylococcus aureus (MRSA). Fusidic acid and SLS showed concentration dependent effect against MRSA. Other tested substances were also ineffective against MRSA, and also failed to improve the susceptibility of MRSA towards clindamycin. The clindamycin + fusidic acid (0.05 µg, 0.1 µg), and clindamycin + SLS (0.5 mg, 1 mg) showed concentration dependent effect on Staphylococcus epidermidis (S. epidermidis). Clindamycin combinations with fusidic acid or SLS showed better inhibition of S. epidermidis, than individual substance. At lower concentration of clindamycin (2 µg), the sorbic acid (25 µg) improves its effectiveness. SLS (0.5 mg, 1 mg) and clindamycin (4 µg, 10 µg) showed almost equal zone of inhibition against S. epidermidis, respectively. Present findings showed that certain pharmaceutical excipients (e.g. SLS) are effective against resistant and susceptible microbes, and suggested that more excipients should be screened for their antimicrobial potential and their ability to improve the efficacy of standard antibiotics.

Effect of Hibiscus sabdariffa and Zingiber officinale on the antihypertensive activity and pharmacokinetic of losartan in hypertensive rats

The present study aimed to determine the effect of Hibiscus sabdariffa and Zingiber officinale on antihypertensive activity and pharmacokinetic of losartan in hypertensive rats.Hypertension was induced in rats by oral administration of L-NAME (40 mg/kg per day). Pharmacodynamics and pharmacokinetics of losartan were evaluated without and with herbal treatment in hypertensive rats.Treatment of hypertensive rats with investigated herbs substantially reduced systolic blood pressure (SBP), and diastolic blood pressure (DBP) of rats. Treatment of rats (n = 5) with L-NAME plus H. sabdariffa plus losartan and L-NAME plus Z. officinale plus losartan reduced SBP by 16.20% and 14.88% and DBP by 14.82% and 17.52% respectively after 12 h, as compared to L-NAME alone treated rats. In a pharmacokinetic study, the Cmax and AUC0-t of losartan in L-NAME plus H. sabdariffa plus losartan and L-NAME plus Z. officinale plus losartan treated rats was increased by 0.7, 1.99 and 1.51, 3.00 fold respectively in comparison to the Cmax and AUC0-t obtained for L-NAME plus losartan treated group. In conclusion, both the investigated herbs significantly increased the antihypertensive effect and plasma concentration of losartan in L-NAME induced hypertensive rats. The current study predicted that the herb-drug interaction between H. sabdariffa-losartan and Z. officinale-losartan could occur; hence these results in rats may warrant further studies in humans, either in humans or in in vitro human liver microsomes.

Potential pharmacodynamic and pharmacokinetic interactions of Nigella Sativa and Trigonella Foenum-graecum with losartan in L-NAME induced hypertensive rats

The objective of this investigation was to study whether Nigella Sativa and Trigonella Foenum-graecum, could modulate the losartan pharmacodynamic (PD) and pharmacokinetic (PK) in experimental L-NAME induced hypertensive rats. For in vivo study, the systolic blood pressure (SBP) of rats was measured by the “tail-cuff system” after the treatment of rats with herb alone and herb + losartan in hypertensive rats. The SBP of rats treated with L-NAME + losartan also recorded. For the PK study, blood samples were obtained for up to 12 h to determine the concentrations of the drug, and various PK parameters were calculated. The data displayed that the SBP was significantly (p < 0.05) decreased in the rats when administered with L-NAME + N. Sativa or L-NAME + T. Foenum-graecum in contrast to the rats administered with L-NAME alone. A more prominent decline (p < 0.05) in SBP was detected in rats administered with L-NAME + N. Sativa + losartan and L-NAME + T. Foenum-graecum + losartan. In a PK study, higher losartan C_max and AUC_0-t were noted in rats treated with N. Sativa + losartan and T. Foenum-graecum + losartan, although the difference was not significant in contrast to the control group. This study proposed that the interaction between N. Sativa & losartan and T. Foenum-graecum & losartan could take place on concurrent administration; consequently, the dose of losartan may need to be accustomed when they are utilized simultaneously.

Effects of sinapic acid on hepatic cytochrome P450 3A2, 2C11, and intestinal P-glycoprotein on the pharmacokinetics of oral carbamazepine in rats: Potential food/herb-drug interaction

Dietary supplements, herbal medicines, and other foods may affect the pharmacokinetics and/or pharmacodynamics of carbamazepine (CBZ), which may possibly lead to potential drug-drug/herb-drug interactions, as CBZ has a narrow therapeutic window. Sinapic acid (SA) is a bioactive phytoconstituent used as a dietary supplement for the treatment of epilepsy. This study determined the effects of SA on the pharmacokinetics of CBZ and proposed a possible interaction mechanism in twenty-four male wistar rats (180-210 g). A single CBZ dose (80 mg/kg) was administered orally to rats with or without SA pretreatment (20 mg/kg p.o. per day for 7 days, n = 6). The CBZ concentration in plasma samples was determined by using a sensitive reversed-phase high-performance liquid chromatography assay. The pharmacokinetic parameters were calculated by using non-compartmental analysis. Significance was determined through Dunnett's multiple comparison test or one-way analysis of variance as appropriate; p < 0.05 were considered significant. The change in the pharmacokinetic parameters (C_max, T_max, AUC_0-t, AUC_0-∞, T_½, and k_el) of CBZ was evaluated after the administration of CBZ alone or after CBZ co-administration with SA pretreatment. The plasma concentration of CBZ was higher after SA pretreatment than that without pretreatment. The pharmacokinetics of orally administered CBZ were found to be significantly altered (p < 0.05) in rats pretreated with SA compared to those in rats administered CBZ alone. The increases in the C_max, AUC_0-t, T_1/2, and MRT of CBZ were 29.79%, 57.18%, 77.18%, and 58.31%, respectively, whereas the k_el and apparent oral CL/F were significantly reduced (p < 0.05) in rats pretreated with SA compared to those in rats not pretreated with SA (43.87% and 42.50%, respectively). However, no significant change was observed in the T_max of CBZ in rats pretreated with SA compared to that in rats that did not receive pretreatment. The enhancement in Cmax, AUC_0-t, T_1/2, and MRT and the reduction in K_el and CL/F values resulted from the significant inhibition of CYP3 A2, the CYP2C11-mediated metabolism of CBZ in the liver, and the inhibition of intestinal P-glycoprotein/MDR1, which enhanced the rate of CBZ absorption. Further studies are required to determine the clinical relevance of these observations.

Sorbitane Monostearate and Cholesterol based Niosomes for Oral Delivery of Telmisartan

BACKGROUND

Niosomes are non-ionic surfactant vesicles used as drug carriers for encapsulating both hydrophobic and hydrophilic drugs. The aim of the present study was to prepare and characterize niosomes formulations for oral delivery of telmisartan and evaluated for its antihypertensive activity.

METHOD

Telmisartan loaded niosomes were prepared using thin film hydration method by varying the Span 60 and cholesterol at several molar ratios and characterized for vesicles size, polydispersity index, zeta potential, entrapment efficiency. The in vivo antihypertensive study of optimized formulation and molecular impact of angiotensin II type-1 receptor (AT1R) messenger Ribonucleic acid (mRNA) and protein expression on smooth vascular muscles of aorta was determined by real-time polymerase chain reaction (RT-PCR) and western blot analysis in Wistar albino rats.

RESULTS

The optimized niosomes formulation NS6 presented vesicles size of 618.47 nm, polydispersity index of 0.86, with entrapment efficiency of 83.83% and possesses negative charge. In vivo study showed that the optimized formulation could reduce the systolic blood pressure in methyl prednisolone acetate induced hypertensive rats in close proximity to normal range of systolic blood pressure and maintain it over an extended period. In addition, telmisartan loaded niosomes treatment to hypertensive rats significantly attenuates the raised mRNA level and protein level of AT1R gene in comparison to hypertensive rats.

CONCLUSION

Results of present study confer the potential of developed niosomes as suitable carriers for improved oral delivery of telmisartan.

Effect of sinapic acid on aripiprazole pharmacokinetics in rats: Possible food drug interaction

Dietary supplements and foods can interact with various drugs, leading to possible clinical concerns. This study aimed to investigate the effect of orally administered sinapic acid (SA) on the pharmacokinetics of aripiprazole (APZ) in rats and its possible modulatory effects on hepatic cytochrome P450 (CYP3A2 and CYP2D6) expression in the liver tissues. Single dose and multiple dose parallel groups of wistar rats were categorized into six groups (n = 6 each) which abstained from food for 12 h prior to the experiment, while water was allowed ad libitum. The investigation was carried out for single dose: Group I was treated with normal saline orally for 15 days (normal control). Group II was administered normal saline orally for 15 days and received APZ (3 mg/kg p.o.) on day 15. Group III received SA (20 mg/kg p.o.) for 15 days and received APZ (3 mg/kg p.o.) on day 15. Group IV was treated with SA (20 mg/kg p.o.) for 15 days. For the multiple dose study, Group I was treated with normal saline orally for 15 days (normal control); Group II received APZ (3 mg/kg p.o.) daily for 15 days; Group III was administered with SA (20 mg/kg p.o.) and APZ (3 mg/kg p.o.) for 15 days and Group IV received SA (20 mg/kg p.o.) for 15 days. The group I and IV were kept common in single and multiple dose groups. After last APZ dose, plasma samples were collected and APZ concentrations were determined using an UPLC-MS/MS technique. The pharmacokinetic parameters were calculated using a non-compartmental analysis. The concomitant administration of APZ with SA (as single or multiple dose) resulted in an increase in APZ absorption and a decrease on its systemic clearance. This was associated with a reduction in CYP3A2 and CYP2D6 protein expressions by 33-43% and -71-68% after the single and multiple co-administration, which are two enzymes responsible of the metabolism of APZ. Therefore, a reduction in the metabolic clearance appears to be the mechanism underlying the drug interaction of dietary supplement containing SA with APZ. Therefore, the concomitant administration of SA and APZ should be carefully viewed. Further investigations are required to assess the clinical significance of such observations in humans.

Solubility determination of raloxifene hydrochloride in ten pure solvents at various temperatures: Thermodynamics-based analysis and solute-solvent interactions

The purpose of the present study was to determine the solubility of raloxifene hydrochloride (RHCl) in ten solvents: water, ethanol, isopropyl alcohol (IPA), ethylene glycol (EG), propylene glycol (PG), polyethylene glycol-400 (PEG-400), Transcutol, 1-butanol, dimethyl sulfoxide (DMSO), and ethyl acetate (EA) at temperatures of 298.2-323.2 K and a pressure of 0.1 MPa. The solubility data obtained was fitted upon "Apelblat and Van't Hoff" equations. The maximum mole fraction solubility of RHCl was obtained in DMSO (5.02 × 10^-2 at 323.2 K), followed by PEG-400 (5.92 × 10^-3 at 323.2 K), EA (3.11 × 10^-3 at 323.2 K), Transcutol (1.22 × 10^-3 at 323.2 K), PG (2.19 × 10^-4 at 323.2 K), 1-butanol (1.96 × 10^-4 at 323.2 K), IPA (1.47 × 10^-4 at 323.2 K), ethanol (7.90 × 10^-5 at 323.2 K), EG (6.65 × 10^-5 at 323.2 K), and water (3.60 × 10^-5 at 323.2 K). Similar fashions were noticed at each studied temperature. The higher solubility of RHCl in DMSO, PEG-400, EA, and Transcutol was possibly referable to their lower polarity in comparison with water. The molecular interactions between the solute and solvent molecules were estimated by calculating parameters like activity coefficients, and more prominent solute-solvent molecular interactions were noted for RHCl-DMSO, RHCl-EA, and RHCl-PEG-400 in comparison with the other solute-solvent combinations. The outcomes of the "apparent thermodynamic analysis" showed that the dissolution of RHCl was "endothermic, spontaneous and entropy-driven" in all investigated solvents. The obtained solubility data of RHCl in commonly used solvents could be useful in the purification, recrystallization, and dosage form design of the drug.

Development and biological evaluation of vesicles containing bile salt of telmisartan for the treatment of diabetic nephropathy

The aim of present study was to develop and evaluate vesicles containing bile salt formulation of telmisartan for the treatment of diabetic nephropathy. Different vesicles containing bile salt formulations were developed by varying ratios of soybean phosphatidylcholine and sodium deoxycholate. Prepared formulations were characterized for their size, polydispersity index, zeta potential, morphology and entrapment efficiency. Further, the renoprotective outcome of optimized formulation was studied in streptozotocin-induced diabetic nephropathy rat model. Results of the present study demonstrated that the average vesicles size, polydispersity index, zeta potential and entrapment efficiency were found to be in the range of 64.98 ± 1.40 to 167.60 ± 6.46 nm, 0.02 ± 0.04 to 0.31 ± 0.01, -24.30 ± 1.39 to -42.60 ± 6.67 mV and 29.68 ± 1.08% to 77.21 ± 0.52%, respectively. Further, the best chosen formulation F4 presented vesicles size, polydispersity index, zeta potential and entrapment efficiency of 64.98 ± 1.40 nm, 0.24 ± 0.02, -35.40 ± 1.48 mV and 77.21 ± 0.52%, respectively. In addition, formulation F4 improved the biological indices in streptozotocin-induced diabetic nephropathy in rats. It was concluded that prepared formulation exerts a valuable results on diabetic nephropathy and it may be a potential pharmaceutical dosage form for the treatment of diabetic nephropathy.

Eprosartan mesylate loaded bilosomes as potential nano-carriers against diabetic nephropathy in streptozotocin-induced diabetic rats

The objective of the present study was to formulate eprosartan mesylate loaded nano-bilosomes and investigates its potential for controlling streptozotocin induced diabetes nephropathy in Wistar rats. The eprosartan mesylate loaded nano-bilosomes comprising of various ratios of soybean phosphatidylcholine/sodium deoxycholate were prepared by thin film hydration technique. The prepared formulations were evaluated for vesicles size, polydispersity index, zeta potential and entrapment efficiency. Further the optimized formulation was characterized for vesicles morphology, and its efficacy for the management of diabetic nephropathy in Wistar rats. The optimized eprosartan mesylate loaded nano-bilosomes exhibited vesicles size, polydispersity index, zeta potential and entrapment efficiency of 63.88±3.46nm, 0.172±0.026, -30.40±2.75mV and 61.19±0.88% respectively. In vivo activity demonstrated that the prepared eprosartan mesylate loaded nano-bilosomes formulation demonstrated a nephro-protecting outcome as shown by the substantial decrease in serum creatinine, urea, lactate dehydrogenase, total albumin, and malondialdehyde. Additionally, an oral administration of eprosartan mesylate loaded nano-bilosomes decreases the raised expressions of Angiotensin II type 1 receptor, inducible nitric oxide synthase, and transforming growth factor-β1 in Wistar rats. Further, histopathological examination established the nephro-protective effect of prepared formulation. In conclusion, the research work in the paper suggests that the prepared eprosartan mesylate loaded nano-bilosomes could serve as a practical oral formulation for diabetic nephropathy in future therapy and may offer potential benefits in cases with hypertension and renal disease.

Solubility and Thermodynamic Analysis of Antihypertensive Agent Nitrendipine in Different Pure Solvents at the Temperature Range of 298.15 to 318.15°K

The aim of the present study was to ascertain the solubility of nitrendipine (NP), an antihypertensive drug in six different pure solvents such as water, ethyl acetate (EA), ethanol, isopropyl alcohol (IPA), polyethylene glycol-400 (PEG-400), and Transcutol at temperature from 298.15 to 318.15 K under atmospheric pressure (p) of 0.1 MPa. Experimental solubility data of NP was fitted with Apelblat and ideal models. The mole fraction solubility of NP was found maximum in PEG-400 (6.85 × 10^-2 at 318.15 K) followed by Transcutol (4.65 × 10^-2 at 318.15 K), EA (1.68 × 10^-2 at 318.15 K), ethanol (2.83 × 10^-3 at 318.15 K), IPA (2.69 × 10^-3 at 318.15 K), and water (1.29 × 10^-7 at 318.15 K). The dissolution activity of NP was observed as an endothermic, spontaneous, and an entropy-driven in most of studied pure solvents. The solubility data of NP obtained in the present study could be useful in purification, recrystallization, and dosage forms design of NP.

Effects of Paeonia emodi on hepatic cytochrome P450 (CYP3A2 and CYP2C11) expression and pharmacokinetics of carbamazepine in rats

Herbal medicines, dietary supplements, and other foods may pharmacokinetically and/or pharmacodynamically interact with carbamazepine (CBZ), which could lead to potential clinical consequences. Paeonia emodi (PE) is one of the herbs used as complementary therapy in the treatment of epileptic patients in some cultures, and may also be co-administered with CBZ. This study evaluates the effects of PE on the pharmacokinetics of CBZ and determines a possible mechanism of interaction. Rats were administered vehicle saline or PE (200mg/kg, p.o. daily for 7days), then administered a single CBZ dose (80mg/kg, p.o.) on day 7. Plasma samples were analyzed for CBZ concentrations using a sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) assay. Pharmacokinetic parameters were calculated using non-compartmental analysis. The co-administration of PE with CBZ resulted in increased plasma maximum concentration (C_max), area under the curve (AUC_0-∞), and half-life (T_½), by 14.61%, 48.12%, and 43.72%, respectively. The calculated oral clearance (CL/F) was reduced by 33.54%, while the volume of distribution (V_ss) was unaffected. The PE extract also showed a significant potential to reduce CYP3A and CYP2C protein expression by approximately 50%. Therefore, a reduction in the metabolic capacity responsible for CBZ clearance appears to be the mechanism behind this herb-drug interaction. Consequently, the concomitant administration of PE and CBZ should be viewed cautiously. Further studies are needed to determine the clinical relevance of these observations.

Oral bioavailability enhancement and hepatoprotective effects of thymoquinone by self-nanoemulsifying drug delivery system

Thymoquinone (TQ) is a poorly water soluble bioactive compound which shows poor oral bioavailability upon oral administration. Due to poor aqueous solubility and bioavailability of TQ, various self-nanoemulsifying drug delivery systems (SNEDDS) of TQ were developed and evaluated for enhancement of its hepatoprotective effects and oral bioavailability. Hepatoprotective and pharmacokinetic studies of TQ suspension and TQ-SNEDDS were carried out in rat models. Different SNEDDS formulations of TQ were developed and thermodynamically stable TQ-SNEDDS were characterized for physicochemical parameters and evaluated for drug release studies via dialysis membrane. Optimized SNEDDS formulation of TQ was selected for further evaluation of in vivo evaluation. In vivo hepatoprotective investigations showed significant hepatoprotective effects for optimized TQ-SNEDDS in comparison with TQ suspension. The oral administration of optimized SNEDDS showed significant improvement in in vivo absorption of TQ in comparison with TQ suspension. The relatively bioavailability of TQ was enhanced 3.87-fold by optimized SNEDDS in comparison with TQ suspension. The results of this research work indicated the potential of SNEDDS in enhancing relative bioavailability and therapeutic effects of natural bioactive compounds such as TQ.

Formulation and characterization of novel soft nanovesicles for enhanced transdermal delivery of eprosartan mesylate

The objective of the present work was to formulate, optimize and evaluate the potential of novel soft nanovesicles i.e. nano-transfersomes, containing eprosartan mesylate (EM) for transdermal delivery. Nano-transfersomes of EM were developed using Phospholipon 90G, Span 80 (SP) and sodium deoxycholate (SDC) and characterized for vesicle size, shape, entrapment efficiency, in vitro skin permeation study and confocal laser scanning microscopy. The optimized nano-transfersomes formulation showed vesicles size of 108.53 ± 0.06 nm and entrapment efficiency of 63.00 ± 2.76%. The optimized nano-transfersomes provided an improved transdermal flux of 27.22 ± 0.29 µg/cm²/h with an enhancement ratio of 16.80 over traditional liposomes through Wistar rat skin. Confocal laser microscopy of rat skin treated with the optimized formulation showed that the formulation was eventually distributed and permeated deep into the rat skin. The present investigation has shown that the nature and concentration of surfactants (edge activators) influence immense control on the characteristics of nano-transfersomes. It was concluded that the developed nano-transfersomes surmount the limitation of low penetration ability of the traditional liposomes across the rat skin. Improved drug delivery presented by nano-transfersomes establishes this system as an encouraging dosage form for the delivery of EM via skin route.

Hepatoprotective activity of Lepidium sativum seeds against D-galactosamine/lipopolysaccharide induced hepatotoxicity in animal model

BACKGROUND

Fulminant hepatic failure (FHF) is clinical syndrome with very poor prognosis and high mortality there is urgent need for the development of safe and non-toxic hepatoprotective agents for the adequate management of hepatitis. Hepatoprotective effect of the Lepidium sativum ethanolic extract (LSEE) was assessed by D-galactosamine-induced/lipopolysaccharide (400 mg/kg and 30 μg/kg) liver damage model in rats.

METHODS

Hepatoprotective activity of LSEE (150 and 300 mg/kg) and silymarin on D-GalN/LPS induced FHF in rat was assessed using several liver function enzyme parameters. Antioxidant properties as antioxidant stress enzymes were assessed in hepatic Liver as well as mRNA expression of cytokines genes such as TNF-α, IL-6, and IL-10 and stress related genes iNOS and HO-1 were determined by RT-PCR. Protein expression of apoptotic genes were evaluated through western blot. MPO and NF-κB DNA-binding activity was analyzed by ELISA. The magnitude of hepatic impairment was investigated through histopathological evaluation.

RESULTS

Marked amelioration of hepatic injuries by attenuation of serum and lipid peroxidation has been observed as comparable with silymarin (25 mg/kg p.o). D-GalN/LPS induced significant decrease in oxidative stress markers protein level, and albumin. LSEE significantly down-regulated the D-GalN/LPS induced pro-inflammatory cytokines TNFα and IL-6 mRNA expression in dose dependent fashion about 0.47 and 0.26 fold and up-regulates the IL-10 by 1.9 and 2.8 fold, respectively. While encourages hepatoprotective activity by down-regulating mRNA expression of iNOS and HO-1. MPO activity and NF-κB DNA-binding effect significantly increased and was mitigated by LSEE in a dose-dependent style as paralleled with silymarin.

CONCLUSION

Our data suggests that pretreatment of LSEE down regulates the caspase 3 and up-regulates the BCl₂ protein expression. The above findings revealed that Lepidium sativum has significant hepatoprotective activity.

Antioxidant Potential and In Situ Analysis of Major and Trace Element Determination of Ood-saleeb, a Known Unani Herbal Medicine by ICP-MS

The intention of the present research work was to investigate the antioxidant activity and trace element analysis of Ood-saleeb, a known herbal medicine. Preliminary screening of phytochemicals showed that the extract of Ood-saleeb had flavonoids and phenolics. The significant activities in all antioxidant assays were observed in the extract of Ood-saleeb in comparison with the standard antioxidant with respect to dose of Ood-saleeb. Incredible activities to scavenge reactive oxygen species were also observed by the extract of Ood-saleeb. The IC50 values of all factors were determined using ascorbic acid as a standard. The inductive coupled plasma-mass spectroscopy (ICP-MS) was employed for the estimation of trace elements in Ood-saleeb extract. The concentrations of up to 18 elements were detected successfully. Silicon was found in high concentration (85.3 μg/g) while lithium was in low concentration (3 ng/g). The trace elements in the sample were found at different percentage levels which play a key role in the treatment of diseases.

Prevalence of UDP-glucuronosyltransferase polymorphisms (UGT1A6∗2, 1A7∗12, 1A8∗3, 1A9∗3, 2B7∗2, and 2B15∗2) in a Saudi population

Glucuronidation is an important phase II pathway responsible for many endogenous substances and drug metabolism. The present work evaluated allele frequencies of certain UDP-glucuronosyl-transferases (UGT 1A6∗2, A7∗12, A8∗3, A9∗3, 2B7∗2, and 2B15∗2) in Saudi Arabians that could provide essential ethnic information. Blood samples from 192 healthy unrelated Saudi males of various geographic regions were collected. Genomic DNA was isolated and genotyping of various UGTs was carried out using polymerase chain reaction (PCR) followed by direct sequencing. For UGT1A6∗2 A/G genotype, the most common variant was the homozygous repeat (AA) and the most common allele was (A) with a frequency of 46.5% and 67.3%, respectively. Similarly, the most common variant for UGT1A7∗12 T/C genotype was the heterozygous repeat (TC) with a frequency of 78.7% while the mutant allele (C) was present in 60.6% of the study population. Both UGT1A8∗3 (G/A) and UGT1A9∗3 (T/C) showed only a wild homozygous pattern in all screened subjects. For UGT2B7∗2, the heterozygous repeat (TC) was found with a frequency of 57.3% and the alleles (A) showed a frequency of 50.8%. In contrast, for UGT2B15∗2 (G253T), the heterozygous repeat (TG) presented 62.3% of the subjects where the most common allele (G) was with a frequency of 66.2%. In conclusion, our data indicate that Saudis harbor some important UGT mutations known to affect enzyme activity. Additional studies are therefore, warranted to assess the clinical implications of these gene polymorphisms in this ethnic group.

Effervescence Assisted Fusion Technique to Enhance the Solubility of Drugs

The solubility of five poorly soluble drugs was enhanced by using an effervescence assisted solid dispersion (EASD) technique. EASDs were prepared by using modified fusion method. Drug and hydrophilic carrier were melted, and in this molten mixture, effervescence was generated by adding effervescence couple comprising organic acid (citric acid) and carbonic base (sodium bicarbonate). Solubility of drug powders, solid dispersions, and EASDs was determined at 25°C using shake flask method. Atorvastatin calcium, cefuroxime axetil, clotrimazole, ketoconazole, and metronidazole benzoate were estimated using a spectrophotometer at 246, 280, 260, 230, and 232 nm (λ max), respectively. Solubility of atorvastatin calcium (from 100 to 345 μg/ml), cefuroxime axetil (from 441 to 1948 μg/ml), clotrimazole (from 63 to 677 μg/ml), ketoconazole (from 16 to 500 μg/ml), and metronidazole benzoate (from 112 to 208 μg/ml) in EASDs was enhanced by 3.45-, 4.4-, 10.7-, 31.2-, and 1.8-fold, respectively. Scanning electron micrographs of drug powder, solid dispersion, and EASDs were compared. Scanning electron micrographs of EASDs showed a uniform distribution of drug particles in the carrier matrix. Morphology (size and shape) of cefuroxime axetil particles was altered in solid dispersion as well as in EASD. EASDs showed better solubility enhancement than conventional solid dispersions. The present technique is better suitable for drugs having a low melting point or melt without charring. Effervescence assisted fusion technique of preparing solid dispersions can be employed for enhancing solubility, dissolution, and bioavailability of poorly soluble drugs.

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.

Understanding and managing oral bioavailability: physiological concepts and patents

Oral delivery of poorly bioavailable therapeuticals is challenging. The challenges are more serious when physiological factors of gut such as cytochrome P450, P-glycoprotein, permeability, pH triggered precipitation and degradation are responsible for poor bioavailability. P-Glycoprotein mediated multidrug resistance is on high agenda for anti-cancer drugs. The present article compiled different methodologies used to curb these challenges of bioavailability. The concepts of poor bioavailability are illustrated along with possible management. Numerous relevant patents for bioavailability enhancement are also highlighted. Though, there is no universal approach for bioavailability enhancement, the drug related challenges are managed by altering its physicochemical characteristics or employing formulation technology, while the effects of physiological factors are minimized by using efflux transport inhibitor or cytochrome P-450 inhibitor or prodrug or through formulation technologies (enteric coating or microenvironment of pH etc.).

Effects of Thymoquinone on the Pharmacokinetics and Pharmacodynamics of Glibenclamide in a Rat Model

Glibenclamide and thymoquinone plasma concentrations were analysed using a sensitive RP-HPLC method, and non-compartmental model pharmacokinetic parameters were calculated. The maximum reduction in blood glucose level was observed 3 hours following glibenclamide administration, which reached 47.4% of baseline, whereas it was reduced by 53.0% to 56.2% when co-administrated with thymoquinone. Plasma concentration of glibenclamide was increased by 13.4% and 21.8% by the co-administration of thymoquinone as single and multiple doses, respectively ( P<0.05). The AUC and T1/2 of glibenclamide were also increased respectively by 32.0% and 17.4% with a thymoquinone single dose, and by 52.5% and 92.8% after chronic treatment. Furthermore, diabetic rats treated with thymoquinone demonstrated a marked decrease in hepatic protein expressions of CYP3A2 and CYP2C11 enzymes that are responsible for the metabolism of glibenclamide. The current data suggest that thymoquinone exhibits a synergistic effect with glibenclamide on glucose level, which could be explained by reducing CYP450 activity at the protein level.

Orally co-administrated oleo-gum resin of Commiphora myrrha decreases the bioavailability of cyclosporine A in rats

Cyclosporine A is a narrow therapeutic indexed immunosuppressant used after organ transplantation. Several herbs have been reported to alter its pharmacokinetics. Myrrh, dried oleogum resin obtained from Commiphora myrrha (Burseraceae) has been used for many common ailments. The present study was carried out to investigate the effect of myrrh on the pharmacokinetics of cyclosporine A. The rats of the control group received 60 mg/kg, p.o. cyclosporine A, and blood samples were collected at predetermined time intervals. Rats of the test group were treated with an aqueous suspension of myrrh (380 mg/kg p.o.) for eight days and on 8th day a single dose of cyclosporine A was administered to the treated group after 1 h of myrrh administration. Blood samples were drawn at predetermined time points and the drug was analyzed in whole blood by using H-Class UPLC-TQD. Pharmacokinetic profiles of control and test group were compared. Statistically significant differences were observed between the pharmacokinetic parameters of control and treated groups. In the myrrh treated group, the AUC(0-t) and C(max) of cyclosporine A was decreased by about 45% and 48%, respectively. The time to reach maximum concentration (T(max)) remained almost unchanged in both groups. Results indicated that the bioavailability of cyclosporine A was reduced by about 45% when co-administered with myrrh. This observation suggests that concurrent consumption of myrrh and cyclosporine A should be avoided. To confirm the clinical relevance of these findings, P-gp and CYP3A based molecular investigations can be performed along with a well-planned clinical study.

Effects of Thymoquinone on the Pharmacokinetics and Pharmacodynamics of Glibenclamide in a Rat Model

Glibenclamide and thymoquinone plasma concentrations were analysed using a sensitive RP-HPLC method, and non-compartmental model pharmacokinetic parameters were calculated. The maximum reduction in blood glucose level was observed 3 hours following glibenclamide administration, which reached 47.4% of baseline, whereas it was reduced by 53.0% to 56.2% when co-administrated with thymoquinone. Plasma concentration of glibenclamide was increased by 13.4% and 21.8% by the co-administration of thymoquinone as single and multiple doses, respectively (P<0.05). The AUC and TI/2 of glibenclamide were also increased respectively by 32.0% and 17.4% with a thymoquinone single dose, and by 52.5% and 92.8% after chronic treatment. Furthermore, diabetic rats treated with thymoquinone demonstrated a marked decrease in hepatic protein expressions of CYP3A2 and CYP2C 11 enzymes that are responsible for the metabolism of glibenclamide. The current data suggest that thymoquinone exhibits a synergistic effect with glibenclamide on glucose level, which could be explained by reducing CYP450 activity at the protein level.

Hepatoprotective effect of Commiphora myrrha against d-GalN/LPS-induced hepatic injury in a rat model through attenuation of pro inflammatory cytokines and related genes

CONTEXT

Commiphora myrrha (Burseraceae), a shrub resembling a small tree, has been used for several centuries for the treatment of various diseases.

OBJECTIVE

This study investigates the hepatoprotective activity of C. myrrha ethanol extract against d-galactosamine/lipopolysaccharide (d-GalN/LPS)-induced acute hepatic injury in an animal model.

MATERIALS AND METHODS

Rats were pretreated with ethanolic extract C. myrrha (250 and 500 mg/kg; p.o.) for 7 d prior to the induction of an acute phase response by d-GalN/LPS. Animals were sacrificed 24 h after d-GalN/LPS (800 mg/kg and 50 µg/kg i.p.) administration for the biochemical and histological analyses.

RESULTS

The administration of d-GalN/LPS increased plasma aminotransferases (174.47 ± 4.5761 and 260.96 ± 1.9839 µkat/l) and total bilirubin levels (1.012 ± 0.0288 mg/dl), which were attenuated by C. myrrha treatment. Hepatic lipid peroxidation activity and nitric oxide content also increased, while the antioxidant activity measured by GSH (0.76 nmol/g protein), SOD (81.91 U/mg protein), and CAT (15.78 U/mg protein) was reduced. Commiphora myrrha provided significant restoration of GSH (0.815 nmol/gm protein), SOD (140.57 U/mg protein), and CAT (27.02 U/mg protein) levels. Furthermore, the acute phase response elicited by d-GalN/LPS administration enhanced mRNA expressions of TNF-α, IL-6, IL-10, iNOS-2, and HO-1, which were ameliorated by C. myrrha treatment.

DISCUSSION AND CONCLUSION

These findings indicate that C. myrrha considerably reduces the oxidative stress of d-GalN/LPS-induced hepatic injury via multiple pathways including adown regulation of inflammatory mediators and cytokines. Such a property might be sufficient to combat cellular damage caused by various conditions that resemble fulminant hepatitis and could be of a potential clinical application.

Rhodamine-123: a p-glycoprotein marker complex with sodium lauryl sulfate

Aim of this study was to investigate the role of sodium lauryl sulfate (SLS) as P-glycoprotein inhibitor. The everted rat gut sac model was used to study in-vitro mucosal to serosal transport of Rhodamine-123 (Rho-123). Surprisingly, SLS decreases the serosal absorption of Rho-123 at all investigated concentrations. Investigation reveals complex formation between Rhodamine-123 and sodium lauryl sulfate. Interaction profile of SLS & Rho-123 was studied at variable SLS concentrations. The SLS concentration higher than critical micelle concentration (CMC) increases the solubility of Rho-123 but could not help in serosal absorption, on the contrary the absorption of Rho-123 decreased. Rho-123 and SLS form pink color complex at sub-CMC. The SLS concentrations below CMC decrease the solubility of Rho-123. For further studies, Rho-123 & SLS complex was prepared by using solvent evaporation technique and characterized by using differential scanning calorimeter (DSC). Thermal analysis also proved the formation of complex between SLS & Rho-123. The P values were found to be significant (<0.05) except group comprising 0.0001% SLS, and that is because 0.0001% SLS is seems to be very low to affect the solubility or complexation of Rho-123.

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.

Potential inhibitory effect of herbal medicines on rat hepatic cytochrome P450 2D gene expression and metabolic activity

The aim of current study was to investigate the effect of some commonly used medicinal herbs on the regulation of rat CYP2D gene expression and its metabolic activity. Wistar albino rats were treated for seven consecutive days with selected doses of five commonly used herbs (Trigonella foenum-graecum, Ferula asafoetida, Nigella sativa, Commiphora myrrha and Lepidium sativum). Thereafter, rat livers were harvested and CYP2D mRNA levels were determined by RT-PCR. The metabolic activity of CYP2D was performed on rat hepatic microsomes using dextromethorphan as specific substrate. All investigated herbs produced inhibition of CYP2D mRNA expression and metabolic activity. The inhibitory potential of investigated herbs on rat CYP2D mRNA was in the following order: Commiphora myrrha > Nigella sativa > Lepidium sativum > Trigonella foenum-graecum > Ferula asafoetida. Whereas, the inhibitory potential of investigated herbs on CYP2D mediated enzyme metabolic activity was found in following order: Nigella sativa > Lepidium sativum > Trigonella foenum-graecum > Commiphora myrrha > Ferula asafoetida. The current study shows that only used herbs reduce CYP2D activity in rat liver microsomes at the transcriptional levels. Such effects could lead to undesirable pharmacological effects of clinically used low therapeutic index CYP2D substrate drugs.

Lepidium sativum but not Nigella sativa affects carbamazepine disposition in an animal model

Efficacy and safety profile of a drug may be affected when concomitantly used with herbal medicines. The present study was conducted to investigate the effects of some commonly used herbal products viz. Nigella sativa (Black seed) and Lepidium sativum (Garden cress) on the pharmacokinetics of carbamazepine (CBZ), a narrow therapeutic index drug, in an animal model. In a control group, five rabbits received 40 mg/kg of CBZ orally and blood samples were withdrawn at different time intervals (0, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12 and 24 hrs) from a marginal ear vein. After a suitable washout period, an aqueous saline suspension of Nigella sativa (200 mg/kg) or Lepidium sativum (150 mg/kg) was given orally for eight days to the rabbits. On day eight, CBZ (40 mg/kg) was re-administrated orally and blood samples were collected using the same sampling scheme. Drug levels in plasma were determined by liquid chromatography and pharmacokinetic parameters were calculated using non-compartmental analysis. No significant difference was observed in the maximum concentration (Cmax), area under concentration curve (AUC), half-life (T1/2), clearance (Cl/F) and volume of distribution (Vz/F) of CBZ following Nigella sativa treatment. Whereas, increased Cmax, absorption rate measured by the time to Cmax (Tmax), and prolongation of the terminal elimination half-life (T1/2) were observed after the co-administration with Lepidium sativum. Findings of the present study suggest that concurrent use of Lepidium sativum alters the pharmacokinetics of CBZ in an animal model. Further confirmation of these results in humans will warrant changes in CBZ dose and/or frequency before co-administration with these herbal medicines.

Impact of Herbal Medicines like Nigella sativa, Trigonella foenum-graecum, and Ferula asafoetida, on Cytochrome P450 2C11 Gene Expression in Rat Liver

AIM

Combined use of herbs and drugs may result in clinically important herb-drug interactions. The majorities of these interactions are thought to be metabolism-based and involve induction or inhibition of cytochrome P450 (CYP). The current study was designed to investigate the effect of some commonly used herbs on rat CYP2C11 gene expression and metabolic activity.

METHODS

Wistar rats were treated for 7 days with increasing doses of 3 herbs; Nigella sativa, Trigonella foenum-graecum, and Ferula asafoetida. Thereafter, CYP2C11 mRNA and protein levels were determined by real-time polymerase chain reaction (RT-PCR) and western blot analyses, respectively. In vitro metabolic activity of CYP2C11 was performed on rat hepatic microsomes using tolbutamide as specific substrate.

RESULTS

Our results showed that all the 3 herbs significantly inhibited the mRNA and protein expression levels of CYP2C11 in a dose-dependent manner. Furthermore, the in vitro enzyme metabolic activity study showed a significant decrease in the formation of 4-hyroxy-tolbutamide, a tolbutamide metabolite, at the higher doses. The inhibitory effects of the investigated herbs on rat CYP2C11 was in the order: Nigella Sativa > Trigonella foenum-graecum > Ferula asafoetida.

CONCLUSIONS

The 3 herbs are strong inhibitor of CYP2C11 expression, which can lead to an undesirable pharmacological effect of clinically used CYP2C11 substrate drugs with a low therapeutic index.

Investigating the Potential Effect of Commiphora myrrha on the Pharmacokinetics of Theophylline, a Narrow Therapeutic Index Drug

AIM

The present study was conducted to investigate the effect of commonly used herb Commiphora myrrha on the pharmacokinetic profile of theophylline (narrow therapeutic index drug) in rabbits.

METHODS

In the experimental groups, theophylline (16 mg/kg) was given orally to the rabbits. Where aqueous saline suspension of Commiphora myrrha (176 mg/kg, p.o.), was given to the rabbits and the blood samples were withdrawn at different time intervals (0, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, 24 and 36 h) from marginal ear vein after dosing and theophylline in plasma was analyzed by HPLC method.

RESULTS

It was observed that there a significant differences in the Cmax, AUC, AUMC, t1/2, and MRT of theophylline when coadministered with Commiphora myrrha which indicate that the herb affect the metabolism and elimination when coadministered with theophylline.

CONCLUSION

Our results suggested that concurrent use of investigated herb alters the pharmacokinetics of theophylline. Confirmation of these results in human studies will warrant changes in theophylline dose or frequency when coadministered with herb under consideration.

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.

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.

High-throughput ultra-performance LC-MS-MS method for analysis of diclofenac sodium in rabbit plasma

A new UPLC-MS-MS method was developed and validated for quantification of diclofenac sodium in rabbit plasma. Acetonitrile-based protein precipitation method was used to extract the drug from plasma samples. Chromatographic separation was carried out on Acquity UPLC(®)BEH phenyl C18 1.7 µm, 2.1 × 50 mm column. Drug elution was facilitated by using mobile phase containing acetonitrile (0.1% glacial acetic) and water (pH 3.5), in a ratio of 75 : 25, flowing at 0.2 mL/min. Molecular ions were generated by using the positive electrospray ionization mode (ESI(+)) and analyzed on a triple-quadrupole mass spectrometer. The ionic transitions of diclofenac (m/z 296 > 214 and 249.9) and flufenamic acid (internal standard) (m/z 282.1 > 166.9 and 244) were measured in multiple reaction modes. Developed method is simple, quick, precise and accurate over a linearity range of 80-4,000 ng/mL. The lower limit of quantification (LLOQ) for diclofenac was 80 ng/mL. The percentage recoveries of diclofenac at three quality control samples were 54 ± 6.1, 67.1 ± 5.4 and 62.3 ± 1.4%. Precision and accuracy of the assay at LLOQ, middle limit of quantitation and higher limit of quantitation were 100 ± 7.0, 100 ± 1.0 and 100 ± 2.0% and 81.8 ± 4.6, 106.6 ± 3.1 and 103.3 ± 4.0%, respectively.

Enhanced anti-inflammatory activity of carbopol loaded meloxicam nanoethosomes gel

The aim of the current investigation is to develop nanoethosomes for transdermal meloxicam delivery. The ethosomes were prepared by varying the variables such as concentrations of phospholipids 90G, ethanol, and sonication time while entrapment efficiency, vesicle size and transdermal flux were the chosen responses. Results indicate that the nanoethosomes of meloxicam provides lesser vesicles size, better entrapment efficiency and improved flux for transdermal delivery as compared to rigid liposomes. The optimized formulation (MCEF-OPT) obtained was further evaluated for an in vivo anti-inflammatory activity in rats. Optimized nanoethosomal formulation with vesicles size of 142.3nm showed 78.25% entrapment efficiency and achieved transdermal flux of 10.42μg/cm(2)/h. Nanoethosomes proved to be significantly superior in terms of, amount of drug permeated into the skin, with an enhancement ratio of 3.77 when compared to rigid liposomes. In vivo pharmacodynamic study of carbopol(®) loaded nanoethosomal gel showed significant higher percent inhibition of rat paw edema compared with oral administration of meloxicam. Our results suggest that nanoethosomes are an efficient carrier for transdermal delivery of meloxicam.

Distribution of selected gene polymorphisms of UGT1A1 in a Saudi population

INTRODUCTION

Glucuronidation is an important phase II pathway responsible for the metabolism of many endogenous substances and drugs to less toxic metabolites, which undergo renal excretion. The aim of the current work was to evaluate genotype and allele frequencies of certain UDP-glucuronosyltransferase 1A1 (UGT1A1) variants in an Arab population.

MATERIAL AND METHODS

Genomic DNA was isolated from 192 healthy unrelated Saudi males of various geographic regions and genotyping of UGT1A1*6, *27, *36, *28, *37, and *60 was carried out using polymerase chain reaction (PCR) amplification followed by direct sequencing.

RESULTS

The most common allele for (TA) repeats was the wild type (TA)6 with a frequency of 74.3% followed by the mutant (TA)7 (i.e., UGT1A1*28) with a frequency of 25.7%. The distribution of UGT1A1*60 allele was 62.4% among subjects with the homozygous mutant genotype of 35.4%, while the wild type variant represents 10.6% only. Both UGT1A1*6 and *27 were not detected as all screened subjects showed a homozygous wild type pattern. Similarly, UGT1A1*36* and *37 were either not present or rarely found, respectively. In comparison to other populations, the frequency of UGT1A1*60 and *28 in the studied population was less than that of African Americans but higher than Asians. The geographical origin of the study subjects also implied some differences in genotype distribution of (TA) repeats and UGT1A1*60.

CONCLUSIONS

Our data indicate that Saudis harbor some important UGT1A1 mutations known to affect enzyme activity. Additional studies are warranted to assess the clinical implications of these gene polymorphisms in this ethnic group.