Omeprazole and PGC-formulated heparin binding epidermal growth factor normalizes fasting blood glucose and suppresses insulitis in multiple low dose streptozotocin diabetes model.

PURPOSE: Our objective was to develop novel nanocarriers (protected graft copolymer, PGC) that improve the stability of heparin binding EGF (HBEGF) and gastrin and then to use PGC-formulated HBEGF (PGC-HBEGF) and Omeprazole (+/- PGC-gastrin) for normalizing fasting blood glucose (FBG) and improving islet function in diabetic mice. METHODS: HBEGF, PGC-HBEGF, Omeprazole, Omeprazole + PGC-HBEGF, Omeprazole + PGC-gastrin + PGC-HBEGF and epidermal growth factor (EGF) + gastrin were tested in multiple low dose streptozotocin diabetic mice. RESULTS: Omeprazole + PGC-HBEGF normalized FBG and is better than EGF + gastrin at improving islet function and decreasing insulitis. Groups treated with Omeprazole, Omeprazole + PGC-HBEGF, or EGF + gastrin have significantly improved islet function versus saline control. All animals that received PGC-HBEGF had significantly reduced islet insulitis versus saline control. Non-FBG was lower for Omeprazole + PGC-gastrin + PGC-HBEGF but Omeprazole + PGC-HBEGF alone showed better FBG and glucose tolerance. CONCLUSIONS: Omeprazole + PGC-HBEGF provides a sustained exposure to both EGFRA and gastrin, improves islet function, and decreases insulitis in multiple low dose streptozotocin diabetic mice. Although HBEGF or EGF elevates non-FBG, it facilitates a reduction of insulitis and, in the presence of Omeprazole, provides normalization of FBG at the end of treatment. The study demonstrates Omeprazole and PGC-HBEGF is a viable treatment for diabetes.

Enhanced oral bioavailability of the hydrophobic chemopreventive agent (SR13668) in beagle dogs.

Potency and activity of SR13668 in cancer prevention have been proven in several in vitro and in vivo cancer models. However, the compound is highly hydrophobic and its limited oral bioavailability has hindered its clinical translation. In this study, we encapsulated SR13668 into polymeric nanoparticles to increase compound aqueous solubility and therefore bioavailability. Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (100-200 nm) encapsulating SR13668 with narrow size distribution and high drug loading were generated by a continuous and scalable process of flash nanoprecipitation integrated with spray dry. A single gavage dose of SR13668-PLGA nanoparticles at 2.8 mg/kg was administered in eight beagle dogs. Drug levels in animal whole blood and plasma were measured over 24 hours. Enhanced bioavailability of SR13668 using nanoparticles compared with formulations of Labrasol® and neat drug in 0.5% methylcellulose is reported. This is the first attempt to study pharmacokinetics of SR13668 in large animals with orally administrated nanoparticle suspension.

Oral toxicity and pharmacokinetic studies of SHetA2, a new chemopreventive agent, in rats and dogs.

SHetA2 is a heteroarotinoid that has shown selective inhibition of cancer cell growth and an induction of apoptosis without activation of nuclear retinoic acid receptors. In the rat study, SHetA2 was administered in 1% aqueous methylcellulose/0.2% Tween 80 by oral gavage at 0, 100, 500, and 2,000 mg/kg/day for 28 days. The high-dose administration induced decreased activity in male rats, decreased body-weight gains and food consumption, and changes in organ weights. The major metabolite of SHetA2 in rat plasma was monohydroxy SHetA2, which was considerably higher than the parent compound after oral and intravenous administration. Pharmacokinetic analysis showed extremely low (<1%) systemic bioavailability of SHetA2 for all doses tested. The dose of 2,000 mg/kg/day was considered as the lowest observed adverse effect level. The no observed adverse effect level (NOAEL) was 500 mg/kg/day. In the dog study, no toxicity of SHetA2 in 30% aqueous Solutol(®) HS 15 was observed in any tested dose groups (0, 100, 400, and 1,500 mg/kg/day). The major metabolite of SHetA2 in dog plasma was also monohydroxy SHetA2, which was equal to or lower than the parent compound after oral administration. SHetA2 levels in dog plasma were notably higher, when compared to levels in rat plasma. However, exposure was not dose proportional, as exemplified by a lack of proportional increase in maximum concentration or area under the plasma concentration-time curve with increasing dose. The NOAEL was not established and was considered to be above 1,500 mg/kg/day.

Protected graft copolymer excipient leads to a higher acute maximum tolerated dose and extends residence time of vasoactive intestinal Peptide significantly better than sterically stabilized micelles.

PURPOSE: To determine and compare pharmacokinetics and toxicity of two nanoformulations of Vasoactive Intestinal Peptide (VIP). METHODS: VIP was formulated using a micellar (Sterically Stabilized Micelles, SSM) and a polymer-based (Protected Graft Copolymer, PGC) nanocarrier at various loading percentages. VIP binding to the nanocarriers, pharmacokinetics, blood pressure, blood chemistry, and acute maximum tolerated dose (MTD) of the formulations after injection into BALB/c mice were determined. RESULTS: Both formulations significantly extend in vivo residence time compared to unformulated VIP. Formulation toxicity is dependent on loading percentage, showing major differences between the two carrier types. Both formulations increase in vivo potency of unformulated VIP and show acute MTDs at least 140 times lower than unformulated VIP, but still at least 100 times higher than the anticipated highest human dose, 1-5 µg/kg. These nanocarriers prevented a significant drop in arterial blood pressure compared to unformulated VIP. CONCLUSIONS: While both carriers enhance in vivo residence time compared to unformulated VIP and reduce the drop in blood pressure immediately after injection, PGC is the excipient of choice to extend residence time and improve the safety of potent therapeutic peptides such as VIP.

Combination treatment with bortezomib and thiostrepton is effective against tumor formation in mouse models of DEN/PB-induced liver carcinogenesis.

Nanoparticle-encapsulated thiazole antibiotic, thiostrepton, has been shown to be an effective agent for inhibiting tumor growth in solid tumor models through the inhibition of proteasomal activity by the induction of apoptosis in cancer cells. Here, we show the efficacy of thiostrepton-micelles in inhibiting tumor growth in a DEN/PB-induced liver cancer model. We also demonstrate an enhanced anticancer effect of the combination treatment of thiostrepton with bortezomib, another proteasome inhibitor in this liver cancer model.

Enhanced oral bioavailability of a cancer preventive agent (SR13668) by employing polymeric nanoparticles with high drug loading.

SR13668 [2,10-Dicarbethoxy-6-methoxy-5,7-dihydro-indolo-(2,3-b)carbazole] has been proven effective in cancer prevention, but the limited bioavailability has hindered its clinical translation. In this study, we have developed a continuous, scalable process to form stable poly(lactic-co-glycolic acid) nanoparticles encapsulating SR13668, based on understanding of the competitive kinetics of nanoprecipitation and spray drying. The optimized formulation achieved high drug loading (33.3 wt %) and small particles (150 nm) with narrow size distribution. The prepared nanoparticle suspensions through flash nanoprecipitation were spray dried to achieve long-term stability and to conveniently adjust the nanoparticle concentration before use. In vitro release of SR13668 from the nanosuspensions was measured in a solution with separated organic and aqueous phases to overcome the limit of SR13668 low water solubility. Higher oral bioavailability of SR13668 by employing polymeric nanoparticles compared with the Labrasol® formulation was demonstrated in a mouse model.

Protected graft copolymer (PGC) basal formulation of insulin as potentially safer alternative to Lantus® (insulin-glargine): a streptozotocin-induced, diabetic Sprague Dawley rats study.

PURPOSE: To develop a long-acting formulation of native human insulin with a similar pharmacodynamics (PD) profile as the insulin analogue insulin glargine (Lantus®, Sanofi-Aventis) with the expectation of retaining native human insulin's superior safety profile as insulin glargine is able to activate the insulin-like growth factor 1 (IGF-1) receptor and is linked to a number of malignancies at a higher rate than regular human insulin. METHODS: Development of protected graft copolymer (PGC) excipients that bind native human insulin non-covalently and testing blood glucose control obtained with these formulations in streptozotocin-induced diabetic Sprague Dawley rats compared to equally dosed insulin glargine. RESULTS: PGC-formulations of native human insulin are able to control blood glucose to the same extent and for the same amount of time after s.c. injection as the insulin analogue insulin glargine. No biochemical changes were made to the insulin that would change receptor binding and activation with their possible negative effects on the safety of the insulin. CONCLUSION: Formulation with the PGC excipient offers a viable alternative to biochemically changing insulin or other receptor binding peptides to improve PD properties.

Detoxification of Nerium indicum roots based on Indian system of medicine: phytochemical and toxicity evaluations.

Indian system of medicine describes the usage of certain very toxic plant based drugs after performing a detoxification process (Shodhana samskara). Nerium indicum is traditionally used as a medicine though known to cause severe allergic symptoms, tachycardia and gastrointestinal effects leading to fatalities. In this study, the detoxification (shodhana) for Nerium indicum was scientifically validated based on phytochemical and toxicity profiles. Shodhana was performed according to traditional literature. HPTLC densitometric studies were performed for the pre- and post-shodhana powders followed by sub-acute toxicity evaluation in rats. Preparative TLC and LC-MS showed the reduction of oleandrin peak in the post-shodhana sample. Prominent features of cardiotoxicity including tachycardia were noted in the pre-shodhana Nerium treated animals along with mortality. However, no such toxicity was encountered in the post-shodhana Nerium treated animals. Hence, using the recommended detoxification (shodhana), the toxicity of an important medicinal plant was significantly nullified. Such studies provide a scientific support towards our traditional medicinal practices using modem analytical and experimental methodologies and may prove to be very useful in establishing standard scientific procedures for routine and safe use of traditional medicines.

Hormonal crosstalk with calcium channel blocker during implantation.

The site specific action of the calcium channel blocker diltiazem in blocking prostaglandin synthesis and hence causing blastocyst implantation failure has been previously described. Based on this understanding it was important to learn if this pathway was under the control of the fine balance in estradiol-progesterone (E2-P4) milieu, considered to be of the utmost significance for effective implantation. In the current study the circulating E2-P4 levels were monitored on the first 6 d of pregnancy at various time points using sensitive chemiluminescence based assays. Next, diltiazem was administered intra-luminally into the uterus at 10-20 h prior to implantation as this time has been previously implicated to be when the best anti-implantation activity of diltiazem can be observed. Following this, the E2-P4 in peripheral circulation was again monitored. On d 6 (post implantation) the implantation sites were observed in the uterus of both diltiazem treated and untreated groups using Chicago blue dye and correlated to the hormonal activity. The levels of both estradiol and progesterone were very similar in both untreated and diltiazem treated groups during and post implantation. However complete implantation failure was noted in the diltiazem treated group whereas prominent implantation sites were observed in the untreated animals. Thus, the previously reported inhibition of blastocyst implantation cascade by calcium channel blockers during the 'implantation window' seems to be an independent mechanism interfering with uterine receptivity without any direct estrogen-progesterone control and further studies to understand its regulation need to be performed.

Inhibitory effect of n-butanol fraction of Moringa oleifera Lam. seeds on ovalbumin-induced airway inflammation in a guinea pig model of asthma.

Moringaceae, which belongs to the Moringa oleifera Lam. family, is a well-known herb used in Asian medicine as an antiallergic drug. In the present study, the efficacy of the n-butanol extract of the seeds of the plant (MONB) is examined against ovalbumin-induced airway inflammation in guinea pigs. The test drugs (MONB or dexamethasone) are administered orally prior to challenge with aerosolized 0.5% ovalbumin. During the experimental period, bronchoconstriction tests are performed, and lung function parameters are measured. The blood and bronchoalveolar lavage fluid are collected to assess cellular content, and serum is used for cytokine (tumor necrosis factor-alpha, interleukin-4, and interleukin-6) assays. Histamine assays of lung tissue are performed using lung tissue homogenate. The results suggest that in ovalbumin-sensitized model control animals, tidal volume is decreased, respiration rate is increased, and both the total and differential cell counts in blood and bronchoalveolar lavage fluid are increased significantly compared with nonsensitized controls. MONB treatment shows improvement in all parameters except bronchoalveolar lavage tumor necrosis factor-alpha and interleukin-4. Moreover, MONB treatment demonstrates protection against acetylcholine-induced bronchoconstriction and airway inflammation. These results indicate that MONB has an inhibitory effect on airway inflammation. Thus, MONB possesses an antiasthmatic property through modulation of the relationship between Th1/Th2 cytokine imbalances.

Establishing the probable mechanism of L-DOPA in Alzheimer's disease management.

Clinical data suggest the role of L-DOPA in Alzheimer's Disease (AD) though its mechanism of action in AD is not clear. Previous results suggest that L-DOPA might have a complex mixture of pro- and antioxidant effects contributing to tissue damage due to oxidative stress. Furthermore, entacapone, a COMT inhibitor, is known to retain greater levodopa levels in plasma during coadministration. Hence, the role of L-DOPA + entacapone in aluminum induced oxidative stress in the rat brain was evaluated. Sprague Dawley rats (n = 6/group) were treated with either the vehicle, aluminum, L-DOPA + entacapone or aluminum + L-DOPA + entacapone for 28 days. The intact brains were processed for lipid peroxidation (LPO) and superoxide dismutase (SOD) activity. Aluminum treatment showed highly elevated levels of LPO while the combination of L-DOPA and entacapone could not control this oxidative burst in the rat brains both in presence and absence of aluminum. No change was observed in the brain or the circulating SOD activity. Hence, it is derived that protective role of L-DOPA in AD management is not exerted through its antioxidant property and may be manifested due to its involvement in other pathways.

Role of the calcium channel in blastocyst implantation: a novel contraceptive target.

The proinflammatory blastocyst implantation cascade involves important mediators like prostaglandins (PG). The influx of calcium via the calcium channel acts as a trigger for the activation of the PG synthesis pathway. Hence, it was hypothesized that calcium channel blockers that are known to possess anti-inflammatory activity may interfere with normal implantation. Pregnant Swiss albino mice (Mus musculus) were treated with diltiazem (1) 4 mg/kg, po on days 1-6 of pregnancy, n=6/day) or (2) at the implantation site (25 microg/animal) via intrauterine injection in the right horn at 5:00 pm on day 4. The intact uterus was used to assay lipid peroxidation and superoxide dismutase activity as markers of membrane fluidity or to observe the day 15 fetus. Oral diltiazem treatment in therapeutic dosage before and during the implantation period did not cause any change in normal uterine milieu during the window of implantation. When injected into the uterine lumen 12-14 h before the average implantation time, however, a complete failure in implantation was observed. Thus, the site specific action of diltiazem may be blocking prostaglandin synthesis, hence causing implantation failure. Oral diltiazem treatment did not mimic this action, indicating that although orally safe in pregnancy in therapeutic dosage, calcium channel blockers may provide a new and yet unknown target in female contraceptive research.

Cyclooxygenase inhibitors: a novel direction for Alzheimer's management.

Research in Alzheimer's disease (AD) currently includes various cellular, molecular, genetic, clinical and therapeutic approaches. The cytopathological significance of oxidative damage has been studied in neurons of AD patients. Many epidemiological studies suggest that use of non-steroidal anti-inflammatory drugs (NSAIDs) delay or slow the clinical expression of AD, and anti-oxidant properties of NSAIDs have also been previously described. Therefore, in this study we examined the role of various cyclooxygenase (COX)-1 and COX-2 inhibitors (NSAIDs) in a rat model of aluminum-induced oxidative stress to mimic AD-like conditions. We found that the animals receiving aluminum treatment for one month (4.2 mg/kg, ip) had highly elevated levels of reactive oxygen species (expressed as malondialdehyde--MDA). Moreover, treatment with the COX-2 inhibitor, rofecoxib (0.83 mg/kg, po), was able to significantly reduce this oxidative stress (p<0.05 when compared to aluminum treatment alone on MDA levels). But, nonspecific COX inhibitors (flurbiprofen, 0.83 mg/kg twice a day po and ibuprofen, 100 mg/kg, po), did not protect again oxidative stress. Thus, in agreement with earlier epidemiological studies, we propose that COX-2 specific NSAIDs may be beneficial in AD management. Further experimental work towards identifying the most efficacious COX-2 inhibitors, as well as the mechanism of action and the optimal dosage regimen should be executed.