Improvement of bone microarchitecture in methylprednisolone induced rat model of osteoporosis by using thiolated chitosan-based risedronate mucoadhesive film

OBJECTIVE

In this study, we investigated the potential of thiolated chitosan-based mucoadhesive film, loaded with risedronate sodium in the treatment of osteoporosis.

SIGNIFICANCE

Risedronate sodium is a bisphosphonate derivative having very low bioavailability when administered through the oral route. Moreover, the adverse effects associated with the drug when administered through GIT necessitate an alternative and feasible route which can improve its bioavailability and therapeutic efficacy.

METHODS

Thiolation of chitosan was interpreted by different analytical techniques. The mucoadhesive films were prepared by the solvent evaporation method and evaluated for drug content analysis, swelling degree, mucoadhesive parameters, and permeation characterization. For the screening of preclinical efficacy and pharmacodynamic parameters, a methylprednisolone induced osteoporotic rat model was used. The trabecular microarchitecture and biochemical markers were evaluated for determination of bone resorption.

RESULTS

The different analytical characterization of synthesized thiolated chitosan revealed that chitosan was successfully incorporated with thiol groups. The formulation containing 2:1 ratio of thiolated chitosan and HPMC-4KM was found to have the maximum swelling degree, mucoadhesive strength with a good force of adhesion and better in vitro permeability compared to the marketed formulation. With respect to trabecular microarchitecture, the drug-loaded film formulation showed superior and promising results. Furthermore, the film formulation also improved the serum level of biomarkers better than the marketed formulation.

CONCLUSIONS

The results significantly suggest that risedronate loaded novel mucoadhesive film formulation could be a logical approach in the therapeutic intervention of osteoporosis.

Antidiabetic antihyperlipidemic and hepato-protective effect of Gluconorm-5: A polyherbal formulation in steptozotocin induced hyperglycemic rats

Background:

The antidiabetic, antihyperlipidemic, and hepato-protective effect of Gluconorm-5, was studied in steptozotocin (STZ) induced hyperglycemic rats.

Materials and Methods:

The hypoglycemic effect of single dose of Gluconorm-5 (150, 300 and 600 mg/kg body weight) made up of five plants namely Camellia sinensis, Punica granatum, Macrotyloma uniflorum, Foeniculum vulgare and Trigonella foenum-graecum was studied in normal, glucose loaded normal and diabetes-induced rats. The extent of antihyperlipidemic and liver-protective effect was studied by estimating the lipid profile, and the liver marker enzymes. Histopathological studies of the pancreatic tissue were also carried out with glibenclamide as standard antihyperglycemic agent.

Results:

Fifteen days of oral feeding of the Gluconorm-5 (300 and 600 mg/kg) to diabetic rats resulted in a significant (P < 0.01) reduction of blood glucose, lipid profile, liver weight and marker enzymes as compared to those rats in whom STZ induced toxicity was untreated. The diabetic rats treated with the drug showed expanded islets as compared to the untreated diabetic rats, which showed the shrunken islets. The animals that received 300 mg/kg of Gluconorm-5 showed pronounced antidiabetic, antihyperlipidemic and hepato-protective effect in the present study, which was comparable with glibenclamide, a standard drug.

Conclusion:

Gluconorm-5 exerts potent antidiabetic antihyperlipidemic and hepato-protective effect, which can be used as adjuvant in the treatment of diabetes mellitus.

Anticonvulsant and neurotoxicity profile of the rhizome of Smilax china Linn. in mice

OBJECTIVE

To study the anticonvulsant activity and neurotoxicity of ethanolic extract and ethyl acetate fraction of the rhizome of Smilax china (EESC and EAF, respectively) in mice.

MATERIALS AND METHODS

The anticonvulsant activities of EESC and EAF were studied against maximal electroshock (MES) and pentylenetetrazole (PTZ)-induced seizures in mice and neurotoxicity was determined using rotarod test.

RESULTS

The duration of hindleg extension in MES test was reduced significantly (P < 0.001) by EESC at a dose level of 400 mg/kg and EAF at both higher dose levels (200 and 400 mg/kg). In PTZ model, the seizure latency was prolonged by all the test groups.

CONCLUSION

The EESC and EAF may help to control petit mal and grand mal seizures.

Immune Augmentation of Single Contact Hepatitis B Vaccine by Using PLGA Microspheres as an Adjuvant

The present study was aimed to replace the alum type adjuvant for hepatitis B vaccine. The hepatitis B vaccine was encapsulated in poly (DL-lactide-co-glycolide) microspheres by solvent evaporation technique. The formulated microspheres were characterized in terms of morphology, particle size analysis, in vitro release study and in vivo immune response in male Wistar rats. The FT IR spectrum illustrates the characteristics bands of poly (DL-lactide-co-glycolide) microspheres and hepatitis B vaccine at 1750 cm(-1) and 1650 cm(-1), respectively. The hepatitis B vaccine loaded poly (DL-lactide-co-glycolide) microspheres were able to release antigens till day 42. Significant enhancement of specific antibodies to HBsAg was produced till day 90 after a single administration of HBsAg encapsulated poly (DL-lactide-co-glycolide) microspheres. However, the conventional alum adsorbed hepatitis B vaccine was not found to produce any significant specific antibody levels till day 90 after a single dose. The results showed that poly (DL-lactide-co-glycolide) microspheres show potential as an adjuvant for hepatitis B vaccine.

Antihistaminic and antiviral activities of steroids of Turbinaria conoides

The steroids 3,6,17-trihydroxy-stigmasta-4,7,24(28)-triene (A) and 14,15,18,20-diepoxyturbinarin (B) were isolated from the cyclohexane extract of brown alga, Turbinaria conoides (J. Agardh) Kutzing, and have been reported for their antimicrobial activity by us. In this study, the isolated compounds were evaluated for comprehensive antihistaminic, antiviral and cytotoxicity screening. The antihistaminic study was performed using in vitro standard animal models. Evaluation of the potency (EC(50)), affinity (pA(2)) and the maximal response (E(max)) of the histamine alone and in the presence of the compounds were determined. Antiviral activity and cytotoxicity were performed in Crandell-Rees feline kidney (CRFK) cells by a colorimetric formazan-based MTS assay. No significant antiviral activity or cytotoxicity were observed for the compounds in the CRFK cells. Compound A inhibited the histamine-induced concentration at 20 µg mL(-1)(p < 0.05). The most significant inhibition (97%) was observed for compound B (p < 0.01) at the same concentration, which was comparable to that of the positive control chlorpheniramine maleate (10 µg mL(-1)). This potentiality suggests that 14,15,18,20-diepoxyturbinarin (B) can be developed as a new lead antihistaminic agent.

Acute toxicity study and antipyretic effect of the brown alga Turbinaria conoides (J. Agardh) Kuetz

The active principles of brown alga, Turbinaria conoides (J.Agardh) Kuetz. (Sargassaceae) was extracted with n-hexane, cyclohexane, methanol and ethanol-water (1:1) and investigated for acute toxicity and antipyretic activity. Phytochemical analysis of the extracts revealed the presence of steroids, flavonoids and reducing sugars. Acute toxicity study was performed in Wistar rats after administration of extracts orally. No mortality was observed up to the dose of 5 g/kg for methanol and ethanol-water (1:1) extracts whereas n-hexane and cyclohexane extracts were found to be toxic at the dose levels of 1 g/kg and 2 g/kg respectively. In biochemical analysis, n-hexane, cyclohexane and ethanol-water (1:1) extracts caused a significant (P<0.01) increase in serum cholesterol, protein and alkaline phosphatase levels. In haematological studies, a significant difference was observed for cyclohexane and ethanol-water (1:1) extracts in polymorphs, lymphocytes and eosinophils when compared to the control. Antipyretic activity of extracts (100-400 mg/kg doses) was carried out on yeast-induced pyrexia in rats. Cyclohexane extract exhibited more significant antipyretic activity (P<0.01) than the other extracts at a dose of 200 mg/kg (54.43%), which was comparable to that of paracetamol at a dose of 33 mg/kg. The findings validated the use of this brown alga in traditional cure of children's fever.

Biopharmaceutical and pharmacodynamic studies on topically applied diclofenac gel available in Indian market

In the present investigation, an attempt was made to study and compare, analgesic and anti-inflammatory activity produced by four marketed topical diclofenac formulations in order to justify their usefulness in the treatment of pain and inflammation. By using a diffusion cell, in vitro percutaneous permeation studies were carried out to correlate in vivo activity. The in vivo analgesic activity study was performed by tail flick method on Wistar albino rats. The anti-inflammatory activity was performed on rats by carrageenan induced inflammation. It was evident from the study that three among tested three gels; diclofenac permeated effectively through the skin and was able to elicit analgesic and anti-inflammatory responses. The study also indicated the presence of therapeutic inequivalence among the marketed topical formulation and the need of bio equivalency and therapeutic equivalency testing of marketed topical applications meant for therapeutic use.