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TopIntroduction
Gymnema sylvestre commonly known as ‘Gudmar’ in Hindi is an important Indian medicinal plant used in different systems of medicine as a remedy for the treatment of diabetes, rheumatism, cough, ulcer, jaundice, dyspepsia, constipation, eyes pain and also in snakebite (Patel et al., 2012). The major phytoconstituents of gymnema sylvestra are gymnemic acids, gudmarin and saponins. Gymnemic acid (C43H68O14) is a pentacyclic triterpenoid and is the main active phytoconstituents of G. sylvestre, exhibiting potent anti-diabetic activity (Shivani Vaidya, 2011). Gymnemic acids show different physiological activities like they suppress taste sensitivity to sweetness, lower plasma glucose and insulin levels in the diabetic subjects and inhibit intestinal glucose absorption (Ankit Saneja et al., 2010). Recent times have witnessed increased incidence of diabetes across the globe, along with increased popularity of herbal products in the international market (Classen, 2012). Gymnemic acids are poorly soluble in water and thus show reduced pharmacological activity (Ankit Saneja et al., 2010). The need for new and improved approaches to increase its solubility and bioavailability remains a key focal point for many researchers (Parijat Kanetkar et al., 2007). Recently, many poorly soluble drugs have been nanonized to increase their dissolution rate, their saturation solubility and in turn to enhance their oral bioavailability (Ravichandran, 2009a,b). In this direction recently we reported the preparation and characterisation of nanosuspension of gymnemic acids (Ravichandran, 2010a) and its oral formulation (Ravichandran, 2010b). In this paper we report the pharmacokinetic and pharmacodynamic behavior of nanoparticulate gymnemic acids.
TopMaterials And Methods
Chemicals
Gymnemic acid was purchased from Amruta Herbals Private Limited, Indore (India). Gymnemic acids nanosuspensions were prepared by high pressure homogenization method and the results of its characterization, and solid dosage form development have been recently reported by us (Ravichandran, 2010a,b). The solid dosage formulation contained GANS-A: Gymnemic acids nanocrystals 50mg + Avicel PH 101 42mg, AcDiSol 5mg, Explotab 0mg, magnesium stearate 2mg, Talc 1mg as Excipients ; GANS- B: Gymnemic acids nanocrystals 50mg + Avicel PH 101 42mg, AcDiSol 0mg, Explotab 5mg, magnesium stearate 2mg, Talc 1mg as Excipients ; GANS- C: Gymnemic acids microcrystals 50mg + Avicel PH 101 42mg, AcDiSol 5mg, Explotab 0mg, magnesium stearate 2mg, Talc 1mg as Excipients ; and GANS-M: Gymnemic acids microcrystals 50mg + 50mg Excipients not known as it is a commercial product. The tablets were prepared using direct compression by a single punch tablet machine.
Experimental Animals
Male Wistar rats weighing 250–300 g were fed with commercial pellet diet (Kamadenu Agencies, Bangalore, India) and water ad libitum. The animals were acclimatized to laboratory hygienic conditions for 10 days before starting the experiment. The animals were maintained in groups of six and were fasted for 8 h prior to the commencement of the study.