Research Article INCLUSION COMPLEX OF HYDROCHLOROTHIAIZDE-ɀ- CYCLODEXTRIN: THE EFFECT ON AQUEOUS SOLUBILITY, DISSOLUTION RATE, BIOAVAILABILITY AND THE EFFECT ON INTESTINAL PERMEABILITY USING USSING CHAMBER TECHNIQUE SANAE MASMOUDI 1 , MOULAY ABBES FAOUZI 2 , BOUCHRA MEDDAH 2 , MOHAMED ELBARGE 1 , HASSAN BOUAYAD 3 , YAHIA CHERRAH 2 , ABDELAZIZ BOUKLOUZE 1* 1 Pharmaceutical and Toxicological Analysis Research Team, 2 Pharmacokinetics Research Team, Laboratory of Pharmacology and Toxicology, Faculty of Medicine and Pharmacy, Mohammed V Souissi University, Rabat, Morocco, 3 Department Medicine, Surgery and Reproduction, Agronomic and Veterinary Institute Hassan II, Rabat, Morocco. Email: a.bouklouze@um5s.net.ma Received: 25 Jun 2013, Revised and Accepted: 04 Aug 2013 ABSTRACT Objective: In this work the effect of ɀ-cyclodextrin (ɀCD) on the aqueous solubility, dissolution rate, bioavailability and intestinal permeability using the Ussing chamber technique of the hydrochlorothiazide was investigated. Materials and methods: A solid inclusion complex between HCT and ɀCD was prepared by co-precipitation method and characterized by X-ray diffraction (XRD) and nuclear magnetic resonance (NMR). A randomized crossover trial was conducted on five dogs to study bioavailability. The effect of ɀCD on the permeability of HCT was investigated using the Ussing chamber technique. Results: Both the solubility and the dissolution rate of HCT-ɀCD were significantly increased by its inclusion with ɀCD. The in-vivo study showed significant improvement of the oral bioavailability of HCT. Compared to the control, the presence of the inclusion complex increases the area under the plasma concentration-time curve (1268.2 ± 102.64 to 2746.27 ± 164.76, p<0.05) and the maximum plasma concentration (192.85 ± 63.11 ng/ml to 353.22 ± 33.84 ng/ml, p<0.05). The permeability rate of HCT was increased significantly by the formation of inclusion complex compared to the control HCT alone ((1.96± 0.27) × 10 -6 to (3.93± 0.81) × 10 -6 cm/s, p<0.05). Conclusion: The present results suggest that ɀCD improves the solubility in water, the dissolution rate, bioavailability and permeability of HCT. Keywords: Hydrochlorothiazide, ɀ- cyclodextrin, Inclusion complex, Bioavailability, Ussing chamber technique. INTRODUCTION Hypertension is the major cause of cerebral vascular accidents, hypertensive heart failure and progressive renal failure. In developed countries, heart disease and stroke are the first and the third-ranked causes, respectively, of morbidity and mortality [1]. For example, in Morocco the total prevalence of hypertension is 33.6% [2]. Diuretics and Ⱦ-blocker drugs are the only two classes of antihypertensive drugs that have been tested and shown to reduce morbidity and mortality. The first line treatment recommended of hypertension is thiazide diuretics, in particular hydrochlorothiazide (HCT) (Figure 1), that has remained the most widely used for years [3]. Fig. 1: Molecular structure of Hydrochlorothiazide HTC belongs to class 4 of the Biopharmaceutics Classification System (BCS), where drugs have low solubility and low permeability [4]. These properties limit their bioavailability in an organism. In order to overcome this problem, HCT was formulated as liquisolid tablets and tested to evaluate the absorption characteristics, using six male beagle dogs [5]. On the one hand, most methods have been tested to improve HCT’s aqueous solubility and bioavailability, such as the use of polymers like polyethylene glycol [6], polyvinylpyrrolidone [7], hydroxypropyl cellulose [8] and sequenced copolymers [9]. On the other hand, the complexation with beta-cyclodextrin was also studied [10,11]. Cyclodextrins (CDs) are a cyclic oligosaccharides, consisting of six Ƚ- cyclodextrin, seven Ⱦ-cyclodextrin, eight ɀ-cyclodextrin or more glucopyranose units linked by Ƚ-(1,4) bonds [12-14]. These cyclodextrins are hydrophilic molecules outside and hydrophobic inside which allows forming inclusion complexes with the majority of hydrophobic molecules [15]. These inclusion complexes have been shown to improve stability, solubility, bioavailability [12, 16, 17] and also known to enhance the absorption of molecules across biological barriers [18]. To our knowledge, there are no studies of the preparation of HCT- ɀCD inclusion and its in-vitro, its in vivo and its intestinal permeability using an Ussing chamber technique investigation. Therefore, the aim of this work was, in the first step, to investigate the aqueous solubility and the bioavailability of HCT after its inclusion with ɀCD. The former was performed by establishing kinetic dissolution profiles, while the latter was evaluated by means of a crossover trial on dogs for the complexed and uncomplexed HCT. In the second step, the intestinal permeability of both HCT and its inclusion complex with ɀCD was evaluated using the Ussing chamber technique. MATERIALS AND METHODS Materials Hydrochlorothiazide (Cambrex, Batch350103. Italy), Ethanol (Merck, K39139083, Germany), acetonitrile (VWR, For HPLC, Batch 1120918), potassium dihydrogen phosphate (Solvachim, Batch 060999, Morocco). All organic solvents used are products for analysis. Animals Five male dogs weighing between 11 and 16 Kg (14.3 ± 2.7) were used in this study. During the test, the animals were kept in individual cages and were fed and watered ad libitum. The dogs were starved for 18 hours prior to the experiment. All experiments made on the animals have been approved by the ethic committee of the Faculty of Medicine and Pharmacy (Morocco). Preparation of the solid complexes )nclusion complex ȋ)CȌ: The complex of (CT with ɀCD was prepared by the co-precipitation method by dissolving ɀCD ȋͳͲͻ mg) and HCT (477mg) (i.e. molar ratio 1:1) in water - ethanol (50:50, v/v). The International Journal of Pharmacy and Pharmaceutical Sciences ISSN- 0975-1491 Vol 5, Suppl 3, 2013 A A c c a a d d e e m mi i c c S S c c i i e e n n c c e e s s