Chitosan based in situ forming polyelectrolyte complexes: A potential sustained drug delivery polymeric carrier for high dose drugs.

The present study investigated the feasibility of using combination of Cationic and anionic polymers as sustained release carrier for the delivery of high dose gastric acid soluble model drug Paracetamol. Various formulations were prepared using wet granulation technique. Briefly a cooled (4°C) neutral solution of chitosan (CH) was combined with cooled aqueous solution (4°C) of anionic polymer such as Gum Ghatti (GG) and Xanthan gum (XG). This polyelectrolyte solution was then used to granulate the model drug Paracetamol. The prepared tablets were evaluated for various pharmacopoeial and non pharmacopoeial parameters viz. Thickness, Hardness, Friability, Weight Variation, Content uniformity and Drug Content. The drug release study carried out in 0.1M HCl revealed in situ Polyelectrolyte complex formation (PEC) between CH and anionic biopolymers. This in situ PEC formation resulted in sustained delivery of high dose gastric fluid soluble drug Paracetamol. Further, effect of incorporation starch and lactose as tablet diluents on release rate was also studied. It was observed that paracetamol release from lactose granulation was faster than tablets prepared with starch as diluents. From the data generated it was concluded that In situ PEC formation approach has sufficient potential to sustain the release of drugs like paracetamol.

Chitosan-Hydroxypropyl Methylcellulose Matrices as Carriers for Hydrodynamically Balanced Capsules of Moxifloxacin HCl.

BACKGROUND: In recent years, gastroretentive, hydrodynamically balanced system (HBS) for stomach-specific floating sustained drug release has gained a lot of importance in improving absorption of drugs especially those absorbed from stomach and small intestine. OBJECTIVE: The objective of the current investigation is to evaluate chitosan-hydroxypropyl methylcellulose (HPMC) based on polymeric matrices as a carrier for single-unit capsules based on HBS for stomach- specific floating sustained drug release using moxifloxacin HCl (MX) as a model drug. METHOD: Various HBS capsules of MX were prepared by physical blending of MX with chitosan (low or medium molecular mass) or HPMC (K4M or K15M) or chitosan-HPMC combinations in varying proportions followed by encapsulation into size 0 capsules made of hard gelatin. The in vitro buoyancy and drug release in 0.1 N HCl (pH 1.2) were evaluated. RESULTS: HBS capsules based on chitosan (low and medium molecular weight and their combination) as polymer matrix failed to float on 0.1 N HCl (pH 1.2). Whereas, formulations containing HPMC (K4M or K15M) or their mixture with chitosan, remained buoyant and released MX over 9 h in the acidic dissolution medium following zero-order kinetics. CONCLUSION: HPMC (K4M, K15M, blend of K4M and K15M) or their mixture with low/medium molecular mass chitosan may constitute excellent carrier systems for the stomach-specific sustained delivery of MX over a longer period.

Helicobacter pylori: past, current and future treatment strategies with gastroretentive drug delivery systems.

Helicobacter pylori have been subject to intense investigation since its discovery from gastric biopsy in 1982. This gastropathogen has been regarded as serious public health problem due to its association with dyspepsia, gastritis, gastroduodenal ulcers, mucus-associated lymphoid tissue lymphoma and gastric carcinoma. In vivo eradication of established H. pylori infections is difficult due to several factors such as gastric niche, coccoid form due to sub-minimum inhibitory concentration of antimicrobials, bacterial load, primary antibiotic resistance, patient compliance and stability of therapeutics in gastric acid secretion. Considering these factors, a logical way to improve the outcome of the treatment is to develop dosage forms which are able to deliver the anti-helicobacter agents in the gastric niche for both local and systemic actions, simultaneously taking care of stability of therapeutics in acidic environment. Such dosage forms, which are popularly known as gastro retentive drug delivery systems (GRDDS), have the immense potential to effectively counter the problem of high bacterial load; prevent induction of coccoid bacteria thereby improving treatment outcome and compliance. This review describes efficacy of various therapeutic agents, treatment strategies and status of different GRDDS until now.