Optimization of Diltiazem hydrochloride osmotic formulation using QBD approach

Abstract Diltiazem hydrochloride (DLH) is a calcium channel blocker useful for the treatment of angina pectoris, arrhythmia, and hypertension. DLH having a short half-life needs frequent administration for successful treatment but this poses a problem of poor patient compliance. These requirements are served by elementary osmotic pump tablets (EOP) based controlled-release (CR) systems. Quality by design (QbD) approach assists in screening various factors with subsequent assessment of critical parameters that can have a major impact on the scalability of EOP. Tablets were formulated using wet granulation method followed by osmotic coating. Factorial design based QbD strategy aided in defining the risk assessment of influential variables such as hydrophilic polymers and osmotic coat component on the in-vitro release kinetics of the designed EOP tablets. These formulated EOP systems followed zero-order kinetics, a characteristic feature of EOPs. EOP tablets were formulated applying a systematic QbD statistical approach. The formulated DLH EOP systems with improved concentration-independent behavior helped to address the challenges of IR formulation. Application of QbD strategy in ascertaining the scalability of DLH EOP formulation would help pharmaceutical industries in the translation of EOP based drug delivery systems from R&D to market.

Microemulsion assisted transdermal delivery of a hydrophilic anti-osteoporotic drug: Formulation, in vivo pharmacokinetic studies, in vitro cell osteogenic activity

Gastrointestinal adverse effects such as esophageal irritation and ulcers are the major disadvantages of the oraladministration of alendronate (ALD) and nitrogen-containing bisphosphonate. We hypothesized that the transdermaldelivery of ALD via water in oil (w/o) microemulsion might help to prevent the aforementioned side effects withoutcompromising the efficacy. The pseudo-ternary phase diagrams were constructed with varying ratios of surfactantmixture and oil to recognize the concentration range of excipients required to form a monophasic microemulsion.Globule size, morphology transmission electron microscopy, and thermal behavior differential scanning colorimetryof drug-loaded microemulsion were investigated. The in vitro permeation studies revealed significantly enhancedpermeation of ALD through microemulsion than pure solution across the rat skin (p < 0.01). In an in vivopharmacokinetic study in Wistar rats, microemulsion achieved around two folds higher bioavailability than pure drugsolution (p < 0.05) when given in equal doses (30 mg/kg). Cell viability assay with human osteoblastic osteosarcoma(MG-63) cells exhibited the positive effects of ALD microemulsion on cell growth. Moreover, alkaline phosphataseand mineralization studies proved that microemulsion as a carrier retains distinct osteogenic properties of ALD.Overall, these outcomes demonstrated that the w/o microemulsion as a transdermal carrier is a promising approach forthe effective delivery of ALD, bypassing the adverse effects associated with oral administration