Physicochemical and Microbiological Stability of Compounded Clonidine Hydrochloride Oral Liquid Dosage Forms in PCCA Base, SuspendIt®.

Abstract

Clonidine Hydrochloride is a centrally acting alpha-agonist hypotensive agent available as tablets for oral administration in three dosage strengths: 0.1 mg, 0.2 mg and 0.3 mg. A review of the therapeutic uses of clonidine hydrochloride reveals the need for flexibility in dosing. This flexibility is readily achieved using an oral liquid dosage form. However, no commercial liquid dosage form of clonidine hydrochloride currently exists. An extemporaneously compounded suspension from pure drug powder would provide a flexible, customizable option to meet unique patient needs with convenient and accurate dosing options. The purpose of this study was to determine the physicochemical and microbiological stability of extemporaneously compounded clonidine hydrochloride suspensions in the PCCA Base, SuspendIt. This base is a sugar-free, paraben-free, dye-free, and gluten-free thixotropic vehicle containing a natural sweetener obtained from the monk fruit. The study design included two clonidine hydrochloride concentrations to provide stability documentation over a bracketed concentration range for eventual use by compounding pharmacists. A robust stability-indicating high-performance liquid chromatographic assay for the determination of the chemical stability of clonidine hydrochloride in PCCA SuspendIt was developed and validated. Suspensions of clonidine hydrochloride were prepared in PCCA SuspendIt at 20-mcg/mL and 100-mcg/mL concentrations, selected to represent a range within which the drug is commonly dosed. Given the potent nature of the drug, a 2% triturate of clonidine hydrochloride in microcrystalline cellulose was used to prepare the samples. Samples were stored in amber plastic prescription bottles at two temperature conditions (5°C and 25°C). Samples were assayed initially, and on the following time points (days): 7, 14, 28, 42, 63, 91, 119 and 182. Physical data such as pH, viscosity and appearance were also noted. Microbiological stability was tested. All measurements were obtained in triplicate. A stable extemporaneous product is defined as one that retains at least 90% of the initial drug concentration throughout the sampling period and is protected against microbial growth. Using this criterion, no significant degradation of the clonidine hydrochloride was observed over the 182-day test period for either concentration under refrigerated conditions. Drug concentrations were at, or above 94.6% of initial values. However, at room temperature the concentration of the 20-mcg/mL samples dropped below 90% after 119 days. No microbial growth was observed. pH values remained fairly constant. The viscosity of the suspensions allowed easy re-dispersal of the drug particles upon shaking. This study demonstrates that clonidine hydrochloride is physically, chemically, and microbiologically stable in PCCA SuspendIt for 182 days in the refrigerator and for 119 days at room temperature at both concentrations studied, thus providing a viable, compounded alternative for clonidine hydrochloride in a liquid dosage form, with an extended BUD to meet patient needs.