Abstract

Sildenafil extemporaneous formulations, used to treat pulmonary arterial hypertension (PAH) in hospitalised children, must be also stable and uniform in content. In this study, we determinedcontent uniformity, stability and therapeutic efficacy of sildenafil in gelatine capsules containing5 mg from three brands (Viagra^®, Maxifort^® and Apodefil^®). The powder from crushed tablets was distributed into 32 gelatine capsules for each brand. Content uniformity and stability at 25and 40°C were analysed by HPLC-UV (mBondapack C₁₈ column, H₂KPO₄ 35 mM (pH 6.0)/ acetonitrile (53:47 v/v), 0.8 ml/min). Therapeutic efficacy of unitary doses was assessed in 25 patients (14 boys and 11 girls), according to clinical improvement and systolic pulmonary arterial pressure (SPAP) decrease, before and after taking sildenafil. Unitary doses showedcontent uniformity (4.93 ± 0.327 ≈ 5 mg) and were stable for 30 days at 25 and 40°C. SPAPvalues decreased to normal in 64% of the patients. Dyspnoea disappeared in 85% (11/13) andcyanosis in 67% (6/9). Two children (8%) showed no therapeutic response. Individualised doses of sildenafil in gelatine capsules are stable, uniform in content, and therapeutically effective, being an alternative to treat PAH in hospitalised and ambulatory patients.

Key words: Pulmonary hypertension, sildenafil capsule, children, unitary doses, content uniformity, stability, extemporaneous preparation.