Rectal suppository as an effective alternative for oral administration

Abstract

Rectal route is an effective alternative for oral administration of drugs in pediatric and geriatric patient. Rectal suppository may have influence on bioavailability and may produce sustained release of drugs. Suppository avoids the complications associated with oral delivery of drugs such as first pass effect, degradation of drugs by gastric enzymes, etc. Previous studies implicated that suppositories produced local effects but recently most interesting publications claimed that these are also producing systemic effects. Since last two decades research is focused to improve bioavailability of drugs from suppositories. The conventional solid suppositories have suffered from disadvantages such as feeling of alien, pain and discomfort. Therefore, liquid suppositories were developed which overcame the disadvantages associated with solid suppositories such as leakage from anus, avoidance of first pass effect and irritation. The selection of appropriate mucoadhesive polymer, surfactant and suppository base may influence the bioavailability and sustained release of drugs. The current review concern the physiological, biopharmaceutical characteristics of rectum and pharmaceutical related factors affecting bioavailability, suppository bases, bioadhesive polymers, and surfactant. It also covers evaluation parameters for solid and liquid suppositories.