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Bioadhesive mini-tablets for vaginal drug delivery.
Marianne Hiorth1, Susanne Nilsen2, Ingunn Tho3
1SiteDel Research Group, School of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway. marianne.hiorth@farmasi.uio.no.
Pharmaceutics
|August 29, 2014
Summary
Hydroxypropylmethyl cellulose (HPMC) and hydroxypropyl cellulose (HPC) mini-tablets show strong bioadhesion and pH-independent drug release for vaginal delivery. These formulations offer prolonged drug release and improved residence time in the vaginal cavity.
Area of Science:
- Pharmaceutical Sciences
- Biomaterials Science
- Drug Delivery Systems
Background:
- Vaginal drug delivery requires formulations with appropriate mechanical strength, bioadhesion, and controlled release characteristics.
- Cellulose derivatives are widely explored as matrix formers for oral and other drug delivery routes.
- Understanding the influence of vaginal pH on drug release is crucial for effective therapeutic outcomes.
Purpose of the Study:
- To evaluate various non-ionic cellulose ethers and microcrystalline cellulose as matrix formers for vaginal mini-tablets.
- To assess the mechanical properties, bioadhesion, and drug release profiles of mini-tablets containing hexyl aminolevulinate hydrochloride (HAL).
- To determine the suitability of these formulations for vaginal drug delivery across different age groups by considering vaginal pH variations.
Main Methods:
- Preparation of mini-tablets using methyl cellulose (MC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), hydroxypropylmethyl cellulose (HPMC), and microcrystalline cellulose (MCC) as matrix formers.
- Characterization of mini-tablets for mechanical strength, bioadhesion (rotating cylinder and detachment tests), and dissolution rate.
- Dissolution testing in simulated vaginal fluid (pH 4.5) and phosphate buffer (pH 6.8) to mimic physiological conditions.
Main Results:
- Mini-tablets formulated with HPMC or HPC exhibited adequate mechanical strength and superior bioadhesive properties towards cow vaginal tissue.
- These HPMC and HPC based mini-tablets demonstrated pH-independent controlled release of the model drug, hexyl aminolevulinate hydrochloride (HAL).
- The observed properties suggest suitability for vaginal administration irrespective of the patient's age and associated vaginal pH.
Conclusions:
- HPMC and HPC are promising matrix formers for developing bioadhesive mini-tablets for vaginal drug delivery.
- These mini-tablets can enhance drug residence time and provide prolonged release, improving therapeutic efficacy.
- The pH-independent release profile ensures consistent drug delivery across different physiological conditions.
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