DROPPING PILLS

Dropping pills are spherical preparations made from drugs and suitable matrix materials by mixing in the melted state and solidifying by dropping into an immiscible inert cooling media.

The manufacturing of dropping pills is related to the dropping method for soft capsules. The difference is that only one phase of the dropping fluid is used,where as in soft capsules there are two phases,i.e the gel phase and drug phase, which are dropped simultaneously. As the formation of dropping pills requires the homogeneous of the drug and the carriers, the solid material should be initially melted at the temperature above the melting points. In a sense,dropping pills are similar to the preparation of solid dispersion by the melting method. Actually dropping pills prepared by the water soluble carriers exhibit fast dissolving characteristics and play an important role in enhancement of the oral bio availability of poorly water soluble drugs. Moreover, if the carriers are composed mainly of lipids, the release rate may be significantly retarded thus achieving sustained release and long acting efficacy.

Carrier materials for dropping pills

Carriers for dropping pills can be divided into hydrophilic and hydrophobic carriers. Hydrophilic carriers include PEGs,poloxamers,cremophors and gelatin/glycerin. Hydrophobic carriers are mainly stearic acid, glycerin monostearate and hydrogenated vegetable oil.

Preparation of dropping pills

Dropping pills can be manufactured by the dropping method similar to the preparation of soft capsules.Either liquid paraffin,vegetable oil,dimethyl silicon oil or water is used as the cooling fluid,depending on the properties of the matrix materials. Moreover, appropriate manufacturing equipment should be according to the properties of the carriers and the cooling solvent.

For example,when the density of the dropping pills is larger than the cooling flood, a“dropping pill” method should be used if the dropping pills are less dense.

The preparation of dropping pills is affected by many factors,so the production rate of the qualified product is low. The most significant problem is unacceptable pill weight variation. This is due to the influence of the dropping nozzle size,the viscosity and the composition of the dropping fluid, all of which result in poor reproduction. Therefore,dropping pills are usually used in TCMs with a less strict requirement for dose control, but seldom for chemical drugs. Another problem is the easy deformation of the final products due to the effects of cooling variables,such as the properties of the cooling fluid,cooling temperature and cooling duration.

If it cools too slowly,the pills can be deformed, when they reach the bottom of the cooling tank due to inadequate hardening.

What is the difference between pills and tablets?

Pills are small, rounded solid bodies with API that are designed for oral delivery. The most common oral dosage form was once pills, although crushed tablets and capsules have since taken their place.

The fact that pills are created using a wet massing and molding procedure sets them apart from tablets, whereas tablets are made through compression.

Quality control

The appearance of dropping pills should be uniform both in color and luster without sticking.

If not specified otherwise refer to the measurement of weight variation for specifications: ≤0.5g, ±12% ; 0.5-1g ,±12% ; 1-2g,±10% ;2-3g,±8% ; 3-6g, ±6% ; 6-9g,±5% ; ≥9g,±4%.

If not specified otherwise refer to general monographs under pills.

All dropping pills should disintegrate within 30 min tested in a disintegration assembly without using the baffle plates whereas coating of dropping pills should disintegrate within an hour.