ISSN 1070-4272, Russian Journal of Applied Chemistry, 2016, Vol. 89, No. 9, pp. 1477−1484. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © H. Salmani, A.Yu. Bilibin,
2016, published in Zhurnal Prikladnoi Khimii, 2016, Vol. 89, No. 9, pp. 1187−1195.
AND POLYMERIC MATERIALS
Effectively Rifampicin Loaded Microspheres
Based on Blends of High- and Low-Molecular-Mass
H. Salmani* and A. Yu. Bilibin
St. Petersburg State University, Universitetskaya nab. 7–9, St. Petersburg, 199034 Russia
Received July 16, 2016
Abstract—Speciﬁ c features of immobilization of Rifampicin drug by poly-D,L-lactic acid microparticles and
the possibility of controlling the uniform Rifampicin release were studied.
Immobilization of functional substances, drugs, bio-
logically active compounds, and catalysts in polymeric
microparticles is widely used as an important strategy
of the development of new materials. Numerous studies
performed in this ﬁ eld concerned the use of micropar-
ticles in drug delivery systems.
Recently there has been interest in the use of biode-
gradable polymer systems for drug delivery. Such sys-
tems do not require ﬁ nding special methods for remov-
ing polymer systems from a living body. For example,
biodegradable and biocompatible polyesters such as
polylactic acid (PLA) and its copolymers  are suc-
cessfully used in drug delivery systems [2, 3].
There are different methods for preparing polymer
micro- and nanoparticles from already synthesized poly-
mers: precipitation, emulsiﬁ cation–solvent evaporation
(ESE), emulsiﬁ cation–solvent diffusion (ESD), etc. .
The drug loading efﬁ ciency and its release proﬁ le
from polymer particles depend on various parameters,
the most signiﬁ cant of which are characteristics of the
polymer matrix , particle size , morphology, and
porosity, and interaction of the polymer material with
the drug .
Rifampicin (Rif) is an antibiotic used for treatment
of various kinds of bacterial infections (tuberculosis,
leprosy, legionnaires’ disease, etc.). The urgency of de-
veloping new drug forms based on Rifampicin is large-
ly determined by the growth of tuberculosis incidence
among both humans and livestock. Encapsulation of Ri-
fampicin in PLA microparticles and determination of its
release proﬁ le still remain topical problems.
In a recent study , Rifampicin was encapsulated
in PLA microparticles by emulsiﬁ cation–solvent
evaporation. The encapsulation efﬁ ciency in that
study was low (<18%). In another study, Rifampicin
was encapsulated in poly(lactic acid-co-glycolic acid)
(PLGA) microparticles by emulsiﬁ cation–solvent
diffusion, with the reported loading efﬁ ciency of up to
The hydrolytic degradation of PLA is a very slow
process. However, with an increase in the oligomer
content, the PLA depolymerization rate increases. This
can be accounted for by facilitated water penetration into
polymer microparticles and, as a consequence, by faster
hydrolytic degradation. Blending of high-molecular-
mass hmm-PLA with o-PLA signiﬁ cantly inﬂ uences
the PLA degradation rate, which can be attributed to
an increase in the acidity of the polymer matrix and to
acceleration of the polyester hydrolysis.
It is known that the hydroxyl, carboxyl, and
piperazine functional groups in Rifampicin and PLA
molecules are involved in hydrogen bonding :